CORTICAL METASTATIC LESIONS OF THE APPENDICULAR SKELETON FROM TUMORS OF KNOWN PRIMARY ORIGIN

Background and Objectives: Metastatic disease represents the most comm on neoplastic process involving bone. Recently, a small subset of cort ical based metastatic lesions has been identified. We attempted to del ineate the incidence, origin, location, and possible significance of t hese lesions within an orthopaedic patient population. Methods: A char t and radiographic review of patients treated for metastatic disease t o bone over a 17-year period was performed. Inclusion criteria for les ions were as follows: 1) an appendicular skeletal site, 2) histopathol ogic confirmation of origin, and 3) presence within a patient diagnose d with a single, known neoplastic process. The lesions were classified as either cortical or medullary based. Results: Eighty-three lesions (70 patients) satisfied inclusion criteria. Most lesions were of pulmo nary (26), breast (22), renal (16), or prostatic (8) tumor origin. Eig hteen lesions (22%) from 15 patients were identified as cortical and r epresented initial presentation in 7 patients. These lesions were of p ulmonary (11), renal (5), and breast (2) tumor origin. Conclusions: Co rtical based metastases within the appendicular skeleton may occur mor e frequently than previously expected. While tumors of pulmonary and r enal origin accounted for 42 of the 83 (51%) appendicular lesions, the y were responsible for 16 of the 18 (89%) cortical metastases. This pr eponderance of pulmonary and renal metastases to the cortex is consist ent with previously published reports. Our findings may be of value wh en diagnosing and treating patients whose initial presentation is a co rtically based lesion. (C) 1998 Wiley-Liss, Inc.