Endocrine Abstracts

Introduction: Serotonin producing neuroendocrine tumors are usually well differentiated, small lesions localised in the small intestine. Visualisation of the primary tumor might be difficult due to its small size.

Case report: A 52 years old man presented with diarrhoea and flushes. Ultrasound examination and computed tomography of the abdomen revealed numerous lesions in the liver. Gastroscopy, colonoscopy and magnetic resonance imaging did not reveal the primary tumor. On histopathological examination of the metastatic lesion poorly differentiated cancer of neuroendocrine origin was diagnosed. Patient was qualified to chemotherapy with cisplatin and etoposide, with no clinical response and no response on imaging examinations. Patient was referred to our center. Somatostatin receptor scintigraphy (SRS) revealed increased uptake of the tracer in liver metastases, in the lymph nodes of mesentery and in the single lymph node in the mediastinum. Owing to the symptoms of the carcinoid syndrome (diarrhoea, six to eight stoolsm per day and flushes three to four times per hour) treatment with long acting somatostatin analogue was started. Owing to still unknown primary ¹⁸F-FDG/PET was performed. The examination revealed the primary tumor in the small intestine, which was excised. On histopathological examination neuroendocrine tumor of the small intestine with Ki67 <2% was confirmed. Owing to the advanced disease, ineffectiveness of chemotherapy and positive result of SRS patient was qualified to peptide receptor radionuclide therapy (PRRT). PRRT led to further improvement of clinical symptoms (diarrhoea, one to two stools per day and flushes, six to eight times a day). Imaging examinations are planned.

Conclusions: Above case report shows possible difficulties in searching for the primary lesion in case of patients with carcinoid syndrome with the use of different imaging modalities. Moreover it presents the known possibility of distinctions in grading between the primary tumor and metastases.