Comparison of immunomarkers for the identification of adrenocortical cells in cytology specimens

Abstract

We studied the immunoreactivity of three antibodies--A103, calretinin, and inhibin alpha in destained Papanicolaou (Pap) smears and cell-blocks of 40 fine-needle aspiration biopsy cases of adrenocortical lesions (35 cases of hyperplasia/adenoma and 5 cases of carcinoma). Five cases of carcinoma (4) and melanoma (1) metastases to the adrenal gland and five cases of renal-cell carcinoma were also included for comparison. In benign adrenocortical lesions, A103 staining was noted in 82% of the destained Pap smears and in 92% of cell-blocks. In malignant adrenocortical lesions, A103 staining was noted in 50% of the destained Pap smears and in 80% of cell-blocks. In comparison, calretinin staining was noted in 6% and 50% of destained smears and in 78% and 60% of the cell-blocks of benign and malignant adrenocortical lesions. Inhibin alpha was not positive in any of the smears and showed the lowest level of positivity in the cell-block sections, namely in 11% of the benign lesions and 25% of the malignant lesions. The sensitivity of A103 was 90% on cell-blocks and 74% on smears, that of calretinin 75% on cell-blocks and 11% on smears, and that of inhibin alpha, 13% on cell-blocks alone. The specificity of A103 was lower than the other two makers, 90% vs. 100% because of positivity in metastatic melanoma in the adrenal gland. Our data show A103 to be the immunomarker with the highest sensitivity for identifying cells of adrenocortical origin in destained Pap's smears and cell-block sections with, however, a lower specificity when compared with calretinin and inhibin alpha. Calretinin is comparable in sensitivity with A103 on cell-block sections alone and not on smears. The results of this study suggest that if metastatic melanoma in adrenal gland is not a consideration then A103 is the marker of choice for identifying cells of adrenocortical origin in the limited material available for diagnostic purposes in cytology specimens.