Hemophagocytosis in Cutaneous Autoimmune Disease.

BACKGROUND:The significance of the histological visualization of hemophagocytosis in tissues depends on the context, varying from a nonspecific phenomenon to a characteristic or diagnostic feature for certain disease entities. Hemophagocytosis is also one of the key features of macrophage activation syndrome (MAS) (hemophagocytic syndrome) a potentially life-threatening complication of underlying conditions such as infections, malignancy, and autoimmune disorders. Clinical manifestations of MAS are high fever, pancytopenia, liver dysfunction, and coagulopathy. These clinical symptoms are due to an abnormal activation of the immune system in a strong association with the cytokine milieu. The diagnosis of MAS may be easily missed; it is usually detected in the bone marrow, lymph node, liver, and spleen. Only few reports exist in the literature with histological description of cutaneous hemophagocytosis as a sign for MAS in patients with lymphoma and infection. In this report, the authors present the clinicopathological and immunohistochemical features of 3 patients with cutaneous hemophagocytosis, specifically erythrophagocytosis, associated with autoimmune disease, and discuss the relevance of these findings. OBSERVATION:The authors report 3 patients who developed cutaneous hemophagocytosis during the course of an underlying autoimmune disorder. One patient suffered from dermatomyositis, the other 2 patients from systemic lupus erythematosus, whereby one of them was a 3-month old girl with neonatal lupus erythematosus. The patient with dermatomyositis developed MAS according to the current diagnostic criteria. Although the 2 other patients had an acute flare of their autoimmune disease with histological signs of cutaneous hemophagocytosis, they did not fulfill the complete criteria for a diagnosis of MAS. Histiocyte proliferation and activation with increase of cytokines could be demonstrated by immunohistology. CONCLUSIONS:This report is the first to describe hemophagocytosis in cutaneous biopsies of patients with autoimmune diseases, associated with a complete or incomplete constellation of MAS. Key players in this process are histiocytes/macrophages engaged in phagocytosis of erythrocytes. Hemophagocytosis observed in skin biopsies may be a diagnostic clue for MAS and an indicator for a potentially aggressive course of the underlying disease.