Mesenteric Fibromyoma Mimicking a Colon Tumor: A Diagnostic Dilemma

Abstract

Introduction: Solid primary tumors of mesenteric origin are quite rare among the intraabdominal soft tissue tumors. The most frequent tumors are Gastrointestinal Stromal Tumors (GIST) and smooth muscle tumors. GISTs as the largest group of these tumors are usually seen in the wall of gastrointestinal tract and 25% of them are malignant. They usually occur in adults and there is no sexual predominance. We present a huge intra-abdominal myoma clinically mimicking GIST. Case Report: A 49-years old male was referred to our deparment because of a growing mass and pain in the right lower quadrant. Physical examination revealed a huge mass with 10 cm in diameter in the right lower quadrant. Computed tomography (CT) revealed a mass with 17 cm in diameter which originated from caecum and extented from umblicus to urinary bladder and right colon. The mass was resected en-bloc with right hemicolectomy. The final diagnosis is ''Fibromyoma of the mesentery''. Discussion: They usually arise de novo and are seen in adults. Myofibroma can occur as a solitary form or it can be seen as multiple lesions like generalized form which is described as myofibromatozis. Myofibromas are characteristically circumscribed masses with a nodular or multinodular growth pattern and they usually show a biphasic growth pattern. The behaviour of mesenteric smooth muscle tumours is unpredictable. Because they arise large diameters and they can cause different clinical symptoms like obstruction and abdominal pain. The treatment of mesenteric fibromyoma is complete resection. Large intraabdominal solid masses pose a diagnostic challenge either grossly or microscopically. Histopathologically, huge benign fibromyomas should be kept in mind of differantial diagnosis of GİSTs.