A 65 year-old woman has a smooth, pinkish papule on her index finger. Let’s diagnose.

A 65-year-old woman visited her doctor about a growth that developed on her finger 2 months prior. It was not painful or itchy and had not grown since she first noticed it. On examination, a solitary, smooth, pinkish papule with a tiny central crust was seen on her distal interphalangeal joint on her right index finger. The patient had a history of osteoarthritis. Skin biopsy histopathology showed a well-circumscribed superficial collection of dermal mucin without a true cyst lining; The overlying epidermis was atrophic, hyperplastic or hyperkeratotic; with a variable increase in fibroblasts and absent fibrous wall.

What’s the diagnosis?

Use the Differential Builder in VisualDx to help you.

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