Late Deltoid Cutaneous and Axillary Recurrence of Cervical Squamous Cell Carcinoma: A Case Report Exploring the Locus Minoris Resistentiae Hypothesis

Cervical cancer typically spreads locally and through the pelvic and para-aortic lymphatic pathways; however, cutaneous metastases and axillary lymph node involvement are rare.This report presents a case involving this uncommon pattern of metastatic spread and discusses its clinical implications.A 67-year-old woman with a history of stage IIIB cervical squamous cell carcinoma, treated with concurrent chemoradiotherapy, had remained in complete remission for five years.Four years after receiving a COVID-19 mRNA vaccination in the left deltoid region, she developed a cutaneous metastasis strictly localized to the injection site, accompanied by ipsilateral axillary lymphadenopathy.Histopathological and immunohistochemical analyses confirmed metastatic squamous cell carcinoma positive for P40, P63, and pan-cytokeratin.A PET-CT scan demonstrated isolated hypermetabolic lesions in the left arm and axillary region.Systemic chemotherapy consisting of paclitaxel, carboplatin, and bevacizumab was initiated.This case illustrates the phenomenon of locus minoris resistentiae, in which injection-site tissue trauma and local inflammation may act as catalysts for metastatic localization.Clinicians should exercise increased vigilance when evaluating abnormalities at injection sites in patients with a history of malignancy.