Derm Dx: Semi-translucent tumor on the finger

A 59-year-old woman presents with a tender bump on her right middle finger. She reports a history of arthritis. The lesion is relatively asymptomatic, except for mild tenderness to palpation. On physical examination, between the proximal nail fold and the distal interphalangeal joint, a solitary, flesh-colored, semi-translucent lesion is observed. A small dark area is noted at the apex of ...