Colonic medullary carcinoma: an exceedingly rare type of colorectal malignancy: a case report and review of the literature.

BACKGROUND: Medullary carcinoma of the colon is a rare subtype of colorectal cancer that has a unique, and sometimes varied, clinical and histologic profile. It usually presents in adult patients older than 50 years. Here, we report a unique case of young male patient who initially presented with abdominal pain followed by a large bowel obstruction. CASE PRESENTATION: A 40-year-old SriLankan male presented with right-sided abdominal pain and on examination, there was a palpable right iliac fossa mass. Colonoscopy and a computed tomography scan revealed cecal mass. Later, while waiting for elective resection, the patient developed symptoms and signs of a large bowel obstruction. He underwent a laparoscopic right hemicolectomy with an uneventful postoperative course. The histopathologic evaluation of the resected specimens showed invasive carcinoma with syncytial growth pattern, foci of lymphoid host response, and dirty necrosis, in keeping with a medullary carcinoma pT4a pN2b. Unlike most reported medullary carcinoma cases, this patient was young and caudal-related homeobox transcription factor 2 positive. CONCLUSION: We have reported another case of medullary carcinoma of the colon in a young patient with unique histologic characteristics. Reporting such cases helps in refine understanding of the histologic and genetic, as well as clinical, phenotypes of medullary carcinoma of the colon.

Tumor-to-Tumor Metastasis of Medullary Thyroid Carcinoma to Paraganglioma in a Multiple Endocrine Neoplasia Type 2B Patient: A Case Report and Literature Review.

Tumor-to-tumor metastasis is a rare phenomenon in which primary tumor cells metastasize to other tumors. Herein, we report an extremely rare case of tumor-to-tumor metastasis of medullary thyroid carcinoma to a paraganglioma in a patient with multiple endocrine neoplasia type 2B. Based on genetic examination, a 36-year-old woman was diagnosed with multiple endocrine neoplasia type 2B when she was 24 years old. She had a history of total thyroidectomy for medullary thyroid carcinoma and bilateral adrenalectomy for pheochromocytomas, which were performed when she was 15 years and 29 years old, respectively. Follow-up computed tomography demonstrated a retroperitoneal tumor of 30 mm in diameter beside the left kidney and a liver tumor of 16 mm in diameter located in segment 6. The retroperitoneal and liver tumors were surgically resected and examined by a pathologist. Histological examination revealed the classic Zellballen pattern in the retroperitoneal tumor, rendering the diagnosis of a paraganglioma recurrence. Inside the tumor, a white nodule positive for carcinoembryonic antigen, weakly positive for calcitonin, and negative for tyrosine hydroxylase, was identified and diagnosed as a metastatic medullary thyroid carcinoma with high malignant potential. The liver lesion was diagnosed as a metastasis of the medullary thyroid carcinoma. This is the first report of tumor-to-tumor metastasis of medullary thyroid carcinoma to paraganglioma in a patient with multiple endocrine neoplasia type 2B twenty years after total thyroidectomy.

Combination Therapy With Bortezomib in Renal Medullary Carcinoma: A Case Series.

