Solitary Fibrous Tumour Presenting as Delayed Neck Swelling Following Carotid Endarterectomy.

Solitary fibrous tumours are rare mesenchymal neoplasms that can arise in a variety of anatomical sites, including the head and neck. We present an unusual case of an elderly man who developed a slowly enlarging, painless swelling in the neck one year after undergoing carotid endarterectomy. Initial suspicion of a delayed post-operative complication was revised after imaging and biopsy confirmed a solitary fibrous tumour extending into the mediastinum. Due to the lesion's size, anatomical complexity, and the patient's comorbidities, surgical resection was not feasible, and he was referred for palliative oncological management. This case underscores the importance of considering rare neoplastic causes in delayed post-surgical swellings and highlights the role of a thorough histopathological evaluation in establishing a definitive diagnosis.