臨床病理学ジャーナル

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Morphological Features of Wilms Tumour in a Tertiary Health Care Institution: Our Findings

Soyemi SS, Osuoji RI, Faduyile FA, Sanni DA, Oyewole OO, Obafunwa JO and Bankole MA

Nephroblastoma or Wilms’ tumour is the most common primary renal malignancy of childhood. Despite being a malignant tumour, a survival rate of over 90% is now seen today (compared to 30% in the thirties) and this resulted from the success of collaborative trials and the use of multimodal therapy. Black children have a 2.5 times increased incidence over their white counterparts and the sex ratio is approximately 1.0. It is also associated with a number of recognised syndromes. The most important prognostic indicators for Wilms’ tumour are the histological subtype and the stage at presentation. Although, studies have been carried out on this tumour focussing on the clinical aspect, it is worthy of note that very little study has been done on the morphological features of this tumour in this centre and the country at large. The purpose of this study is therefore to look at the morphological patterns of Wilms’ tumour seen in this centre and if possible determine whether a relationship exists between the size, position of the tumour and the histological subtype, and finally, if a particular histological subtype is age-related.

Patients and method: This is a retrospective study of the cases of Wilms’ tumour seen in the division of paediatric surgery in our tertiary health care institution over a 5-year period i.e. (from Jan 2008 to Dec 2012). The nephrectomy samples of these patients were sent to the department of pathology and forensic medicine in the same institution. During grossing of the samples, adequate attention was paid to any obvious degenerative changes such as haemorrhage and necrosis. Where these changes were seen, they were recorded. The tumour sizes in the largest diameter and weights were also recorded. This was followed by histopathological reports which not only included the diagnosis, but also the histological types. These were all recorded in a pre-designed data form. The age at presentation in months and sex were also recorded in the form. All these were analysed using the statistical package for social science (SPSS) Software version 17.

Results: In this study, 44 patients had Wilms’ tumour with males representing 26 (59.1%) while females accounted for 18 (40.9%) and a male to female ratio was 1.4:1. The ages of the patients ranged from 10 months to 8 years with mean age value of 4 ± 2.91. The mode as well as the median age was 3 years. 24 (54.5%) of the tumours were located on the left position while 20 (45.5%) were seen on the right side. Most of the tumours weighed between 501-1000 grams representing (40.9%). In terms of tumour volume, majority measured between 1001-2000 cm3 accounting for (40.9%). Necrosis was observed in 95.5% of the cases. It is also worthy of note that all the tumours had areas of haemorrhage grossly, and 100% exhibiting triphasic histological pattern. This characterizes the classical WT. Bilateral or Synchronous tumour was not seen in this study.

Conclusion: The predominant histological pattern of Wilms’ tumour in this centre is the triphasic pattern representing the classical wilm’s tumour. It is most common in children between the ages of 1 and 5 years with average tumour weight of between 501 and 1000 gm. The bilateral (synchronous) or metachronous type of Wilms’ tumour was not seen in this study.