In this feature, AAOS Now publishes a series of images, challenging readers to diagnose the condition depicted.

This month’s challenge was submitted by Waldo E. Floyd III, MD, of Ortho Georgia in Macon, Ga.

A 62-year-old, healthy woman had a 10-year history of a painful and bulbous left middle finger terminal segment (Fig. 1). There was no history of cold hypersensitivity. Radiographs demonstrated an expansile lesion in the distal phalanx (Fig. 2). Bone scan demonstrated no other site of involvement. Chest radiographs were negative. What’s your diagnosis?

Fig. 2 Radiograph of the finger.
Courtesy of Waldo E. Floyd III, MD

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Do you have a challenging case you’d like to submit for publication? Email a short case description and any accompanying images to aaoscomm@aaos.org

Answer
According to Waldo E. Floyd III, MD, who submitted the case, the patient had an intraosseous epidermal inclusion cyst.

“Fifteen years ago, the patient injured her nail in a car door. We used a midaxial approach to expose the distal phalanx and excised the encapsulated cystic mass. We packed the distal phalangeal cavity with cancellous bone graft from the olecranon,” reported Dr. Floyd.