Aberrant malignant invasive thymoma presenting as isolated left internal jugular vein thrombosis.and resected by VATS...

Though superior vena cava (SVC) syndrome due to local invasion by malignant thymoma has been well described in the literature, isolated local obstruction of the internal jugular vein with venous thrombosis has not been reported previously. Though SVC thrombosis has been frequently reported previously, this is the first reported case of isolated jugular vein thrombosis due to compression by an aberrant thymoma arising from an anomalous accessory thymus located behind the innominate vein.

Patient is a 51-year-old male who noticed prominent left neck veins of 1-month duration. Ultrasound of neck veins revealed left internal jugular vein thrombosis. Computed tomography (CT) scan of neck and thorax showed a 5 cm thymoma arising from an anomalous left lobe located behind the left innominate vein and compressing the internal jugular-subclavian vein junction. Internal jugular vein thrombosis resolved after 1 week of anticoagulant therapy. Preoperative assessment showed no evidence of myasthenia gravis (MG) or other paraneoplastic syndromes. Patient underwent a left video-assisted thoracoscopic surgery (VATS) thymectomy. Intraoperative findings showed a locally invasive malignant thymoma arising from an anomalous left lobe of the thymus behind the left innominate vein. There was no local invasion of the vein, but mechanical compression of the innominate vein, internal jugular vein junction by the tumour, causing venous thrombosis. VATS radical thymectomy was done. Postoperative recovery was uneventful. Final histology showed a stage 3 World Health Organisation (WHO) Type B2 thymoma. Postoperative mediastinal radiotherapy was given. Follow-up CT scan thorax, done 1 year post-surgery shows no tumour recurrence.

Malignant thymoma arising from an aberrant accessory left lobe behind the innominate vein can present as isolated internal jugular vein thrombosis. It can be resected safely by a "no-touch, tumour last" VATS oncological technique.