CONTEXT: Melanoma markers, especially the new microphthalmia transcription factor (mitf), have not been previously compared in hepatic and renal angiomyolipomas. OBJECTIVES: To evaluate expression of the novel melanocytic markers mitf and tyrosinase in angiomyolipomas, and to compare these markers with the established markers HMB-45 and melan-A in both hepatic and renal tumors. DESIGN: Clinical, histopathologic, and immunohistochemical features of 15 hepatic angiomyolipomas were compared with those of 10 renal angiomyolipomas. RESULTS: No significant differences between patients with hepatic angiomyolipomas and renal angiomyolipomas were found with respect to age, gender, race, and tumor size. Hepatic angiomyolipomas exhibited a predominance of the epithelioid smooth muscle cell component, in contrast to their renal counterparts, which were predominantly spindled. The smooth muscle cells expressed HMB-45 in 100% of cases in both groups, melan-A in 14 of 15 hepatic angiomyolipomas and 8 of 9 renal angiomyolipomas, mitf in 5 of 12 hepatic angiomyolipomas versus 6 of 10 renal angiomyolipomas, and tyrosinase in 3 of 12 and 2 of 10 hepatic angiomyolipomas and renal angiomyolipomas, respectively. The extent and intensity of immunostaining with HMB-45 and melan-A were dependent on whether spindled or epithelioid cells predominated; the epithelioid cells showed stronger and more widespread reactivity than the spindled cells. CONCLUSION: We believe that the best immunohistochemical marker for confirming the diagnosis of angiomyolipoma is HMB-45, followed by melan-A. Routine use of mitf and/or tyrosinase is not indicated.
CONTEXT: Melanoma markers, especially the new microphthalmia transcription factor (mitf), have not been previously compared in hepatic and renal angiomyolipomas. OBJECTIVES: To evaluate expression of the novel melanocytic markers mitf and tyrosinase in angiomyolipomas, and to compare these markers with the established markers HMB-45 and melan-A in both hepatic and renal tumors. DESIGN: Clinical, histopathologic, and immunohistochemical features of 15 hepatic angiomyolipomas were compared with those of 10 renal angiomyolipomas. RESULTS: No significant differences between patients with hepatic angiomyolipomas and renal angiomyolipomas were found with respect to age, gender, race, and tumor size. Hepatic angiomyolipomas exhibited a predominance of the epithelioid smooth muscle cell component, in contrast to their renal counterparts, which were predominantly spindled. The smooth muscle cells expressed HMB-45 in 100% of cases in both groups, melan-A in 14 of 15 hepatic angiomyolipomas and 8 of 9 renal angiomyolipomas, mitf in 5 of 12 hepatic angiomyolipomas versus 6 of 10 renal angiomyolipomas, and tyrosinase in 3 of 12 and 2 of 10 hepatic angiomyolipomas and renal angiomyolipomas, respectively. The extent and intensity of immunostaining with HMB-45 and melan-A were dependent on whether spindled or epithelioid cells predominated; the epithelioid cells showed stronger and more widespread reactivity than the spindled cells. CONCLUSION: We believe that the best immunohistochemical marker for confirming the diagnosis of angiomyolipoma is HMB-45, followed by melan-A. Routine use of mitf and/or tyrosinase is not indicated.
Authors: Ruifeng Guo; Maria Franco-Palacios; Madison Russell; Lindsey Goddard; Lewis Hassell; Elizabeth Gillies; Kar-Ming Fung Journal: Int J Clin Exp Pathol Date: 2013-07-15
Authors: Pier Selenica; Niamh Conlon; Carlene Gonzalez; Denise Frosina; Achim A Jungbluth; Regina G H Beets-Tan; Mamta K Rao; Yanming Zhang; Ryma Benayed; Marc Ladanyi; David B Solit; Sarah Chiang; David M Hyman; Martee L Hensley; Robert A Soslow; Britta Weigelt; Rajmohan Murali Journal: Am J Surg Pathol Date: 2021-01 Impact factor: 6.394