Immune cell infiltration in gingival epithelioid angiomatous nodule: Case report and immunohistochemical analysis

Epithelioid angiomatous nodule (EAN) is a rare benign vascular proliferation, regarded as part of the morphologic spectrum of benign and malignant epithelioid vascular lesions. EAN is a rare lesion affecting the oral mucosa and, to date, only three cases have been reported in the English-language literature. We report the second EAN case affecting the gingival mucosa of a 69-year-old female patient. Oral examination revealed an asymptomatic, well-defined nodule exhibiting a smooth and erythematous surface, measuring 0.8 cm in greater diameter. The lesion was fully excised and histopathological study showed a mucosal epithelioid proliferation with solid and organoid growth patterns, and vascular lumens scattered focally throughout the lesion. The large epithelioid cells showed intracytoplasmic vacuoles and vesicular nuclei with prominent nucleoli, surrounding by scarce extravasated erythrocytes. Immunohistochemistry showed positivity for vimentin, α-SMA, CD34, focally for D2-40, and Ki-67 was 15%. Noteworthy, numerous immune cells (HLA-DR+/CD68+/CD163+/FXIIIa +) scattered throughout the lesion, were detected. To the best of our knowledge, this is the first report, which highlights the immune cell population, with M2-like phenotype, as an important component of EAN, suggesting the participation on their etiopathogenic mechanisms.