Cutaneous granulomas in the setting of primary immunodeficiency: a report of four cases and review of the literature.

Importance Cutaneous granulomas without an identifiable infectious etiology are a rare manifestation of primary immunodeficiency (ID). These cutaneous lesions can be misdiagnosed, often as sarcoidosis, when the skin findings precede the diagnosis of immunodeficiency. Objective We present four cases from our institution and review the literature in order to emphasize the clinical relevance of this association, discuss the histologic and immunohistochemical features, and explore possible pathogenic mechanisms of granuloma formation. Evidence Review We retrospectively reviewed case reports of all patients presenting with cutaneous granulomas in the setting of primary immunodeficiency. Cases with insufficient information to confirm an immunodeficiency state were excluded. Four patients from our clinic were included, for 54 total cases. Findings The majority of cutaneous granulomas are seen in three types of immunodeficiencies: ataxia-telangiectasia, severe combined immunodeficiency, and combined variable immunodeficiency. Twenty-six percent of patients developed cutaneous granulomas prior to their immunodeficiency diagnosis. Histologically, various granulomatous patterns have been described. Immunohistochemistry revealed a CD4+/CD8+ lymphocyte ratio of less than or equal to 1 in our four patients, which may help differentiate cutaneous granulomas in primary ID from sarcoidal granulomas that typically show a CD4+ predominance. Conclusions and Relevance Cutaneous granulomas are a rare manifestation of primary ID and occur predominantly in immunodeficiencies that affect T and B cell compartments.