Swollen thumb

A middle-aged African American gentleman presents to the office with a lump on his Rt. thumb that has been progressively enlarged over the past few years. He does not recollect any trauma and does not have similar lump anywhere else on his body. Examination shows a 3- 4 cm, soft- firm, non-inflamed, relatively immobile and non-translucent lump on the dorsum of the Rt. thumb near the DIP.
Which of the following is the most likely diagnosis?

1. Tendon cyst
2. Epidermal inclusion cyst- ANSWER
3. Lipoma
4. Mucinoid cyst
5. Heberden’s node