A generally well 82-year old man presented to a general surgical outpatient clinic with a swelling of the medial aspect of his left thigh. It started as a small lump which grew quickly over a few weeks to approximately 6 cm. There was no history of trauma or thromboembolic complication and the patient was asymptomatic. On examination, there was a firm round swelling which was non-tender and non-pulsatile. It did not seem to be attached to deeper structures and was not anatomically related to the nervous system. The patient was reviewed by a consultant – the diagnosis of a chronic sebaceous cyst was considered and he was offered an excision biopsy under local anaesthetic. Postoperatively, the patient had an unremarkable recovery but presented with a localized haematoma (Figure 1) on routine follow up, which was managed conservatively. Histology revealed the mass was in fact a venous aneurysm of the long saphenous vein.