Multimodality imaging findings of leiomyomatosis peritonealis disseminata

Leiomyomatosis peritonealis disseminata (LPD) is a rare disorder of subperitoneal proliferation of benign, leiomyoma-like smooth muscle tumors occurring predominantly in females of reproductive age1-3. Approximately 100 cases of LPD have been described in the literature, with only a handful of case reports dedicated to the imaging findings and one report describing the appearance of the disorder on magnetic resonance imaging (MRI)4-6. We describe a case of LPD, provide a brief review of clinical and pathological features, and correlate computed tomography (CT), MRI, and ultrasound findings in an attempt to clarify when this unusual condition should be a diagnostic consideration. The etiology of LPD is unknown, but a hormonal imbalance has been postulated1. The majority of cases occur in young women, with exceptional cases reported in postmenopausal women and in men2, 3. Genetic causes have also been suggested7. Our patient was a 31-year- old African-American woman, gravida 1 para 1, without significant medical history, who underwent imaging evaluation for complaints of right lower quadrant abdominal pain. LPD is most commonly asymptomatic, manifesting with vague abdominal or pelvic complaints. Urinary frequency, gastrointestinal bleeding, ovarian torsion and peritonitis have been reported5. Findings on physical examination are often non-specific. The imaging features of LPD entail a broad differential diagnosis, including, most ominously, peritoneal carcinomatosis4-6. Other primary neoplasms of the peritoneum and such entities as liposarcoma, lymphoproliferative disorders and disseminated endometriosis must also be considered8-10. Previously reported CT and ultrasound findings have demonstrated non-specific solid or complex soft tissue masses. Most commonly, these have shown enhancement characteristics similar to those of normal uterine parenchyma4-6. Typically, no associated ascites, omental caking or solid organ involvement is seen, in contrast to peritoneal carcinomatosis4-6. Our ultrasound and CT (Figure 1) examinations showed similar findings, prompting an MRI examination prior to surgical exploration. On MRI, the masses of LPD are mildly heterogeneous and parallel the signal intensity of skeletal muscle or uterine parenchyma on all sequences, with variable degrees of enhancement5. Our findings were similar, showing multiple lesions in the pelvic cavity (Figures 2 and 3). Contrast-enhanced axial multidetector computed tomography image of the abdomen and pelvis in a case of leiomyomatosis peritonealis disseminata showing multiple, hyper-enhancing masses in the pelvis (white arrows). These masses share enhancement characteristics with uterine leiomyomata (black arrow). T2-weighted fast spin-echo magnetic resonance image of the pelvis in sagittal view in a case of leiomyomatosis peritonealis disseminata showing innumerable hypointense masses throughout the peritoneal/pelvic cavities. The largest masses are delineated by the arrows. The masses are isointense to uterine fibroids (arrowheads). T2-weighted fast spin-echo magnetic resonance image of the pelvis in coronal view in a case of leiomyomatosis peritonealis disseminata, showing multiple hypointense masses (white arrows point to the largest masses) which are isointense to skeletal muscle (black arrows). There is a mass effect on the superior aspect of the urinary bladder due to the largest tumor (arrowhead). Biopsy from our patient showed the characteristic histological features of LPD. Gross specimens consist of irregular, yellow-tan lobulated fatty tissue, analogous to uterine leiomyoma. Microscopic features include spindle cells with a high degree of cellularity and little or no mitotic activity1, 3. The mainstay of treatment for LPD is decreasing hormonal stimulation, implying cessation of oral contraceptives or hormone replacement and avoidance of pregnancy1-5. If conservative therapy is ineffective, surgical debulking or castration via bilateral oophorectomy are considerations2, 4, 5. Regression of tumors has been shown with the use of gonadotropin-releasing hormone agonists10. Regular follow-up is recommended, as recurrence and malignant transformation have been documented2, 3, 5. Our patient opted for a conservative approach. In summary, an understanding of LPD is important for physicians involved in the interpretation of gynecological imaging. The patterns of imaging findings described above coupled with appropriate clinical attributes may be able to suggest the diagnosis prior to tissue sampling. It is necessary for more patients with LPD to be evaluated in order to establish that a definitive diagnosis by imaging is possible, but MRI is a promising modality in this regard. D. A. Covarrubias*, P. Nardi*, A. Duncan , * Department of Radiology, Long Island College Hospital, New York, USA, Department of Surgery, Long Island College Hospital, New York, USA