Extra-gastrointestinal stromal tumor presenting as a huge peritoneal mass and mimicking as mesothelioma - A case report.

Introduction And Importance: Extra-gastrointestinal stromal tumors are group of soft tissue neoplasm, which originates outside the gastrointestinal tract comprising of less than 5% of the total gastrointestinal stromal tumors.

Case Presentation: A 67 years old male came with a history of vague abdominal pain, discomfort and loss of appetite. Per abdominal examination showed a palpable firm mass which was filling both the flanks. Radiological imaging revealed a large abdomino-pelvic mass with central necrotic areas. Exploratory laparotomy was done and the mass was excised intact from the sigmoid mesocolon. Histopathological diagnosis was given as extra-gastrointestinal stromal tumors.

Clinical Discussion: Extra-gastrointestinal stromal tumor was first described by Miettinen et al. in 1999. The tumor can arise from the pleura, omentum, mesentery, retroperitoneum and prostate. The clinical presentation of the tumor depends on its location and the size of tumor. Patients with these tumors present with abdominal pain, followed by abdominal mass and distention. These tumors show pathological, immunohistochemical and molecular biological characters similar as that of gastrointestinal stromal tumor.

Conclusion: Extra-gastrointestinal stromal tumor is a rare tumor and can reach to a considerable large size before presenting with clinical symptoms especially if the tumor arises from the mesocolon. IHC study plays an important role to reach to the final diagnosis as the tumor can mimic mesothelioma in routine staining.