BACKGROUND: Many neuroendocrine carcinomas exhibit medullary infiltration and expanded proliferation. Differentiated tubular adenocarcinoma is frequently seen in the superficial region in many neuroendocrine carcinoma cases. However, the present case showed non-medullary infiltration and signet ring cell carcinoma in the superficial region, with intramural metastases distributed throughout the whole of the stomach.

CASE REPORT: A 67-year-old man was referred to our institution for treatment of gastric cancer. Type IIc-like advanced gastric cancer was detected in the greater curvature of the middle body of the stomach. The patient underwent total gastrectomy, splenectomy with D2 lymph node dissection, and Roux-en-Y reconstruction with curative resection. The tumor was diagnosed as a large-cell endocrine carcinoma of the stomach. A solid growth of signet ring cells was seen in the mucosa and submucosa. Intramural metastases were observed in many other depressed lesions. Large-cell carcinoma invaded the submucosa, mainly in the intramural metastatic site. Metastasis to one lesser curvature lymph node was also seen on histological examination. The final diagnosis was a gastric cancer of type 0–IIc (T4a) [M] (with intramural metastases) at T4aN1H0P0M0 Stage IIIA. This patient has remained alive without recurrence for 72 months after surgery.

CONCLUSIONS: We recommend close preoperative examination of neuroendocrine carcinoma, taking intramural metastases into consideration.

Keywords: Carcinoma, Signet Ring Cell - pathology, Carcinoma, Large Cell - pathology, Neoplasms, Multiple Primary - pathology