Surgical Curability of Medullary Thyroid Cancer in Multiple Endocrine Neoplasia 2B

Abstract

This investigation aimed at exploring the suitability of nonendocrine manifestations preceding medullary thyroid cancer (MTC) for early diagnosis of multiple endocrine neoplasia type 2B (MEN 2B). MEN 2B patients, running a high risk of metastatic MTC, must be diagnosed early for biochemical cure. Forty-four MEN 2B patients carrying inherited (3 patients) and de novo (41 patients) M918T RET mutations were examined for signs and symptoms prompting MEN 2B. All 3 patients with inherited mutations were diagnosed before the age of 1 year and cured of their C-cell disease. Among 41 patients with de novo mutations, MEN 2B was diagnosed in 12 patients after recognition of nonendocrine manifestations [intestinal ganglioneuromatosis (6 patients), oral symptoms (5 patients), ocular ("tearless crying") (4 patients), and skeletal stigmata (1 patient) alone or concomitantly]. In the remaining 29 patients with de novo mutations, the diagnosis of MEN 2B was triggered by symptomatic MTC (28 patients) or pheochromocytoma (1 patient). The former patients, being significantly (P < 0.001) younger (means of 5.3 vs 17.6 years) and having lower calcitonin levels (means of 115 vs 25,519 pg/mL), smaller tumors (67% vs 0% were ≤10 mm) and less often extrathyroidal extension (0% vs 81%), lymph node (42% vs 100%), and distant metastases (8% vs 79%), were biochemically cured more often (58% vs 0%). MTC is curable in patients with de novo mutations when nonendocrine MEN 2B components are quickly appreciated and surgical intervention is performed before patients turn 4 years old.