Giant cell tumor of the tendon sheath treated by brachytherapy (surface mold) technique-A technical illustration

Giant cell tumors of the tendon sheath (GCTTS) are rare tumors involving diverse locations and have a tendency to recur postoperatively. Hence, radiotherapy (RT) plays a pivotal role as an adjuvant modality to prevent local recurrences. Although RT is an attractive treatment modality, treating these tumors in complex anatomical locations, such as the thumb with external beam radiation (EBRT), and ensuring adequate dosimetric coverage can be challenging. Literature regarding the optimal RT technique to treat GCTTS is limited in view of the rarity of these lesions and their complex anatomical locations. In this report, we describe a case of GCTTS of the thumb treated successfully with surface mold radiotherapy using a customized thermoplastic mold for the thumb. The patient tolerated the treatment well with excellent local control and functional outcome.

We developed a brachytherapy mold technique using a customized thermoplastic thumb mold with interstitial catheters and irradiated the target volume homogeneously using microselectron iridium-192 high-dose-rate (Nucletron B.V., Veenandaal, The Netherlands) sources.

The index patient treated with surface mold therapy illustrates that this technique is safe and practical method to achieve excellent local tumor control with good functional outcome.