Etiological Analysis of Rare Recurrence of OSCC on a DCIA Myo-Osseous Flap Reconstruction Site.

The vascularized iliac crest free is widely used for reconstructing composite tissue defects after oral squamous cell carcinoma (OSCC) resection due to its high compatibility with mandibular bone morphology, and the myofascial undergoes mucosalization post-surgery. However, recurrence in the reconstructed area is extremely rare. This study reports a case of a 61-year-old female OSCC patient who underwent left mandibular gingival lesion and mandibular resection, ipsilateral modified radical neck dissection, and reconstruction with a deep circumflex iliac artery myo-osseous flap. At the tenth month post-surgery, a mass lesion was identified in the reconstructed region, with imaging and pathology confirming OSCC recurrence located centrally within the myofascial flap, distant from the primary tumor resection margin. Pathologic and follow-up data suggest that recurrence may be associated with precancerous epithelial coverage of the myofascial flap, the post-surgery inflammatory microenvironment, and radiotherapy-induced aberrant cellular proliferation. This study highlights early detection of abnormal epithelial changes and optimization of postsurgery monitoring protocols are critical to reducing recurrence risk in the reconstructed region, particularly in patients with extensive precancerous lesions or those requiring post-surgery radiotherapy.