Pattern of bone tumours seen at Addis Ababa University, Ethiopia

Abstract

Background: Primary bone tumors are uncommon malignancy, but they are important causes of cancer morbidity and mortality, especially among young people. To measure the strength of agreement in Clinical, Radiological and Histopathological diagnosis of all Bone Tumors in a -5-year study period from December, 2003 – March, 2008. Faculty of Medicine, Black-Lion Teaching Hospital, Addis Ababa University, Ethiopia. The study was also aimed at looking into the spectrum of bone tumors referred to BLH.

Methods: All bone tumor patients, who presented to all the three departments at BLH between the study periods of December, 2003 – March, 2008 were recruited. All files related to these patients were reviewed. All patients had a clinical examination, plain radiographs and biopsies of the affected part of the extremity. Radiographs of few selected difficult cases were usually discussed at the weekly joint Orthopedic & Radiologic sessions. 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: From the total of 216 bone tumor patients presented and biopsied in the five year period, complete information could not be gathered only for 11 (5%) of the patients and these are excluded. Hence there were 111(51.3%) males and 94(48.7%) females with Histopathological tissue diagnosis of the bone tumor. Male to female ratio was nearly 1. The ages ranged from 7 to 55 years with a peak in the 15-29 years age group. There were 32 different types of tumors histopathologically diagnosed. In 74 (36 %), the tumors were malignant. The commonest primary malignant tumour was Osteosarcoma (28.5%). It was also the single most common Clinical, Radiological and Histological diagnosis made. Exostosis was second. Considering all bone tumors 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 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. All mixed density lesions located in the metaphysis of long bones around the knee joint in young adults with sharp pain should be investigated as Osteosarcoma until proven otherwise. In set-ups 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.