Published 7/1/2013

What’s Your Diagnosis?

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

This month’s challenge was submitted by Howard R. Epps, MD, of Texas Children’s Hospital in Houston. Dr. Epps explains that this 10-year-old girl was referred to him by her pediatrician for evaluation of a developing mass on her foot. The mass was first noticed 4 years earlier and has grown slowly over time. The mass is not painful, but due to its increasing size, she is having difficulty finding shoes that fit. On examination, a firm mass—immobile and not tender to palpation—was noted on the lateral border of the foot. What’s your diagnosis?

Find the answer to this month’s challenge below

Lateral (
A), oblique (B), and standing anterior (C) radiographs showing a mass on the lateral border of the foot. The patient is a 10-year-old girl, and the mass has been growing slowly over the past 4 years.
Larger image (PDF)

The diagnosis is tumoral calcinosis, a condition characterized by periarticular deposits of calcium phosphate. The deposit was surgically removed.

Tumoral calcinosis may have a genetic or hereditary component and frequently involves multiple joints. Surgical excision must be complete to avoid recurrence. Onset of the condition frequently occurs early in life.

Send AAOS Now your case
Do you have a challenging case you’d like to submit for publication? Email a short case description and any accompanying images to