Perivascular hemophagocytosis: report of 2 cases and review of the literature.

Hemophagocytosis may be encountered in association with a variety of underlying conditions, including primary or familial disorders, and secondary forms induced by infections, malignancy, and metabolic disorders. It is usually observed in organs such as the spleen, lymph nodes, bone marrow, and central nervous system, but rarely in the skin. When hemophagocytosis coexists with a sepsis-like systemic disorder it is termed hemophagocytic syndrome or hemophagocytic lymphohistiocytosis. Recently, 2 cases with evidence of perivascular hemophagocytosis in skin biopsy specimens of patients without additional findings of hemophagocytic lymphohistiocytosis have been reported. We report 2 additional cases of patients with cutaneous lesions suggestive of leukocytoclastic vasculitis whose skin biopsies showed a perivascular and interstitial infiltrate of neutrophils with nuclear dust and extravasated erythrocytes, and the presence of histiocytes with phagocytized red blood cells and nuclear fragments. There was also evidence of fibrin in the walls of the venules. One patient presented with a sepsis-like clinical scenario, but an extensive work-up failed to demonstrate any underlying disease or infection. The second patient was asymptomatic at the time of presentation, but further work-up revealed an underlying B-cell lymphoma. Whether these histologic findings represent late lesions of leukocytoclastic vasculitis or an incomplete presentation as part of a hemophagocytic syndrome is debatable, because both are associated with activated immunity and cytokine release, which could account for the presence of hemophagocytosis. Although the histopathologic finding alone of hemophagocytosis is insufficient to label as a syndrome, it should incite the clinician for further systemic evaluation.