Osteosarcoma of limb bones: a clinical, radiological and histopathological diagnostic agreement at Black Lion Teaching Hospital, Ethiopia.

OBJECTIVES: To measure the strength of agreement in clinical, radiological and histopathological diagnosis of osteosarcoma in a 5 year study period.
SETTING: Addis Ababa University, Black-Lion ('Tikur Anbessa') Hospital-BLH, is the country's highest tertiary level referral and teaching hospital. The departments involved in this study (Radiology, Pathology and Orthopedics) receive referred patients from all over the country.
METHODS: All bone tumor patients, presenting to the three departments at BLH between the study period, December, 2003 - March, 2008 were recruited for the study. 51 patients with radiological diagnosis of osteosarcoma of the extremities were identified and their clinical and histopathological diagnoses reviewed in detail. All patients had a clinical examination, plain radiographs and biopsies of the affected part of the extremity. Radiographs of selected difficult cases were discussed at joint orthopedic & radiologic sessions every week. The radiological and histopathological diagnoses made were categorized separately using WHO classification of bone tumors. Strength of agreement between radiological and histopathological diagnoses was measured using Cohen's Kappa test.
RESULTS: Of the total of 216 bone tumor patients presented and biopsied in the five year period, fifty one (51) had osteosarcoma of extremity bones. Commonest age affected by osteosarcoma was 16 (7-55 years) and sex ratio was 1:1. Osteosarcoma was also the single most common clinical, radiological and histological diagnosis made. Considering all bone tumors presented together, the study indicated that radiological diagnosis was confirmed by similar histological diagnosis in 172 out 205 cases (84%) and the corresponding Cohen's Kappa value (0.82) showed excellent level of agreement between radiological and histological diagnoses of all bone tumors. The agreement between radiological and histopathological diagnoses of osteosarcoma of the limbs was 84.5%.
CONCLUSION: There is an excellent agreement between clinical, radiological and histopathological diagnoses of bone tumors in general and osteosarcoma in particular. In setups where there is limited or no histopathological service, joint clinical and radiological decision could lead to a higher degree of accuracy in diagnosis of bone tumors, especially osteosarcoma. Radiological diagnosis of bone tumors at Black Lion Hospital, Addis Ababa is excellent.