Clinical characteristics and treatment outcomes in six cases of malignant tenosynovial giant cell tumor: initial experience of molecularly targeted therapy.

This study confirms that TGCT may transform into an aggressive malignant tumor. Lymph node and pulmonary metastases are common. Local recurrence rates are exceedingly high. Conventional cytotoxic chemotherapy showed clinical benefit, whereas tyrosine kinase inhibitors against CSF1R showed limited activity. Given its rarity, a prospective registry of malignant TGCT patients is needed to further understand the entity and to develop effective strategies for systemic treatment.