Background <p>Spindle cell squamous cell carcinoma (SCSCC) is a rare and poorly differentiated variant of squamous cell carcinoma that may mimic sarcoma, melanoma, and other spindle cell malignancies. Orbital involvement is exceptionally uncommon and may pose substantial diagnostic and therapeutic challenges, particularly when overt squamous differentiation is absent.</p> Case presentation <p>A 60-year-old woman with a history of left ocular evisceration for a blind painful eye presented six months later with rapidly progressive painful swelling of the left lower eyelid and medial canthus. Orbital magnetic resonance imaging demonstrated an infiltrative, heterogeneously enhancing orbital mass, and positron emission tomography-computed tomography showed hypermetabolic uptake in the orbital lesion with additional ipsilateral cervical and parotid-region foci. The patient underwent orbital exenteration combined with radical neck dissection and radical parotidectomy. Histopathologic examination revealed a malignant spindle cell neoplasm with marked pleomorphism and frequent mitotic activity, without definite keratinization or overt squamous differentiation. Immunohistochemical staining showed strong positivity for pancytokeratin AE1/AE3, CK OSCAR, and CK8/18, supporting epithelial differentiation and a diagnosis most consistent with spindle cell squamous cell carcinoma. Despite adjuvant radiotherapy and systemic chemotherapy, metastatic disease developed within three months, and the patient died six months after orbital exenteration.</p> Conclusions <p>This case highlights the diagnostic difficulty and aggressive clinical behavior of orbital spindle cell malignancies with features most consistent with spindle cell squamous cell carcinoma. Broad immunohistochemical evaluation, careful clinicopathological correlation, comprehensive staging, and early multidisciplinary management are essential in such rare and high-risk tumors.</p>