This case explores a rare initial presentation of Rosai-Dorfman disease isolated to the peri-renal space. Also described as sinus histiocytosis with massive lymphadenopathy, Rosai-Dorfman disease is non-neoplastic and most often presents with massive cervical lymphadenopathy, but the disease can affect any organ system.1 Not often considered by those in the urology community or found in urology journals, this report reviews a clinical presentation of Rosai-Dorfman disease affecting bilateral kidneys and the fundamental histopathology needed for its diagnosis.
A 60-year-old Caucasian man presented to the office with a 7-year history of fatigue and cough associated with anemia and thrombocytosis of unknown cause. The patient had previously seen rheumatology, otolaryngology, and gastroenterology specialists without resolution of symptoms or discovery of a definitive diagnosis. On abdominal examination, a mass was palpated in the upper left quadrant and subsequent CT scan revealed bilateral perinephric soft tissue masses encasing both kidneys, with the greatest on the left side measuring 12 cm × 11 cm × 22 cm (Figure 1 and 2). Imaging also revealed mild bilateral hydronephrosis; however, the patient’s renal function was normal and he was urologically asymptomatic.
Given the uncertainty of the diagnosis based on the CT images, CT-guided biopsy of the left-side perinephric mass was performed. Pathology from the mass revealed tissues composed predominantly of histiocytes, plasma cells, and lymphoid aggregates (Figure 3) with histiocytes that stained positively for protein S-100 and CD68. This histological pattern was consistent with Rosai-Dorfman disease. The patient was consequently referred to hematology and prescribed the treatment of prednisone, 30 mg daily. He was followed conservatively with repeat imaging after 3 months. The follow-up CT revealed some right-side improvement with the left side remaining stable. He continues to be followed with imaging and conservative management and will likely remain on steroids for the duration of his life.
Rosai-Dorfman disease was first described in 1969 by Rosai and Dorfman as sinus histiocytosis with massive lymphadenopathy (SHML).2 Rosai-Dorfman is a non-neoplastic disorder in which massive lymphadenopathy occurs as a result of histiocyte invasion and aggregation within the sinuses of lymph nodes. Classically patients present with bilateral, non-tender, exceptionally large lymphadenopathy of the cervical lymph nodes during their first and second decades.1 However, Rosai-Dorfman is not constrained to the lymphatic system and can affect any organ system, with extra-nodal disease being found in approximately 33% of patients. Involvement of the kidney is a poor prognostic indicator; up to 4% of cases have kidney involvement3 with 40% of these dying with the disease due to local organ failure.1 Rarely, Rosai-Dorfman can manifest solely in the urologic system. Complicating the diagnosis of SHML, most patients are in good health and are asymptomatic in relation to their disease.4
As seen in Figures 1 and 2, the mass effect from this disease can be catastrophic. In cases involving the renal system it can cause occlusion of the renal vasculature or the collecting system by mass effect without being directly infiltrative.
Rosai-Dorfman must be diagnosed with biopsy; in our case CT-guided biopsy was enough. The characteristic histopathologic feature of SHML is emperipolesis, in which histiocytes are viewed phagocytizing lymphocytes, plasma cells, erythrocytes, or polymorphonuclear leukocytes without digesting them.4 However, this is much less prominent in the extranodal variant of Rosai-Dorfman disease like that involving the kidney. Immunohistochemistry typically shows protein S-100 positive histiocytes and immunoreactivity against CD68, α-1-antichymotrypsin, and MAC387 antibodies.5
Most often Rosai-Dorfman is a self-limiting disease that runs an indolent course with full spontaneous resolution. However, those with extra-nodal involvement often have persistent, stable disease that never fully resolves. In symptomatic disease, the use of corticosteroids has been proposed in multiple case reports with many patients reporting improvement of symptoms, but there is a lack of evidence as to its true efficacy.3 Various chemotherapy and radiotherapy regimens have also been reported to show a positive response in these patients. Surgical removal is considered only if the mass effect of the disease compromises neighboring vital organs.
In our case, the patient had a partial response to steroids and his symptoms have been improving. The authors do not expect a complete resolution of his disease as it was quite advanced upon initial presentation. However, in cases such as these we recommend beginning with steroid management and escalating to other treatments only if the disease is non-responsive to steroids and the symptoms are unmanageable or life threatening. We recommend imaging for any change in symptoms and biannually for the first 2 years with annual follow-up thereafter.
This case, to our knowledge, represents the second reported case of Rosai-Dorfman disease isolated to bilateral kidneys or peri-renal space. Because of the rarity of SHML and its non-specific image findings, this diagnosis is not often considered by the urologic community. However, when a patient presents with bilateral renal or peri-renal masses with no known neoplastic origin, there is a potential for this diagnosis. Therefore, urologists should have a basic understanding of the disease process and prognosis for the benefit of our patients.