[Paget disease of the bone: differential diagnosis of osteolytic lesions. Report of one case].

We report a 48 years old female with Paget's disease of the bone who consulted for leg pain. After exhaustive examination a magnetic nuclear resonance revealed a 7 mm intradural schwannoma that was resected without improvement. Four years later, with generalized, progressive bone pains, several osteolytic rib lesions were detected. A bone scintigraphy showed extensive areas of hyperfixation of Tc99 DPM. Biochemical tests were normal with exception of very high serum alkaline phosphatases. Looking for some neoplastic disease, a breast nodule was detected by mammography. Biopsy demonstrated benign disease. Finally, a rib lesion biopsy disclosed diagnosis of Paget's disease of the bone. Treatment with calcitonin, etidronate and vitamin D resulted in partial clinical improvement, reduction of abnormal isotope hyperfixation in bone scintigraphy and of serum alkaline phosphatase levels.