Sinus histiocytosis with massive lymphadenopathy. An analysis of 14 deaths occurring in a patient registry.

Sinus histiocytosis with massive lymphadenopathy (SHML) is generally regarded as a benign disorder in spite of its propensity to form large masses and to disseminate to both nodal and extranodal sites. Although in most patients the extent of SHML does not appear to determine disease outcome, recent reports have documented that infiltrates of SHML can cause death. To gain perspective on the role of SHML in patient deaths in this population, the authors analyzed the 14 known fatalities in an SHML registry comprising 215 patients. The average age at death was 33 years. Autopsy was performed on eight patients. SHML infiltrates were clearly the cause of death in only two patients (previously reported). In another four cases persistent SHML was prominent at death. The other deaths were the result of complications of defined immunologic abnormalities (five), or of unusual infections (three). The authors have not seen an example of cytologic malignant transformation of SHML.