[1100] Uterine Leiomyosarcoma with an Adipocytic Differentiation (Lipoleiomyosarcoma): A Clinicopathologic Study of Seven Cases.

Yoshiki Mikami, Marisa R Nucci, Yoshiaki Yuba, Sachiko Minamiguchi, Shinji Sawada, Yoshiko Uemura. Kyoto University Hospital, Japan; Brigham and Women's Hospital, Boston, MA; Kitano Hospital, Osaka, Japan; Kyoto Medical Center, Japan; Nagahama City Hospital, Shiga, Japan; Kansai Medical School, Hirakata Hospital, Osaka, Japan

Background: Uterine leiomyosarcoma may rarely have heterologous differentiation, resulting in the presence of components of rhabdomyosarcoma, osteosarcoma, or liposarcoma. Those with adipocytic differentiation have been described in single case reports under a variety of names including lipoleiomyosarcoma, and thus morphologic diversity and clinicopathologic features remain undetermined.
Design: Seven cases of uterine leiomyosarcoma with adipocytic components (“lipoleiomyosarcoma”) were reviewed to determine clinicopathologic features and morphologic characteristics.
Results: The patient age ranged from 41 to 63 years (mean; 50.3, median: 44). All cases had features of ordinary leiomyosarcoma, but five also showed epithelioid features and/or myxoid changes. Three cases showed a mixture of spindle cells and mature adipocytes with bland nuclear morphology, and thus in areas resembled lipoleiomyoma or spindle cell lipoma. In addition, two cases harbored components resembling pleomorphic lipoma, one of which was associated with lipolieomyoma-like component. Adipocytic component was well-differentiated and/or cytologically pleomorphic, and in two cases showed myxoid changes. In these two cases mature adipocyte-like or epithelioid cells with multiple intracytoplasmic vacuoles were embedded in the myxoid matrix. Features of prototypical myxoid/round cell liposarcoma were not identified. Immunohistochemically the tumors in all four cases were positive for alpha-smooth muscle actin, h-caldesmon, and/or desmin. CD34 and S-100 protein were negative in leiomyosarcomatous component but CD34 were positive in areas of adipocytic component in three tumors, and S-100 protein in two. Adipocytic component was confirmed to be positive for CDK4 and MDM2 in four and two tumors, respectively. All four patients with follow-up information had recurrent disease within 2 years (interval; 2-16 months).
Conclusions: Adipocytic differentiation in leiomyosarcoma is frequently associated with myxoid and epithelioid features, and may harbor lipoleiomyoma- and/or bizarre leiomyoma-like component, resulting in diagnostic difficulty, particularly with limited sampling.
Category: Gynecologic & Obstetrics

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 183, Wednesday Afternoon


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