ESPE Abstracts

Background: Gorham-Stout syndrome (GSD) is a rare disorder characterized by lymphangiomatosis, osteolysis and potentially lethal in the presence of chilothorax.

Objective and hypotheses: As the management of GSD is not univocal and outcomes are unpredictable we build a multifaced protocol in order to study its natural history, biomarkers of bone disease and to treat uniformly patients.

Method: Seven patients (five males, two females, 3 months–26.0 yrs) with GSD confirmed by biopsy underwent clinical, biochemical (Ctx, BAP, PTH, 25OHD, D-Dimer, karyotype, CGH-array) and imaging evaluations (total body- (TB) and spine DXA and STIR total body MRI) at baseline and than yearly. All patients presented osteolysis at baseline (clavicle n=1, ribs n=2, femur n=1, sternum n=1, omerus n=1, scapula n=2, ulna n=1, cranial basis) and one lately (parietal bone), three reported pathological fractures (clavicle n=one female, femur n=one male, rib n=one male) and four chylothorax. Three males underwent INFα2b treatment, two males pamidronate, two males and one female zolendronate therapy.

Results: One male and female presented reduced TB and two males and one female reduced spine bone mineral density (z-scores between −2.8 and −1.1) with mildly increased bone turnover markers and elevated D-Dimer at baseline and during recidivism of bone or pleura. TB Stir MRI revealed aspecific involvement (hyperintensity in STIR and hypointensity in T₁) of multiple skeletal sites far from the primary localization in all and new foci of disease in two subjects. Five patients reached 4 years follow up; subjects on bisphosphonates displayed increase in BMD of about 1 z-score and all a sensible reduction of D-Dimer and pain. Karyotype and CGH were normal.

Conclusion: As chilothorax may be the early complication of a massive osteolysis in GSD, a multidisciplinary team is warranted. Our preliminary findings suggest i) the potential usefulness of STIR TB MRI technique in detecting early skeletal foci of disease, although further studies are needed and ii) the potential of disease control by anti-angiogenic and anti-reabsorption therapies.