Neuroendocrine tumor arising from the greater omentum treated with laparoscopic tumor resection: a case report

BACKGROUND: Primary omental tumors are extremely rare. Herein, we report the first case of a primary omental neuroendocrine tumor (NET). CASE PRESENTATION: A 59-year-old woman was referred to our hospital for the treatment of an 18-mm tumor located at the ventral side of the duodenum. No other tumor was detected. The preoperative imaging diagnosis was omental tumor. A laparoscopic tumor resection was performed. Histopathological examination revealed that the tumor consisted of cuboidal cells with eosinophilic, granular cytoplasm showing trabecular or ribbon architecture. No other component was seen. The mitotic count was of 5 per 10 high-power fields. Immunohistochemical staining was positive for chromogranin A, synaptophysin, and CD56. Her Ki-67 index was 5%. These results led to the diagnosis of grade 2 omental NET. The patient was discharged on the 3rd postoperative day without any complications and did not develop any recurrence for 3 years. CONCLUSIONS: We encountered a very rare case of omental NET. Complete resection is recommended with minimally invasive surgery for the diagnosis of NET. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40792-021-01217-4.