Occult trauma mimicking metastases on bone scans in pediatric oncology patients

Background. Tracer-avid osseous lesions are usually considered to represent metastases in pediatric oncology patients. However, sites of minor, clinically occult, skeletal trauma may be mistaken for osseous metastases. Objective. The objective of this study was to review our experience with skeletal scintigraphy in pediatric oncology patients to determine specificity for metastatic disease. Materials and methods. We reviewed 164 bone scans performed on 96 consecutive patients (ages 5 months to 23 years) at presentation with malignancy or during chemotherapy. Tumors included osteosarcoma (13), Ewing sarcoma (11), lymphoma (19), neuroblastoma (12), brain tumors (16), rhabdomyosarcoma (10), renal tumors (5), and miscellaneous neoplasms (10). Scintigraphic abnormalities were considered metastatic based on radiographic findings, subsequent tumor progression, or multiplicity of lesions. Lesions were considered benign when spontaneous resolution occurred without change in therapy or radiographs demonstrated a traumatic or other benign lesion. Results. Of the 96 patients, 51 had normal studies or showed only the primary lesion. Of the 45 patients with abnormal scintigraphy, 16 (35 %) had metastases and 29 (65 %) had one or more focal benign lesions. These lesions included abnormalities due to stress/trauma (25), benign neoplasm (2), infection (3), disuse (6), surgery (10) and artifacts (4). Conclusion. The majority of scintigraphic abnormalities have nonmalignant etiologies, most commonly stress reaction and trauma. In patients without known extraosseous metastases, one or two skeletal lesions should not be assumed to represent metastatic disease. Received: 11 December 1995 Accepted: 28 June 1996