Ultrasound-guided core needle biopsy in dogs with thyroid carcinoma.

Currently, a histological diagnosis of highly vascularized canine (c) thyroid carcinoma (TC) is primarily obtained following excisional biopsy (EB) through thyroidectomy. Non-EBs are contraindicated in unresectable invasive cTCs due to their highly vascularized nature, which subsequently, lack histological diagnosis. We hypothesised ultrasound-guided core needle biopsy (UGCNB) to be a safe biopsy technique to obtain an accurate histological diagnosis in unresectable TCs. Nine client-owned dogs with suspected naturally occurring TC, presented for surgical excision, were included. First, a UGCNB was taken from the cervical tumour, followed by EB. Haemorrhage following UGCNB was evaluated preoperatively and once the tumour was surgically exposed by visual inspection and ultrasonography. Histological analysis, including cell organisation, tumour capsular and vascular invasion, and immunohistochemistry were performed and compared between both biopsy specimens (i.e., UGCNB and EB) of the same dog. Pre- and peroperative visual inspection revealed minor, localised haemorrhage, subsequent to the UGCNB, in 7/9 dogs. Histology of the EBs confirmed TC in 8/9 dogs and was inconclusive in 1/9 dogs. Histology of the UGCNBs revealed neoplastic thyroid tissue in 7/9 UGCNBs and was inconclusive in 1/9 UGCNBs. The remaining UGCNB contained no mass related tissue and was, therefore, excluded. Histological parameters (i.e., cell organisation, tumour capsular and vascular invasion) were not concordant between 6/8 included UGCNBs and their respective EB. Immunolabelling for thyroglobulin and calcitonin was concordant between all eight included UGCNBs and their respective EB. The remaining evaluated immunohistochemical markers (i.e., cyclooxygenase-2 [COX-2], P-glycoprotein and vascular endothelial growth factor [VEGF]) were concordant between the included UGCNBs and the EBs in 6/8 dogs. To conclude, UGCNBs can be safely obtained in suspected cTCs and enable a reliable diagnosis of the thyroid origin, thyroid cell origin and potential therapeutic markers such as COX-2, P-glycoprotein and VEGF. Subsequently, UGCNB enables clinicians to establish an individually tailored treatment plan in dogs with unresectable TC.

Thyroid carcinosarcoma masquerading as a paraesophageal abscess in a Cane Corso dog.

A 12-year-old castrated male Cane Corso dog was presented with cervical swelling, lethargy, anorexia, and cough. An extensive neck mass with necrotic cysts was observed, severely adherent to surrounding tissues. Based on diagnostic imaging including ultrasound, computed tomography, and fine-needle aspiration cytology, paraesophageal abscess was tentatively diagnosed. However, after the mass was surgically removed, a diagnosis of thyroid carcinosarcoma composed of neoplastic cell populations with epithelial and mesenchymal origins was made via histopathology and immunohistochemistry. The dog died of a recurrent mass with pulmonary metastasis 105 d after surgery. This report describes a rare type of canine thyroid cancer, thyroid carcinosarcoma, preoperatively masquerading as an abscess and postoperatively confirmed by histopathology. Key clinical message: Thyroid carcinosarcoma, despite its rarity in dogs, should be included in the differential diagnoses of cervical mass especially with an aggressive progression.

Carcinosarcome thyroïdien déguisé en abcès paraoesophagien chez un chien Cane Corso. Un chien Cane Corso mâle castré de 12 ans a été présenté avec de l'enflure cervicale, de la léthargie, de l'anorexie et une toux. Une masse étendue du cou avec des kystes nécrotiques a été observée, adhérente fortement aux tissus environnants. Sur la base de l'imagerie diagnostique comprenant l'échographie, la tomodensitométrie et la cytologie par aspiration à l'aiguille fine, un abcès paraoesophagien a été provisoirement diagnostiqué. Cependant, après l'ablation chirurgicale de la masse, un diagnostic de carcinosarcome thyroïdien composé de populations de cellules néoplasiques d'origine épithéliale et mésenchymateuse a été posé par histopathologie et immunohistochimie. Le chien est décédé d'une masse récurrente avec métastase pulmonaire 105 jours après la chirurgie. Ce rapport décrit un type rare de cancer de la thyroïde canine, le carcinosarcome thyroïdien, se faisant passer pour un abcès en préopératoire et confirmé en postopératoire par histopathologie.Message clinique clé:Le carcinosarcome thyroïdien, malgré sa rareté chez le chien, doit être inclus dans les diagnostics différentiels de masse cervicale surtout à évolution agressive.(Traduit par Dr Serge Messier).

