Imaging findings of recurrent tumors after orbital exenteration and free flap reconstruction

Purpose: Tumors that recur following orbital exenteration may not be evident on clinical examination, highlighting the need for imaging surveillance. The goal of this study was to report the imaging characteristics of recurrent tumors following orbital exenteration and free flap reconstruction. Methods: The authors retrospectively reviewed the records of 48 patients who underwent orbital exenteration for the treatment of orbital malignancy and identified 17 recurrent tumors in 17 patients. The lesions were assessed for the presence of a soft tissue mass, imaging characteristics, and fluorodeoxyglucose avidity. Results: The recurrent tumors were detected 1 month to 6 years 10 months (median, 1 year 3 month) after orbital exenteration. On both CT and MRI, all 17 lesions were soft tissue masses at presentation. On CT, the lesions demonstrated heterogeneous to homogeneous to centrally necrotic enhancement; on MRI, the lesions were T1 hypointense to isointense and T2 hypointense to hyperintense. Twelve of the 15 recurrent tumors with available preoperative imaging had an enhancing appearance similar to that of the original tumor. Thirteen of the 17 recurrent tumors were at the margin of a flap placed for reconstruction; the other 4 lesions were remote from the operative site. Conclusion: Recurrent tumors following orbital exenteration and free flap reconstruction demonstrate a wide range of imaging appearances but most often appear as a soft tissue masses often similar in appearance to the primary tumor and arising near the flap margin. Awareness of the imaging features of recurrent disease is important because failure to diagnose recurrence can delay appropriate treatment.