A 33-year-old male patient was referred for consultation because he presented with a tumour in the basal mandibular region at the parasymphyseal level on the right side with several years of evolution and slow growth. His medical history included tuberous sclerosis and having undergone a kidney transplant after a nephrectomy for renal angiomyolipoma. Symptoms of the disease included Pringle's sebaceous adenoma of Pringle in the nasolabial region, retinal hamartomas in the fundus and fibrotic lesions in the posterior cervical region. Clinical examination revealed a hard lesion adhering to the mandible, approximately 2x2 cm in diameter, with mild pain on palpation. On the skin of the lateral cervical region and on the nape of the neck, multiple small excrescent lesions of dark colouring and fibrotic appearance were observed. Intraoral examination revealed gingival hyperplasia, which was attributed to chronic anticonvulsant treatment with hydantoin to prevent the epileptic seizures typical of his underlying syndrome, which the patient had previously suffered.

Panoramic X-ray showed increased bone density at the mandibular level in the parasymphyseal region, and CT scan showed chondroid bone excrescence and erosion of the mandibular cortex at the right parasymphyseal level with no soft tissue mass component. The radiographic differential diagnosis included: ameloblastoma, odontogenic myxoma, aneurysmal cyst, chondromyxoid fibroma, central haemangioma or eosinophilic granuloma.

Under general anaesthesia and using a cutaneous approach, the hard round lesion was excised with a safety margin in the mandible. In addition, the cervical fibroids were excised in the same surgical procedure using a CO2 laser. The day after the operation the patient was discharged from the hospital. He has subsequently been seen in outpatient clinics without any signs or symptoms of recurrence of the mandibular lesion for three years.

Pathological examination of the excised mandibular bone lesion revealed a lesion consisting of a small number of fibroblasts and a stroma with a large amount of hyalinised collagen. Bone spicules were observed within the lesion without osteoid rim indicative of bone infiltration of the tumour. The lesion had spindle-shaped cells with elongated, uniform nuclei with few mitoses and no atypia, which made it benign. The study concluded that it was a desmoplastic fibroma.