HMB45 negative intramuscular angiomyolipoma : a case report and literature review

Abstract EN

Intramuscular angiomyolipoma (AML) is a rare, benign hamartomatous lesion, that typically occurs in the kidney.

Extrarenal AMLs are extremely rare and have been commonly described in the liver, spleen, and reproductive system.

We report a case of AML of the upper arm and a review of the literature on this condition.

The patient was a 34-year-old man who presented with a palpable mass that was in his left upper arm for 4 years.

Histopathologic evaluation demonstrated a hamartomatous lesion consisting of a mixture of thin and thick blood vessels, mature adipose tissue, and smooth muscle bundles in the triceps brachii muscle.

Immunohistochemically, tumor cells showed negative immunoreactivity for HMB45.

These findings were consistent with an extrarenal AML.

This was the second reported case of intramuscular AML arising in the extremities.

Pathologists should be aware of such an entity whenever they see extrarenal vascular hamartomas not associated with tuberous sclerosis and HMB45 positivity.