BACKGROUND: Renal medullary carcinoma (RMC) is a very rare, aggressive neoplasm occurring almost exclusively in adolescents and young adults with sickle cell trait. Given the rare nature of this tumor, accounting for less than 0.5% of all renal carcinomas, most of the published data on therapies is from case reports and small case series, and current treatments are insufficient, with most patients succumbing to their disease in months. We report our experience with a cytotoxic chemotherapy regimen consisting of platinum-based therapy, doxorubicin, and bortezomib. METHODS: Three patients with metastatic RMC at a single institution were treated off-label with a perioperative chemotherapy regimen for 4 cycles of 2 alternating regimens: regimen A consisting of cisplatin, doxorubicin, and bortezomib; regimen B consisting of carboplatin, paclitaxel, and gemcitabine. A radical nephrectomy was performed on all patients. Surveillance imaging was performed on all patients to assess response and disease burden. Patients received up to 12 months of maintenance therapy with everolimus. RESULTS: Three African American patients - 2 males and 1 female aged 14, 28, and 31 - with sickle cell trait and metastatic disease were treated with this regimen. The median follow-up was 18 months. All had resection of the primary tumor - 2 patients after receiving neoadjuvant therapy, and one patient underwent resection prior to referral. All 3 patients achieved complete responses based on imaging, 2 of which lasted for 12 months, and another is still in remission over 7 years after diagnosis. CONCLUSIONS: This regimen of alternating cycles of platinum-based chemotherapy with bortezomib appeared to be active against RMC and was generally well-tolerated. Given the extremely rare nature of this disease and dismal prognosis, new treatment modalities should be pursued, and whenever possible, patients should be enrolled in a clinical trial. We propose that a multiinstitution clinical trial of this regiment may be warranted.

Ultrasound features and risk stratification systems to identify medullary thyroid carcinoma.

OBJECTIVE: Recently, several scientific societies designed ultrasound (US) risk stratification systems (RSS) to guide the workup of thyroid nodules and decide which nodules should undergo fine-needle aspiration cytology (FNAC). However, these systems have been developed against papillary thyroid carcinoma, and scanty data on their role in identifying medullary thyroid carcinoma (MTC) are available. The aims of this study are to describe the US features of MTC and evaluate the performance of RSS in identifying MTC. METHODS: Data of 152 consecutive patients with MTC was evaluated. The results of the pre-operative neck US of all patients were collected. Ultrasound features of each MTC were evaluated and classified according to the five main RSS available. RESULTS: Median MTC dimension was 1.3 cm. Most of the nodules showed solid composition, hypoechoic pattern, and regular margins. About half of them showed the presence of calcifications, but only a subgroup had microcalcifications. A minority of the nodules showed a 'taller than wide' shape. Only 7.9% of all MTC showed the simultaneous presence of at least four US features suggestive of malignancy. Ultrasonographic high-risk of malignancy of the MTC included in the five RSS, varied from 45.4 to 47.4%, and performing FNAC was suggested in only 48.7 to 63.8% of all MTC. CONCLUSIONS: In this series, neither single nor the association of US features are specific for MTC. The five main RSS correctly identify less than 50% of MTC and do not suggest performing FNAC in about half of them with potentially missed or delayed diagnosis.

Renal medullary carcinoma involving serous cavity fluids: a cytomorphologic study of 12 cases.

INTRODUCTION: Renal medullary carcinoma (RMC) is a highly lethal adenocarcinoma with a propensity for widespread metastatic disease in young patients. It is strongly associated with sickle cell trait and shows the loss of SMARCB1 (also known as INI1 or BAF47) protein expression. In the present study, we reviewed a series of 12 patients for whom the cytology specimens played a significant role in patient treatment. MATERIALS AND METHODS: We performed a retrospective case review of patients with a history of RMC from 3 large tertiary care pathology practices. RESULTS: A total of 12 patients were identified with histologically confirmed RMC who had had pleural, pericardial, or urine specimens involved by their disease or had undergone initial kidney fine needle aspiration. Patient age ranged from 13 to 37 years (median, 21.5 years). All 12 patients were black or of African descent, and 10 had a confirmed history of sickle cell trait. Of the 12 patients, 11 (92%) had fluid specimens involved by metastatic tumor at some point in their clinical course, and 4 (33%) had initially presented with pericardial and/or pleural effusions or urine specimens that were positive for malignancy. Cytologic examination predominantly showed fragments of 3-dimensional "tumor balls" with smooth borders, fine pale cytoplasm with vacuolization, and highly pleomorphic nuclei with irregular nuclear membranes and coarse to vesicular chromatin and single prominent nucleoli. CONCLUSIONS: The cytomorphology of RMC involving serous fluids is nonspecific and in keeping with metastatic high-grade adenocarcinoma. In a young patient presenting with no history of malignancy and a pleural or pericardial effusion, triaging the material for ancillary studies and a nuanced assessment of patient history and radiologic findings will be critical.

