Detection of Pneumocystis and Morphological Description of Fungal Distribution and Severity of Infection in Thirty-Six Mammal Species.

Pneumocystis spp. are thought to adapt to the lungs of potentially all mammals. However, the full host range, fungal burden and severity of infection are unknown for many species. In this study, lung tissue samples originating from 845 animals of 31 different families of eight mammal orders were screened by in situ hybridization (ISH) using a universal 18S rRNA probe for Pneumocystis, followed by hematoxylin and eosin (H&E) staining for determining histopathological lesions. A total of 216 (26%) samples were positive for Pneumocystis spp., encompassing 36 of 98 investigated mammal species, with 17 of them being described for the first time for the presence of Pneumocystis spp. The prevalence of Pneumocystis spp. as assessed by ISH varied greatly among different mammal species while the organism load was overall low, suggesting a status of colonization or subclinical infection. Severe Pneumocystis pneumonia seemed to be very rare. For most of the Pneumocystis-positive samples, comparative microscopic examination of H&E- and ISH-stained serial sections revealed an association of the fungus with minor lesions, consistent with an interstitial pneumonia. Colonization or subclinical infection of Pneumocystis in the lung might be important in many mammal species because the animals may serve as a reservoir.

Clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis: 19 cases (2015-2019).

OBJECTIVE: To report clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis. ANIMALS: 19 rabbits. PROCEDURES: Medical records for client-owned rabbits that had a histologic diagnosis of appendicitis were reviewed. RESULTS: Median age of the rabbits at presentation was 24.0 months (range, 4 to 84 months). Seventeen cases occurred during the summer and fall seasons. Decreased appetite (17/19 rabbits), abnormal rectal temperature (hyperthermia, 9/16 rabbits; hypothermia, 4/16 rabbits), hypocalcemia (8/11 rabbits), and hypoglycemia (7/15 rabbits) were common signs. Abdominal ultrasonography and CT findings were suggestive of appendicitis in 6 of 8 rabbits and in 1 of 2 rabbits, respectively. Of the 6 rabbits that received medical treatment, 3 died at 48 hours, 1 died at 24 hours after hospitalization, and 1 died at 10 days after presentation; 1 rabbit was alive at 1,030 days after presentation. Of the 8 rabbits that underwent appendectomy, 3 died before discharge from the hospital and 1 died 113 days after surgery; 4 rabbits were alive at 315, 334, 1,433, and 1,473 days after presentation. The remaining 5 rabbits either died or were euthanized before treatment could be instituted. In each of the 19 rabbits, the appendix had evidence of severe inflammation with mucosal ulceration, heterophilic inflammation, and necrotic debris. CLINICAL RELEVANCE: For rabbits with decreased appetite and an apparently painful abdomen, hyperthermia, hypocalcemia, or hypoglycemia, appendicitis should be considered as a differential diagnosis. Further comparisons of medical and surgical treatments are required to establish treatment recommendations for rabbits with appendicitis.

Molecular characterization of Prototheca in 11 symptomatic dogs.

Protothecosis is an uncommon disease caused by algae of the genus Prototheca. In dogs, the infection is usually first localized to the colon but has the propensity to later disseminate hematogenously to many other organs, with marked tropism for the eyes and central nervous system. Diagnosis is established by culture and/or evidence of Prototheca organisms in cytologic or histologic preparations. Species characterization, however, requires molecular investigations. Our laboratory set up a real-time PCR targeting portion D1/D2 of the 28S rRNA for identification of Prototheca species from both positive cultures (of rectal swabs and urine) and formalin-fixed, paraffin-embedded tissue. Prototheca bovis, P. ciferrii, and P. wickerhamii were characterized in 11 dogs with systemic or cutaneous protothecosis. Prototheca identifications were phylogenetically consistent with the new taxonomy proposed for this genus based on the mitochondrial cytochrome b gene. As a pilot study, we screened feces and rectal scrapes from 200 asymptomatic dogs, using 2 cohorts of stray and owned animals, to determine the prevalence of intestinal carriage of Prototheca spp. The Prototheca-negative results from both cohorts of healthy dogs suggest that predisposing factors related to the host probably contribute more to the acquisition of clinical disease than exposure to contaminated environments.

Epidemiology of Breed-Related Mast Cell Tumour Occurrence and Prognostic Significance of Clinical Features in a Defined Population of Dogs in West-Central Italy.

