EXTRANODAL ROSAI-DORFMAN DISEASE AFFECTING THE MAXILLA AND MAXILLARY SINUS: A CASE REPORT AND LITERATURE REVIEW

Introduction Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy, is a benign, self-limiting non-Langerhans cell histiocytosis of unknown etiology. It commonly affects younger individuals in their first 2 decades of life, showing no significant gender or racial predilection. RDD traditionally presents with bilateral, painless cervical lymphadenopathy with constitutional symptoms. Examples of extranodal RDD have been described in literature, whereby the nasal cavity and paranasal sinuses are common locations, being the site of involvement in 11% of cases. Case Report This report highlights a case of extranodal RDD presenting as a progressively enlarging left maxillary intrabony mass in a previously healthy 10-year-old female patient. Radiographic examination revealed a mixed radiolucent-radiopaque lesion with poorly defined margins affecting the left maxilla, extending superiorly to involve the ipsilateral maxillary sinus. Histologic evaluation showed a diffuse infiltrate consisting predominantly of plasma cells with interspersed large cells showing a clear cytoplasm and a vesicular nuclear chromatin pattern. No active emperipolesis was seen within these large cell clear cells. CD3 and CD20 immunohistochemical stains highlighted the presence of scattered reactive T- and B-cells respectively. CD138 confirmed the presence of numerous background plasma cells, which ultimately stained positive for IgG4. The large clear cells stained positive for S100 and CD68 but were negative for CD1a. Conclusions Because of its rarity, wide phenotypic expression, and uncertain etiology, the treatment of RDD is not standardized. Extranodal RDD affecting the craniofacial complex tends to have an indolent behavior and is often self-limiting.