A Pregnant Woman with Multi-Fragmented Giant Cell Tumor of Tendon Sheath: A Rare Anatomical Location.

Giant cell tumor of the tendon sheath (GCTTS) in the foot is a rare pathology and is involved in the differential diagnosis of soft-tissue tumors of the foot and ankle. Although it can affect any age group, GCTTS mainly occurs at the 3rd and 5th decade and is more common in females. Histopathologic examination is a major definitive method for diagnosis, although physical examination and radiologic imaging are helpful in reaching a diagnosis preoperatively. Many treatment options exist but marginal excision is the most commonly used treatment. We describe the case of a 26-year-old pregnant woman with a multi-fragmented mass extending from the first web space to the plantar aspect of the metatarsophalangeal joint (MTP) of the left great toe associated with flexor hallucis longus tendon after trauma. She had pain that worsened with activity and wearing shoes. After pregnancy, a marginal excision with dorsal longitudinal incision in the first web space was performed under spinal anesthesia. The lesion was diagnosed as a localized type tenosynovial giant cell tumor. At the last follow-up appointment in the 23rd month, the patient was doing well and there was no recurrence of the lesion. GCSST should be considered in the differential diagnosis of plantar masses of foot. Although, GCTTS is frequently seen in females, it has not been previously reported in a pregnant woman with an extremely rare condition after trauma.