[582] Adrenocortical Carcinomas: An Immunohistochemical Analysis of 40 Cases

Annikka Weissferdt, Alexandria Phan, Saul Suster, Cesar A Moran. University of Texas Health Science Center at Houston, Houston, TX; MD Anderson Cancer Center, Houston, TX; Medical College of Wisconsin, Milwaukee, WI

Background: Adrenocortical carcinomas are uncommon tumors of the adrenal cortex that are known to pursue an aggressive clinical course with frequent recurrence and early metastasis. The distinction of these tumors from other, often metastatic neoplasms may sometimes prove difficult due to overlapping clinical, morphological and even immunophenotypical features. To this end, we performed a comprehensive immunohistochemical analysis using traditional and novel markers in 40 cases of adrenocortical carcinoma.
Design: Forty cases of resected adrenocortical carcinoma were reviewed and representative whole tissue sections were selected for immunohistochemical studies using antibodies directed against high molecular weight cytokeratin (HMWCK), low molecular weight cytokeratin (CAM5.2), inhibin-α, melan A, chromogranin A, synaptophysin, calretinin, steroid receptor coactivator-1 (SRC1), Pax8 and Ki67. The percentage of positive tumor cells as well as the intensity of staining were evaluated and scored; for Ki67 the percentage of positive tumor cells was recorded.
Results: Positive staining was observed for SRC1 (39/40; 97.5%), inhibin-α (37/40; 92.5%), calretinin (32/40; 80%), synaptophysin (29/40; 72.5%) and melan A (26/40; 65%). CAM5.2 was expressed in 9/40 tumors (22.5%). Rare cases showed positivity for chromogranin A (2/40; 5%) and Pax8 (1/40; 2.5%). None of the cases showed any reactivity with HMWCK. The Ki67 proliferative index ranged from <5 to 20%.
Conclusions: There are no specific markers to reliably distinguish adrenocortical carcinomas from other primary or metastatic neoplasms. However, a combination of immunohistochemical stains in a panel consisting of SRC1, inhibin-α, calretinin and HMWCK may be of aid in the differential diagnosis of these tumors. In addition, Pax8 is only rarely positive in adrenocortical carcinomas which is a useful tool in their separation from renal neoplasms.
Category: Endocrine

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 54, Wednesday Afternoon

 

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