Use of 18 F-2-deoxy-2-fluoro-D-glucose positron emission tomography/computed tomography for staging thyroid carcinoma in a cat.

Thyroid nodules are common in older cats and are mostly benign; however, carcinomas may occur infrequently. In cats, thyroid carcinomas tend to be highly metastatic. The role of 18 F-2-deoxy-2-fluoro-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) in human thyroid carcinoma has been well established. However, guidelines have not yet been established for veterinary medicine. Metastasis assessment has typically been performed using CT in veterinary medicine; however, it is poorly sensitive in detecting regional lymph nodes or distant metastases if these lesions are not abnormally contrast-enhanced, enlarged or cause overt mass effects. This case suggested that FDG PET/CT may be used for staging feline thyroid carcinoma, and the results contributed to treatment recommendations.

Metastatic thyroid carcinoma in the appendicular skeleton and tibial plateau leveling osteotomy site of a dog.

A 13-year-old spayed female Labrador retriever cross dog was referred to the Foster Hospital for Small Animals at Tufts University for evaluation of a metastatic carcinoma discovered at the site of a previous tibial plateau leveling osteotomy (TPLO). The dog was previously evaluated at the primary care veterinarian for a complaint of lameness, and radiographs of the previous TPLO site revealed bony lysis associated with the TPLO plate. Surgical exploration of the site by the primary veterinarian provided evidence of osteolysis. The lytic area of the proximal tibia was biopsied, and a metastatic carcinoma was confirmed. The patient was referred for further evaluation. Following consultation and examination, a full body computed tomography (CT) scan was performed to determine the source of the carcinoma. A well-defined soft tissue attenuating mass effacing the right thyroid gland was located, along with 3, well-defined soft tissue attenuating nodules within the pulmonary parenchyma, consistent with metastatic disease. The previously diagnosed osteolytic, aggressive bone lesion of the proximal left tibia was visualized. Following the CT scan, palliative left hind-limb amputation via coxofemoral disarticulation was performed. Histological examination of the hind limb revealed neoplastic epithelial cells admixed with reactive bone. Neoplastic cells were arranged in packets with rare colloid-filled microfollicles consistent with a diagnosis of metastatic thyroid carcinoma. To the authors' knowledge, this is the first clinical report of metastatic thyroid carcinoma in the appendicular skeleton and TPLO site of a dog. Key clinical message: Our findings emphasized that thyroid carcinoma may metastasize to the appendicular skeleton, and causes other than osteomyelitis or implant-associated osteosarcoma should be considered when evaluating osteolytic lesions at a TPLO site.

Carcinome métastatique de la thyro ï de dans le squelette appendiculaire et site d'ostéotomie de n ivellement du plateau tibial d'un chien. Une chienne croisée Labrador retriever stérilisée âgée de 13 ans a été référée au Foster Hospital for Small Animals de l'Université Tufts pour l'évaluation d'un carcinome métastatique découvert sur le site d'une ostéotomie de nivellement du plateau tibial (TPLO) antérieure. Le chien a été précédemment évalué chez le vétérinaire de soins primaires pour une plainte de boiterie, et les radiographies du site TPLO précédent ont révélé une lyse osseuse associée à la plaque TPLO. L'exploration chirurgicale du site par le vétérinaire initial a mis en évidence une ostéolyse. La zone lytique du tibia proximal a été biopsiée et un carcinome métastatique a été confirmé. Le patient a été référé pour une évaluation plus approfondie. Après consultation et examen, une tomodensitométrie (CT) du corps entier a été réalisée pour déterminer la source du carcinome. Une masse d'atténuation des tissus mous bien définie effaçant la glande thyroïde droite a été localisée, ainsi que trois nodules d'atténuation des tissus mous bien définis dans le parenchyme pulmonaire, compatibles avec une maladie métastatique. La lésion osseuse ostéolytique et agressive du tibia gauche proximal précédemment diagnostiquée a été visualisée. Après la CT, une amputation palliative du membre postérieur gauche par désarticulation coxofémorale a été réalisée. L'examen histologique du membre postérieur a révélé des cellules épithéliales néoplasiques mélangées à de l'os réactif. Les cellules néoplasiques étaient disposées en paquets avec de rares microfollicules remplis de colloïdes compatibles avec un diagnostic de carcinome thyroïdien métastatique. À la connaissance des auteurs, il s'agit du premier rapport clinique de carcinome thyroïdien métastatique dans le squelette appendiculaire et le site TPLO d'un chien.Message clinique clé :Nos résultats ont montré que le carcinome thyroïdien peut métastaser au squelette appendiculaire et que des causes autres que l'ostéomyélite ou l'ostéosarcome associé à l'implant doivent être prises en compte lors de l'évaluation des lésions ostéolytiques sur un site TPLO.(Traduit par Dr Serge Messier).

