A suggestion for pathological grossing and reporting based on prognostic indicators of malignancies from a pooled analysis of renal epithelioid angiomyolipoma.

PURPOSE

Epithelioid angiomyolipoma (EAML) is a rare entity of the kidney. The guideline for grossing and reporting of renal EAML has not been established for Chinese patients. We planned this study to provide some preliminary indicators for draft guidelines of pathological diagnosis among Chinese people.

METHODS

The histopathological characteristics of 11 EAML cases from Cancer Hospital, Chinese Academy of Medical Sciences, were reviewed, and a pooled analysis based on our cases and cases from published articles was performed on the histopathological characteristics and prognosis of 56 Chinese patients with EAML. All the cases met the criteria of the 2004 World Health Organization classification of renal tumors.

RESULTS

The ratio of female to male was 1.2:1 with the mean age of 43.4 in the 11 cases. All the 11 cases were sampled following the guideline of renal cell carcinoma. The mean tumor size was 6.5 cm. Four (36.4 %) cases showed necrosis. Six (54.5 %) cases showed invasive borders. Only one case showed metastases. In pooled analysis of the total 56 cases with EAML, 10 cases (17.9 %) showed adverse prognosis. Tumor size, necrosis and invasive edge showed significant difference between favorite and adverse prognostic groups (P < 0.05).

CONCLUSION

The majority of EAML is benign, and true malignant EAML is rare. The sample of EAML should follow the sample guidelines of renal cell carcinoma with some modifications, emphasizing the presence of necrosis and invading edge. The information of tumor size, necrosis and invasive edge should be included in the diagnostic report of each EAML case.