This is a 7-year-old girl, with no relevant pathological or neonatal history, who presented for consultation with a clinical picture of 8 months' evolution consisting of a right upper gingival nodular lesion of approximately 3 x 3 cm in diameter, and who reported slow growth for 8 months, which accelerated in the 2 months prior to consultation. A computerised tomography (CT) scan was requested which showed a right maxillary tumour with infiltration towards the antrum and nasal cavity measuring 3 x 3 cm in diameter. In view of this diagnosis, the Paediatric Surgery Department indicated marginal resection of the maxillary tumour using a sublabial approach and the histopathological report of the resection specimen showed a 3 cm maxillary chondrosarcoma with grade II differentiation. The patient was subsequently sent for complementary treatment with adjuvant radiotherapy, which she did not attend. One year later she was readmitted to hospital with a recurrence of the tumour after 2 months of evolution. The tumour now showed accelerated growth, measuring 9 x 6 cm in diameter on CT scan and occupying the entire right maxilla and partially the left maxilla. Chemotherapy treatment was indicated at that time for tumour reduction and the patient received 9 cycles of Doxurrubicin 30 mg per m2 of body surface area; Vincristine 1.5 mg per m2; Mesna 300 mg per m2 and Cyclophosphamide 300 mg per m2, for 5 months, without achieving the desired effect. In view of this, the Plastic Surgery, Oncological Surgery and Head and Neck Surgery Departments were asked to assess the patient and decided to submit her to a new surgical intervention in which, after a tracheostomy, we performed a bilateral subtotal maxillectomy with palatectomy, including the tumour in its entirety and preserving the soft palate. The resection specimen was 10 x 8 cm, greyish, firm, with reddish mucosa, haemorrhagic and with areas of necrosis of 30%. The histopathological study performed with light microphotography and haematoxylin/eosin staining confirmed the diagnosis of grade II chondrosarcoma, cellular pleomorphism with 2 mitotic figures per field and with surgical edges free of tumour and without vascular permeation. In the same surgical procedure we carried out partial and temporary maxillary reconstruction with titanium mini-plates and alloplastic prosthesis. After 8 months of follow-up after radical surgery, the patient is in good general condition, with an adequate scarring process, with no evidence of local or distant tumour activity as evidenced by both clinical and CT scans.