First Account of Primary Leiomyosarcoma of the Lesser Omentum since Establishment of c-Kit Mutations in Gastrointestinal Stromal Tumors

Abstract

Background Primary omental leiomyosarcoma is an extremely rare type of tumor. Leiomyosarcomas originating from the lesser omentum have not been reported since immunohistochemical staining for c-kit has been used for the diagnosis of mesenchymal abdominal tumors. They are yet to be reported since gastrointestinal stromal tumors were categorized. Here we reported a case of successful resection of a lesser omental leiomyosarcoma. Case Presentation A 71-year-old man underwent ultrasonography at the outpatient clinic through which an upper abdominal tumor was identified. Following computed tomography and endoscopy, a 4.5 cm submucosal tumor in the lesser curvature of the stomach was highly suspected. A laparoscopic partial resection of the stomach was performed. Histopathological examination revealed the tumor to be a leiomyosarcoma arising from the lesser omentum that did not invade the stomach. Immunohistochemical staining showed that the tumor was negative for CD34, c-kit, and S-100 and positive for desmin and α-smooth muscle actin. No recurrence had been observed 1 year after surgery without adjuvant chemotherapy. Conclusions Primary lesser omental leiomyosarcoma, which is difficult to diagnose before surgery given the location of the primary tumor in the lesser omentum, has rarely been reported. Considering the high possibility of malignancy, close observation is essential.

Primary huge gastric leiomyosarcoma with multiple metastases in a 60-year-old female: a case report

“…Because this tumor's growth is often insidious, and it is usually discovered at an advanced stage. As a result, knowledge of the biology and scientific behavior of LMS in the stomach is restricted, and the presentation of new cases is vastly necessary [ 4 , 5 ]. We present a 60-year-old female diagnosed with gastric LMS with multiple metastases, focusing on its clinical manifestations, diagnosis, and treatment.…”