Sinus histiocytosis with massive lymphadenopathy.

Sinus histiocytosis with massive lymphadenopathy is a lymphoreticular disorder of obscure pathogenesis with extranodal lesions and a variable clinical course. Clinical manifestations are most often in the head and neck, with 97% of patients showing cervical lymphadenopathy and a significant but lesser number having lesional infiltrates in the upper aerodigestive tracts, particularly the nasal cavity and salivary glands.