Sinus histiocytosis with massive lymphadenopathy.

Sinus histiocytosis with massive lymphadenopathy (SHML) is a newly recognized, distinct, pseudolymphomatous benign entity with very characteristic microscopic features. Most patients are children or young adults with massive painless cervical adenopathy, although other node groups and extranodal sites often are involved. Sixteen patients with SHML involving the upper respiratory tract and/ or salivary gland are presented. Nine of the patients had ear, nose, and throat (ENT) manifestations at the time of presentation. In most cases the ENT involvement resulted in prominent clinical symptoms. Treatment included surgery, antibiotics, irradiation, chemotherapy, and steroids, frequently in combination, but no consistent pattern of response emerged from the study. These 16 patients were very similar clinically to patients with SHML who did not have ENT disease, indicating that extranodal involvement is not associated with more aggressive disease.