MYC Analysis by Fluorescent In Situ Hybridization and Immunohistochemistry in Primary Adrenal Angiosarcoma (PAA): a Series of Four Cases.

Primary adrenal angiosarcomas (PAA) are rare with 36 cases reported in the English literature. MYC protein expression and gene amplification have been detected in secondary angiosarcoma (AS), and a subset of primary AS. The aim of this study was to report the clinicopathologic features of PAA and examine these tumors for MYC amplification and protein expression in a small series of four cases (resection, n = 4). Three had available material for ancillary studies and were investigated for MYC gene abnormalities and protein expression using fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC), respectively. Tumors occurred in three females and one male with a mean age of 69 (53-75) years. The sizes ranged from 8.5 to 15 (mean 11.5) cm and were epithelioid in morphology. All tumors had prominent necrosis, and the mitotic count ranged from 4 to 41/10 high-power fields (HPFs) (mean 20/10 HPFs, ×400). Immunohistochemically, the tumor cells were positive for CD31 in 4/4 cases, CD34 in 1/4 cases, and cytokeratin in 4/4 cases. The mean follow-up period was 10.8 (3-19) months, of which three patients died of disease with distant metastases, and one patient was alive with disease. MYC nuclear staining was identified in the three cases tested. Two cases showed polysomy of chromosome 8 without MYC amplification or rearrangement. Two MYC-positive cases by IHC demonstrated copy number gain in chromosome 8, and one MYC-positive case was not associated with a chromosome 8/MYC gene abnormality. In the context of new targeted therapies, MYC positivity in PAA may be clinically valuable in treating patients with these aggressive neoplasms.