ESPE Abstracts

Gorham-Stout disease(GSD), also known as vanishing bone disease is an extremely rare skeletal disorder characterized by idiopathic intraosseous proliferation of lymphatic vascular structures resulting in progressive resorption of bone. Herein, we report a case of a 4-year-old girl with GSD treated with the combination treatment with bisphosphonate, sirolimus, and atenolol. A 4-year-old girl presented with prolonged back pain for 2 weeks. The thoracolumbar spine radiography revealed mild to severe compression fractures and diffuse verterbral body flattening in T9-L3. Spine magnetic resonance imaging(MRI) showed diffuse T1 and T2 low signal intensity in C1-T8 spines, suggesting bone marrow dysplastic or infiltrative disease. A soft tissue and bone biopsy from the supraspinous region of T12 vertebrae was done. The soft tissue lesion was composed of hyperplastic blood vessels and fibrous tissues, similar to hemangioma. Bone biopsy showed nonspecific findings. Based on the above clinical, radiological and histopathological findings, the diagnosis of Gorham-Stout disease was established. The treatment with sirolimus (0.5mg twice a day) was started. The patient persistently had back pain, and intravenous bisphosphonate (pamidronate, 1mg/kg for 3days, total 3mg/kg every 4 months) was added after 1month of sirolimus treatment. Following the combination with bisphosphonate and sirolimus, she showed immediate improvement of back pain. Trough level of sirolimus was monitored and the dose was escalated from 1mg to 2.75mg a day, and she maintained the dose for 9 months. At this point, initial dual-energy X-ray absorptiometry(DXA) was done, since the patient’s age reached 5 years old, and her age-matched total body less head(TBLH) Z-score was -0.3. Spine radiography revealed ongoing scoliosis of the involved spines. Whole body MRI done after 9 months of bisphosphonate and sirolimus showed mildly increased extent of paraspinal lymphangiomatosis, and mild aggravation of compression fractures in T9-L5. Atenolol, a selective beta-blocker, which have been used in the treatment of infantile hemangioma, was added. Follow-up MRI after 4 months of the combination treatment with bisphosphonate, sirolimus, and atenolol showed decreased extent of paraspinal lesions at L1-L5. The patient underwent total 11 months of combination treatment of bisphosphonate, sirolimus, and atenolol, and MRI showed further regression of paraspinal lesions. Follow-up DXA showed increased TBLH Z-score of 0.1, compared to the previous data. In conclusion, bisphosphonates seems to be useful in relieving pain and a therapeutic combination of bisphosphonate, sirolimus, and atenolol may be helpful in controlling disease progression and improving the prognosis of GSD.