Neuroendocrine gastric carcinoma expressing somatostatin: a highly malignant, rare tumor

Abstract

Poorly differentiated gastric neuroendocrine carcinomas, although rare, deserve particular attention, as they are aggressive and have an extremely poor prognosis. In this report we describe a gastric neuroendocrine carcinoma with rapidly fatal outcome. Immunohistological staining of the resected specimens revealed that the tumor was an endocrine carcinoma. The tumor disclosed intense immunoreactivity to pan-neuroendocrine markers and diffuse somatostatin immunoreactivity. There were no psammoma bodies and no demonstrable association with von Recklinghausen's neurofibromatosis. In the gastrointestinal tract, neuroendocrine tumors producing predominantly somatostatin have been described only in the duodenum. To the best of our knowledge, the present report is the second case report of a neuroendocrine gastric carcinoma expressing diffusely somatostatin as the only neuroendocrine regulatory peptide.

Figure 1

Micrograph of histological section of the neuroendocrine gastric carcinoma showing a proeminent trabecular architecture, organoid pattern with pseudoglandular structure, uniform cells and abundant mitoses. (Hematoxilin & Eosin staining; original magnification, × 200).

Figure 2

Immunohistochemistry of the neuroendocrine gastric carcinoma showing intense and diffuse somatostatin-positive imunoreactivity in the neoplastic cells (Immunoperoxidase, primary antibody anti-human somatostatin-code A0566-Dako A/S^®, Copenhagen, Denmark, original magnification, × 400).