# Cutaneous Angiomyolipoma of the Forearm

## TL;DR

A rare case of cutaneous angiomyolipoma on the forearm is reported, emphasizing the importance of histopathology for accurate diagnosis.

## Contribution

This paper presents a rare case of cutaneous AML in the forearm, highlighting its distinct histopathological and immunohistochemical features.

## Key findings

- The tumour consisted of mature adipose tissue, thick-walled blood vessels, and smooth muscle cells.
- Immunohistochemistry was negative for HMB-45, distinguishing it from renal AML.
- Cutaneous AML is non-invasive and can be surgically removed without recurrence.

## Abstract

Angiomyolipoma (AML) is defined as a benign tumour that is commonly identified in the kidneys, and most cases are associated with tuberous sclerosis. Although extrarenal AML cases have been reported, the association with the liver remains the most prevalent. We hereby report a rare case of cutaneous AML on the forearm of a 62-year-old gentleman, enduring for 10 years. Histopathology of AML revealed a combination of mature adipose tissue, thick-walled blood vessels, and smooth muscle cells, which distinguishes AML from other tissue tumours, such as lipoma, angiolipoma, hemangioma, and other mixed mesenchymal neoplasms. Immunochemistry was negative for human melanoma black-45 (HMB-45), emphasising the diagnosis of cutaneous AML and excluding it from renal and extrarenal AML. Cutaneous AML is a well-circumscribed, solitary, and non-invasive tumour that can be completely removed via surgery without recurrence. We want to highlight the importance of histopathology and immunohistochemistry evaluation in identifying cutaneous AML. We report a case of a 62-year-old gentleman who presented with a painless and gradually enlarging single subcutaneous swelling on his left forearm for a duration of 10 years.