Diffusion weighted imaging changes in extra-abdominal desmoid tumor after cryotherapy.

Area of Science:

• Oncologic Imaging
• Radiology
• Tumor Biology

Background:

• Desmoid tumors (DT) are rare benign neoplasms with potential for local invasion and recurrence.
• Current management often involves watchful waiting, with cryotherapy as an option for symptomatic or progressing extra-abdominal DT.
• Magnetic resonance imaging (MRI) is crucial for DT follow-up, but diffusion-weighted imaging (DWI) data, especially post-cryotherapy, are limited.

Purpose of the Study:

• To characterize diffusion-weighted imaging (DWI) patterns in extra-abdominal desmoid tumors (DT) following cryotherapy.
• To differentiate expected post-cryotherapy changes from signs of tumor recurrence on DWI.
• To establish the significance of early DWI findings after cryotherapy for DT management.

Main Methods:

• Review of literature regarding diffusion-weighted imaging (DWI) in desmoid tumors (DT) and post-cryotherapy changes.
• Analysis of reported DWI signal intensities and apparent diffusion coefficient (ADC) values in DT after cryotherapy.
• Comparison of early DWI findings with histological changes of cryoablation and potential recurrence indicators.

Main Results:

• Early post-cryotherapy DWI in DT can exhibit hyperintensity with low ADC values (<1.00 × 10^-3mm²/s), mimicking residual or recurrent tumor.
• These early DWI changes are associated with tumor necrosis and gelatinous transformation due to cryotherapy's freezing-thawing cycles.
• Later DWI follow-up typically shows a decrease in signal intensity in the treated lesion.

Conclusions:

• Hyperintensity on DWI with low ADC values is an expected early finding after cryotherapy for extra-abdominal desmoid tumors, reflecting tumor necrosis.
• Radiologists must be aware of these DWI patterns to avoid misinterpreting them as tumor recurrence.
• Understanding these specific DWI changes is paramount for accurate MRI-based follow-up of cryotherapy-treated DT.