Figure 1. Severe exophthalmos.
Figure 2. Abnormal tissue completely occupying the orbital spaces, slightly infiltrating the anterior fossa up to the sella.
Figure 3. Orbital tissue. Left, Sheets of large, pale to eosinophilic polygonal histiocytic cells with large vesicular nuclei and small nucleoli; occasional multinucleated histiocytes and spindle-shaped histiocytes were also present (hematoxylin-eosin, original magnification ×150). Right, The histiocytic cells stained positive for S100 protein (alkaline phosphatase anti–alkaline phosphatase, original magnification ×150).
Rosai-Dorfman disease (RDD) is an uncommon proliferative disorder of histiocytes that was first described in 1969.1
Generally, RDD is characterized by massive lymphadenopathy (frequently accompanied by anemia), increased erythrocyte sedimentation rate, and elevated levels of serum immunoglobulins. Histologically, this condition is characterized by a proliferation of large pale cells that show striking lymphocytophagocytosis (emperipolesis) and immunoreactivity for S100 protein.2 However, it has only recently been described as a distinct entity in soft tissue, with pernicious locally recurrent lesions.3,4
The disease is often not recognized in the soft tissue.3,4 Emperipolesis can be less conspicuous and proliferating histiocytes are spindled, associated with collagen deposition, and arranged in a vague storiform pattern with scattered lymphoplasmacytic aggregates. Lymph node involvement can be present or not.3
These features lead to a variety of misdiagnoses, including benign inflammatory and fibrohistiocytic lesions, lymphoma, and malignant fibrous histiocytoma.3
Rosai-Dorfman disease of the soft tissue occurs more often in older patients than does nodal RDD.3 Areas involved can include face, leg, arm, shoulder, abdomen, groin, buttock, back, retroperitoneum, orbit, and chest wall.3- 5
Optimal therapy has not been established.6 Knowing that RDD of soft tissue mimics fibrous and inflammatory lesions of soft tissue is important for prompt diagnosis and selection of the most appropriate therapy.
Accepted for publication May 19, 1999.
Reprints: Raffaella Zannolli, MD, Instituto di Clinica Pediatrica, Universita Degli Studi di Siena, via della Scotte 531000, Siena, Italy.
Pathological Case of the Month. Arch Pediatr Adolesc Med. 1999;153(11):1199-1200. doi: