Superficial angiomyxoma affecting the buccal mucosa: A detailed immunohistochemical study and literature review

Superficial angiomyxomas (SAs) are rare benign myxoid lesions, frequently affecting the skin of head and neck, trunk, and genital region, in male adults. To date, to the best of our knowledge, about 12 intraoral cases of SA have been reported. A 74-year-old man, without systemic alterations, was referred presenting a nodular lesion on the left buccal mucosa several months ago. Considering the clinical diagnosis of a benign mesenchymal neoplasm, an excisional biopsy was performed. By microscopy, a large proliferation of myxoid tissue, admixed with several small blood vessels, and permeated by numerous mast cells, were noticed. A detailed immunohistochemical analysis revealed positivity for vimentin, CD10, CD34, Bcl-2 (focal), and tryptase (mast cells). INI-1 and Rb expression was retained, while Ki-67 highlighted rare cells. The vascular structures were evidenced through α-SMA, calponin, and h-caldesmon. Pan-CK AE1/AE3, EMA, p63, p40, CD56, CD99, S100, NKI/C3, STAT6, and Glut-1, were negative. The final diagnosis was intraoral SA. After 2-year of follow-up, the patient is well, without recurrences.