Breast metastasis from medullary carcinoma of thyroid: A case report with literature view.

Primary Breast cancer is the most common malignancy in females but secondary involvement of breast is very rare. The Most common sites of primaries for breast metastasis are breast carcinoma of contra lateral side, Lymphoma and leukaemia. Medullary Thyroid Carcinoma (MTC) itself is rare and commonly metastasises to liver, lung and bones. Secondary breast involvement by MTC is very rare with only few case reports in literature. Clinically and radiographically breast secondaries mimic benign lesions and may cause diagnostic challenges. To avoid unnecessary surgery and for appropriate treatment decision,accurate diagnosis is important. We present here our experience of a similar case of secondary breast carcinoma from MTC seen at MINAR cancer hospital Multan. The patient presented clinically and radiologically with benign breast lumps. Fine needle aspiration (FNAC) showed atypical cells and Ultra sound guided Trucut biopsy confirmed it to be a secondary from MTC. Patient is under treatment of an oncologist, has been treated with chemotherapy and is on follow up till date.

Pancreatic Ductal Adenocarcinoma.

The most frequent indication for pancreatic fine-needle aspiration sampling is to confirm or exclude a pancreatic ductal adenocarcinoma (PDAC). PDAC is the most common malignant neoplasm of the pancreas, and the term pancreatic cancer typically connotes this entity. The conventional type of PDAC is a tubular adenocarcinoma, with a number of morphological variations described. Morphologically distinct but related entities include adenosquamous carcinoma, undifferentiated carcinoma, and undifferentiated carcinoma with osteoclast-type giant cells. Unrelated carcinomas with ductal lineage include colloid carcinoma and medullary carcinoma. Less commonly reported carcinomas include signet ring cell carcinoma, hepatoid carcinoma, and oncocytic carcinoma. Here we will focus on the cytological findings of PDAC and other carcinomas of ductal lineage, briefly touching upon their clinical features, histologic appearance, and clinically useful serum markers. The differential diagnosis, pitfalls, and useful ancillary studies will also be reviewed. A diagnosis of PDAC should not be taken lightly given that it can potentially result in a pancreatic resection. Familiarity with the entities described in this review will help practicing cytopathologists confront these cases with appropriate information needed in order to render a clinically valuable diagnosis.

PET en el diagnóstico de la patología de tiroides / PET in diagnosis of thyroid diseases

INTRODUCCIÓN Y OBJETIVO: La PET/TC es una técnica cuyas indicaciones en Oncología se encuentran en expansión y el cáncer de tiroides es una de ellas. MÉTODO: Revisión narrativa. COMENTARIOS: En el presente artículo se revisan las indicaciones establecidas hasta la fecha, así como aquellos campos en los que son necesarias investigaciones adicionales que permitan establecer la utilidad de esta técnica en los distintos tipos de patología maligna tiroidea

INTRODUCTION AND OBJECTIVE: PET/CT is a technique which oncological indications are now increasing, being thyroid cancer one of them. METHOD: narrative review. COMMENT: The present study is a review of well-known indications, as well as those fields in which more studies are needed to establish the utility of this technique in every kind of malignant thyroid pathology

Chinese siblings with hereditary medullary thyroid carcinoma caused by RET mutation: implications for RET oncogene detection.

