Endocrine Abstracts

Introduction: Mixed adenoneuroendocrine carcinoma (MANEC) is a rare tumor of the gastrointestinal tract that consists of a dual adenocarcinomatous and neuroendocrine differentiation. The clinical behavior seems to be influenced by the neuroendocrine component. We report a patient with mixed adenoneuroendocrine carcinoma of cecum who presented 18 years after her initial diagnosis and treatment.

Case report: A 59-year-old woman presented with a 3-month history of episodic hypotension, tachycardia and face and upper trunk flushes. She had a history of cecum tumor resection 18 years ago. It was a poorly differentiated mixed adenoneuroendocrine carcinoma. The tumor extended in the pericolic adipose tissue with perineural and lymphonodular invasion. It was TNM stage IIIB (T3N1M0). Postoperatively, she received interferon and 5-fluoracil chemotherapy for 6 months.

The patient was asymptomatic for 18 years until symptoms of carcinoid syndrome (CS) appeared. Serum chromogranin A and 24-h urine 5-hydroxy-indole-acetic-acid (5-HIAA) were abnormally high. An abdominal magnetic resonance imaging revealed multiple metastatic liver lesions confirmed by biopsy. In111-pentetreotide scintigraphy detected the lesions in the liver and others in the left shoulder and the right sternum-clavicle joint. Bone lesions were also demonstrated by Tc-99m DTP scan. Octreotide LAR 30 mg per month was initiated and resulted in amelioration of symptoms. Chromogranin A and 5-HIAA decreased but remained above normal range. The symptoms of CS reappeared after 2 years and the patient received 9 cycles of targeted radiotherapy (177Lu-Dotatate), which finally resulted in clinical and imaging improvement.

Conclusion: We report a rare case of a patient with a mixed adenoneuroendocrine carcinoma of the cecum who presented with metastatic disease and carcinoid syndrome 18 years postoperatively. Due to the rarity of these tumours and the unknown natural history, lifelong follow up is required.