Abstract 4808: Small intestinal leiomyosarcoma in a young adult

Abstract

Abstract Objectives: • Outline the epidemiology of leiomyosarcoma•Identify the immunohistochemistry of a leiomyosarcoma Introduction: Primary small intestinal malignancies are rare malignancies as compared with other malignancies of the gastrointestinal tract. Here, we present a case of a jejunal leiomyosarcoma in a young adult. Case Presentation: A 23-year-old Caucasian male with GERD presented with five months of abdominal pain, intermittent nausea with non-bloody emesis, and a 20-pound weight loss. Presenting vital signs were within normal limits. Physical exam revealed conjunctival pallor with epigastric tenderness to palpation. Serology demonstrated iron deficiency anemia, hemoccult positive stool, negative CEA, CA19-9, and AFP tumor markers. HIV antigen antibody and EBV-PCR were non-reactive. CT of the abdomen and pelvis revealed markedly thickened heterogenous jejunal loop in the left hemiabdomen with associated mesenteric adenopathy and small volume pelvic ascites. EGD with push enteroscopy revealed a single, malignant appearing and ulcerated mass in the proximal jejunum. PET-CT showed a hypermetabolic, multilobulated, ill-defined mass involving multiple loops of jejunum. He underwent exploratory laparotomy with resection of a proximal jejunal mass (10x8 x7 cm), mesenteric lymphadenectomy, and a jejunojejunostomy creation. Pathology demonstrated leiomyosarcoma (pT2aN0MoG3), and he was initiated on cyclophosphamide and doxorubicin. Discussion: Primary small intestinal malignancies are rare malignancies with an incidence of less than 5% of all GI malignancies. 56 cases of GI leiomyosarcoma in adults were identified between 2000-2012 with a peak incidence between 55-59 years of age (Aggarrwal 2012). Leiomyosarcomas are soft tissue sarcomas arising from bones, tendons, blood vessels, or muscles with a spectrum of disease ranging from low-grade cutaneous lesions to aggressive lesions of internal organs with significant potential for metastasis (Pipe 2002). Diagnosis is based on immunohistochemical positivity for SMA, desmin, and h-caldesmon, and negativity for CD117, CD34, and DOG1.1, notably lacking KIT and PDGFRA mutations (Aggarwal 2012). Treatment involves surgical resection and a cost benefit analysis of adjuvant chemotherapy with (Reynolds, 2014). This case of a 23 year old, without significant risk factors, diagnosed with a jejunal leiomyosarcoma presents as one of the youngest cases ever to be reported and emphasizes the importance of recognizing the cancer in a broader range of the adult population. Citation Format: Alyssa A. Guo, Blake H. Bentley, Abigail L. Ellington, Haiyan Lu, William C. Lippert. Small intestinal leiomyosarcoma in a young adult [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4808.