PMC5021780_01
(a) Axial noncontrast CT of the pelvis shows a large lytic lesion in the posterior left ilium (large asterisk) with prominent expansile remodeling of the ilium (arrows). The lesion is likely at the site of prior bone graft harvesting during prior spinal surgery. Note small similarly located lesion in the contralateral ilium (small asterisk). (b). Axial T1-weighted SE MR image shows the mass extending anteriorly into the iliacus muscle (large arrows), displacing the psoas muscle (small asterisk) anteriorly. The mass shows heterogeneous signal intensity with areas of increased signal (large asterisk) consistent with subacute bleeding. Subtle fluid levels (small arrows) are noted. While not specific for a diagnosis, they are characteristic of prior hemorrhage.
gr1.jpg
PMC5021780_01_gr1.jpg
fig0005
Lumbar CT imaging showed a 12 cm left-sided mass located over the iliac bone (Fig. 1a). Posteriorly, it extended into the subcutaneous tissue (Figs. 1 b & 2 a).
(a) Corresponding axial inversion recovery image shows the mass to have a complex, relatively intermediate, signal intensity. The small fluid levels seen on the T1-weighted image are not appreciated. (b). Corresponding fused image from PET/CT shows the small lesion in the posterior right ilium (small white asterisk) to have relatively low level metabolic activity. The large lesion on the left (large white asterisk) shows a focus of somewhat greater metabolic activity (black asterisk), reaching that which can be seen with malignancy.
gr2.jpg
PMC5021780_01_gr2.jpg
fig0010
Increased metabolic activity was noted on PET/CT with a standardized uptake value of 1.8 (Fig. 2b).
Late arterial phase image from pre-embolization arteriogram shows areas of prominent vascularity associated with the lesion (oval).
gr3.jpg
PMC5021780_01_gr3.jpg
fig0015
The patient underwent a hybrid procedure of preoperative embolization of the left internal iliac and left deep circumflex arteries (Fig. 3), followed by surgical debridement and resection.
(a) & (b) Intraoperative images showing two necrotic masses that were dissected out from the surrounding tissue. The mass on the left measured approximately 2.5 x 2.0 x 0.3 cm while the one on the right measured approximately 10.0 x 6.0 x 5.0 cm.
gr4.jpg
PMC5021780_01_gr4.jpg
fig0020
The surgical procedure consisted of an open biopsy and debridement of the tumor bulk (Fig. 4a & b).
Pathology slide demonstrating areas of dense fibrosis, chronically inflamed granulation tissue and a fibrin capsule. No areas of malignancy noted.
gr5.jpg
PMC5021780_01_gr5.jpg
fig0025
Frozen section showed no evidence of malignancy and the pathological findings were consistent with that of hemophilic pseudotumor (Fig. 5).