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

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 nuclei and deeply eosinophilic cytoplasm containing well-defined 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 epithelial-appearing 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.