Thyroidectomy in dogs with thyroid tumors: Survival analysis in 144 cases (1994-2018).

BACKGROUND: Few studies have assessed predictors of outcome in dogs with thyroid tumors undergoing thyroidectomy. OBJECTIVE: To estimate the survival and identify prognostic factors in dogs with thyroid tumors treated by thyroidectomy. ANIMALS: A total of 144 client-owned dogs with thyroid neoplasia that underwent thyroidectomy. METHODS: Retrospective study. Data for analysis included hospital attended and year of surgery, signalment, thyroxine concentration, thyroid tumor features (lobe involvement, size, invasiveness, histopathological type), thrombosis, metastasis, additional surgery and therapy, administration of adjuvant chemotherapy. The association of predictors with survival (time from surgery to death) were assessed by calculating cause-specific hazard ratios (HRcs ) and 95% confidence intervals (CI). Causes of death were classified as thyroid-related or because of other cause. RESULTS: Overall median survival time was 802 days (CI95% = 723-1015 days); 89 dogs (77.4%) survived >500 days. Metastases were identified at admission in 12 (8.3%) dogs and were associated with higher thyroid cancer-related fatality (HR = 5.83, CI95% = 1.56-21.78; P = .009). Thrombosis occurred in 40 dogs and was associated with increased risk of death because of other cause (HR = 2.73, CI95% = 1.18-6.35; P = .019). Nonfollicular carcinoma (HR = 4.17, CI95% = 1.27-13.69; P = .018) and administration of chemotherapy (HR = 3.45, CI95% = 1.35-8.82; P = .01) were associated with higher risk of thyroid cancer-related death. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with thyroid tumors undergoing thyroidectomy have a long life expectancy. Despite the rare presence of nonfollicular carcinoma and metastases, thyroidectomy should still be considered in some of these dogs.

Organoids of patient-derived medullary thyroid carcinoma: The first milestone towards a new in vitro model in dogs.

Organoid cultures could constitute a valuable in vitro model to explore new treatments for canine (c) medullary thyroid carcinoma (MTC). The study's objectives were to establish and characterize 3D organoid cultures of cMTC using histology and immunohistochemistry (IHC) and to evaluate the effect of antitumor drugs on organoids' viability. Five cMTC tissue samples were used to develop organoid cultures of which one organoid line, named cMTC N°2, could be passaged for an extended period. This cMTC N°2 organoid line was further compared to the primary tumour regarding morphology and IHC expression of thyroid transcription factor-1 (TTF-1), thyroglobulin, calcitonin, synaptophysin, vimentin, Ki-67, cyclooxygenase-2 (COX-2), P-glycoprotein and vascular endothelial growth factor (VEGF). Quality control of the cMTC N°2 organoid line was achieved by a single nucleotide polymorphism (SNP) array of the organoids, primary tumour and healthy blood cells of the same dog. The effect of carboplatin, meloxicam and toceranib phosphate (TOC) on cMTC N°2 organoids' viability was evaluated. The cMTC N°2 organoid line was cultured for 94 days and showed similar histological features with the primary tumour. Immunolabelling for TTF-1, thyroglobulin, calcitonin and VEGF was similar between the primary tumour and cMTC N°2 organoids. Compared to the primary tumour, organoids showed higher immunolabelling for vimentin and Ki-67, and lower immunolabelling for synaptophysin, COX-2 and P-glycoprotein. The SNP genotype was similar for each chromosome between healthy blood cells, primary tumour and cMTC N°2 organoids. Carboplatin, meloxicam and TOC had no effect on cMTC N°2 organoid cell viability within achievable in vivo concentration range. In conclusion, the cMTC N°2 organoid line is a promising first milestone towards an established in vitro organoid model to explore pathophysiology and new treatment modalities in cMTC.

