[Paget's disease: case report]

Paget's disease is a chronic metabolic condition characterized by a local imbalance between the resorbing activity of osteoclasts and the osteogenic activity of osteoblasts which leads to the remodeling of bone tissue with richly vascularised foci of loose and compact bone. The disease usually affects the elderly and males predominate. Lesions generally occur in pelvic bones, bodies of lumbar vertebrae, femoral bones, skull, and tibiae. Symptoms depend on the extent of lesions and include pain caused by microfractures or secondary degenerative-productive lesions, warmth in the affected area, bone deformations, fractures, neurological symptoms in the form of compressive or ischemic radiculopathy or compression of cranial nerves, and external carotid steal syndrome with increased flow through the affected bone. The natural course of the disease can be divided into the following stages: hot (prevalence of increased bone resorption); mixed (bone destruction is accompanied by formation of new bone); cold (predominance of osteoblast activity, diffuse enhancement of bone density, bone enlargement and expansion). Laboratory tests reveal higher levels of markers of bone formation (alkaline phosphatase, N-telopeptide alkaline phosphatase, osteocalcin) and markers of bone resorption (telopeptide of type 1 collagen, hydroxyproline in urine). Radiology of long bones shows the coexistence of foci of compact and loose bone tissue. The spine reveals picture-frame vertebral bodies with increased anteroposterior dimension and sclerotic remodeling, Thickening of the skull cap is noted. Paget's disease should be differentiated with fibrous dysplasia of bone, hyperparathyroidism, 'juvenile Paget's disease' (familial idiopathic hyperphosphatemia), lymphoma, and metastatic cancer. Salmon calcitonin represented a breakthrough in therapy. Today, bisphosphonates are recommended to treat Paget's disease.

We present the case of a 50-year-old female who underwent physical examination in January 2011 and was diagnosed with a bone tumor of the skull cap in the right forehead area. X-ray showed osteosclerosis of the skull suggesting Paget's disease. The patient was admitted in March 2011 to the Department of Hematology where multiple myeloma was excluded. Diagnosis was reattempted in January of 2012 at the Clinical Unit of Rheumatology and Connective Tissue Diseases, Second University Hospital in Bydgoszcz. During her stay at the hospital, several laboratory tests (alkaline phosphatase, calcium, parathyroid hormone, osteocalcin, telopeptide of type 1 collagen), together with radiographs of the skull, forearm, pelvis, and lower leg provided ground for the diagnosis of Paget's disease. The patient was qualified for treatment with ibandronic acid.