Follicular lymphoid hyperplasia of the palate: case report and literature review.

Follicular lymphoid hyperplasia (FLH) of the palate is a very rare benign, proliferative process, with only 20 cases published so far in the English language literature. We describe a case, in a 55-year-old Caucasian female, who developed a swelling in the left posterior hard palate. Bony involvement was absent. Importantly, the medical history was positive for a previous non-Hodgkin lymphoma. Following incisional biopsy, histological examination revealed a vaguely nodular lymphoid proliferation composed of small well-differentiated lymphocytes. The lymphoid follicles were positive for CD20, CD79a, CD10, CD21 and BCL6, while negative for BCL2. The parafollicular areas revealed positivity for CD3, CD5, CD30, and CD15. Both areas were CD45 positive. Subsequent immunoglobulin heavy chain gene rearrangement analysis revealed a polyclonal lesion. No further treatment was instituted, and the patient is currently being followed-up every three months. This report demonstrates that FLHs are especially important due to their clinical and, occasionally, microscopic resemblance to follicular lymphomas. Morphologic and immunohistochemical analyses and molecular studies are essential to achieve accurate diagnosis and to implement appropriate management.