Reactive nodular fibrous pseudotumor involving the pelvic and abdominal cavity: a case report and review of literature.

There are several entities that can present with multiple nodular lesions within the peritoneal cavity, such as "disseminated peritoneal leiomyomatosis," "peritoneal fibrosis," "calcifying fibrous pseudotumor," and the recently described lesion of "reactive nodular fibrous pseudotumor of the gastrointestinal tract and mesentery." Here we present one such lesion in a 28-year-old woman with a history of dysmenorrhea and ergotamine use for migraine attacks. Intraoperative exploration of our patient disclosed numerous nodules located throughout the pelvic and abdominal peritoneum. Histopathologically, these lesions were fibrocollagenous nodules composed of sparse wavy spindle cells within hyalinized "keloid-like" collagen surrounded by an inflammatory infiltrate. Some of the nodules were associated with small foci of endometriosis. We believe this lesion is best described by the term "reactive nodular fibrous pseudotumor" and that endometriosis and the use of ergotamine derivatives may be contributing factors.