Cutaneous epithelioid angiomatous nodule: a distinct lesion in the morphologic spectrum of epithelioid vascular tumors.

Cutaneous epithelioid vascular proliferations comprise a morphologic spectrum ranging from benign, reactive to frankly malignant conditions. We present a group of morphologically distinct epithelioid vascular lesions in the skin that defy classification according to current criteria. Clinically, the lesions presented as single (14/15) or multiple (1/15) small (< 1.5 cm, median = 0.5 cm) erythematous to bluish nodules or papules of short duration (weeks to months) without gender predilection (M:F = 1:1). Age distribution ranged from 15 to 79 years (median: 37). Lesions were predominantly located on the trunk (8/15) but also involved the extremities (5/15), face (1/15), and nasal mucosa (1/15). No patient was immunocompromised. Treatment was simple surgical excision. Histologically, the lesions were located superficially in dermis (or submucosa) and consisted of a circumscribed, unilobular, mainly solid proliferation of large polygonal epithelioid endothelial cells with vesicular nuclei and conspicuous nucleoli. Cytoplasm was abundant and contained frequent intracytoplasmic vacuoles. Nuclear atypia was absent. Mitotic figures (up to 5/10HPF) were observed in 8 lesions. Formation of endothelial-lined channels was a focal but constant feature. Also noted were adjacent dilated dermal vessels (8/15), hemosiderin deposition (6/15), and mild fibrosis (9/15). The lesion was accompanied by a chronic inflammatory infiltrate with a lymphoplasmacytic component (14/15), most pronounced at the periphery of the lesion, and varying numbers of eosinophils scattered throughout the lesion (12/15). Eosinophils were conspicuous in only 4 cases. Epidermal hyperplasia was present in 11 cases. By immunohistochemistry, lesional cells stained positively for at least one endothelial marker. Clinical follow-up (median = 30 months) showed no recurrence or metastases. Epithelioid angiomatous nodule is a benign, likely reactive cutaneous lesion in the clinical and morphologic spectrum of epithelioid vascular proliferations. It differs from conventional epithelioid hemangioma both in its clinical presentation with predominant involvement of trunk and extremities as well as its histologic features, which more closely resemble epithelioid angiosarcoma.