Facial Venous Tumour Thrombus from Submandibular Gland Mucoepidermoid Carcinoma: An Atypical Tumour Spread in Head and Neck Cancer

Tumour thrombus of the facial vein is an exceedingly rare complication arising from mucoepidermoid carcinoma of the salivary glands. Early detection is pivotal for appropriate management, as delays can lead to metastatic disease, worsening the prognosis. We present a case involving a 76-year-old male with a history of mucoepidermoid carcinoma of the right submandibular gland, previously treated with surgical resection and radiotherapy. The patient, a long-term worker in a rubber factory, presented with a painless, firm swelling in the right cheek, persisting for three months. Contrast-enhanced computed tomography (CECT) showed distended facial vein with enhancing thrombus confirmed by sonographic correlation demonstrating intralesional vascularity. Cannon ball pulmonary nodules were also noted. Radiological findings led to a core biopsy, confirming tumor thrombosis of the facial vein due to mucoepidermoid carcinoma. However, the patient declined a biopsy of the pulmonary nodules, and has been referred to oncology for further management. This case highlights the critical importance of considering venous tumour thrombus in patients with previous salivary gland malignancies presenting with new or persistent facial swellings. It emphasises the role of advanced imaging techniques in the early identification of this rare entity. Additionally, it stresses the need for healthcare providers to engage in thorough discussions with patients about the potential consequences of forgoing recommended treatments, reinforcing the need for vigilance in monitoring such patients. Tumours of head and neck may cause thrombosis of veins by direct invasion resulting in a tumour thrombus, or indirectly by exerting a mass effect and vein compression.These can be distinguished by contrast-enhanced computed tomography (CECT) or magnetic resonance imaging (MRI).Doppler ultrasound may show patchy neovascularisation in a tumour thrombus, which would be absent if thrombosis was caused by compression.