Iliac Insufficiency Fracture: "Bow Sign" on Bone Scan

Area of Science:

• Nuclear Medicine
• Radiology
• Oncology

Background:

• Pelvic insufficiency fractures (IFs) are commonly diagnosed via technetium-99m methylene diphosphonate bone scans (BS).
• Iliac bone involvement in pelvic IFs is exceptionally rare, posing diagnostic challenges.
• Distinguishing IFs from bone metastases is critical in patients with a history of malignancy.

Purpose of the Study:

• To report a rare case of iliac bone insufficiency fracture.
• To emphasize the diagnostic utility of bone scintigraphy (BS) in identifying pelvic insufficiency fractures.
• To illustrate the characteristic appearance of IFs on BS, aiding differentiation from metastases.

Main Methods:

• Technetium-99m methylene diphosphonate bone scan (BS) was performed.
• Imaging focused on evaluating pelvic pain in a patient with a history of cervical carcinoma treated with radiotherapy.
• Radiological findings were analyzed for characteristic patterns of insufficiency fractures versus metastatic disease.

Main Results:

• The bone scan (BS) revealed findings diagnostic for an iliac bone insufficiency fracture.
• The characteristic appearance on BS obviated the need for further investigations to confirm the diagnosis.
• The findings effectively differentiated the insufficiency fracture from potential skeletal metastases.

Conclusions:

• Bone scintigraphy (BS) is a valuable tool for diagnosing pelvic insufficiency fractures, even in rare locations like the iliac bone.
• Characteristic BS findings can reliably differentiate iliac bone IFs from metastases, simplifying patient management.
• This case underscores the importance of considering IFs in patients with pelvic pain, particularly after radiotherapy.