In this feature, AAOS Now publishes a series of images, challenging readers to diagnose the condition depicted. The images for this month’s challenge were submitted by Valerae O. Lewis, MD, from the MD Anderson Cancer Center in Houston, Texas. Dr. Lewis provides the following information:
“The patient is a 14-year-old male who was seen for pain and swelling in the left knee. Plain film radiograph (A) revealed eccentric radiolucency with an osteolytic lesion of the distal lateral femur. A bone scan did not reveal any indication of femoral lesion. An MRI of the left femur showed a focal mass in the lateral aspect of the femoral epiphysis, with surrounding edema (B). A biopsy (C) was taken.”
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Last month, the diagnostic challenge was a 66-year-old recent Burmese immigrant with a 6-year history of soft-tissue masses of his left hand and both feet, which were neither painful nor tender to palpation. According to medical student and future orthopaedic resident Meagan McCarthy, who submitted the images, the correct diagnosis was gout.
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A, Plain radiograph showing osteolytic lesion of the distal lateral femur; B, MRI of the left femur—a focal mass can be seen in the lateral aspect of the femoral epiphysis, with surrounding edema; C, Hematoxylin-eosin staining of the biopsy specimen (×100).