BACKGROUND: Hereditary medullary thyroid carcinoma (MTC) is mainly caused by germline mutations in the RET proto-oncogene, which accounts for 20-30% of all MTC according to foreign studies. However, no English literatures have reported Chinese hereditary MTC. Here, we reported two Chinese brothers with MTC that caused by germline RET mutation. CASE PRESENTATION: The younger brother was diagnosed with MTC at 29 years ago and suffered recurrence more than 10 years. For elder brother, the diagnosis of MTC was made by postoperative pathological examination at age 61. Both patients received total thyroidectomy and lymph node dissection. Since they had a significant family history for MTC, genetic detection was performed and identified a germline mutation in RET exon 10 (p.C620Y). This mutation was also detected in their offspring, indicating a moderate risk of MTC. CONCLUSIONS: This is the first report presenting a Chinese family with hereditary MTC caused by the RET p.C620Y variant. This case series emphasize the importance of genetic detection of RET proto-oncogene for MTC patients, and bring out managements for individuals after detection of RET mutations.

Clinical and ultrasonographic features of medullary thyroid microcarcinomas compared with papillary thyroid microcarcinomas: a retrospective analysis.

BACKGROUND: To identify the sonographic features that help to differentiate medullary thyroid microcarcinomas (MTMCs) from papillary thyroid microcarcinomas (PTMCs). METHODS: A total of 46 MTMCs in 41 patients and 136 PTMCs in 104 patients that were proven by surgery and pathology were included in the study. Patient age and nodule size were analyzed by independent sample t-tests, and sex, multiplicity and cervical lymph node metastases were analyzed by χ2 or Fisher's exact tests. Univariate analysis and multivariate logistic regression analysis were performed on the sonographic features of thyroid nodules, including location, shape, boundary, margin, peripheral halo ring, echogenicity, composition, calcifications and vascularization. RESULTS: Compared with the corresponding number of patients with PTMCs, more MTMC patients had cervical lymph node metastases (P = 0.040). There were no significant differences in age, sex, nodule size, multiplicity, location, boundary, margin, peripheral halo ring, echogenicity or microcalcifications between MTMCs and PTMCs (P > 0.05 for all). However, significant differences were found in shape (P = 0.000), composition (P = 0.032), macrocalcifications (P = 0.004) and vascularity (P = 0.000) between the two groups. CONCLUSIONS: There were some overlapping sonographic features between MTMCs and PTMCs. However, MTMCs tended to have a > 50% solid composition, be ovoid to round nodules with macrocalcifications and be hypervascular. Cervical lymph node metastases were more common in MTMC patients.

Pulmonary Function in Patients With Multiple Endocrine Neoplasia 2B.

CONTEXT: Multiple endocrine neoplasia type 2B (MEN2B) is a rare cancer predisposition syndrome resulting from an autosomal-dominant germline mutation of the RET proto-oncogene. No prior studies have investigated pulmonary function in patients with MEN2B. OBJECTIVE: This study characterized the pulmonary function of patients with MEN2B. DESIGN: This is a retrospective analysis of pulmonary function tests (PFTs) and chest imaging of patients enrolled in the Natural History Study of Children and Adults with MEN2A or MEN2B at the National Institutes of Health. RESULTS: Thirty-six patients with MEN2B (18 males, 18 females) were selected based on the availability of PFTs; 27 patients underwent at least 2 PFTs and imaging studies. Diffusion abnormalities were observed in 94% (33/35) of the patients, with 63% (22/35) having moderate to severe defects. A declining trend in diffusion capacity was seen over time, with an estimated slope of -2.9% per year (P = 0.0001). Restrictive and obstructive abnormalities were observed in 57% (20/35) and 39% (14/36), respectively. Computed tomography imaging revealed pulmonary thin-walled cavities (lung cysts) in 28% (9/32) of patients and metastatic lung disease in 34% (11/32) of patients; patients with metastatic lung lesions also tended to have thin-walled cavities (P = 0.035). CONCLUSIONS: This study characterized pulmonary function within a MEN2B cohort. Diffusion, restrictive, and obstructive abnormalities were evident, and lung cysts were present in 28% of patients. Further research is required to determine the mechanism of the atypical pulmonary features observed in this cohort.

Renal Medullary Carcinoma on Dual-Time Point FDG PET/CT Imaging.

