17 ECE Poster presented at: 303-EP Vassilatou Evangeline DOI: 10.3252/pso.eu.17ece.2015 Calcium, vitamin D and bone FRAGILITY FRACTURES AS THE INITIAL MANIFESTATION OF INDOLENT SYSTEMIC MASTOCYTOSIS E. Vassilatou 1 , N. Gkavogiannakis 3 , A. Chatzipetrou 3 , Ch. Koulias 3 , M. Makris 3 , E. Garoflos 1 , D. Hadjidakis 1,2 , D. Rigopoulos 4 , G. Dimitriadis 2 METHODS Fourteen patients (9 women, 7 premenopausal), aged 27-63 years, diagnosed with ISM according to World Health Organization criteria (2008) were studied retrospectively. Clinical examination, biochemical evaluation and bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry at the lumbar spine (L 1 -L 4 ), the total proximal femur, the femoral neck and the distal one-third radius were performed. T-score was used to define osteopenia (<-1 to >-2.5 SD) or osteoporosis (-2.5 SD or lower) in postmenopausal women or men aged 50 years or older, and z-score ≤−2.0 for low BMD in younger men and premenopausal women, according to the guidelines of International Society for Clinical Bone Densitometry. Fractured vertebrae were excluded from BMD measurement. No patient reported other diseases or use of treatments known to affect bone or mineral metabolism, at initial assessment. Table 1: Clinical characteristics of ISM patients. Table 2: Laboratory characteristics of ISM patients. Table 3: Fracture history and BMD of ISM patients. CONCLUSION Bone involvement is frequent in ISM patients and may be the initial manifestation. Osteoporotic fractures of unknown aetiology should lead to the suspicion of SM particularly in individuals younger than 50 years. RESULTS  Three patients (21.4%) had fragility fractures: a 43-year-old premenopausal woman (patient No 4) & a 38-year-old man (patient No 10) had vertebral fractures, while a 31-year-old premenopausal woman (patient No 9) had non-vertebral fractures (Table 1).  Fragility fractures were the cause for SM investigation since none of these patients had cutaneous mastocytosis and only 1 patient reported a mild episode of anaphylaxis, at diagnosis (Table 1).  25(OH)D 3 deficiency (<20ng/ml) was detected in 7 patients (50%) (Table 2) .  Bone densitometry showed osteoporosis in 2 patients (14.3%), osteopenia in 2 (14.3%) and low BMD in 7 (50%) (Table 3). BMD z- score was generally lower at the spine than at the hip and at the femoral neck (all patients) (p<0.001).  Serum tryptase levels were negatively correlated (r= -0,615, p= 0,019 with lumbar spine BMD z-score (all patients) (Figure 1). OBJECTIVE To evaluate bone mineral density and fragility fractures in ISM patients. (*) Age at initial bone mineral density evaluation REFERENCES 1. Rossini M et al. Bone mineral density, bone turnover markers and fractures in patients with indolent systemic mastocytosis. Bone 2011;49:880 2. van der Veer E et al. High prevalence of fractures and osteoporosis in patients with indolent systemic mastocytosis. Allergy 2012: 67; 431 3. Guillaume N et al . Bone complications of mastocytosis: a link between clinical and biological characteristics. Am J Med. 2013: 126; 75.e1 4. Rossini M et al. Bone involvement and osteoporosis in mastocytosis. Immunol Allergy Clin N Am 2014; 34: 383 1 Endocrine Unit, 2 2nd Department of Internal Medicine-Propaedeutic, 3 Mastocytosis Outpatient Clinic, Allergy Unit “D. Kalogeromitros”, 4 2 nd Department of Dermatology and Venereology, “Attikon” University Hospital, Athens, Greece Figure 1: Correlation between serum tryptase levels & LS BMD z-score INTRODUCTION Systemic mastocytosis (SM) is a rare disease (2 cases per 100.000 population/ year) characterized by clonal proliferation of abnormal mast cells in several tissues, most often skin and bone marrow. Indolent systemic mastocytosis (ISM) is the commonest disease variant in adults, characterized by very low rate of mast cell proliferation. SM has been recognized as a cause of secondary osteoporosis. Lumbar spine BMD z-score r= -0,615 p= 0,019 Frag fractures: fragility fractures, LS: lumbar spine (L1-L4), T Hip: total hip, 1/3 radius: distal one-third radius, denotes osteoporosis, denotes osteopenia, denotes low bone mass (*) Fractured vertebrae were excluded from BMD measurement. Spearman correlation analysis