Concurrent Parathyroid Adenoma and Thyroid Carcinoma in a Domestic Shorthaired Feline.

A 10 yr old female spayed domestic shorthair was referred for an 11mo history of persistent total hypercalcemia and elevated ionized calcium with intermittent episodes of lethargy, vomiting, and diarrhea with a history of recurrent urinary tract infections and intermittently elevated kidney values. An abdominal ultrasound, thoracic radiographs, cervical ultrasound, and ionized calcium level, parathyroid hormone (PTH), and PTH-related peptide (PTHrp) levels were assessed. Results were consistent with chronic kidney disease, splenomegaly, diffuse thickening of small intestines, nodular lesions noted in the left thyroid and right parathyroid, and elevated ionized calcium, PTH, and elevated PTHrp levels. A left thyroidectomy and right cranial parathyroidectomy were performed. Hypocalcemia and anemia developed postoperatively, which were managed with calcium carbonate, calcitriol, and calcium gluconate and benign neglect of anemia. Histopathology was consistent with a left thyroid carcinoma and right cranial parathyroid adenoma. Thyroid carcinoma and parathyroid adenomas have not previously been reported to occur concurrently in domestic felines and should be considered when ionized calcium is elevated with both PTH and PTHrp levels increased in addition to ultrasonographic lesions.

Multiorgan metastases with massive bone involvement of a medullary thyroid carcinoma in a dog.

A 10-year-old mixed-breed male dog was referred for a subcutaneous mass on the ventral neck. Based on total-body computed tomography (TBCT), the mass was located in the left thyroid lobe. Further alterations included enlargement of the ipsilateral mandibular and prescapular lymph nodes (LNs). Surgical excision of the mass and enlarged LNs was performed. Histopathology and immunohistochemistry were consistent with a medullary (C-cell) thyroid carcinoma, with no evidence of nodal metastases. Surgery was considered curative, and no medical treatment was provided. Periodic follow-up rechecks were unremarkable. After 18 months, the dog exhibited lethargy, vomiting, anorexia, and hind leg stiffness. TBCT revealed polyostotic osteopathy, and cytology suggested a metastatic endocrine carcinoma. Due to the dog's poor clinical condition and prognosis, the owner elected euthanasia, and a necropsy was performed. Based on gross pathology, histopathology, and immunohistochemistry, multiple metastases of the previous thyroid carcinoma were diagnosed, involving the occipital bone, multiple vertebrae, left sacral wing, fourth right rib, left scapula, left humerus, intrathoracic LNs, lung, spleen, and adrenal glands. This report describes a case of medullary thyroid carcinoma with distant multiorgan metastases and massive bone involvement after a disease-free interval of 18 months.

[99m-Technetium-pertechnetate- and 99m-Technetium-sestamibi-scintigraphy for visualization of hypofunctioning thyroid tissue and staging in a dog with thyroid carcinoma]. / 99m-Technetium-Pertechnetat- und 99m-Technetium-Sestamibi-Szintigrafie zur Darstellung von hypofunktionellem Schilddrüsengewebe und Staging bei einem Hund mit Schilddrüsenkarzinom.

