ORAL PSEUDOLYMPHOMA: A DIAGNOSTIC CHALLENGE

Pseudolymphoma (PL) is a benign reactive lymphoproliferative disease secondary to known or unknown stimuli mimicking a lymphomatous-appearing picture with potential misdiagnosis of overt lymphoma. A 64-year-old white man was referred for evaluation of ulceration on the left side of the buccal mucosa with 1 week of duration. The medical history revealed Alzheimer disease treated with donepezil and vildagliptin. Regional lymphadenopathy was absent and computerized tomography (CT) scans did not show alterations. An incisional biopsy was performed and microscopic analysis showed foci of angiocentric and perivascular lymphoid infiltrate containing atypical cells surrounded by fibrous stroma. Immunohistochemical analysis revealed positivity for CD3, CD4, CD25, and FOXP3. There was weak positivity for CD10 and BCL2. Almost all atypical cells were Ki-67 positive. Epstein-Barr virus-encoded RNA 1 and 2 (EBER1, EBER2) was negative. Complete blood counts and serology for herpes simplex virus 1 and 2 (HSV1, HSV2), cytomegalovirus (CMV), and Epstein-Barr virus (EBV) were noncontributory. Four weeks after biopsy, the lesion disappeared, without treatment or modification or discontinuation of medications. A diagnosis of idiopathic PL was made.