Diffuse Tenosynovial Giant Cell Tumor Encircling the First Metatarsal Bone Remodeling after Resection. A Case Report.

Introduction: The term tenosynovial giant cell tumor encompasses a group of rare soft-tissue tumors. A new classification divides the group in localized and diffuse type, depending on the involvement of the surrounding tissues. Due to the unclear origin and heterogeneity in extend of the diffuse-type giant cell tumors, there is only limited evidence on the tumor-specific treatment. Thus, every case report has an added value toward setting disease-specific guidelines. Case Report: Presentation of a diffuse type tenosynovial giant cell tumor encircling the first metatarsal. The tumor had mechanically eroded the plantar aspect of the distal metaphysis, with no signs of tumor spread. After an open biopsy, resection of the mass was performed without debriding or resecting the first metatarsal. Repeat imaging postoperatively showed no recurrence at 4-year follow-up and a bony remodeling of the lesion. Conclusion: Bone remodeling is possible after complete resection of diffuse tenosynovial giant cell tumor when the erosion is caused by mechanical pressure and no intraosseous expansion of the tumor is present.