Abstract

Acroangiodermatitis, also known as pseudo-Kaposi sarcoma, represents an infrequent benign angioproliferative condition often associated with chronic venous insufficiency or vascular anomalies. The presence of symplastic changes, while thought to stem from degenerative atypia, can imitate symplastic hemangioma, angiosarcoma, and other malignant sarcomas.

In this report, we present the case of a 76-year-old female with a notable medical history including multiple instances of deep vein thrombosis in the lower extremities and significant bilateral lower extremity lymphedema. The patient presented with a 3.0 cm pretibial lesion on her right lower extremity, exhibiting scabbing. A biopsy of the lesion revealed an ulcerated and partially necrotic lesion consisting of a lobulated vascular proliferation. Large, stellate, spindle-to-epithelioid cells were scattered amidst the vessels, displaying bizarre atypia. These cells contain amphophilic cytoplasm and one to multiple nuclei with variable nuclear irregularities. The chromatin pattern ranges from open to "smudgy", some with prominent nucleoli. Occasional cells contain multiple intracytoplasmic vacuoles resembling lipoblasts. Hemosiderin pigment is noted in aggregates of macrophages as well as in some of the atypical cells. No mitotic activity is identified in the atypical cells. The blood vessels remain well-delineated without endothelial cell atypia. Some vessels demonstrate fibrinoid change and hyalinization. Classic stasis changes are seen towards the periphery of the specimen. Immunohistochemical analysis demonstrated that the atypical cells were positive for CD10 while being negative for CD34, CD163, ERG, HHV8, p63, S100, ALK1, SMA, and Desmin. CD34 and ERG staining exclusively highlighted the blood vessels, corroborating the absence of atypical vascular proliferation.