Histopathological characteristics of adult renal tumours: a preliminary report.

OBJECTIVE To determine the relative frequencies of different renal tumours in adults and to analyze the histopathologic characteristics of renal cell carcinoma and its variants in the population studied. METHODS The study was carried out at Histopathology Department, Sindh Institute of Urology and Transplantation (SIUT) from April 2004 to October 2004. All consecutive adult patients with renal tumours managed surgically with tumour nephrectomies, were included. Nephrectomy specimens were fixed in 10% formalin. Gross and microscopic examination of the specimens was done according to standard protocol. Patients' demographic and clinical data were obtained from clinical charts and the histopathological features of tumours were retrieved from biopsy reports. RESULTS Among 50 patients, 33 (66%) were males and 17 (34%) females. Mean age was 47.9 +/- 15.1 years (range; 17 - 80 years). Most tumours were malignant: 47 (94%) vs. 3 (6%) benign. Among malignant tumours, renal cell carcinoma (RCC) was commonest; 41 (87.2%). Various subtypes of RCC included: conventional/clear cell RCC, 30 (73.2%); papillary RCC, 6 (14.6%); chromophobe RCC, 1 (2.4%) and sarcomatoid RCC, 4 (9.7%). Other malignant tumours were: rhabdomyosarcoma, 2 (4.2%); primitive neuroectodermal tumour, 1 (2.1%); transitional cell carcinoma, 2 (4.2%); and squamous cell carcinoma, 1 (2.1%). Benign renal tumours included one case each of angiomyolipoma, oncocytoma and metanephric adenoma. CONCLUSION The spectrum of adult renal tumours in this study consistent with that of previously reported literature. RCC is the commonest malignant tumor and conventional/clear cell RCC is the most common subtype. However, RCC presentation is delayed with a large size and an advanced stage of the disease, compared to published literature.