Hemorrhagic Synovitis of the First Metatarsophalangeal Joint: A Case Report.

Case: A 69-year-old woman presented with a painful mass at her first metatarsophalangeal joint. Further evaluation was concerning for a neoplastic process, leading to surgical intervention. Pathological examination demonstrated hemosiderotic synovitis, and hematologic evaluation led to a new diagnosis of von Willebrand disease.
Conclusion: Hemorrhagic synovitis, involving mostly larger joints, has been well described. However, a literature search demonstrates no cases of this in the foot or toes. Presentation of hemarthroses and underlying coagulopathies can be subtle and must be considered in patients presenting with soft-tissue masses or pseudotumors, despite having no previous diagnosis.