S2602 Gastric Leiomyosarcoma: A Rare Case of Upper GI Bleeding

Abstract

Introduction: Leiomyosarcoma (LMS) is a tumor arising from parts of the body containing smooth muscle cells such as the uterus, stomach and walls of blood vessels. Primary gastric leiomyosarcomas are extremely rare, accounting for 0.1%-3% of gastrointestinal malignancies. They can be differentiated from Gastrointestinal Stromal Tumors (GIST) based on immunohistochemical staining that is positive for desmin and SMA and negative for staining of KIT (CD 117), CD 34, and DOG1.1. LMS is usually asymptomatic but can present with anorexia, weight loss, nausea, vomiting, or bleeding. Here we present a rare case of an aggressive LMS manifesting as hematemesis and melena. Case Description/Methods: A 76-year-old male with a past medical history of Hypertension, Bladder Cancer and Prostate Cancer presented with a chief complaint of three days of hematemesis and melena. Upper Esophagogastroduodenoscopy (EGD) done five months prior was notable for an esophageal ulcer and gastritis. Labs on admission were notable for Hg of 10.3. EGD was performed which showed a large polypoid mass at the gastroesophageal (GE) junction. Biopsies were notable for smooth muscle cells that tested positive for SMA and caldesmon but negative for desmin, CD34, CD117 and DOG-1 most consistent with leiomyosarcoma. Ultimately, the patient underwent surgical resection of a 8.5 × 7.2 × 3.3 cm tumor with negative surgical margins and no evidence of lymphovascular invasion. The patient did well post-operatively and has been following with oncology for further management (Figure 1). Discussion: Prior to 1998, gastrointestinal stromal tumors (GIST) were misdiagnosed as LMS due to lack of molecular markers. Since then there are only 10 reported cases of gastric leiomyosarcoma in the post-GIST era. On CT imaging LMS tends to show up as irregular central zones of low attenuation suggestive of extensive necrosis or hemorrhage. Endoscopically, LMS tends to appear mainly in the muscularis propria with increased vascularity and a heterogeneous appearance. For tumors greater than 2 cm surgical resection is the preferred method of treatment. For metastatic disease, however, there has been no clear benefit of adjuvant chemotherapy as there is a high risk of recurrence. Routine follow up for completely resected tumors consists of abdominal and pelvic imaging which should occur every three to six months for two to three years, and then annually. In conclusion, we highlight a rare case of an aggressive type of Leiomyosarcoma at the GE junction presenting as an upper GI bleed.Figure 1.: (1) Upper Endoscopy showing mass lesion at the gastroesophageal (GE) junction. (2) Axial computed tomography (CT) image showing mass lesion in the gastric cardia (3) Spindle cells with marked atypia, necrosis, rare mitosis and moderate pleomorphism (H and E, x20)