Pictorial Urology

87Urology Journal    Vol 6    No 2    Spring 2009

Leiomyomatous Angiomyolipoma of Kidney 

A 24-year-old man was diagnosed with a mass in the left kidney on abdominal computed tomography  
(Figure A). Nephrectomy specimen showed a smooth-surfaced tumor, sized 9 × 6 × 6 cm, attached to 
the hilar area, which was homogenous, well-circumscribed, grayish white, and solid, compressing the renal  
parenchyma, but not invading it (Figure B). Microscopic examination showed spindle cells arranged in whorls,  
rich in blood vessels (Figure C). On immunohistochemistry, the tumor cells expressed smooth muscle  
actin, vimentin, desmin, and HMB-45 (Figure D). A diagnosis of leiomyomatous angiomyolipoma was made.

Leiomyomatous angiomyolipoma is a benign mesenchymal tumor which is typically composed of 
a mixture of vessels, smooth muscle, and fat. In addition, it contains clear or pale epithelioid cells, 
currently known as the perivascular epithelioid cells,(1) which show positivity for HMB-45 in addition 
to expected smooth muscle markers. On computed tomography, leiomyomatous angiomyolipoma 
shows a characteristic appearance because of abundant adipose tissue, the lack of which pose a problem. 
Microscopically, leiomyomatous angiomyolipomas with predominant spindle cells of smooth muscle 
type may look like leiomyomas, leiomyosarcoma, or gastrointestinal stromal tumors.(2) The presence of 
perivascular epithelioid cells in tumoral tissue, which shows reactivity to melanocytic markers such as 
HMB-45 in addition to smooth muscle markers, clinches the diagnosis.(1)

Kavita Munjal,1* Shyam Agrawal,2 Saroj Munjal1
1Department of Pathology, Sri Aurobindo Institute of Medical Sciences, Indore, India
2Department of Urology, Geeta Bhawan Trust Hospital, Manoramaganj, Indore, India

*E-mail: kavita_munjal@rediffmail.com

REFERENCES
1. Bonetti F, Pea M, Martignoni g, et al. The perivascular epitheloid cell and related lesions. Adv Anat Pathol. 1997;4:343-58.

2. Nonomura A, Minato H, Kurumaya H. Angiomyolipoma predominantly composed of smooth muscles cells: problems in 
histological diagnosis. Histopathology. 1998;33:20-7.

Urol J. 2009;6:87. 
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