[Results of fine-needle aspiration cytology (FNAC) in the diagnosis of indeterminate solid renal tumours].

Objective: To evaluate the accuracy of fine-needle aspiration cytology for the diagnosis of imaging indeterminate solid renal tumours.

Materials And Methods: From February 2003 to February 2009, 60 cytoaspirations have been performed to 20 female and 40 male patients (average age: 62.0+/-14.2 years) with an indeterminate solid renal mass by imaging. The average tumour size was 3.4+/-2.8 cm. The cytoaspiration was performed through a 22 Gauge needle under CT (n=39) or US (n=21) guidance. Papanicolaou staining was used. All slides were examined by one experienced cytologist without any clinicoradiological information. The results were given as malignant, benign, suspect or non significant. A classification of subtypes of renal cancer might be added by the cytologist.

Results: Twenty-one cytoaspirations (35%) were non significant while 39 (65%) showed cells of interest. Among these 39 cellular cytoaspirations, the specificity for malignancy or benignity was 89.7%. The proportion of non-significant samples was the same in tumors lesser than 2 cm (38.4%) as in tumors 2-4 cm (38.8%) (p=1.000, Fisher's exact test). Subtype identification was only reliable for clear cell carcinomas. No complication was observed.

Conclusion: The fine-needle aspiration cytology is an auxiliary technique for the diagnosis of indeterminate solid renal tumours. This simple and mini-invasive technique had a high specificity but a low sensitivity in our experience. Fine-needle aspiration is complementary to core biopsy which remains the gold standard of percutaneous sampling.