Fine‐needle aspiration cytology of angiolymphoid hyperplasia with eosinophilia: A case report with electron microscopy and immunohistochemistry

Abstract
Angiolymphoid hyperplasia with eosinophilia (ALHE) is an uncommon vascular inflammatory lesion usually involving the dermis or subcutaneous tissue of the head-neck region of middle-aged women. Histologically, this lesion shows a florid proliferation of vessels lined by particular endothelial cells and an inflammatory infiltrate composed of lymphocytes and eosinophils. The fine-needle aspiration (FNA) cytology of a nodular lesion in the retroauricolar region of a 18-yr-old woman showed spindle-shaped and polygonal cells with vesicular nuclet and deeply eosinophilic cytoplasm containing welldefined vacuoles in a background of eosinophils and lymphocytes. These features were consistent with a proliferation of epithelioid endothelial cells, and a diagnosis of ALHE was suggested. The histology confirmed the preoperatory diagnosis, and ultrastructural and immunohistochemical studies further demonstrated the endothelial nature of epithelialappearing cells. Because the clinical appearance of the lesion may mimic a large number of benign and malignant diseases, a preoperatory diagnosis of ALHE is rarely made. The FNA cytology may represent a simple and reliable method with which to study and diagnose proliferations of epithelioid endothelial cells.