Clinicopathological and immunophenotypic characterization of extranodal idiopathic lymphoid hyperplasia/follicular lymphoid hyperplasia of the oral cavity: a multicenter case series.

OBJECTIVES

To describe the clinicopathological and immunophenotypic features of extranodal idiopathic lymphoid hyperplasia/follicular lymphoid hyperplasia (ILH/FLH) of the oral cavity.

STUDY

DESIGN

A case series conducted across nine Brazilian oral and maxillofacial pathology centers. Cases were morphologically evaluated using hematoxylin and eosin staining and a panel of immunohistochemical markers. Data were analyzed descriptively.

RESULTS

Of the 97 cases initially screened, 15 fulfilled the diagnostic criteria. Most patients were female (73.3%), aged between 32 and 88 years. The palate was the most frequently affected site (40%). Lesions had a mean size of 15.7 mm and a mean duration of 12.9 months, typically presenting as painless nodules (73.3%) with a smooth surface (53.3%). Histopathological examination revealed dense lymphoid infiltrates with follicular architecture and well-developed germinal centers. Immunohistochemically, CD20 was positive in germinal centers, CD3 in interfollicular zones, Bcl-2 was negative in germinal centers, and Ki-67 exhibited focal positivity.

CONCLUSION

Extranodal ILH/FLH of the oral cavity is a benign, indolent lymphoproliferative disorder that predominantly affects women beyond the third decade of life. CD20 and Bcl-2 are key markers for accurate differential diagnosis and microscopic confirmation.