CASE 135

By: Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: 42-year-old male with repeated falls.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

CT scan of the pelvis with IV contrast demonstrates a well-defined multilobulated lytic expansile lesions of variable size in the iliac wings, and sacrum. Lesions in the lytic regions demonstrate scalloping, but they cause a thick wall which enhances following IV contrast administration.

DIFFERENTIAL DIAGNOSIS:

Since these are lytic expansile lesions, one can use the differential diagnosis is that of FEGNOMASHIC. However, since there is evidence of multiloculation and well definition and expansion, one must think of hemophilic pseudotumor.

Differential diagnosis of lytic bone lesions with septations and trabeculations include:

·         benign lesions:

o    unicameral bone cyst.

o    aneurysmal bone cyst.

o    giant cell tumour.

o    non-ossifying fibroma.

o    intraosseous lipoma.

o    fibrous dysplasia.

o    Brown tumour.

o    ameloblastoma.

o    adamantinoma.

o    haemophilic pseudotumour.

o    chondromyxoid fibroma.

·         malignant lesions:

o    plasmacytoma.

o    telangiectatic osteosarcoma.

o    malignant fibrous histiocytoma.

o    metastases.

DIAGNOSIS:

Hemophilic pseudotumor of the pelvis.

PEARLS AND DISCUSSION:

Hemophilic pseudotumor is a rare complication of hemophilia from progressive cystic swelling of the muscle and bone and occurs in 1-2% patients with hemophilia.

Hemophilic pseudotumors are characterized as osseous or soft tissue lesions purely from an anatomical perspective.

This pseudotumor sometimes grows as a slowly expanding encapsulated cystic mass because of recurrent hemorrhage.

Repetitive bleeding into the bones results in an osseous pseudotumor whereas repetitive bleeding in the joints leads to hemophilic arthropathy. When the bones are frequently implicated the femur followed by the pelvis, tibia and small bones of the hand are a common location.

Most occur in the muscles and bones of the lower limb since they have abundant blood supply.

FURTHER READING:

1. Hermann G, Gilbert MS, Abdelwahab IF. Hemophilia: evaluation of musculoskeletal involvement with CT, sonography, and MR imaging. AJR Am J Roentgenol. 1992;158 (1): 119-23. 

2. Ng WH, Chu WC, Shing MK et-al. Role of imaging in management of hemophilic patients. AJR Am J Roentgenol. 2005;184 (5): 1619-23. 

3. Greenspan A, Remagen W. Differential diagnosis of tumors and tumor-like lesions of bones and joints. Lippincott Williams & Wilkins. (1998) ISBN:0397517106.