A 10-year-old female mixed breed dog was presented for thyroid scintigraphy due to a cervical mass. Apart from 99m-Technetium-pertechnetate (Tc-pertechnetate) scintigraphy, a second scintigraphy using 99m-Technetium sestamibi (Tc-MIBI) was performed because of additional hypothyroidism suspective for a "cold" nodule and as screening for metastases.Twenty minutes following intravenous injection of 38 MBq Tc-pertechnetate, a "hot" cervical as well as a "hot" intrathoracal nodule were seen with an uptake of 8.40 and 0.25 %, respectively. The second scintigraphy was performed 20 minutes after intravenous injection of 364 MBq Tc-MIBI and 70 minutes following the first. After subtraction of pertechnetate activity and decay correction, both nodules showed an uptake of 0.99 and 0.03 %. Additionally, both thyroid lobes were visible in the thyroid loge with a weak MIBI-uptake. For both lesions, the ratio Tc-uptake/Tc-MIBI-uptake was 8.48 and 8.33, respectively.Following the extirpation of the cervical mass, histopathology revealed atrophied healthy thyroid tissue almost completely displaced by a well-differentiated follicular thyroid carcinoma.This case report describes performance, utility and calculative correction of consecutive pertechnetate- and MIBI-scan, that enable a visualization of hypofunctional thyroid tissue.Therefore and because of their similar MIBI metabolic activity, both nodules were considered to be dystopic tissue/metastases so that this dog had to be classified as prognostically less favorable WHO stabe IV. Different from human patients, both scintigraphies should be performed shortly after another in dogs in order to avoid the necessity of a second anesthetic procedure. A reliable qualitative/visual evaluation of the MIBI-scan is therefore not possible, so that a quantitative assessment using the uptake after calculative correction of the pertechnetate activity is recommended.

A recurrent somatic missense mutation in GNAS gene identified in familial thyroid follicular cell carcinomas in German longhaired pointer dogs.

BACKGROUND: We previously reported a familial thyroid follicular cell carcinoma (FCC) in a large number of Dutch German longhaired pointers and identified two deleterious germline mutations in the TPO gene associated with disease predisposition. However, the somatic mutation profile of the FCC in dogs has not been investigated at a genome-wide scale. RESULTS: Herein, we comprehensively investigated the somatic mutations that potentially contribute to the inherited tumor formation and progression using high depth whole-genome sequencing. A GNAS p.A204D missense mutation was identified in 4 out of 7 FCC tumors by whole-genome sequencing and in 20 out of 32 dogs' tumors by targeted sequencing. In contrast to this, in the human TC, mutations in GNAS gene have lower prevalence. Meanwhile, the homologous somatic mutation in humans has not been reported. These findings suggest a difference in the somatic mutation landscape between TC in these dogs and human TC. Moreover, tumors with the GNAS p.A204D mutation had a significantly lower somatic mutation burden in these dogs. Somatic structural variant and copy number alterations were also investigated, but no potential driver event was identified. CONCLUSION: This study provides novel insight in the molecular mechanism of thyroid carcinoma development in dogs. German longhaired pointers carrying GNAS mutations in the tumor may be used as a disease model for the development and testing of novel therapies to kill the tumor with somatic mutations in the GNAS gene.

Mixed medullary and follicular cell thyroid carcinoma in a dog.

A 12-y-old, castrated male Weimaraner dog was presented for a wellness examination. A 7-cm, firm mass was palpated on the left, ventral, mid-lateral neck. The neck mass was removed surgically and submitted for histopathology. A thyroid carcinoma was diagnosed based on microscopic examination. Immunohistochemistry for chromogranin-A, calcitonin, and thyroglobulin identified dual immunoreactivity of the latter two, and a final diagnosis was of a well-differentiated, compact, mixed medullary and follicular cell thyroid carcinoma. These neoplasms are rare in humans and have not been reported in dogs, to our knowledge.

Hypofractionated radiation therapy of a thyroid tumor in a pet raccoon (Procyon lotor).

Thyroid neoplasia has been documented in raccoons; however, successful management and treatment has not been well-described. A 15-year-old, intact female pet raccoon (Procyon lotor) was examined for evaluation of a right-sided ventral cervical mass and a cough of 4 to 5 mo duration. Cytology and computed tomography (CT) findings of the mass were most consistent with a thyroid tumor. The raccoon was treated with a hypofractionated external beam radiation protocol (8 Gy/fraction for 4 once/wk fractions). Treatments were well-tolerated and no radiation-induced side effects were detected. This is the first report of radiation treatment of thyroid neoplasia in a raccoon, presenting the challenges of animals that are difficult to handle or medicate.

