Monday, May 29, 2017

Rind-like Perirenal Soft-Tissue Masses

rind-like enhancement around the kidney in a patient with retroperitoneal fibrosis
Rind-like perirenal soft tissue masses: Retroperitoneal fibrosis

Differential diagnosis for rind-like perirenal soft-tissue masses:
  • Lymphoma (and Waldenstrom Macroglobulinemia)
    • Usually due to contiguous spread from retroperitoneal or renal lymphoma: Distinct imaging patterns: multiple masses, solitary mass, diffuse infiltrating mass, rindlike soft-tissue thickening, and direct invasion from adjacent retroperitoneal lymphadenopathy
    • Isolated perirenal lymphoma very unusual (<10% of cases): Uniformly attenuating rindlike soft-tissue mass.
    • Does not necessarily affect renal function.
  • Erdheim-Chester disease
    • Rindlike soft-tissue lesions surrounding the kidneys and ureters
    • Severe compression of renal parenchyma and ureters leads to progressive renal failure
    • Percutaneous nephrostomy made difficult because due to fibrous perinephritis.
  • Retroperitoneal Fibrosis (shown above)
    • Typically localized to infrarenal aorta and common iliac arteries
    • Isolated or related to multifocal fibrosclerosis (may include autoimmune pancreatitis, sclerosing cholangitis, scleroderma, Riedel thyroiditis, fibrotic pseudotumor of the orbit, and fibrosis involving multiple organ systems).
    • Perirenal involvement can be from extension from retroperitoneal fibrosis, without associated retroperitoneal fibrosis, or one of manifestations of multifocal fibrosclerosis
    • Perirenal involvement: Soft-tissue mass enveloping kidneys without displacing them.


Surabhi VR, Menias C, Prasad SR, Patel AH, Nagar A, Dalrymple NC. Neoplastic and non-neoplastic proliferative disorders of the perirenal space: cross-sectional imaging findings. Radiographics. 2008 Jul-Aug;28(4):1005-17.

Saturday, May 13, 2017

Toxic Osteoblastoma

Toxic osteoblastoma is an extremely rare variant of osteoblastoma that is associated with systemic symptoms, such as fever, anorexia, weight loss. There is also marked systemic periostitis, not only of the involved bone, but also at other skeletal sites.

Patients tend to be young children (5-7 years of age). On physical examination, there is massive swelling, warmth, and induration of the overlying skin and prominent superficial vessels overlying the lesion. Patients can also have hyperdynamic circulation and even high-output cardiac failure. Regional adenopathy can also be present.

The systemic response is thought to be due to an exaggerated immune response to the tumor. Interleukins can lead to fever and the diffuse periostitis, as well as anemia and massive limb swelling and vascular proliferation. Another possibility is toxic substances released by the tumor itself.

The lesions are highly vascular, and arteriovenous shunting within the lesion can lead to finger clubbing and diffuse periostitis and can account for hyperdynamic circulation.

Differential considerations include osteomyelitis and osteosarcoma.