Gorham-Stout Disease with Clinical Response to Sirolimus Treatment.

Gorham-Stout disease (GSD) is a rare clinical entity of unknown aetiology, with osseous resorption, vascular structure proliferation and inflammation of adjacent soft tissues. The clinical spectrum varies from asymptomatic patients to patients with pain, functional limitation or deformity. GSD may affect 1 or multiple bones in any location; however, predilection for the maxillofacial area and upper limbs has been described. We present the case report of a 33-year-old male patient with facial pain and loss of dental pieces; imaging showed extensive lytic involvement of the mandible and cranial bones. After exclusion of malignant, metabolic, infectious, or autoimmune disease, a diagnosis of GSD was made. Treatment with sirolimus was prescribed, achieving a symptomatic improvement and stability of imaging findings. The importance of the knowledge of this orphan disease is highlighted, to achieve a prompt diagnosis and medical treatment. LEARNING POINTS: Gorham-Stout syndrome constitutes an orphan disease with an unknown aetiology, it must be considered in young patients with osteolysis of unknown cause.The diagnosis of Gorham-Stout syndrome is an exclusion one.Drugs with antiproliferative and antiangiogenic activity such as mTOR inhibitors are an attractive option for the management of this disease. © EFIM 2021.