[Tubulopapillary tumours of the kidney: prognostic value and therapeutic implications of the distinction between type 1 and type 2 based on a series of 58 cases].

Objective: The purpose of this study was to demonstrate the prognostic value of subdivision of tubulopapillary tumours into 2 histological subtypes and to discuss the therapeutic implications.

Materials And Methods: This was a single-centre retrospective study of 58 cases from a series of 414 patients operated for renal cancer between 1988 and 2001 based on review of histology slides (biopsies and operative specimens). The radiological assessment was based on ultrasound reports and review of CT scans. Karyotypes were described by cytogenetic analysis.

Results And Discussion: Tubulopapillary tumours represented 14% of all kidney tumours with a male prevalence of 77% and a mean age of 56.5 years. The overall mean follow-up was 62.6 months. Treatment consisted of 25 right radical nephrectomies, 29 left radical nephrectomies and 4 partial nephrectomies. 84% of tumours were low-grade and 80% were low stage T1 or T2. Multifocal lesions were observed in 31% of cases. Synchronous bilateral lesions were observed in 12% of cases. The 5-year survival was 95% and the 10-year survival was 87%, correlated with stage, grade, tumour diameter, presence of necrosis and low enhancement. According to the data reported by Delahunt, 2 subtypes can be distinguished: Type I tumours (75%) with low grade and low stage were correlated with a high rate of multifocal lesions (30%) with a genetic predisposition. Type 2 tumours (25%), usually unifocal, were correlated with a higher grade and stage, confirmed by their poorer prognosis. Biopsy allows a distinction of the type and grade of the tumour.

Conclusions: In our series, for equivalent mean tumour diameters (55 mm), tubulopapillary tumours treated by radical nephrectomy had a good prognosis regardless of their subtype. Classification of the tumour by biopsy prior to surgery could have implications for therapeutic management. For type 1 tubulopapillary tumours identified on preoperative biopsy, we propose radical nephrectomy due to the high risk of multifocal lesions (30%). Although partial nephrectomy may be indicated for type 1 tubulopapillary tumours less than 4 cm, the patient must be informed about the risk of recurrence and the importance of long-term follow-up. Studies including a larger number of patients must be conducted to compare the survival associated with type 2 tumours compared to that of the classical histological subtype.