Multiple localized giant cell tumor of the tendon sheath (GCTTS) affecting a single tendon: a very rare case report and review of recent cases.

INTRODUCTION: Giant cell tumors of the tendon sheath (GCTTS) are very common. More recently, a small number of case reports have identified the presence of multifocal GCTTS in the hand. These case reports have identified the presence of a maximum of two simultaneous lesions of a giant cell tumor affecting the same tendon sheath. We present an exceptionally rare case of simultaneous multiple localized GCTTS in which five lesions were identified on a single tendon simultaneously. This number of lesions on a single tendon has never been previously reported. CASE: A 37-year-old tree surgeon initially complained of pain in the region of the base of the ring and little fingers. A month later, he developed multiple soft tissue swellings at these sites and a soft tissue mass in the center of the palm relating to the left ring finger. A magnetic resonance imaging (MRI) scan suggested multiple GCTTS. These masses were excised completely without MRI evidence of a recurrence. Multiple GCTTS should be a differential diagnosis of multiple soft tissue swellings in the hand with an MRI scan and complete excision being the appropriate imaging and treatment modality respectively.