A Rare Case of Uterine Leiomyosarcoma With Metastasis to the Colon

Abstract

Laeeq Butt, MD, MBA, Rajiv Mallipudi, MD, Swami Nathan, MD A Rare case of Uterine Leiomyosarcoma with Metastasis to the Colon and Small Bowel Introduction: Uterine leiomyosarcoma is an extremely rare and aggressive malignancy with an overall poor prognosis. It typically metastasizes through hematogenous dissemination to the lungs, bones and brain. However, there have not been many cases of metastasis to the colon. In reported cases the patients presented with acute abdomen secondary to uterine leiomyosarcoma invasion of the small bowel or colon. Here we present an extremely rare case of a leiomyosarcoma of the uterus with metastasis to the colon.Figure: P1: Colonoscopy image of the tumor.Figure: P2: Colon mass pathology shows Spindle Cells (elongated narrow cells) indicative of Sarcoma.Case: 48 year old female with uterine leiomyosarcoma with metastasis presented with acute blood loss anemia, small bowel obstruction and intussusception. Colonoscopy showed a 20mm ascending colon mass with pathology consistent with high grade sarcoma consistent with metastatic leiomyosarcoma (P1,P2). CT scan showed hypodensity in the right quadriceps muscle of 1.2 x 1 cm and intraluminal metastatic lesions causing intermittent intussusception and dilated small bowel loops. Three metastatic lesions in the lung were also identified (P3). Immunohistological staining showed that the colon mass was strongly positive for C-kit, DOG1 and negative for CD34. Karetin stains (MN116, AE1.3 and high molecular weight Keratin) did not stain the tumor. Key sarcoma markers such as Desmin, Actin and smooth muscle were negative. Metastatic tumors on occasion can be dedifferentiated and fail to express expected markers; therefore, pathologist believed that given recent diagnosis this colon tumor must be metastasis from the uterine leiomyosarcoma. Patient was offered palliative chemotherapy and surgical treatment and was lost to follow up post discharge.Figure: P3: Chest X-Ray with metastatic lesions identified.Conclusion: Melenoma is the most comon tumor that metastesizes to the colon. Metastasis to small bowel and colon from uterine leiomyosarcoma is extremely rare and is a sign of advanced disease. The more common sites for metastasis are lung, liver, abdomen, pelvic/aortic lymph nodes. Bone and brain are less common. It is important to differentiate between primary tumors of the colon versus metastatic and immunohistochemistry can be utilized to differentiate between the two. Metastasis to the heart is also possible via direct extension, hematogenous spread, and implantation or via lymphatic route.