Endocrine Abstracts

Introduction: Medullary thyroid cancer (MTC) is characterized by elevated calcitonin levels, stemming from genetic factors or occurring sporadically. Carcinoid syndrome involves symptoms triggered by substances released by tumors, such as hormones and amines. This case report details a patient who developed carcinoid syndrome linked to medullary thyroid cancer.

Case: A 77-year-old male presented with flushing, diarrhea, and dizziness. No other health issues or medication use were reported, except for flushing and hypotension during a hemorrhoid operation a year ago. While routine tests showed normal results, neck CT revealed calcified nodules in the thyroid and pathological lymph nodes. Calcitonin was elevated at 11312 pg/ml, CEA at 126 ng/ml. Thyroid ultrasound displayed a 19.1×21×35.9 mm calcified nodule with pathological cervical lymph nodes. Ga-68-DOTA-PET confirmed thyroid and cervical involvement. Fine needle aspiration biopsy confirmed medullary carcinoma. Catecholamine and 5-HIAA levels were normal. Chromogranin was normal. Surgery was planned for MTC, involving bilateral total thyroidectomy and lymph node dissection. Sandostatin infusion was initiated for carsinoid symptoms 24 hours before surgery, continuing intraoperatively and 48 hours postoperatively, gradually decreasing over a week. Postoperatively, calcitonin was 639 pg/ml, CEA 110 ng/ml on day one. Three months later, similar symptoms recurred, with calcitonin at 2600 pg/ml . Re-operation confirmed MTC, with a 5 cm retrosternal mass in the right lobe. Postoperatively, calcitonin decreased to 312 pg/ml . Two months later, a patient with similar complaints had a calcitonin level of 261 pg/ml, and residual tissue? was observed in the right lobe on thyroid ultrasonography. A spherical lymph node with the largest size of 10 cm was identified in the right level IV. Biopsy results were non-diognastic, and calcitonin washouts results of 4.9 pg/ml and 15.2 pg/ml, respectively. Due to ongoing symptoms, the patient was readmitted with a preliminary diagnosis of carcinoid syndrome, and short-acting sandostatin was initiated. After the post-operative follow-up Ga-68 DOTA-PET, as regression and the absence of new metastases were observed, tyrosine kinase inhibitors were not considered. The patient was discharged with lanreotide 120 mg/month, and no attacks were observed following the treatment.

Conclusion: MTC can manifest with flushing in carcinoid syndrome. When diagnosing flushing, consider MTC, pheochromocytoma, pancreatic tumors, hyperthyroidism, and male hypogonadism. Treating carcinoid syndrome involves addressing the underlying disease, and also sandostatin relieves symptoms in these patients. Keep MTC in mind when patients present with flushing or carcinoid syndrome.