Small cell carcinomas are the most aggressive, highly malignant neuroendocrine tumors; among these, gastric small cell carcinoma (GSCC) is extremely rare. Here we report a case of a patient with primary GSCC, presenting as linitis plastic, who was diagnosed using endoscopic ultrasound (EUS)-guided biopsy. With undiagnosed linitis plastica, an 80-year-old woman was referred to our institution. Abdominal computed tomography revealed irregular wall thickening extending from the gastric body to the antrum. Endoscopy suspected to have Borrmann type IV advanced gastric cancer. EUS of the stomach showed diffuse submucosal thickening of the gastric wall, mainly the antrum. EUS-guided bite-on-bite biopsy confirmed the diagnosis of GSCC. In general, GSCC is difficult to diagnose and careful examination is necessary to determine the therapeutic strategy; however, EUS is particularly helpful in the differential diagnosis of a lesion presenting as linitis plastica.
Primary gastric small cell carcinoma (GSCC) is a rare and the most poorly differentiated neuroendocrine tumor, accounting for less than 0.1% of all gastric cancers and 15% of all gastric neuroendocrine tumors [
An 80-year-old female with undiagnosed linitis plastica was referred to our institution for epigastric pain. Before visiting our hospital, she had undergone endoscopy at another hospital and was suspected of having Borrmann type IV advanced gastric cancer; however, histological examination had not confirm the malignancy. She showed epigastric tenderness after eating, which had gradually aggravated in the last month. Results of her initial physical examination were unremarkable except for epigastric pain. Her family health history was negative, whereas her medical history included medications for hypertension and diabetes mellitus over the last 10 years. Laboratory values for the serum levels of carcinoembryonic antigen and carbohydrate antigen 19-9 were within normal limits. Abdominal computed tomography of the patient revealed irregular wall thickening extending from the gastric body to the antrum, with no remarkable findings such as metastasis and infiltration of the lymph nodes or peripheral tissues (
Generally, the clinical course of GSCC is as aggressive as that of lung small cell carcinoma. Arai and Matsuda reported that approximately all GSCC patients die within a year of the diagnosis [
The first case of GSCC was reported in 1976 by Matsusaka et al. [
Linitis plastica is a type of gastric cancer characterized by poorly differentiated tumor cells that diffusely infiltrate the gastric wall, leading to reactive fibrosis. Its endoscopic characteristics include poor distension of the gastric walls and morphological changes in the gastric folds. These features make it difficult to diagnose before operation. Furthermore, though bite-on-bite biopsy is a commonly used approach for the diagnosis of linitis plastica, the diagnostic yields of the samples have not been determined [
EUS may be an important diagnostic tool with increased diagnostic accuracy to safely detect gastric infiltrating tumors, based on their endosonographic characteristics [
Immunohistochemical examination is remarkably valuable for the pathological diagnosis of GSCC. GSCC has an immunohistochemical presentation similar to that of lung small cell carcinoma, but it is unique in its positive reactions to synaptophysin, chromogranin A, neuron-specific enolase, CD56, and S-100 protein, indicating the presence of neurosecretory granules [
In conclusion, we report a rare case of GSCC presenting as linitis plastica that was successfully diagnosed using EUS-guided bite-on-bite biopsy. Although GSCC is difficult to diagnose before treatment, careful examination should be performed to determine the appropriate therapeutic strategy, and EUS may be particularly helpful in the differential diagnosis of a lesion presenting as linitis plastica.
Abdominal computed tomography showing diffuse thickening of the gastric wall extending from the body to the antrum (arrow).
Positron emission tomography-computed tomography of the chest, abdomen, and pelvis showing fluorodeoxyglucose uptake along the gastric antrum and body (arrow), with a maximum standardized uptake value of 7.76.
Esophagogastroduodenoscopy showing diffuse circumferential thickening and poor distension of the gastric walls from the antrum to the gastric body.
Conventional endoscopic ultrasound (EUS) images. A gastric infiltrating tumor diagnosed using EUS (A, B). EUS showing homogeneous, slightly hypoechogenic thickening of the submucosal layer (12 mm) and intact muscularis propria layer shows reactive wall thickening (C, arrow). The thinnest part of the mucosal lesion was selected for the biopsy after EUS localization (D, arrow).
Microscopic findings of the gastric tissue. Hematoxylin and eosin stained biopsy specimens show small tumor cells with irregular nuclei and scant cytoplasm (A). Tumor cells stained positive for cytokeratin (B) and CD56 (C), while they were negative for thyroid transcription factor-1 staining (D). Detection of a strong Ki-67 reactivity was observed (E). All the images were captured at ×200 magnification.