Profile of osteolytic lesions on bone scan

Full text: Retrospective analysis of 35 osteolytic lesions seen radiologically was done. All the patients were subjected to three-phase bone scintigraphy. They were categorized into Category 1: Vascular (n = 10), Category 2: Nonvascular (n = 25). The nonvascular lesions were sub classified into those associated without biochemical evidence of metabolic bone disease (Class A) and those with biochemical as well as scan evidence of metabolic bone disease (Class B). Class B was divided into B1 - Osteomalacia and B2 - Hyperparathyroidism. In Category 1: 9/10 lesions were malignant. 1/10 lesion had septic arthritis. In Category 2: Class A - 3/15 had malignancy. (2 metastases, 1 plasmacytoma). (The nonmalignant lesions were 4 Fibrous dysplasia, 1 Eosinophilic granuloma, 4 Bone cysts, 1 Osteoid osteoma, 1 Avascular necrosis, 1 Inflammatory). Class B1 (n = 5) had low serum calcium, normal or high serum phosphorous, and high serum alkaline phosphatase. Class B2 (n = 5) has high serum calcium, low or normal serum phosphorous, high serum alkaline phosphatase and high serum parathyroid hormone level. Parathyroid scanning in-group B2 revealed parathyroid adenomas in the neck as the cause of hyperparathyroidism. It was observed that majority of vascular osteolytic lesions were malignant (90%). 75% of malignant lesions had evidence of hypervascularity on first and second phase (9/12). 80% of nonvascular lesions were benign. Metabolic bone disease is a frequent cause of osteolytic lesions (28.5%). (author)