Renal medullary carcinoma is a rare and highly aggressive tumor seen almost exclusively in young individuals of African descent with sickle cell disease. Here, we describe a case of a 29-year-old man, who did not have sickle cell disease, with pathologically confirmed renal medullary carcinoma using dual-time FDG PET/CT.

Mucinous versus medullary breast carcinoma: mammography, ultrasound, and MRI findings.

Mucinous and medullary breast cancers (BCs) have different histological substrates that manifest as different imaging features on mammography, ultrasound, and MRI. The aim of the present review is to demonstrate the differences between these two rare BC subtypes and to describe the microscopic features, review the imaging methods for detection of both cancer subtypes, illustrate the imaging findings and present useful pearls and pitfalls. Out of a total of 30 patients with mucinous BC and nine with medullary BC, we have selected typical and also unusual imaging features that best represent these cancers. The patients underwent a mammography and breast ultrasound followed by magnetic resonance imaging. We briefly exhibit histological characteristics for a better understanding of the imaging aspects.

Clinical utility of 177 Lu-DOTATATE PRRT in somatostatin receptor-positive metastatic medullary carcinoma of thyroid patients with assessment of efficacy, survival analysis, prognostic variables, and toxicity.

BACKGROUND: The primary aim of this study was to evaluate the therapeutic efficacy and outcome of 177 Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) in somatostatin receptor-positive metastatic medullary thyroid carcinoma (MTC), including progression-free survival (PFS) and overall survival (OS), and also to determine the various prognostic variables. The secondary aim was toxicity assessment of PRRT in this group of patients. METHODS: A total of 43 somatostatin receptor-positive metastatic MTC patients, treated with 177 Lu-DOTATATE PRRT in a large tertiary care center, were included in this analysis. After receiving the therapy, post-treatment response evaluation was undertaken for symptomatic and biochemical responses (serum calcitonin) and imaging responses with 68 Ga-DOTATATE, 18 F-FDG PET-CT, CeCT (PERCIST and RECIST 1.1 criteria). Calcitonin doubling time (CtnDT) was calculated by the American Thyroid Association calculator. The adverse events were graded according to the NCI-CTCAE v5.0 criteria. The observed Kaplan-Meier curves for both PFS and OS since first PRRT were compared with CtnDT (more than 24 months vs less than 24 months) by log-rank (Mantel-Cox) test. The prognostic variables were investigated for their association with CtnDT and response to PRRT using Cox proportional-hazards model. RESULTS: The median OS was 26 months (95% CI 16.6-35.3 months) and the median PFS 24 months (95%.CI: 15.1-32.9 months). Following 177Lu-DOTATATE PRRT, the observed median PFS and OS was longer in patients who had CtnDT more than 24 months compared to those with CtnDT less than 24 months (median PFS not yet reached vs 10 months and median OS 60 months vs 20 months). Assessing from the time-point of first 177 Lu-DOTATATE PRRT cycle, the patients with CtnDT more than 24 months had a significantly longer PFS (P < .001) and OS (P < .001) compared to those with less than 24 months. Less than 5 lesions, FDG uptake in lesions (SUVmax of <5) and patients alive at the time of analysis were the significant variables for association with CtnDT (more than 24 months). Out of 43 patients, 26 were responders (61%) and 17 nonresponders (39%) based upon PERCIST criteria, and 27 were responders (62%) while 16 patients were nonresponders (38%) based upon RECIST 1.1 criteria. The univariate analysis showed significant association between responses to PRRT with following prognostic variables: (a) size of lesions (<2 cm) and (b) FDG uptake in lesions (SUVmax of <5). PRRT was well tolerated in all patients without any major grade 3 or 4 toxicity. CONCLUSION: The results demonstrated that, 177 Lu-DOTATATE is a potentially efficacious and safe therapeutic option in SSTR avid metastatic MTC patients.

