[Appendicular desmoid tumor: unusual case and review of the literature].

Background: Desmoid type fibromatosis is a benign neoplastic process non-encapsulated locally invasive and aggressive, which arises from a proliferation of bland-looking fibroblasts and myofibroblasts. The most frequent location of fibromatosis is extraabdominal (60%), abdominal wall (25%) and intra-abdominal (8-15%), rarely can originate in the viscera (0.73%), such as the pancreas, gastroesophageal junction, diaphragm and appendix. The annual incidence of desmoid tumor is estimated at 2 to 5 cases per million. In this article, we report a case of unusual presentation, originated in the cecal appendix.

Case: A 41-year-old female patient with acute pelvic pain, admitted to surgical ward with a clinical and ultrasound diagnosis of probably ovarian pedicle tumor. An explorative laparotomy revealed a solid mass of 15 cm in diameter arising from the cecal appendix, with the anatomopathological study corresponding to a desmoid tumor of the cecal appendix.

Conclusions: The desmoid tumor can arise from several extra and intra-abdominal locations, the latter being the rarest and most aggressive. Accurate preoperative diagnosis is very difficult and almost always patients enter to surgery with suspected diagnosis of intraabdominal tumor of unknown etiology. The risk factors associated to its appearance are not yet characterized. The complete surgical resection of the tumor -with free surgical margins (R0)- is the treatment of choice; however, the risk of recurrence is high even with optimal tumor removal.