Radiothérapie hypofractionnée d'une tumeur thyroïdienne chez un raton-laveur ( Procyon lotor ). La néoplasie thyroïdienne a été documentée chez les ratons-laveurs; cependant, la gestion et le traitement réussis n'ont pas été bien décrits. Un raton-laveur femelle intact de 15 ans (Procyon lotor) a été examiné pour l'évaluation d'une masse cervicale ventrale droite et d'une toux d'une durée de 4 à 5 mois. Les résultats de la cytologie et de la tomodensitométrie (CT) de la masse étaient les plus compatibles avec une tumeur thyroïdienne. Le raton-laveur a été traité avec un protocole de rayonnement externe hypofractionné (8 Gy/fraction pour quatre fractions 1 fois/semaine). Les traitements ont été bien tolérés et aucun effet secondaire radio-induit n'a été détecté. Il s'agit du premier rapport de radiothérapie d'une néoplasie thyroïdienne chez un raton-laveur, présentant les défis des animaux difficiles à manipuler ou à soigner.(Traduit par Dr Serge Messier).

Anaplastic thyroid carcinoma in a brush-tailed rock-wallaby (Petrogale penicillata).

BACKGROUND: Neoplasia is considered to be rare in macropods. Anaplastic thyroid carcinoma (ATC) also known as undifferentiated or giant cell carcinoma, is a rare but aggressive and lethal solid tumour reported to affect humans, dogs, cats, racoons and birds. It is derived from poorly differentiated follicular cells and lacks the characteristic architectural pattern of arrangement of tumour cells. ATC has not previously been reported in macropods. CASE REPORT: A brush-tailed rock-wallaby (Petrogale penicillata) was presented for a mass on the ventral neck. A clinical diagnosis of thyroid carcinoma was suspected based on radiology, ultrasound and cytology. Other than palliative care, treatment was declined. Four months later the wallaby was found dead and submitted for necropsy. Gross examination and histopathology demonstrated a unilateral ATC with vascular neoplastic emboli and distant metastases to the heart, lungs and liver. CONCLUSION: The clinical signs associated with thyroid tumours may be the result of localised growth and expansion of the thyroid, metastatic disease or a combination of these effects. Most thyroid tumours are nonfunctional. Based on the lack of typical clinical signs associated with functional thyroid tumours, in this case, we conclude that the thyroid tumour in this wallaby was likely to be nonfunctional. The cause of death in this wallaby was likely due to the heavy tumour burden with compromised cardiorespiratory function exacerbated by dorsoventral compression of the larynx. More study is needed to better understand thyroid neoplasia in macropods.

Clinical outcomes of thyroid tumours with concurrent epithelial and mesenchymal components in 14 dogs (2006-2020).

BACKGROUND: While rare, multiple individual case reports have described mixed thyroid tumours in dogs containing both epithelial and mesenchymal neoplastic components. OBJECTIVES: In this retrospective case series, we describe the clinical presentation, treatment and outcome of 14 dogs of canine thyroid tumours with concurrent mesenchymal and epithelial neoplastic populations. METHODS: Fourteen cases were retrospectively abstracted from nine institutions. Histopathologic samples and reports were collected from 10/14 dogs and reviewed by a single board-certified anatomic pathologist. RESULTS: All 14 dogs had curative-intent surgery to remove the thyroid neoplasm. The most common surgery performed was a unilateral thyroidectomy (10/14 dogs). Postoperatively, systemic therapy was administered in eight dogs. Six dogs developed local recurrence with a median time to loco-regional recurrence of 53 days. Ten dogs developed metastatic disease with the most common metastatic site being the lungs (6/10 dogs), with a median time to metastasis of 93 days. Ten dogs were euthanised due to locoregional or distant progression of their mixed thyroid neoplasm. The overall median survival time was 156 days (95%CI: 49-244). The median survival time for dogs treated with adjuvant therapy was 189 days (95%CI: 24-244), whereas dogs without adjuvant therapy had a median survival time of 156 days (95%CI: 35-upper limit could not be calculated; p = 0.62). CONCLUSION: The thyroid tumours with both mesenchymal and epithelial components in this small sample set were associated with a poor prognosis after surgical excision with or without adjunctive therapy.

Biodistribution and image characteristics of 124 I-positron emission tomography in dogs with neuroendocrine neoplasia.