Canine mast cell tumours (MCTs) present a wide variety of challenging clinical behaviours in terms of predicting the prognosis and choosing appropriate treatment. This study investigated the frequency, risk, and prognostic factors of MCTs in dogs admitted to a single veterinary teaching hospital (VTH). Breed, age, sex, and sexual status in ninety-eight dogs with MCTs (MCT-group) were compared with a control group of 13,077 dogs (VTH-group) obtained from the VTH clinical database from January 2010 to January 2016. Within the MCT-group, signalment, location, size, mass number, ulceration, histopathological grading, presence of lymph node, or distant metastases were compared with each other and with the outcome. Boxers (OR 7.2), American Pit Bull Terriers (OR 5.4), French Bulldogs (OR 4.4) and Labrador Retrievers (OR 2.6) were overrepresented. The MCT-group was significantly older than the VTH-group (p < 0.0001). In comparison with the VTH group, in the MCT-group neutered dogs (OR 2.1) and spayed females (OR 2.3) were predominant compared to intact dogs and intact females, respectively. Ulceration (OR 5.2) and lymph node metastasis (OR 7.1) occurred more frequently in larger MCTs. Both ulceration and MCTs > 3 cm were highly associated with lymph node metastasis (OR 24.8). Recurrence was associated with MCT-related death (OR 10.50, p = 0.0040), and the latter was associated with shorter survival times (p = 0.0115). Dogs with MCTs > 3 cm (p = 0.0040), lymph node metastasis (p = 0.0234), or elevated WHO stage (p = 0.0158) had shorter survival times. A significantly higher frequency of MCTs was found in specific breeds, and in older and neutered dogs. MCTs > 3 cm and lymph node or distant metastases were associated with shorter survival times.

Sertoli cell tumour in a pet rabbit (Oryctolagus cuniculus): histological and immunohistochemical characterization.

The present study describes a case of a spontaneous, unilateral Sertoli cell tumour (SCT) in a 6-year-old pet rabbit. The rabbit was presented with a palpable, unilateral, subcutaneous left inguinal mass, consistent with the suspected clinical diagnosis of neoplasia developing within the retained testis in the inguinal canal. The intrascrotal contralateral testis was palpable, but reduced in volume. The rabbit underwent orchiectomy and both the testes were collected, formalin-fixed, and submitted for histopathological examination. Microscopically, the enlarged testis was effaced by an intratubular SCT in which numerous intratubular microliths were evident. The contralateral testis was severely atrophied. Immunohistochemical stains showed neoplastic Sertoli cells that were diffusely positive for vimentin and anti-Müllerian-Hormone and multifocally positive for cytokeratins and desmin. Eighteen months after the surgery, the rabbit showed no clinical signs of disease. This is the first report of a spontaneously occurring rabbit SCT histologically described and immunohistochemically investigated.

Canine Clitoral Carcinoma: A Clinical, Cytologic, Histopathologic, Immunohistochemical, and Ultrastructural Study.

Vaginal and vulvar tumors are uncommon in dogs. Knowledge of canine primary clitoral neoplasia is restricted to a few case reports, and only carcinomas have been reported. Cytologic and histologic features reported in the literature seem to overlap with those of canine apocrine gland anal sac adenocarcinoma (AGASA). Clinical features also recall those of canine AGASA, such as locoregional metastases and hypercalcemia of malignancy (HM). In this study, 6 cases of primary canine clitoral carcinomas (CCCs), with and without HM, were investigated by means of cytology, histopathology, electron microscopy, and immunohistochemistry for neuroendocrine markers including chromogranin A (CGA), synaptophysin (SYN), neuron-specific enolase (NSE), and S-100. In all 6 tumors, cytologic findings were consistent with malignant epithelial neoplasia of apocrine gland origin. The tumors examined were classified into 3 different histological patterns representing different degrees of differentiation: tubular, solid, and rosette type. Both CGA and SYN were mildly expressed in 2 of 6 tumors, while NSE was consistently expressed in all 6 cases. None of the tumors were S-100 positive. Transmission electron microscopy revealed electron-dense cytoplasmic granules compatible with neuroendocrine granules in all 6 cases. CCCs presented clinicopathologic features resembling AGASAs with neuroendocrine characteristics, and 2 of 6 neoplasms were considered as carcinomas with neuroendocrine differentiation and were positive for 3 neuroendocrine markers. CCCs can often present with HM, and long-term outcome is likely poor. Our study concludes that CCC seems to be a rare tumor, but it might be underestimated because of the overlapping features with AGASA. Further studies should aim to define the true incidence of this disease.

A study of multiple Felis catus papillomavirus types (1, 2, 3, 4) in cat skin lesions in Italy by quantitative PCR.

