Introduction: Small cell carcinoma is most frequently found in the lung. Only 4% of small cell carcinomas are present in the urinary bladder, prostate, oesophagus, stomach, colon, rectum, gallbladder, larynx, salivary glands, cervix and skin. Primary gastric small cell carcinoma (GSCC) is a very rare and poorly differentiated neuroendocrine tumour. We present a case of primary gastric small cell carcinoma and a systematic review of literature. Case Presentation: A 58 year-old man presented with epigastric pain, nausea and melena. Several exams showed an antro-pyloric poorly differentiated grade III gastric small cell carcinoma classified as cT4 cN+ cM0. The tumour board recommended neoadjuvant treatment with six cycles of cisplatin-etoposide, with the last two cycles associated with radiotherapy. Re-staging showed a good partial response and no spread of the disease, therefore we completed treatment with a radical gastrectomy with D2 lymph node dissection. The surgery was performed in August 2019 and the patient was discharged after ten days. Pathology report showed a mix large and small cells neuroendocrine carcinoma . Due to the neoadjuvant treatment, the small cell component seen in a preoperative biopsy had largely disappeared and the case was diagnosed as a mixed large and small cell neuroendocrine carcinoma ypT4a N3a (9/28) G3 L1 V1 Pn1 R0. Discussion: Clinical manifestations of gastric small cell carcinoma (GSCC) are similar to classic gastric adenocarcinomas. However, gastric small cell carcinoma can secrete ectopic hormones like parathyroid hormone, antidiuretic hormone, calcitonin or serotonin. Upper gastrointestinal endoscopy is the method of choice for the diagnosis, supplemented with an immunohistochemical examination with a positive reaction to neuro-specific enolase (NSE), chromographin A, synaptophysin, CD56 and Grimelius. The treatment strategy for GSCC is unclear. There is no difference in the pathological features, response to chemotherapy, incidence of progression and survival between the different anatomical locations of these tumours. A review of the literature limited to GSCC recommended multi-modal approach combining surgery, radiotherapy and platinum-based adjuvant chemotherapy. Ten months after surgery, the patient is still disease free. Conclusion: GSCC is a rare and aggressive entity with low survival rate. The rarity of this entity makes treatment challenging. Unlike small cell lung cancer, surgery remains part of the multi-modality treatment of GSCC.