Introduction
For the first time in 1969, Rosai and Dorfman described a new clinicopathologic entity of histiocytic proliferative disorders, which they named sinus histiocytosis with massive lymphadenopathy (SHML)1. SHML, also known as the Rosai-Dorfman disease (RDD), is a non-Langerhans cell histiocytosis disorder with unknown etiology that is histologically characterized by benign proliferation of S100–positive histiocytes within the expanded sinus of lymph nodes and lymphatic vessels of visceral organs 2. This rare disease mainly affects children and younger adults but can also occur as late as the eighth decade 3. Evidence suggests that patients with a background of immunologic and autoimmune diseases are more susceptible to developing this disease 4, 5.
Patients with RDD most commonly present with massive and bilateral painless enlargement of cervical lymph nodes, accompanied by non-specific symptoms such as fever, night sweat and weight loss. In approximately 40% of cases, RDD can also display extranodal involvement with the most common affected sites being the bone, skin, soft tissue, and upper respiratory tract 6. RDD is usually self-limited and has an overall good prognosis; however, the extranodal involvement of vital organs, as well as the presence of immunological disorders is associated with unfavorable outcomes and might require therapeutic interventions such as surgery or medical treatment5, 7.
Kidney involvement occurs in an estimated four percent of patients with extranodal RDD and is associated with a poor prognosis6. Thus far, only two cases of isolated bilateral renal RDD have been reported, which had both been symptomatic at presentation 8, 9. Here, we report the third case of isolated bilateral renal RDD in a 67-year-old asymptomatic woman who presented with an elevated erythrocyte sedimentation rate (ESR) and increased serum creatinine level. In addition, we briefly review the radiologic findings of previously reported cases of renal RDD and compare them with other differential diagnoses.