Medullary thyroid carcinoma treated with percutaneous ultrasound-guided radiofrequency ablation.

PURPOSE: Minimally invasive image-guided thermal ablation has been proposed as alternative to surgery for treatment of benign thyroid nodules and recurrent differentiated thyroid carcinoma. Here, we report for the first time the use of radiofrequency ablation (RFA) in a patient with non-metastatic medullary thyroid carcinoma (MTC) who did not undergo surgery due to high anesthesiological risk. METHODS AND RESULTS: A 64-year-old woman was referred to our institution for a routine endocrinological visit. No thyroid-related symptoms were present. She had a history of metabolic, cardiovascular and neurological diseases. On clinical examination, a nodular lesion of about 10 mm was palpable in the right thyroid lobe; ultrasonography (US) confirmed the presence of a 13 mm thyroid nodule in the lower pole of the right lobe, that was hypoechoic and with regular margins. Serum calcitonin (Ctn) level was significantly high (647 pg/mL). Fine-needle aspiration (FNA) of the thyroid nodule was negative for malignant cells, but the marked increase of Ctn level in the FNA wash-out fluid confirmed the diagnostic suspicion of MTC. Since patient refused surgery due to high anesthesiological risk, percutaneous US-guided RFA in single session was performed. At 6-months follow-up the serum Ctn level decreased from the initial value of 647 pg/mL, reaching near-normal range (15 pg/mL), and neck ultrasound showed a complete necrosis of the tumour. Afterward, serum Ctn slowly increased to 49 pg/mL at 15-month follow-up. The US performed at 6 and 12 months of follow-up revealed fibrotic tissue in place of the thyroid nodule, without evidence of cervical lymph-node metastases. CONCLUSIONS: This clinical case suggests that RFA may be effective and safe for treatment of MTC when surgery cannot be performed.

Renal medullary carcinoma in a young mixed-race man in Japan.

Renal medullary carcinoma (RMC) is a rare and aggressive cancer associated with the sickle cell trait. The diagnosis of RMC depends on recognition of its histologic features and immunohistochemical deficiency of INI1, but correct diagnosis is sometimes difficult, especially if a patient's information on race, past, and family medical history is unclear. At present, this is the first report on RMC in Japan.

68Ga-DOTANOC and 18F-FDG PET/CT in metastatic medullary thyroid carcinoma: novel correlations with tumoral biomarkers.

OBJECTIVE: Metastatic disease is common in medullary thyroid carcinoma (MTC) and it is usually detected by raising calcitonin and carcinoembryonic antigen (CEA) levels. Nuclear medicine imaging has an important role in lesion identification/characterisation. We aim to compare 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT performance and to explore the correlations between tumoral markers and functional imaging. METHODS: This a retrospective cross-sectional study including 13 patients with MTC and high calcitonin/CEA levels that underwent both 68Ga-DOTANOC PET/CT and 18F-FDG PET/CT. RESULTS: 68Ga-DOTANOC PET/CT identified MTC metastases in 2twopatients that were 18F-FDG-negative (sensitivity of 69.2% vs. 53.9%, respectively). 68Ga-DOTANOC PET/CT also detected a higher number of lesions than 18F-FDG PET/CT in seven patients, with only one patient showing the opposite pattern. Both differences lacked statistical significance (p = 0.50 and p = 0.86, respectively) but 68Ga-DOTANOC PET/CT better performance allowed changes in patients' management. 68Ga-positive/18F-FDG-negative patients were the ones with the lowest calcitonin doubling time and presented a CEA doubling time >24 months, while the patient with more 18F-FDG-positive lesions was the one with the highest CEA/calcitonin ratio. The number of lesions found in 68Ga-DOTANOC PET/CT were correlated with calcitonin levels (r = 0.73; p < 0.01) but not with CEA ones (r = 0.42; p = 0.15). The number of 18F-FDG hypermetabolic focus were correlated with CEA levels (r = 0.60; p < 0.05) but not with calcitonin (r = 0.48; p = 0.09). CONCLUSIONS: This is the first study to describe a positive correlation between 68Ga-positive lesions and calcitonin levels and between 18F-FDG-positivity and CEA levels. Tumoral markers pattern in metastatic MTC could help clinicians to decide which exam to perform first.

