Clinical, Radiological and Histological Correlation in the Diagnosis of Orbital Tumours in Kenyatta National Hospital

Abstract

INTRODUCTION Orbital tumours constitute a diverse range of benign and malignant lesions. These tumours lead to morbidity and mortality in affected patients. Diagnosis of orbital tumours depends on thorough clinical evaluation and impression, appropriate imaging and histology results. STUDY OBJECTIVES This study was conducted to assess the level of agreement between clinical, radiological, and histological diagnoses of orbital tumours at Kenyatta National Hospital. The study was also done to describe the clinical patterns of orbital tumours at Kenyatta National Hospital. STUDY DESIGN AND METHODS A clinicopathological audit was conducted on patients with biopsy-proven orbital tumours seen at Kenyatta National Hospital eye clinic between 1st January 2014 and 31st December 2022. The clinical, radiological and histological features and diagnoses of these patients were recorded in a data abstraction tool. Concordance between clinical, radiological and histological diagnoses was analysed using kappa statistics and accuracy of clinical and histological diagnoses reported as percentage sensitivity and positive predictive value. Clinical patterns and features of orbital tumours are presented in tables and figures. Data was analysed using Statistical Package for the Social Sciences software. RESULTS A total of 137 patients with a histology report of orbital tumour were identified. In the sample,37.2% were children and 62.8% were adults. The male: female ratio was 1: 1.4. The sex difference was statistically significant(p=0.022). The mean age was 33.2 years (SD 25.2), while their median age was 34.0 years (IQR 9-50). There was substantial agreement between clinical and histological diagnoses-kappa 0.63 (0.53-0.72), fair agreement between radiological and histological diagnosis-kappa 0.33(0.18- 0.47) and moderate agreement between clinical and radiological diagnoses-kappa 0.45 (0.30-0.60). Overall, accuracy of 56.2% for clinical and 23.6% for radiological diagnoses respectively were found when compared to the histology report as the gold standard. Retinoblastoma and conjunctival squamous cell carcinoma showed the highest sensitivities and Positive 8 Predictive Values (PPV) of 100% and 95% respectively in clinical diagnosis. Retinoblastoma and meningiomas had highest sensitivities and PPV of 100% and 75% respectively in radiological diagnosis. Peripheral nerve lesions and myogenic lesions showed the lowest sensitivities (14.3%, 14.3%) and PPV (16.7%,20%) in clinical diagnosis while conjunctival squamous cell carcinoma had surprisingly the lowest sensitivity (12%) in radiological diagnosis owing to many cases of no definite diagnosis on radiology report. 54.9% of tumours in children were benign while 53.2% of tumours in adults were malignant. There was a statistical difference in type of tumour with age (p=0.005). The mean duration of symptoms was shorter for malignant tumours (mean 0.7 years SD 0.5) than for benign tumours (mean 2.4 years SD 0.9). CONCLUSION Clinical examination and imaging techniques alone are generally insufficient for accurately distinguishing between orbital tumours at Kenyatta National Hospital. Orbital surgical biopsy with histology should thus remain the gold standard for accurately diagnosing orbital tumours. Nonetheless, retinoblastoma with orbital invasion, conjunctival squamous cell carcinoma with orbital involvement, and meningioma showed relatively good diagnostic accuracy.