A large desmoid fibromatosis of mesentery presenting as ovarian tumor - A rare case report

Desmoid fibromatosis is a rare tumor of locally aggressive nature and associated with a high risk of recurrence. Although it possesses benign morphologies such as the absence of necrosis and atypical mitoses, it is classified as an intermediate malignant neoplasm due to its potential of infiltrating into the adjacent structures and the high rate of local recurrence even after excision. A 22-year-old unmarried female came with the complaint of abdominal pain and lump. The preoperative diagnosis was in favor of ovarian leiomyosarcoma but to the surprise intraoperative, tumor was found to be arising from mesentery of ileum. Following the complete resection, tumor was sent for histopathology. The histopathology examination report along with immunohistochemistry was suggestive of desmoids fibromatosis. Mesenteric desmoids fibromatosis is a rare tumor. It should be differentiated from gastrointestinal stromal tumor, leiomyoma, leiomyosarcoma, neurofibroma, and solitary fibrous tumor because of its completely different management and outcome. Histopathology and immunohistochemistry is the key for its diagnosis.