Donor Site Metastasis in Oral Cavity Carcinoma: A Rare Oncologic Phenomenon

Abstract

Background: Donor site metastasis following reconstructive surgery for oral cavity carcinoma is a rare and underrecognized phenomenon. It challenges conventional pathways of tumour spread and raises concerns regarding iatrogenic tumour seeding during oncologic surgery. Case Presentation: A 37-year-old female with locally advanced carcinoma of the left buccal mucosa underwent composite resection with segmental mandibulectomy, ipsilateral neck dissection, and reconstruction using a bipaddled pectoralis major myocutaneous (PMMC) flap. The surgical pathology report revealed perineural invasion and nodal metastases, so she was initiated on adjuvant concurrent chemoradiotherapy. During adjuvant concurrent chemoradiotherapy, after completion of 26 fractions of radiotherapy and four cycles of weekly cisplatin, she developed a painful, indurated swelling at the PMMC donor site over the left anterior chest wall. Fine-needle aspiration cytology (FNAC) demonstrated metastatic squamous cell carcinoma, and imaging revealed infiltration into the underlying musculature and adjacent ribs. Discussion: Donor site metastasis is a rare entity, most plausibly explained by intraoperative tumour implantation, although hematogenous and lymphatic dissemination have also been proposed as possible mechanisms. Conclusion: This case underscores the importance of strict adherence to oncologic surgical principles, early evaluation of atypical donor-site symptoms, and heightened clinical vigilance for rare patterns of disease spread.