By A. Vaglio

Dr A. Vaglio Department of Clinical Medicine, Nephrology and Health Science University of Parma Parma, Italy

Author's CV

 

A 68-year-old Caucasian man was admitted to hospital because of low-grade fever of two months' duration, fatigue, subcontinuous abdominal and lumbar pain, and bone pain mainly affecting the knees and the legs. His past medical history was unremarkable and he was taking no medications at the time of hospital admission.

Physical examination disclosed diffuse abdominal tenderness, palpable abdominal masses and a moderate edema of the lower limbs.

The results of routine laboratory tests showed high erythrocyte sedimentation rate (ESR) (64 mm/Ih) and C-reactive protein (CRP) levels (87 mg/l, normal <5). A mild anemia (Hb 11.3 g/dl) was also found, whereas the white cell count was normal. Renal and liver function tests were unremarkable and urinalysis was normal. Autoantibodies were negative.

An abdominal sonography showed a peri-aortic and peri-iliac hypoechoic mass and apparently “enlarged kidneys”: the renal parenchyma was normal, but a moderate bilateral hydronephrosis was found. A chest x-ray was normal. Thus, an abdominal computed tomography (CT) scan was performed: the retroperitoneal space was affected by a diffuse infiltration of soft tissue density with moderate contrast enhancement, which was more prominent in the periaorto-iliac region and, bilaterally, in the peri-renal areas. The perirenal fat tissue was diffusely infiltrated by dense septa; the retroperitoneal mass also seemed to affect the mesenteric root (Figures 1A, 1B).

Figure 1A	Figure 1B

Table 1

Retroperitoneal fibro-inflammatory lesions: differential diagnosis

Trauma, hemorrage

Inflammation primarily involving kidneys, bowel, appendix, pancreas

Malakoplakia

Idiopathic (or secondary) retroperitoneal fibrosis

Malignant lymphoma with sclerosis

Metastatic carcinoma (lobular breast carcinoma, signet ring carcinoma)

Retroperitoneal and mesenteric fibromatosis

Weber-Christian disease and other forms of inflammatory panniculitis

Inflammatory myofibroblastic tumour

Liposarcoma

Hystiocytosis

Inflammatory malignant fibrous histiocytoma

Inflammatory fibrosarcoma

The above CT findings were not diagnostic of any well-defined disease, but they could represent the manifestation of a wide spectrum of retroperitoneal diseases, ranging from benign/inflammatory to malignant (Table 1) 1. Thus, a laparotomy was carried out and multiple retroperitoneal biopsies were performed. The results of the histological examination showed a diffusely sclerotic and edematous tissue, with the presence of abundant collagen bundles; furthermore, a mononuclear cell inflammatory infiltrate (Figure 2A) consisting of lymphocytes and plasma cells was present, together with several multinucleated giant cells. The examined specimens also showed a focal but intense xanthogranulomatous infiltration by “foamy” histiocytes within the sclerotic tissue (Figure 2B, see arrows). Neither signs of vasculitis nor neoplastic cells were found. The polymerase chain reaction for the detection of mycobacterial DNA was negative.

Figure 2A	Figure 2B

QUESTION 1