Disseminated Peritoneal Leiomyomatosis Clinically and Radiologically Mimicking Malignancy

A 35-year-old woman presented with complaints of abdominal distention, nausea, and loss of appetite of 1-month duration. She gave history of hysterectomy 3 years prior for leiomyoma. A sonographic examination of the abdomen showed multiple intra-abdominal solid nodules. Guided biosy was nondiagnostic. With a clinical and radiological impression of disseminated peritoneal malignancy the patient was taken up for surgery. Preoperatively, there were multiple nodular deposits all over bowel surface, omentum, peritoneum, and filling the pelvis. An intraoperative frozen section study was done, which showed interlacing fascicles of benign spindle cells. A provisional diagnosis of leiomyomata was given and the masses were resected. The specimen we received consisted of omentum studded with firm nodules, ranging in size from 1 to 10 cm (Figure 1). The cut sections of all were gray-white and whorled. There were no areas of hemorrhage, necrosis, or cystic degeneration. Histopathology showed interlacing fascicles of benign spindle cells with moderate eosinophilic cytoplasm and cigar-shaped nucleus. Mitotic activity was sparse. No necrosis was noted (Figure 2). The spindle cells were positive for smooth muscle actin, estrogen receptor, and progesterone receptor, and were negative for C-kit immunohistochemical stains. A diagnosis of disseminated peritoneal leiomyomatosis (DPL) was made. Disseminated peritoneal leiomyomatosis is a rare entity, first described by Wilson and Peale in 1952. DPL is characterized by multiple smooth muscle, myofibroblastic and fibroblastic nodules in the intraperitoneal cavity giving the clinical impression of a widespread malignant tumor. It usually occurs in premenopausal women. The pathogenesis of DPL is still uncertain. Several theories have been proposed, all of which point toward hyperestrogenic status as a strong causal factor. DPL has been associated with pregnancy, uterine leiomyoma, prolonged oral contraceptive use, and so on. Reduction of estrogen exposure is generally sufficient to cause regression of DPL. Another view is that DPL is the result of metaplastic transformation of submesothelial mesenchymal cells into smooth muscle cells. The submesothelial location and the fact that DPL is associated with other metaplastic lesions such as endometriosis, endosalpingosis, and so on, support this view. Surgical resection is not potentially curative but can be used to treat symptomatic lesions. Gonadotropin releasing hormone agonists can be used in case of progression or 507600 IJSXXX10.1177/1066896913507600International Journal of Surgical PathologyRaveendran Nair et al research-article2013