CONTEXT: Renal angiomyolipoma is a tumor composed of varying amounts of fat, smooth muscle, and blood vessels. Characteristically, tumor cells express melanocytic markers such as HMB-45 and Melan-A. Recently, several other markers have been described as having excellent diagnostic sensitivity in cutaneous melanocytic lesions. OBJECTIVES: To compare the sensitivities of 5 melanocytic markers in renal angiomyolipoma and to study the expression patterns of these markers in the 3 different components of angiomyolipoma. DESIGN: A tissue microarray of 20 renal angiomyolipomas was constructed. For each case, 3 cores containing fat, blood vessels, and smooth muscle were taken. The tissue microarray was then stained for HMB-45, Melan-A, tyrosinase, NK1-C3, and CD117. RESULTS: HMB-45 was positive in 95%, Melan-A in 85%, NK1-C3 in 70%, tyrosinase in 50%, and CD117 in 40% of the cases. All (20/20) were positive for HMB-45 and Melan-A combined. These 5 markers had different sensitivities in the 3 components. HMB-45 was positive in 90%, 85%, and 80% of fat, smooth muscle, and blood vessel components, respectively; Melan-A in 70%, 60%, and 40%; NK1-C3 in 55%, 55%, and 45%; tyrosinase in 30%, 40%, and 10%; and CD117 in 20%, 40%, and 10%, respectively, of these 3 components. CONCLUSIONS: HMB-45 and Melan-A combined were positive in 100% of the renal angiomyolipomas. We recommend the use of these 2 markers in the workup of this entity, including those with predominantly 1 component. Other melanocytic markers are of limited use. A tissue block comprising predominantly fat or smooth muscle components should be used when performing melanocytic marker immunostain.
CONTEXT: Renal angiomyolipoma is a tumor composed of varying amounts of fat, smooth muscle, and blood vessels. Characteristically, tumor cells express melanocytic markers such as HMB-45 and Melan-A. Recently, several other markers have been described as having excellent diagnostic sensitivity in cutaneous melanocytic lesions. OBJECTIVES: To compare the sensitivities of 5 melanocytic markers in renal angiomyolipoma and to study the expression patterns of these markers in the 3 different components of angiomyolipoma. DESIGN: A tissue microarray of 20 renal angiomyolipomas was constructed. For each case, 3 cores containing fat, blood vessels, and smooth muscle were taken. The tissue microarray was then stained for HMB-45, Melan-A, tyrosinase, NK1-C3, and CD117. RESULTS:HMB-45 was positive in 95%, Melan-A in 85%, NK1-C3 in 70%, tyrosinase in 50%, and CD117 in 40% of the cases. All (20/20) were positive for HMB-45 and Melan-A combined. These 5 markers had different sensitivities in the 3 components. HMB-45 was positive in 90%, 85%, and 80% of fat, smooth muscle, and blood vessel components, respectively; Melan-A in 70%, 60%, and 40%; NK1-C3 in 55%, 55%, and 45%; tyrosinase in 30%, 40%, and 10%; and CD117 in 20%, 40%, and 10%, respectively, of these 3 components. CONCLUSIONS:HMB-45 and Melan-A combined were positive in 100% of the renal angiomyolipomas. We recommend the use of these 2 markers in the workup of this entity, including those with predominantly 1 component. Other melanocytic markers are of limited use. A tissue block comprising predominantly fat or smooth muscle components should be used when performing melanocytic marker immunostain.
Authors: J O R Hernandez; X Wang; M Vazquez-Segoviano; M Lopez-Marfil; M F Sobral-Reyes; A Moran-Horowich; M Sundberg; D O Lopez-Cantu; C K Probst; G U Ruiz-Esparza; K Giannikou; R Abdi; E P Henske; D J Kwiatkowski; M Sahin; D R Lemos Journal: Nat Commun Date: 2021-11-11 Impact factor: 17.694