A Case of Gastric Neuroendocrine Carcinoma with Disseminated Recurrence 14 Years after Initial Surgery

Abstract

Introduction: Gastric neuroendocrine carcinoma (NEC) is a rare disease among gastric cancers, accounting for only 0.1%-0.6% of all cases. This disease is known to have a poor prognosis and a higher risk of recurrence compared to conventional gastric adenocarcinoma.

Case presentation: At the age of 44, a 60-year-old female underwent a laparoscopic-assisted proximal gastrectomy for gastric cancer at a previous hospital. Neuroendocrine carcinoma was diagnosed following a postoperative pathological examination based on histological findings and immunostaining results. The patient was followed up without any recurrences. After 14 years, a follow-up contrast-enhanced CT revealed a 9-mm mass on the greater curvature side of the gastric antrum, which was suspected to be lymph node swelling at the previous hospital. After 8 months, she came to our hospital with abdominal discomfort and distention. The CT scan revealed a 55-mm mass, indicating an increase in the previously mentioned mass. At our hospital, the patient underwent open tumor resection. The pathological findings revealed a recurrence of gastric NEC. The patient has been recurrence-free for 6 months following surgery.

Conclusions: We present a case of gastric NEC with disseminated recurrence. To our knowledge, this is the first report of a disseminated case in which a recurrent lesion caused by omental dissemination grew in size and infiltrated a portion of the gastric serosa approximately 14 years after the initial surgery.

Keywords: disseminated recurrence; gastric neuroendocrine carcinoma; postoperative recurrence.

Fig. 1. Preoperative CT images. (A) CT scan conducted at a previous hospital. It showed a 9-mm mass on the greater curvature side of the gastric antrum (arrows). (B) CT scan conducted at our hospital. A 55-mm hypervascular mass with internal necrosis and a clear border was observed at the sub-umbilical level (arrows). The tumor demonstrated early enhancement in the arterial phase (left image), with a decrease in the contrast effect in the late phase (right image).

Fig. 2. Preoperative MRI. (A) T1-weighted image. The tumor displayed low signal intensity (arrows). (B) T2-weighted image. The tumor showed a mixture of low and remarkably high signal intensities (arrows). (C) Contrast imaging demonstrated an early enhancement effect (arrows).

Fig. 3. Surgical findings. (A) The tumor (arrows) was in contact with the abdominal wall, the omentum, and the stomach wall. (B) The tumor was in contact with the stomach wall (arrow); a combined resection of the stomach wall was performed. (C) The tumor was oval, measuring 8.0 × 5.5 × 3.5 cm. No notable findings were observed in the resected gastric mucosa (arrows).

Fig. 4. Pathological findings. (A) Hematoxylin–eosin staining. The tumor consisted of atypical cells with rounded, enlarged nuclei undergoing proliferation, with a mitotic index of more than 40/10 HPF. (B, C) Immunostaining. The tumor demonstrated positive staining for chromogranin A (B) and synaptophysin (C). (D) The Ki-67 labeling index was more than 60%. (E) Hematoxylin–eosin staining. The gastric cancer from 14 years ago appeared similar to the current tumorous lesion.

HPF, high-power field