We present the case of a 50-year-old woman affected by a rectal gastrointestinal stromal tumor (GIST), with a recurrence in pre-sacral and pre-coccygeal space after surgery and Imatinib therapy. GISTs are the most common mesenchymal tumors of the gastrointestinal tract and rectal GISTs are rare (only 2% of cases); magnetic resonance and computed tomography are the main imaging techniques for diagnosis and follow-up, while ultrasound and contrast-enhanced ultrasound may be useful to perform a percutaneous biopsy, as in the case presented: the imaging features of the lesion in all these imaging methods are displayed.