Imaging description

The posterior iliac crest is an excellent site to obtain cancellous bone for bone grafting at other locations or bone marrow for autologous bone marrow transplantation. These procedures can result in a focus of lucency or heterogeneity in the posterior iliac crest sometimes associated with a cortical break at CT or MRI or increased uptake on bone scintigraphy that can simulate a tumor (Figures 98.1–98.3) [1,2].

Importance

Misinterpretation of a focal iliac bone lesion due to bone harvesting as a potential malignancy may result in unnecessary anxiety or biopsy [1]. However, this pseudotumor has other consequences. Chronic donor site pain occurs in up to 39% of patients and may be related to degenerative changes induced in the sacro-iliac joint due to destabilization [3, 4]. Iliac bone growth disturbance has been reported in children [5]. Because of these donor site complications, some surgeons backfill the donor site [6], which may result in a sclerotic appearance that mimics osteoblastic malignancy (Figure 98.2).

Typical clinical scenario

Iliac pseudotumor due to bone harvesting is typically seen in patients who have undergone spinal fusion surgery or who have had autologous bone marrow transplantation for treatment of high-risk or recurrent pediatric solid tumors such as neuroblastoma.