Castleman Disease with MDM2/CDK4 Protein Expression: a Potential Mimic of Inflammatory Variant of Liposarcoma with Significant Consequences

Abstract

Castleman disease is a rare benign lymphoproliferative disorder that includes a spectrum of distinct histopathological entities. The differential diagnosis of Castleman disease is broad and includes lymphomas, HIV-related lymphadenopathy, autoimmune disorders, and inflammatory liposarcoma. When Castleman disease occurs in the retroperitoneum, the distinction from the inflammatory variant of well-differentiated liposarcoma can be very challenging in small biopsies. Herein we report a case of Castleman disease that presented as a retroperitoneal mass and expressed MDM2 and CDK4 by immunohistochemistry. To our knowledge, this is the first report of Castleman disease staining positively for MDM2/CDK4, and it underscores how immunohistochemistry can potentially serve as a pitfall when differentiating this rare entity from retroperitoneal sarcomas.

Expression of MDM2 in Giant Follicular Dendritic Cell Sarcoma: A Potential Diagnostic Pitfall

“…Finally, Castleman’s disease and the inflammatory variant of well-differentiated liposarcoma are other entities to consider in the differential diagnosis, specially the former since reports with MDM2 positivity have been described. 7 Therefore, in this context, FISH technique should be carefully evaluated in conjunction with morphological and immunohistochemical features.…”