Onkológia 5/2012

Renal angiomyolipoma – a description of 11 cases and histopathological aspects of disease

Angiomyolipoma (AML) is a rare and usually benign mesenchymal tumor histologically composed of adipose tissue, smooth muscle cells and abnormal blood vessels. It occurs most commonly in the kidney, less frequently in another anatomical locations. In submitted work we retrospectivelly assessed the prevalence of renal AMLs in the set of patients with renal neoplasms and evaluated the basic clinico-pathological parameters of disease. The whole study group consisted of 223 primary kidney tumors, which had been histologically diagnosed between January 2009 − June 2012. In this 3.5- year period, we found 12 cases (5.3 %) of renal AML from 12 subjects (10 women, 2 men) in the age range from 35 to 65 years (average 48.1 years). Right (n = 5) and left (n = 6) kidney was affected almost equally and one man suffered from bilateral involvement. The size of lesions varied between 0.5 − 10 cm (average size 4.7 cm). Except two patients with multifocal angiomyolipoma manifestation, all the others were solitary. There were two cases of coincidence of AML with another tumor types in the same kidney. Microscopically, we found all basic structural components of AMLs in almost all lesions, however, their proportion differed significantly. Half of the cases corresponded to monophasic AML s with a marked predominance of only one histological component. Immunohistochemically, all cases were at least focally positive for Melan-A and HMB-45 and smooth muscle component was diffusely positive for actin. In comparision with literature data, we revealed somewhat higher prevalence of renal AML. From the view of the biopsy practice there is important, the histomorphological components variations in the individual lesions, as well as the occurrence of some rare AML variants may mimic other tumor. Thus, it may cause a differential diagnosis more difficult. Because of a relatively common multifocality of AML, as well as coincidence with another neoplasms within the same kidney, it is necessary to process a biopsy material preciselly and to investigate microscopically all suspicious pathological foci.

Keywords: angiomyolipoma, PEC-omas.