Objectives The aim of the study was to investigate, by quantitative PCR (qPCR), the presence of papillomavirus in feline viral plaques (VPs), Bowenoid in situ carcinoma (BISC), squamous cell carcinoma (SCC) and actinic keratosis (AK). Methods Twenty-nine cases with previously established diagnoses of feline VPs, BISC, invasive SCC and AK were selected from a dermatopathological database. A critical re-evaluation of diagnosis was performed by defining clear criteria toward carcinomatous vs non-carcinomatous, in situ vs invasive (if carcinomatous) and viral vs actinic. Cases were evaluated for p16 immunolocalisation. The presence of the target viral genes for Felis catus papillomavirus (FcaPV)-1, FcaPV-2, FcaPV-3 and FcaPV-4 was determined by qPCR. The data generated ΔΔCq values, which represent a normalised measure of DNA viral quantity. Samples with a positive ΔΔCq value were submitted to sequence analysis. Results Four VPs, 19 BISCs, four SCCs and one case of AK were included. By ΔΔCq analysis we found that all VPs were positive for FcaPV-1 or FcaPV-2; eight BISCs were positive for FcaPV-1, FcaPV-2 and FcaPV-4. FcaPV-2 was the most prevalent among the group of VPs and BISCs. Conclusions and relevance Using the ΔΔCq method we report the first evidence of FcaPV-1, FcaPV-2 and FcaPV-4 in Italy. FcaPV-2 was the most frequently detected; to a lesser extent, FcaPV-1 and FcaPV-4 were detected in the examined samples. FcaPV-3 was never associated with viral-induced lesions by ΔΔCq investigation. Compared with conventional PCR the ΔΔCq method has the advantage of establishing a possible role of the virus in the outcome of infection.

Laryngeal paralysis associated with a muscle pseudotumour in a young dog.

An 18-month-old male entire Bloodhound dog was presented with a six-week history of progressive inspiratory dyspnoea, stridor, dysphonia and exercise intolerance. CT scan performed elsewhere had revealed the presence of an unencapsulated nodular mass (3x1x5 cm) dorsal to the larynx and first tracheal rings. Laryngoscopy demonstrated the presence of bilateral laryngeal paralysis and distorted laryngeal architecture suggestive of extraluminal compression. Histopathology results of incisional biopsies from the mass were suggestive of a benign non-neoplastic muscular lesion. Surgery was performed to manage laryngeal paralysis and attempt mass excision. A second histopathology examination confirmed an inflammatory and dysplastic lesion suggestive of a pseudotumour. All clinical signs resolved after surgery and at the 13 months follow-up the dog remains asymptomatic. To the authors' knowledge, this is the first report of a case of laryngeal paralysis caused by a muscle pseudotumour in a young dog.

Primary leiomyosarcoma of the jugular vein in a dog.

A four-year-old, male, Labrador retriever was referred for removal of a spindle cell sarcoma involving the right jugular vein. A post-contrast CT scan showed a seven-centimeter subcutaneous mass originated from the right external jugular vein, which was partially obstructed and showing contrast stasis, suggested a primary intravascular tumor of the jugular vein. The mass was resected, and histological evaluation was consistent with grade II intravenous spindle cell sarcoma of the jugular vein. Immunohistochemical positivity for vimentin, desmin, and αSMA antibody and negativity for S-100 protein confirmed venous leiomyosarcoma. The dog received five doses of intravenous doxorubicin, and there was no recurrence of the tumor 30 months post treatment. In dogs, primary intravascular sarcomas are rare and primary venous leiomyosarcoma has not been described. A venous tumor may be considered as a differential diagnosis in dogs with ventral neck swelling.

Two cases of feline paraneoplastic alopecia associated with a neuroendocrine pancreatic neoplasia and a hepatosplenic plasma cell tumour.

BACKGROUND: Feline paraneoplastic alopecia (FPA) is a rare condition listed among the cutaneous paraneoplastic syndromes, which occurs in association with pancreatic carcinoma, cholangiocarcinoma, hepatocellular carcinoma and metastatic intestinal carcinoma. OBJECTIVES: To describe the clinicopathological findings of paraneoplastic alopecia in two cats each with an uncommon tumour not previously reported in association with FPA. ANIMALS: Paraneoplastic alopecia was associated with neuroendocrine pancreatic neoplasia in a Persian cat and with a hepatosplenic plasma cell tumour in a domestic short hair cat. RESULTS: FPA was suspected based on age, rapid onset of clinical signs, ventral distribution of alopecia, shiny appearance of the skin and telogenization/miniaturization of the follicles on histopathology. The nature of the tumours was determined through cytology, postmortem, histopathological and immunohistochemical examination, and capillary immunoelectrophoresis. A causative association between the skin lesions and the tumour was suggested by clinical and histopathological features shared with previously published cases. CONCLUSIONS AND CLINICAL IMPORTANCE: Pancreatic neuroendocrine and plasma cell tumour should be considered as differential diagnoses when evaluating FPA.

