The variable pathologic presentations of medullary and micro-medullary thyroid carcinoma: an institutional experience

Medullary thyroid carcinoma (MTC) is a rare tumor; its pathologic diagnosis can be difficult due to variability in its clinical presentation, size, morphology, and follow-up. We report our institutional experience with 45 cases of MTC diagnosed at University of Pennsylvania Medical Center between 2000 and 2007. The collected data points included patient's age, sex, family history, tumor size, method of diagnosis, calcitonin and CEA levels, presence of concomitant follicular derived thyroid carcinoma (FDTC), lymph node (LN) status, and clinical follow-up. The cohort included 17 males and 28 females (average age 53 years); 6 had a history of multiple endocrine neoplasia II (MENII). Pre-operative FNA was performed in 33/45 cases (33%); 23/33 were diagnosed as MTC or suspicious for MTC. Of 45 cases 20 were micro-MTC; 15 occurred with other thyroid malignancies. LN metastases were present at primary resection in 18/45 cases. Calcitonin levels rose or remained elevated postoperatively in 4 cases; of these, 2 had regional LN recurrence and 1 developed distant metastases and subsequently died of disease. MTC is a heterogeneous disease. Sporadic micro-MTC carcinoma is an indolent tumor and can occur with other malignant tumors of the thyroid gland.