Diplopia-an unheralded consequence of neck dissection: case report.

INTRODUCTION: Neck dissection is a part of the standard surgical procedure in the management of head and neck malignancy. Diplopia following neck dissection is a rare entity; hence, its diagnosis and management strategies needed to be discussed for prevention of its grave consequences. CASE REPORT: A 30-year-old male patient presented with binocular horizontal diplopia following total thyroidectomy and neck dissection. On evaluation, there was internal jugular vein (IJV) thrombosis followed by cerebral venous sinus thrombosis (CVST). After meticulous medical management with diuretics and antiplatelet drugs, diplopia resolved completely and normal vision was restored. CONCLUSION: Therapeutic ligation of internal jugular vein during neck dissection may result in IJV thrombosis followed by CVST leading to raised intracranial tension (ICT). It has to be anticipated and addressed as early as possible to prevent its grave consequences like blindness and death.

Resección hepática radioguiada con 18F-DOPA en un paciente con carcinoma medular de tiroides metastásico / Radioguided hepatic resection with 18F-DOPA in a patient with metastatic medullary thyroid carcinoma

Introducción: El carcinoma medular representa el 1-2% de todas las neoplasias tiroideas malignas. El 13-20% de los pacientes presenta metástasis a distancia, afectando al hígado en el 45% de los casos. Presentación de un caso: Una mujer de 50 años de edad, diagnosticada de carcinoma medular de tiroides, fue sometida a tiroidectomía total y disección cervical modificada en 1999. Se trataron con resección quirúrgica 2 recidivas ganglionares en el cuello; durante el periodo de vigilancia, la paciente desarrolló niveles elevados de calcitonina, identificándose la localización de la recidiva en el hígado mediante PET/TC con 18F-DOPA. La actividad metabólica no se asoció a lesión visible en TC, RM y ecografía. La cirugía radioguiada con 18F-DOPA permitió la resección anatómica de los segmentos IVb y V. Discusión: En pacientes con carcinoma medular y elevación de calcitonina durante el periodo de vigilancia, la PET/TC con 18F-DOPA es una opción para evaluar la localización de la recidiva. La resección radioguiada fue posible en esta paciente, cuya recidiva hepática no resultó visible con ningún otro método de imagen. Conclusión: La resección hepática radioguiada con 18F-DOPA en el carcinoma medular de tiroides metastásico es factible cuando la localización de la recidiva no puede identificarse anatómicamente mediante otros estudios de imagen

Introduction: Medullary carcinoma accounts for 1-2% of all thyroid malignancies. 13-20% of patients present with distant metastasis, with 45% of the cases affecting the liver. Clinical case: A 50-year-old woman, diagnosed with medullary thyroid carcinoma, was treated with total thyroidectomy and a modified neck dissection in 1999. Two lymph node recurrences in the neck were treated with surgical resection; during surveillance, she developed elevated calcitonin levels, the recurrence site was identified with 18F-DOPA PET/CT in the liver. Metabolic activity was not associated with a visible lesion in CT, MRI nor ultrasound. Radioguided surgery with 18F-DOPA allowed an anatomic resection of segments IVb and V. Discussion: In patients with medullary carcinoma and elevated calcitonin during surveillance, 18F-DOPA PET/CT is an option to evaluate the site of recurrence. Radioguided resection was feasible in this patient, whose hepatic recurrence was not visible with any other imaging method. Conclusion: Radioguided hepatic resection with 18F-DOPA in metastatic medullary thyroid carcinoma is feasible when the recurrence site is not anatomically identified by any other imaging studies