Clinicopathological Features and Epidermal Growth Factor Receptor Gene Status of Adrenocortical Oncocytic Carcinoma

  Objective  To explore the clinicopathological features of adrenocortical oncocytic carcinoma and protein expression, gene mutation, and gene copy number alteration of epidermal growth factor receptor (EGFR) in this carcinoma.

  Methods  We reviewed the clinical and histomorphological features of 9 adrenocortical oncocytic carcinoma cases who received surgical resection in the period of January 2000 to December 2009 in Peking Union Medical College Hospital, and 9 adenoma cases were included as control. EGFR protein expression, EGFR gene mutation and EGFR gene copy number alteration in both groups were detected by immunohistochemistry, Scorpion Amplification Refractory Mutation System (ARMS), and fluorescence in situ hybridization (FISH), respectively.

  Results  The 9 cases of adrenocortical oncocytic carcinomas included 2 cases of Cushing's syndrome and 7 cases of nonfunctional cortical carcinoma. All cases were followed up for 6 to 56 months, and 2 patients with adrenocortical oncocytic carcinomas lost to follow-up, and 6 died. In the adrenocortical oncocytic carcinoma patients, EGFR overexpression was found in 77.8% (7/9), and EGFR FISH was positive in 55.6% (5/9). In contrast, only 22.2% (2/9) of the adrenocortical adenoma patients showed EGFR weak expression and none had positive FISH result. No EGFR gene amplification or mutation was found in the 2 groups of patients.

  Conclusions  Adrenocortical oncocytic carcinoma is rare. EGFR overexpression and chromosome 7 polysomy are frequent abnormality in the adrenocortical oncocytic carcinomas, which may be used in the differential diagnosis. Also, an investigation of the gene status of EGFR should facilitate the identification of a target therapeutic regimen for carcinoma patients.