Benign ulceration as a manifestation of soft tissue radiation necrosis: imaging findings.

BACKGROUND AND PURPOSE The purpose of this study was to review CT imaging findings of soft tissue mucosal ulceration in patients following radiation treatment for head and neck malignancies and to correlate these with patient outcomes. MATERIALS AND METHODS The CT examinations in 20 patients with soft tissue ulceration after radiation therapy for treatment of head and neck cancer were reviewed. External beam radiation therapy was completed between 3 and 61 months (mean, 11.5 months) before the initial diagnosis of soft tissue ulceration. In all 20 patients, the initial diagnosis was made or confirmed on CT examination. RESULTS Of the 20 ulcerations, 12 did not demonstrate enhancement, and the results of biopsy in 9 of these 12 were negative. Of the 12 nonenhancing ulcerations, biopsy was not performed in 3, but they have been followed clinically and radiologically for 15.7 months without evidence of recurrence. Of the 20 ulcerations, 8 demonstrated adjacent enhancement, and the results of a biopsy in 4 were positive for recurrent cancer and negative in 2; these 2 have been followed for 16.3 months without evidence of recurrence. Biopsy was not performed in 2 ulcerations, but they have been followed for 15.0 months without evidence of recurrence. CONCLUSION For soft tissue ulceration occurring after radiation treatment, if there is no enhancement or clinical evidence of recurrence, it is likely benign and follow-up without biopsy seems warranted. If the ulceration is associated with adjacent enhancement, then differentiation between radiation necrosis and recurrent tumor is difficult. In these cases, correlation with clinical examination with close interval follow-up is necessary if a biopsy is not performed.