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Atypical Tumoral Presentation of Calcium Pyrophosphate Deposition Disease: A Case Report
Ryan Krochak1, Maya Deza Culbertson, Vincent Vigorita
1Departments of Orthopaedic Surgery (R.K., M.D.C., and H.G.) and Pathology (V.V.), Maimonides Medical Center, Brooklyn, New York.
Case:
A 55-year-old man presented with a history of forefoot pain and swelling. Radiographs revealed a mass with internal calcifications and osseous erosion of the fifth metatarsophalangeal bone. The mass was isointense to muscle on T1-weighted magnetic resonance imaging (MRI) and hyperintense on T2-weighted MRI. A biopsy was performed, and intraoperatively, the lesion appeared as chalky white material, which under polarized light microscopy was composed of weakly positively birefringent rhomboid crystals, leading to a diagnosis of tophaceous pseudogout.
Conclusion:
Tophaceus pseudogout should be included in the differential diagnosis of neoplastic-appearing lesions in the foot, and polarized light microscopy should be used when examining biopsy specimens.
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