Radioactive iodine is frequently used for staging of human thyroid carcinomas. Iodine-124 scans performed using position emission tomography (PET) allow for more precise dosimetry of therapeutic radioiodine. The distribution of I-124 has not previously been described in veterinary medicine. The purpose of this prospective, exporatory, descriptive study is to evaluate the whole-body distribution of I-124 in dogs with suspected thyroid carcinoma. Ten dogs with either a cytologic diagnosis of a neuroendocrine neoplasm or biochemical hyperthyroidism were enrolled in a prospective clinical study. Whole-body I-124 PET/CT scans were performed and were evaluated for physiologic and pathologic uptake of I-124. The maximum and mean standardized uptake values (SUVmean) were recorded for several normal and abnormal tissues. Varying degrees of uptake were found in thyroid tumors (SUVmean = 66.37), ectopic thyroid masses (21.44), presumed metastatic lesions in lymph nodes (32.14), and the pulmonary parenchyma (4.50). In most dogs, physiologic uptake above background, measured in maximum SUV, was identified in parotid and mandibular salivary glands (14.00 and 1.57) the urinary tract (1.83), the gastrointestinal tract (19.90 stomach, 6.15 colon), the liver (1.41), and the heart (1.88). Occasionally, uptake was identified in the nasolacrimal duct (3.42), salivary duct (2.73), gallbladder (2.68), and anal gland (2.22). Physiologic uptake was also identified in normal thyroid glands and ectopic thyroid tissue. This study provides a baseline of pathologic and physiologic uptake of I-124 in dogs with thyroid carcinoma, to guide interpretation of future studies.

Radioactive iodine dose and survival in cats with hyperthyroidism (2015-2020).

OBJECTIVES: Radioactive iodine (131I) is the preferred treatment for feline hyperthyroidism but neither the optimal 131I dose nor consistent predictors of post-treatment azotaemia have been determined. The aims of the study were to evaluate the relationships between: (1) 131I dose and survival; and (2) pretreatment and post-treatment serum creatinine concentration. METHODS: Medical records of hyperthyroid cats treated with 131I at a single referral hospital were reviewed. Information regarding signalment, body weight, pretreatment and post-treatment serum total thyroxine concentration (TT4), serum creatinine concentration, 131I dose and survival were determined. Multivariable Cox proportional hazards analysis was used to identify variables associated with survival. Multivariable linear regression analysis was used to identify variables associated with post-treatment serum creatinine concentration. RESULTS: One hundred and ninety-eight (79 male, 119 female) cats were treated for hyperthyroidism with 131I (median dose 138 MBq; interquartile range 92-168). Median survival time was 1153 days (range 16-1871). Post-treatment serum creatinine (P <0.001) and age (P = 0.049) were significantly associated with survival. Every 10 µmol/l increase in post-treatment serum creatinine concentration and every year increase in age was associated with a 1.07-fold (confidence interval [CI] 1.04-1.11) and 1.17-fold (CI 1.00-1.37) increase in the daily hazard of death, respectively. Pretreatment serum creatinine concentration was directly, and post-treatment serum TT4 concentration was inversely, associated with post-treatment serum creatinine concentration. Every 1 µmol/l increase in pretreatment serum creatinine concentration was associated with an increase in post-treatment serum creatinine concentration of 0.7 µmol/l (SE 0.17; P <0.001). Conversely, every 1 nmol/l decrease in post-treatment serum TT4 concentration was associated with a 1.2 µmol/l (SE 0.61; P <0.001) increase in post-treatment serum creatinine concentration. CONCLUSIONS AND RELEVANCE: Post-treatment serum TT4 concentration was associated with post-treatment azotaemia, which was associated with survival. Although 131I dose was not directly associated with survival, dosing strategies that minimise post-treatment hypothyroidism and azotaemia could improve patient survival.

Familial follicular cell thyroid carcinomas in a large number of Dutch German longhaired pointers.

Thyroid carcinomas (TCs) originating from follicular cells of the thyroid gland occur in both humans and dogs, and they have highly similar histomorphologic patterns. In dogs, TCs have not been extensively investigated, especially concerning the familial origin of TCs. Here, we report familial thyroid follicular cell carcinomas (FCCs) confirmed by histology in 54 Dutch origin German longhaired pointers. From the pedigree, 45 of 54 histopathologically confirmed cases are closely related to a pair of first-half cousins in the past, indicating a familial disease. In addition, genetics contributed more to the thyroid FCC than other factors by an estimated heritability of 0.62 based on pedigree. The age of diagnosis ranged between 4.5 and 13.5 years, and 76% of cases were diagnosed before 10 years of age, implying an early onset of disease. We observed a significant higher pedigree-based inbreeding coefficient in the affected dogs (mean F, 0.23) compared to unaffected dogs (mean F, 0.14), suggesting the contribution of inbreeding to tumour development. The unique occurrence of familial thyroid FCC in this dog population and the large number of affected dogs make this population an important model to identify the genetic basis of familial thyroid FCC in this breed and may contribute to the research into pathogenesis, prevention and treatment in humans.

