Wolf in Sheepʼs Skin

Abstract

Purpose: A 57-year-old male presented for evaluation of bloody diarrhea for about 4 years. He had negative basic labs; stool studies, colonoscopy, esophagoduodenoscopy and small bowel follow through in the past. However, he was managed as irritable bowel syndrome. He reported the stools were watery, 7-10 per day including at night. He denied abdominal pain, dairy intolerance, food allergies, joint, and skin or eye symptoms. The stools were not difficult to flush and no mucus. There was no weight loss, history of laxative / antibiotic use, or travel history. Past medical and family history was non-contributing. Patient smokes 2-3 packs of cigarettes daily; drank alcohol occasionally and not on any medication. On examination, he was awake, alert, oriented and no distress, afebrile, his blood pressure was 110/60 mmHg, pulse 88/min. His neck examination revealed barely palpable cervical lymph node and rest of the examination was unremarkable. Laboratory work showed normal complete blood count, complete metabolic, thyroid profile, gastrin and serotonin level. However, a calcitonin (20220 pg/ml) and CEA (4050 ng/ml) level were elevated. His CAT scan abdomen revealed a mass in the right lobe of the liver. Patient was started on sandostatin to control diarrhea. A thyroid ultrasound revealed solid mass with calcification involving the lower 2/3rd of the left lobe. CAT scan confirmed the solid mass in the left thyroid lobe and further showed small lymph nodes scattered throughout the anterior and posterior cervical triangle and metastases to lungs. Patient was referred to ENT for management of the thyroid mass. Patient underwent total thyroidectomy with neck dissection during surgery carcinoma was found to be infiltrating into the muscle and adipose tissue around the thyroid. Pathology confirmed medullary carcinoma of thyroid infiltrating fibro-adipose tissue and the mediastinal and cervical lymph node were completely replaced by metastatic medullary carcinoma. Patient was negative RET mutation for MEN type 2 syndrome. Patient's diarrhea frequency improved post resection, however, it did not completely resolve due to presence of metastasis. Medullar thyroid carcinoma is a rare tumor which accounts for 3% of thyroid neoplasms. Systemic symptoms occur due to hormonal secretion and diarrhea is a wolf in sheep's skin.