After another four weeks, an enormous increase in the size of the tumor leading to an ulceration had evolved (Fig. 1). The function of the whole right extremity was completely impaired due to the weight of the lesion. The neurologic function was as far as assessable not deficient.  A decision to perform the best possible resection in a function-preserving manner was taken after a multidisciplinary discussion with the CWS tumor board. Prior to the operation, the total body MRI showed a tumor measuring 2cm x 6cm x 9.5cm (342 ml) with direct contact of the tumor with the extensor tendons, vessels and nerves as well as a close relationship to the metacarpalia in interdigital space I and II. No distant metastatic lesions were found. The excision of the tumor was performed at the age of 6 months. Intraoperatively, a very precise preparation was required to preserve the function of the hand (Fig. 2). The tumor was removed in total and the large wound area with the preserved skin margins were closed. Postoperatively, the motor function of the arm and hand regained normal function (Fig. 3).