Diffuse xanthogranulomatous dermatitis and systemic Langerhans cell histiocytosis: A novel case that demonstrates bridging between non-Langerhans cell histiocytosis and Langerhans cell histiocytosis

The advent of electron microscopy and immunohistochemical stains allowed for reclassification of the histiocytoses based on the predominant cell in the infiltrate. Although the current schema simplicity provides a good foundation, some patients display overlapping clinical and immunohistochemical features that defy classification. The patient herein illustrates bridging between histiocytic disorders. Through this case we review the various conditions classified under the non-Langerhans cell histiocytosis and Langerhans cell histiocytosis rubric.