Comparison between radiographic and histopathological diagnosis of primary bone tumours at Moi Teaching and Referral Hospital

Abstract

Background: A primary bone tumor is an abnormal tissue growth arising from bone. Primary bone tumors are uncommon, but they are important causes of morbidity and mortality. Management outcome depend on early diagnosis. Plain radiography is the primary imaging modality of these primary bone tumours. It is cheap and readily available compared to the scarce histopathology services in our region. Objective: To determine the plain radiographic features of primary bone tumours and assess the percentage agreement between plain radiographic and histopathological diagnosis of primary bone tumours at MTRH.Also to assess the sensitivity and specificity of plain radiography in diagnosing primary bone tumours. Methods: This was a cross sectional, descriptive study conducted from 1st October, 2016 to 30th September, 2017, at MTRH, Eldoret-Kenya. A total of forty seven patients who had both the radiological and histological results of primary bone tumours were enrolled into the study. Data was collected using questionnaires where the radiographic diagnosis of the correspondents were filled in to the questionnaire. Histopathological diagnoses were followed up and recorded. Data was analyzed using STATA/MP version 13E. The radiological and histopathological diagnoses were then categorized separately using WHO classification of bone tumors.Percentage agreement between plain radiographic and histopathological diagnoses of primary bone tumours at MTRH as well as sensitivity and specificity of plain radiography in diagnosing primary bone tumours established. Results: The age of participants ranged from 10 to 74 years with a mean age of 26 years. The commonest presenting symptom was painless bony swelling, that is 29(61%) of cases. Plain radiography diagnosed 19(40.4%) of the cases as benign, majority being ameloblastoma and 28 (59.6 %) as malignant bone tumours with majority being osteogenic sarcoma. Lesion margin had a strong association with final histological diagnosis (p<0.001, Fisher Exact test,) while soft tissue involvement had a weak association with the histological diagnosis (p=0.176, Fisher Exact test). Percentage agreement of radiology and histopathology was higher for malignant bone tumours at 82.14% in comparison to their benign counterpart at 68.42%. The observed percentage agreement between the two diagnostic tests was 87%.plain radiography sensitivity was 88.2% and specificity was 86.7%. Conclusion: There was excellent percentage agreement between radiological and histopathological diagnoses in diagnosis of primary bone tumours with a good plain radiography sensitivity and specificity. Recommendation: Plain radiography can be used to diagnose primary bone tumours when histopathology services are unavailable, that is in resource poor set-ups.