Background: Renal cell tumours are numerous and heterogeneous. Because of their clinicopathological heterogeneity, their accurate diagnosis may be challenging. In case of an equivocal diagnosis, immunohistochemistry may be a useful mean of diagnosis. Recently, alpha-methyl CoA racemase has been identified as a useful marker in kidney cancers.
Aims: Our objectives are to highlight the role of alpha-methyl CoA racemase (AMACR) as a diagnostic marker in papillary renal carcinoma and to assess its utility in the other tumour types.
Methods: Aretrospective review was performed on 62 patients who were treated for renal tumours between January 1994 and November 2005. Immunoreactivity was evaluated with a qualitative manner. Positive AMACR staining was defined as a coarse dense cytoplasmic granularity.
Results: The 62 renal tumours were diagnosed as papillary tumours in 22 cases, clear cell tumours in 18 cases, chromophobe carcinoma in 12 cases and oncocytoma in 10 cases among the 22 cases of papillary tumours, all the cases (100%) showed cytoplasmic immunoreactivity staining. 4 cases between the 18 clear cell carcinomas (22%) showed positivity with AMACR. The 12 cases of chromophobe carcinoma didn't express AMACR by immunohistochemistry. Only one case between the oncocytomas (1%) expressed AMACR.
Conclusion: This study confirms the high sensitivity of AMACR for papillary renal cell carcinomas but we must keep in mind that weak focal AMACR staining could be present in other renal cell carcinomas.