Rare case report of an aggressive follicular lymphoid hyperplasia in maxilla.

Follicular lymphoid hyperplasia is a very rare though benign reactive process of an unknown pathogenesis that may resemble a follicular lymphoma, clinically and histologically. Oral reactive follicular hyperplasia (RFH) has been described on the hard or soft palate and at the base of the tongue. We describe here the first case of RFH presenting as an aggressive tumor on the right posterior side of the maxilla in a 24-year-old male patient. The lesion had a clinical evolution of 18 months and was noticed after the surgical extraction of the right third molar, although we cannot assume a cause-effect relation with that surgical event whatsoever. His medical history was unremarkable. Following an incisional biopsy, histological examination revealed lymphoid follicles comprised by germinal centers surrounded by well-defined mantle zones. The germinal centers were positive for Bcl-6, CD10, CD20, CD21, CD23, CD79a, and Ki-67, while negative for Bcl-2, CD2, CD3, CD5, and CD138. The mantle and interfollicular zones were positive for Bcl-2, CD2, CD3, CD5, CD20, and CD138. Both areas were diffusively positive for kappa and lambda, showing polyclonality. The patient underwent a vigorous curettage of the lesion with no reoccurrences at 36 months of follow-up. This case report demonstrates that morphologic and immunohistochemical analyses are crucial to differentiate RFH from follicular lymphoma, leading to proper management.