[Clinical, humoral and scintigraphic assessment of a bisphosphonate as potential treatment of diaphyseal dysplasia: Ribbing and Cammurati-Engelmann diseases].

Cammurati-Engelmann's Disease or Progressive Diaphyseal Dysplasia (PDD), is a rare autosomal dominant disorder, sometimes non hereditable, which begins in childhood, and is characterized by symmetrical excess of osseous apposition in diaphysis and metaphysis of long bones. In severe cases skull and vertebrae could be involved. Clinically, patients refer limb pain, muscular weakness and atrophy, easy fatigability and waddling gait. Later on S. Ribbing described an illness that he thought was a separate entity with sclerosis and enlargement of diaphysis of femora and tibiae, which begins after puberty, is less extensive, not always symmetric and without gait or neurological involvement. Some authors think it may be an adult form of the PDD. As no specific treatments are available we report one case of each entity, treated with the bisphosphonate pamidronate, by the oral route. A white female, 69 years old, with clinic and radiology of Ribbing's Disease, had positive scintigraphy in the affected areas and elevated bone biochemical markers: Serum alkaline phosphatase (SAP): 57 UKA. Total urinary hydroxyproline (THP): 60 mg/24 h. Bone Gla protein (BGP): 40 ng/ml. Considering the high bone turnover treatment with oral pamidronate, 400 mg/day plus Calcium 1g/day was started, dose was then progressively reduced. After two months pain almost disappeared, and THP became normal: 14 mg/24 h; with normalization of BGP values: 8 ng/ml, and a decrease of SAP: 21 UKA, 99mTc MDP uptake by affected bones decreased after 1 year of treatment. Because of these results we decided to begin treatment in a white female 17 years old, 32 kg weight, 1.47 m height with PDD characteristics and also a high bone turnover (THP: 95 mg/24 h. SAP: 32 UKA). After six months of Calcium 1 g/day, given with meals, and oral pamidronate 100 mg/day, she became painless with normal strength and gait, almost normalization of THP (48 mg/24 h). Although a small decrease of SAP, and no charges in scintigraphy. These results obtained with pamidronate suggest that it may be useful to treat dysplasias with high bone turnover.