Background Osteomalacia is a defect of mineralization of the protein framework of the skeleton.

Objectives We try through our series to determine the presentation modalities and the various causes of this fragile benign osteopathy.

Methods It is a descriptive retrospective study of cases collected in our rheumatology department between 2001 and 2016, concerning patients with osteomalacia

Results Twenty patients were collected: 13 women and 7 men with an average age of 53±19 years [22 years, 80 years]. The mean duration of the disease is 45 months [5–172]. The findings were: bone pain in 55% of cases, pelvic pain in 45% of cases, a waddling gait in 5 cases (25%), fractures with low energy in 40% of cases, Functional impotence of the lower limbs in 35% of cases and a biological discovery in 2 cases (10%). Hypocalcemia, phosphorus deficiency and hypocalciuria were found in 14 cases, ie 70%. Alkaline phosphatases were elevated in 12 cases, with a variable rate of 2 to 7 times normal.The PTH, performed in 17 cases, was elevated in 53% of the cases. In our series, all patients had hypovitaminosis D. In addition, an associated iron deficiency anemia was detected in 50% of the cases, biological stigma of digestive malabsorption in 40% of the cases and renal insufficiency in 15% of the cases. Standard radiographs showed diffuse demineralization in 90% of cases, Looser-Milkman streaks in 40% of cases and fractures in 30% of cases. Bone scintigraphy among 8 patients revealed diffuse hyperfixation in 4 cases (50%), localized hyperfixation in 3 cases (37%) and non conclusive images in only one case (12.5%). Bone densitometry performed in 5 patients showed secondary osteoporosis in 80% of cases. The diagnosis of osteomalacia was retained in 2 cases, celiac disease in 5 cases, renal insufficiency in 1 case, phosphate diabetes in 3 cases including Fanconi syndrome, hypophosphatasia in one case and tubular involvement as part of ankylosing spondylitis In one case. Etiology was a neoplastic cause in 4 cases including multiple myeloma. All the patients had a vitamin-calcium treatment (calcium intake between 500mg and 2g per day with an average of 2.5 cp/d, phosphorus in 3 cases and an etiological treatment in 3 cases. The resection of the tumor was the reason behind a clinical-biological improvement in the case of thyroid tumors. The outcome was favorable in the short term for all cases.

Conclusions Osteomalacia is a generalized benign osteopathy, essentially linked to a deficiency in vitamin D often unrecognized. The diagnosis is simple and the treatment is easy, but the ignorance of the etiological forms can be responsible for an unfavorable evolution.

Disclosure of Interest None declared