Calvaria and orbital metastases of pulmonary adenosquamous carcinoma in a cat: a diagnostic challenge.

An 11-year-old cat with a 4-month history of lethargy, inappetence, dysphagia, partial mandibular paralysis and weight loss, was euthanized due to the rapid deterioration of his condition. Post-mortem radiographic examination revealed severe bone lysis of the left zygomatic arch, temporal and parietal bones. Magnetic resonance imaging of the head showed a large isointense mass of the left side of the skull associated with extensive lysis of the parietal and temporal bones and destruction of the adjacent tympanic bulla. Gross and histological examinations revealed a pulmonary adenosquamous carcinoma of the left lung, with metastases to the spleen, liver, mesenteric lymph nodes, mesentery, diaphragm, abdominal aorta, left orbit and calvaria. No limb or digit metastases were detected.

Detection of Pneumocystis infections by in situ hybridization in lung samples of Austrian pigs with interstitial pneumonia.

Pneumocystis carinii f. sp. suis is a fungus multiplying in the respiratory tract of pigs which occasionally is associated with interstitial pneumonia. Identification of Pneumocystis in tissue samples is considered difficult and there are only scarce data on its occurrence in European pigs. This investigation presents an in situ hybridization (ISH) procedure for identification of Pneumocystis spp. in paraffin wax embedded tissue samples and its application for labeling the agent in lung samples of pigs with interstitial pneumonia. Thirty-two out of 100 lung samples from pigs on Austrian farms were identified as positive, five of them with multiple, 12 with moderate and 15 with few organisms but Grocott's methenamine silver staining demonstrated that only 20 cases were unequivocally positive for Pneumocystis carinii. In addition to interstitial pneumonia Pneumocystis-positive pigs were more frequently affected with granulomatous pneumonia than Pneumocystis-negative pigs. Frequently concurrent infections with different viral or bacterial lung pathogens were noted but there was no positive correlation between Pneumocystis- and PCV-2-infections. With other infections, no clear-cut differences between Pneumocystis-positive and Pneumocystis-negative animals were found. This study shows that Pneumocystis infections occur frequently in Austrian pigs with interstitial pneumonia. It remains to be shown which are the factors triggering severe multiplication and whether infection with Pneumocystis alone is able to induce lung disease in pigs.

Severe thymic hyperplasia in a newborn calf associated with impaired T-cell differentiation.

A 1-day-old female Holstein-Friesian calf was presented for severe dyspnea. Physical examination revealed respiratory distress, moderate edema of the ventral neck, and swollen jugular veins. The calf died and was submitted for necropsy. A severely enlarged thymus (40 cm × 20 cm × 10 cm) weighing 1.37 kg was detected on gross examination. Histomorphology was normal but no tingible body macrophages were observed in the medullary areas. Immunohistochemistry was characterized by the lack of thymic cluster of differentiation 3 and major histocompatibility complex class II expression compared to age-matched controls. The findings were consistent with severe thymic hyperplasia, a rare congenital condition that is also described in children. Immunohistochemical findings were suggestive of impaired T-cell development and selection associated with lack of apoptosis of thymic cells (lack of tingible body macrophages). Thymic hyperplasia in juvenile animals should be considered among the differential diagnoses of mediastinal masses as a rare cause of respiratory distress in newborn calves.

A case of umbilical cord teratoma in an aborted foal.

A 16-year-old primiparous mare aborted an apparently normal fetus at 240 days of gestation. A large, oval mass, measuring approximately 20 cm × 30 cm × 20 cm, was detected attached to the umbilical cord of the fetus. On the cut surface, the mass showed multifocal cystic structures, foci of mineralization, and diffuse hemorrhages. Histological examination of the mass revealed haphazardly arranged cartilage, bone, mesenchymal stroma, adipose tissue, vascular structures, smooth muscle, ciliated epithelium, squamous cornifying epithelium, and undifferentiated germ cells with areas of necrosis and mineralization. The mass was diagnosed as an umbilical cord teratoma, which is an extremely rare tumor in human beings and, to the authors' knowledge, has only described in the veterinary literature on one occasion.