Extranodal Rosai-Dorfman Disease- a Review of Diagnostic Testing and Management

Rosai-Dorfman disease (RDD) is a rare, benign histiocytic proliferative disorder primarily occurring in the lymph nodes. Extranodal disease can occur in skin and soft tissue, central nervous system, gastrointestinal tract, and breast. Here we present a case of a 55-year-old female with a history of hypertension, hyperlipidemia, and diabetes mellitus who presented with a fixed solid mass localized to the right medial thigh. Excision revealed S100 and CD 68 positive scattered lymphoid aggregates and emperipolesis, hallmark molecular and cytopathologic features of RDD. RDD is a nonmalignant, classically sporadic histiocytosis. Clinical outcome in terms of mortality seems to be favorable in most cases, however given the benign and slowly progressive nature of the disease, conservative management with observation is typical, with surgical excision recommended for larger lesions. Currently, therapy revolves around surgical and immunosuppressive treatments, but the optimal diagnostic and therapeutic management of RDD remains to be defined.