Sinus histiocytosis with massive lymphadenopathy.

A 22-month-old child presented with massive cervical adenopathy accompanied by a retropharyngeal mass that caused stridor and dysphagia. Biopsy from both sides was consistent with sinus histiocytosis with massive lymphadenopathy (SHML). SHML is an unusual benign lesion that characteristically presents with painless, massive cervical adenopathy. Extranodal sites such as orbit, nose and skin are usually affected in association with cervical adenopathy. The pharyngeal involvement in this and several other recently reported cases adds to the heterogeneity of presentation of this unusual disease. The etiology remains unknown. No treatment is required, nor is any treatment known to be consistently effective. Gradual resolution of adenopathy over six months to several years is the expected outcome.