Everolimus as a Therapy of a Benign, Infiltrative Growing Bone Tumor of the Mandibula: A Rare Manifestation with Tuberous Sclerosis

We report a patient with tuberous sclerosis (TSC) who shows a firm swelling of the right mandibula (29 × 56 × 45 mm) at the age of 2.6 years. The histologic evaluation demonstrated a desmoplastic fibroma, a benign yet aggressive and infiltrative growing bone tumor with high recurrence rates. The swelling led to a loosening of the teeth and an impairment of the mouth function.

Therapy of choice is a wide mandibular resection and reconstruction. We started a therapy with everolimus, an inhibitor of the mTOR-pathway on the assumption that the desmoplastic fibroma is due to a defect of the mTOR-pathway. This therapy resulted in a partial remission (23 × 41 × 36 mm) with an everolimus level of 7 to 12 µg/L.

Summary: Desmoplastic fibromas are associated rarely with tuberous sclerosis. A therapy of desmoplastic fibromas with everolimus has not been described yet and has led to a partial remission in our patient. A therapy with an mTOR inhibitor should be considered in patients with a desmoplastic fibroma associated with TSC before a mandibular resection.