A 56-year-old man attends having knocked his finger while working in the garage. He repos having had a small lump on his finger for some months and, since knocking his finger, this has been leaking, as shown below. What is the single most likely diagnosis?

Myxoid cysts Ganglions of the distal interphalangeal joint. They grow slowly and often cause grooving of the nail as they grow. They are benign but can become painful. Treatment is by aspiration of the thick jelly inside or injection with steroid, or surgical excision if they recur. A keratoacanthoma has a plug of keratin in the center. Pyogenic granuloma usually grows rapidly at the site of trauma. Sebaceous cysts are not typically seen on digits.