Difficult situation in treatment of medullary thyroid carcinoma in patient with multiple endocrine neoplasia type 2 B(MEN2B)

INTRODUCTION: Multiple endocrine neoplasia type 2B (also known as ‘MEN2B’,‘Multiple endocrine neoplasia type 3′ or ‘Wagenmann–Froboese syndrome’) is a genetic disease characterized by the presence of medullary carcinoma of the thyroid, pheochromocytoma, mucosal neuromas, marfanoid features and multiple skeletal abnormalities such as kyphoscoliosis and pes cavus. CLINICAL CASE: A 16 years male presented with neck swelling and dysmorphic feature in the form of marfanoid habitus, including multiple tongue and oral mucosal swelling with mucosal neuromas on the anterior third of the tongue, the lips and the inner eyelid. Lips are thickened and bumpy. Visible neck swelling, palpable solid neck mass, high arm span to height ratio at >1.05, elongated fingers, pes cavus and positive wrist sign which is defined as when the distal phalanges of the thumb and fifth finger overlap on encircling the opposite wrist, were present. Ultrasound of the neck revealed a left solid irregular mass (57mmx33mm), that is hypoechoic, has coarse calcification, hypervascularity, that is mostly central, Multiple cervical lymph node(abnormal nodes include shape (round), absent hilum, intranodal necrosis, reticulation, calcification, peripheral vascularity),Investigation at beginning, Normal thyroid function test and biochemical and electrolyte were observed, Chest x ray was normal, FNAC done for thyroid nodule that showed multiple clumps of large hyperchromatic oval cells picture suggesting high suspicion of thyroid malignancy, thyroid biopsy advised, The patient was referred the FDEMC center for further evaluation and investigation prior to the surgery. During investigation at FDEMC center, thyroid function test normal, biochemistry normal, including PTH and electrolytes, Calcitonin was very high 465 pg/mL (0.2–27.7 pg/mL),GH under GTT was normal, IGF 1 182µg/L (150–350),Plasma metanephrine 40 pg/ml(<90pg/ml),and Plasma normetanephrine 27pg/ml(<196pg/ml) were normal. The patient referred to surgery, total thyroidectomy with radical neck dissection with multiple lymph node resection was performed. The biopsy revealed medullary thyroid carcinoma with cervical lymph node secondaries (bilateral multiple foci in both lobes). The patient kept on levothyroxine tab 100mcg.The follow up of the patient after one month by ultrasound and calcitonin level revealed residual thyroid tissue and two large cervical LN in the the ultrasound and a calcitonin level of 322 pg/mL Another surgical neck dissection to the metastatic LN <multiple LN 7×5cm, multiple suprasternal mass dissection 3×2.5cm,remnant of thyroid tissue 0.8cm,Follow up the patient after one month by ultrasound and calcitonin level still showed that there is residual pathological cervical LN, while the calcitonin level still high 412 pg/mL. PET scan done for him showed there is uptake in the head, neck and chest. The calcitonin was repeatedly was high.