暂无摘要。

We experienced a case of multiple endocrine neoplasia type 2A(MEN2A)diagnosed with medullary thyroid carcinoma. The patient was a 50s woman who was referred for a thyroid nodule detected in the right lobe during a carotid ultrasound examination. After undergoing a hemithyroidectomy, it was determined that the tumor was medullary carcinoma. RET gene test was performed, confirming a mutation at codon768, leading to the diagnosis of MEN2A. A completion thyroidectomy was performed to remove the remaining thyroid tissue. Postoperatively, the patient is undergoing systemic surveillance.

Papillary thyroid carcinoma (PTC) is the most common type of differentiated TC, while medullary TC (MTC) accounts for 4%. The concomitant presence of PTC and MTC is rare.
This is a retrospective, single-center observational study conducted over 16 years (2001-2017). The data were collected from the clinical records of patients who underwent total thyroidectomy at the Endocrine Unit-Department of Medicine of the University Hospital of Pisa, Italy.
Over 690 analyzed cases, 650 (94.2%) were exclusive DTC, 19 exclusive MTC (2.75%) and 5 PTC/MTC (0.7%). No case of mixed medullary/follicular TC or hereditary MTC (familial MTC/multiple endocrine neoplasia type 2) was found. Among the five PTC/MTC cases, there was a male prevalence (M:F = 3:2), and all PTC components were at stage I, whereas 40% of MTC were at stage I and III and 20% of MTC were at stage II; microPTC (mPTC) was prevalent (80%) and also microMTCs were frequent (40%); 60% of MTC patients recovered, while 40% of patients developed metastatic disease. The search for germline mutations of the RET gene resulted in being negative in all cases.
The incidence of PTC/MTC has been increasing over the past 30 years. The etiology of PTC/MTC forms is still unknown, and although this simultaneous occurrence could be only a coincidence, we cannot exclude the hypothesis of a shared genetic origin.

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.
METHODS: 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.
CONCLUSIONS: 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 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.

The patient is a 79-year-old woman who visited her local doctor with a chief complaint of abdominal pain. A lower gastrointestinal endoscopy revealed a circumferential type 3 mass in the transverse colon. The patient was diagnosed with transverse colon cancer (cT3N0M0, cStage Ⅱa)and underwent laparoscopic transverse colectomy(D3). The postoperative course was good, and she was discharged on POD 9. Pathological results showed a diagnosis of medullary carcinoma(pT3N0M0, pStage Ⅱa)with MSI-high. The patient was treated with UFT/UZEL for 6 months as postoperative adjuvant chemotherapy. The patient has been recurrence-free for 1 year and 6 months postoperatively and is under outpatient follow-up. Medullary carcinoma is a rare histologic type that is estimated to account for 2-3% of all colorectal cancers. Medullary carcinoma of the colon is more common in elderly patients, women, and the right side of the colon, with a relatively favorable prognosis. We report a case of medullary carcinoma of the transverse colon in which the patient had a relatively long survival, with some discussion of the literature.

BACKGROUND: Renal medullary carcinoma (RMC) is a diagnostically challenging, aggressive primary renal malignancy associated with abysmal survival. Delays in diagnosis contribute to most patients having diffusely metastatic disease at the time of initial presentation.
METHODS: We present the case of a 13-year-old African American male with sickle cell trait who presented with a renal mass and hematuria. Evaluation included imaging, fluid cultures, and cytologic assessment.
RESULTS: Patient was diagnosed with RMC based on cytologic assessment of sub-centimeter fluid collections aspirated from the left kidney at the time of cortical biopsy for suspected renal mass. The additional fluid aspiration in conjunction with renal biopsy was an atypical but crucial step in early diagnosis.
CONCLUSIONS: Cytomorphologic evaluation of fluid biospecimens is not currently part of the standard work-up for patients with renal masses but, when available, can provide crucial information that reduces time to diagnosis. Prompt symptom recognition and treatment initiation may improve patient outcomes.

Small intestinal medullary carcinoma (MC) is a newly recognized subclass of small intestinal carcinomas and is an exceptional entity for this site. A search of the literature for similar cases arising in the small intestine revealed only six previously reported cases. Here we present a case of MC arising in the jejunum of a 65-year-old male. The patient presented to the emergency with features of perforation peritonitis with liver metastasis and no known predisposing factors like inflammatory bowel disease and celiac disease. Studies conducted on this tumor\'s colonic counterpart have shown microsatellite instability (MSI) and B-type Raf kinase (BRAF) mutations; however, few exceptions are known. Also, this subtype of carcinoma is known to have a better prognosis than its other histological subtypes.

A case is reported of an oncocytic tumor of the thyroid expressing simultaneously follicular and neuroendocrine markers, but not calcitonin. The data reported in the literature and the possible relationships of these lesions with the calcintonin-negative medullary carcinomas were examined.

BACKGROUND: Pancreatic medullary carcinoma (PMC) is a rare pancreatic tumor, usually showing the presence of microsatellite instability, mostly MLH1 silencing, and a wild-type KRAS mutation status. We report here a PMC arising from a Pancreatic Intraductal Papillary Mucinous Neoplasm (IPMN), both having KRAS and TP53 mutations.
METHODS: We report the case of a 73-year-old woman presenting with right iliac fossa pain. MRI revealed a 16 mm diameter mass in the pancreas, leading to a pancreatic duct stricture and upstream a dilatation of the distal pancreatic duct of Wirsung. A fine needle aspiration was performed, and pathology analysis revealed malignant glandular cells. The patient underwent distal pancreatectomy. Gross examination revealed an12 mm indurated white lesion, adjacent to a cystic lesion extending into the rest of the pancreatic body. Microscopically, the cystic area represented a mixed (gastric-type and pancreatobiliary-type) IPMN, involving the main and secondary pancreatic ducts with low-grade and high-grade dysplasia. In the periphery of this IPMN, a 14mm associated invasive carcinoma was observed, characterized by focal gland formation and by poorly differentiated cells with a syncytial appearance, associated with a dense lymphoplasmocytic and neutrophilic infiltrate. Immunohistochemical analyses showed loss of MSH2 and MSH6 expression. Microsatellite instability was confirmed by molecular test. Molecular analysis was performed both on the invasive carcinoma and on the high-grade dysplasia IPMN, revealing the same mutation profile with KRAS and TP53 mutations. The proposed diagnosis was mixed IPMN with associated invasive medullary carcinoma that presented loss of MSH2 and MSH6 expression.
CONCLUSIONS: The present case reports for the first time, at the best of our knowledge, the coexistence of IPMN lesions and PMC, both having the same molecular alterations. It also describes the second case of PMC with microsatellite instability, MSH2 and MSH6 silenced.