Details

Autor(en) / Beteiligte

• Asch-Kendrick, Rebecca J., MD
• Shetty, Shashi, PhD
• Goldblum, John R., MD
• Sharma, Rajni, PhD
• Epstein, Jonathan I., MD
• Argani, Pedram, MD
• Cimino-Mathews, Ashley, MD

Titel

A Subset of Fat-Predominant Angiomyolipomas Label for MDM2: A Potential Diagnostic Pitfall

Ist Teil von

• Human pathology, 2016-11, Vol.57, p.7-12

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2016

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Summary Angiomyolipomas (AMLs) are typically benign mesenchymal tumors with variable histologic composition. Fat-predominant AMLs can mimic well-differentiated liposarcomas (WDLS) both radiographically and histologically due to the abundance of fat with admixed atypical cells resembling lipoblasts. However, the treatment and prognosis of AML and WDLS are vastly different. Immunohistochemistry for MDM2 has been used to support a diagnosis of WDLS, however MDM2 labeling has not been specifically evaluated in fat-predominant AMLs. Here, we evaluated MDM2 immunohistochemistry in 36 AML (including 14 conventional AML, 13 fat-predominant AML, 6 fat-rich AML, 3 epithelioid AML) and 10 WDLS. In addition, we labeled cases for HMB45, calponin or actin, which are immunostains traditionally used to label AML. We performed fluorescence in situ hybridization (FISH) for MDM2 amplification on selected cases. By immunohistochemistry, 14% (5/36) AML were MDM2 +, including 23% (3/13) fat-predominant AML. All MDM2+ AML evaluated by FISH (n = 4) were negative for MDM2 amplification. By immunohistochemistry, 90% WDLS were MDM2+, and both MDM2+ WDLS evaluated by FISH (n = 2) were MDM2 amplified. All 36 AML labeled with HMB45 and calponin or actin. No WDLS labeled with HMB45, however 80% WDLS labeled with calponin or actin. Although uncommon, MDM2 labeling is seen in a subset of fat-predominant AMLs and is a potential diagnostic pitfall in the evaluation of fatty tumors of the retroperitoneum. HMB45 is more sensitive and specific for AML than calponin or actin, and an immunopanel containing both HMB45 and MDM2 may be warranted to distinguish between fat-predominant AML and WDLS in histologically ambiguous cases.