A Challenging Differential Diagnosis Between Brain Radionecrosis and Recurrent Metastatic Disease, with Temporary Clinical/Radiological Response to Bevacizumab and Later Imaging Suspicious for Oligoprogression.

BACKGROUND

Brain radiation necrosis is a side effect of radiotherapy that can occur months, or even years, after the end of treatment. From an anatomical-pathological perspective, it is characterized by avascular damage, demyelination, and necrosis.

METHODS

We present a case of a patient with breast cancer cT2N1M0 and multiple brain metastases occurring at 2 years after diagnosis, who was treated with whole-brain radiotherapy (WBRT) and Stereotactic Radiotherapy (SRT) for tumor progression. Dynamic imaging revealed right parietal post-therapeutic changes in aggravation, requiring differential diagnosis between tumor progression (TP) and brain radionecrosis (BRN).

RESULTS

Brain radionecrosis and tumor progression are difficult to differentiate due to their similar radiological and clinical characteristics. MRI perfusion plays an important role in differentiating the two entities.

CONCLUSIONS

Differentiating radiation necrosis from a recurrent tumor is crucial for appropriate treatment. Medical management includes corticosteroids as first-line treatment, after which bevacizumab is administered as secondary therapy.