CASE 15403 Published on 29.01.2018

Renal involvement in Rosai-Dorfman disease

Section

Uroradiology & genital male imaging

Case Type

Clinical Cases

Authors

Tonolini Massimo, M.D.

"Luigi Sacco" University Hospital,
Radiology Department;
Via G.B. Grassi 74
20157 Milan, Italy;
Email:mtonolini@sirm.org
Patient

54 years, female

Categories
Area of Interest Kidney, Spleen ; Imaging Technique Ultrasound, CT
Clinical History
Middle-aged female patient with history of systemic disease (diagnosis revealed later) including axillary lymphadenopathies and past history of neurosurgical intervention to remove an extra-axial mass in the dorsal spine causing medullary compression. Main laboratory abnormality represented by severe hypochromic microcytic anaemia, refractory to iron supplementation, plus monocytosis.
Imaging Findings
Performed at an outside facility, ultrasound (Fig.1) showed splenomegaly with “gross” echotexture and hypoechoic tissue encasing poles of both kidneys, which did not exert appreciable mass effect and did not cause hydronephrosis.
Hospitalised at our institution, CT (Fig. 2) showed medium-sized kidneys with normal parenchymal thickness and symmetrical, mildly delayed nephrographic enhancement, and confirmed the bilateral presence of a lobulated, well-demarcated perirenal soft-tissue with solid attenuation, homogeneous and persistent enhancement, which extended into the renal hilum on both sides.
Additionally, an ovoid subfascial solid homogeneous mass isoattenuating with the perirenal tissue was noted in the dorsum. Additionally, the spleen was enlarged (17 cm craniocaudal diameter).
These CT findings were consistent with the previous histological diagnosis of histiocytosis (Rosai-Dorfman disease type), and were confirmed by bone marrow aspiration showing proliferation of histiocytes with phagocytosis, without neoplastic changes.
Discussion
Histiocytic disorders encompass a complex, heterogeneous group of conditions of unknown aetiology, characterised by proliferating histiocytes. Differentiation between these rare disorders is challenging and relies on a combination of clinical, imaging, histological and immunohistochemical features. Among these, Rosai-Dorfman disease (RDD) is categorised as a Class I (benign, non-Langerhans cell) form, which is thought to arise from exaggerated reactive hemopoietic response in the lymph nodes to immunological triggers such as Epstein-Barr and Herpes Simplex 6 viruses. RDD generally manifests in children and young adults (mean age 20 years) with painless cervical adenopathy, lymphoma-like systemic symptoms and unspecific laboratory changes, and often follows a self-limiting course. Histological confirmation relies on scattered foci of lymphocytic aggregation, prominent “foamy” histiocytes showing emperipolesis and strong S-100 reactivity [1].
Extranodal involvement occurs in 43% of patients and most commonly involves the head and neck, bones (5-10%), skin and soft tissues (9%), thorax and airways. The genitourinary system is rarely affected, either in the testis or kidney (2%). Patients with visceral involvement tend to be older (6th-8th decades) and have a poor prognosis (40% mortality) [1-4].
As in this patient, renal RDD involvement may characteristically appear as a diffusely infiltrating soft tissue, nearly isoattenuating to muscles with mild contrast enhancement, which may encase both kidneys. The subcapsular and perirenal distribution probably results from lymphatic spread. Alternatively, RDD may form unusual hilar masses. Complications such as urinary obstruction or acute renal failure may occur [3-5].
In this case, the key differential diagnosis is Erdheim-Chester disease (EDD) which occurs in middle-aged individuals, generally spares the spleen but characteristically affects the long bones, and may lead to perinephric soft-tissue infiltration (“hairy kidney” appearance). Immunohistochemistry differentiates ECD from RDD as being CD68-positive and S-100-negative. Other diseases which may involve the perinephric space include lymphomas and leukaemia, extramedullary haemopoiesis, retroperitoneal fibrosis with or without the typical periaortic disease, and discrete metastases. However, isolated “rind-like” perinephric lymphoma without adenopathies and renal cortical masses is very uncommon, and metastases are rarely encountered without history of neoplastic disease [6-9].
Differential Diagnosis List
Perirenal and hilar involvement in Rosai-Dorfman disease.
Erdheim-Chester disease
Retroperitoneal fibrosis
Extramedullary haemopoiesis
Lymphoma / Leukaemia
Rare retroperitoneal benign tumours e.g.lymphangioma
Perirenal metastases
Final Diagnosis
Perirenal and hilar involvement in Rosai-Dorfman disease.
Case information
URL: https://eurorad.org/case/15403
DOI: 10.1594/EURORAD/CASE.15403
ISSN: 1563-4086
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