Endocrine Abstracts

Introduction: Over expression of somatostatin receptors (SSTR) is the characteristic feature of well differentiated neuroendocrine neoplasms (NENs). We present two patients with well differentiated NENs of the large intestine with negative SRS and without SSTR expression confirmed with immunohistochemical (IHCH) examination and symptoms of carcinoid syndrome with good clinical response to the therapy with long acting somatostatin analogs.

Case reports: 53 years old man after right-sided hemicolectomy due to NETG2 (Ki67 5%) of the ileo-cecal valve with mesenteral lymph nodes and liver metastases. Patient presented with flushes. Therapy with long-acting somatostatin analog led to release of symptoms. Laboratory findings prior to the therapy: 5OHIAA 545.7 umol/24 h (N: 10-40) and CgA 112 ng/ml (N: 0-6). While somatostatin receptor scintigraphy (SRS) revealed increased pathological uptake only in the single mesenteral lymph node IHCH examination was performed. IHCH examination confirmed only low focal SSTR 1–5 expression.

Sixty four years old man with inoperable NETG1 (Ki67<2%) of the cecum with lymph nodes and liver metastases. Patient also presented with severe flushes. Therapy with long-acting somatostatin analog led to release of symptoms. Laboratory findings prior to the therapy: 5OHIAA 287 umol/24h and CgA 248 ng/ml. While SRS did not reveal any pathological uptake of the tracer in the lesions visualized with CT IHCH examination was performed. IHCH did not reveal any SSTR expression.

Conclusions: Presented case reports indicate the necessity of immunohistochemical assessment of the expression of SSTR in case of patients with well differentiated NENs and negative SRS results. Confirmed lack of SSTR expression make it necessary to change the imaging modalities and therapeutic options used for patients’ management. However we would like to emphasize the observed release of symptoms of carcinoid syndrome in response to the therapy with long acting somatostatin analogs in case of presented patients.