Different histologic patterns of cutaneous granulomas in systemic lymphoma

Background Patients with Hodgkin's and non-Hodgkin's lymphomas may develop non-infectious granulomas in both involved and uninvolved organs, but rarely in the skin. Cutaneous granulomas in the setting of a systemic lymphoma are of two types. The first type is characterized by granulomatous infiltrates admixed with neoplastic cells within specific skin lesions of malignant lymphomas. The second type consists of granulomatous skin processes that are non-specific manifestations of the underlying lymphoma. Objective To describe the variegate histologic patterns of cutaneous granulomatous reactions of the second type in patients with systemic lymphomas. Methods We describe three patients with systemic lymphomas who exhibited three different histologic patterns of cutaneous granulomatous lesions. Results The first patient had non-Hodgkin's lymphoma with cutaneous tuberculoid-type granuloma mimicking tuberculoid leprosy; the second patient had Hodgkin's lymphoma with palisaded, necrobiotic granuloma of granuloma annulare-type; and the third patient had non-Hodgkin's lymphoma with sarcoid-type granuloma. No evidence of the underlying systemic lymphoma was found in the cutaneous lesions involved by the granulomatous process. Conclusions Cutaneous granulomas may be a non-specific sign of an underlying systemic lymphoma. Their histologic patterns are variegate and include sarcoid-type granuloma, palisaded and necrobiotic granuloma of granuloma annulare-type, and tuberculoid granuloma. In patients who present with non-infectious, granulomatous skin reactions in the absence of another sound explanation, the possibility of a systemic lymphoma should be considered.