Response of canine thyroid carcinomas to radioiodine.

Radioactive iodine (131 I) has previously been reported to prolong survival in dogs with thyroid carcinoma. This study aimed to describe tumour response and progression-free interval (PFI) in dogs with thyroid carcinomas treated with 131 I. Secondary aims were to describe overall survival time (OST) and prognostic factors. A bi-institutional retrospective review of records identified 66 dogs with thyroid carcinoma treated with 131 I from January 2010 to April 2020. Response was described using RECIST or a subjective response assessment where specific tumour measurements were not available. Forty-eight dogs (72.7%) were treatment naïve and 18 dogs (27.3%) had received prior therapy at the time of 131 I treatment. Objective responses were available for 34 dogs and subjective responses for 58 dogs. The overall response rate was 35.3% (four complete and eight partial responses). Improvement of clinical signs was seen in 76.2% of dogs (32/42). Kaplan-Meier-estimated median PFI (95% confidence interval [CI]) was 301 (217-578) days and OST (95% CI) was 564 (421-865) days. Prior therapy was associated with a lower hazard for progression (hazard ratio [HR] 0.260 95% CI 0.123-0.548, p = .0004). Treatment of thyroid carcinoma using 131 I can effectively alleviate clinical signs and reduce disease burden in a proportion of dogs.

Bilateral thyroid adenomas in an alpaca.

A 7-year-old neutered male alpaca (Vicugna pacos) was presented for evaluation of a 3-year history of large, bilateral, firm ventral cervical masses causing esophageal and tracheal impingement. Ultrasound examination, radiographic evaluation, histopathological findings, and magnetic resonance imaging confirmed the masses to be bilateral thyroid adenomas. Conservative medical treatment by unilateral chemical ablation, using 10% formalin by aspiration technique, was performed on the left mass. Chemical ablation proved to be effective in decreasing the size of the mass, with no apparent adverse effects. To our knowledge, this case is the first known report of bilateral thyroid adenomas in an alpaca, a condition previously described in humans, horses, dogs, and cats.

Evaluation of hemostasis in hyperthyroid cats.

BACKGROUND: Hyperthyroid cats might have a predisposition to arterial thrombus formation. The mechanism for thrombogenesis currently is unknown but could be associated with systemic hypercoagulability as seen in hyperthyroid humans. OBJECTIVE: Our purpose was to evaluate markers of hemostasis in hyperthyroid cats compared to healthy cats, and in hyperthyroid cats before and after radioactive iodine treatment (RIT). ANIMALS: Twenty-five cats with hyperthyroidism and 13 healthy euthyroid cats >8 years of age. METHODS: Prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, antithrombin (AT), D-dimers, thrombin-antithrombin complexes (TAT), von Willebrand Factor antigen (vWF : Ag), and activity of factors VIII and IX were measured. An echocardiogram was performed in all cats. Hemostatic markers and echocardiogram were evaluated again 6 to 9 months after successful RIT in 7 cats. RESULTS: Hyperthyroid cats had higher fibrinogen concentration (P < .0001), AT activity (P < .0001), and vWF : Ag concentration (P = .01) than healthy control cats with all results decreasing significantly post-RIT. Hyperthyroid cats were not more likely to be in a hypercoaguable state than euthyroid cats (P = .08). Serum T4 concentration was not a predictor of a hypercoagulable state (P = .53). CONCLUSIONS AND CLINICAL IMPORTANCE: Hyperthyroid cats have evidence of altered hemostasis that does not appear to be solely attributable to cardiac abnormalities, but no evidence of a hypercoagulable state. Findings suggest altered hemostasis resolves after RIT. Hyperthyroid cats could have endothelial dysfunction as indicated by increased vWF : Ag which could potentiate thrombogenesis.