Abstract
Background : Unlike conventional angiomyolipomas, epithelioid angiomyolipomas (eAML) of the kidney often display aggressive behavior with recurrence and metastasis. Herein we report on a case of eAML diagnosed with pathological and imprint cytological examination and describe the cytological features with a review of the literature.
Case : A man in his 20s was seen in the hospital because of hematuria. Imaging examinations revealed a 4 cm in diameter, well-circumscribed solid mass in the upper pole of the left kidney. A left nephrectomy was performed. Intraoperatively, imprint cytology of the tumor mass was performed, in which many atypical cells that varied in size were seen in a necrotic background. Tumor cells showed an abundant granular cytoplasm, variably sized nuclei, prominent nucleoli with hyperchromasia, and intranuclear cytoplasmic inclusions. Histopathologically, atypical epithelioid cells were similarly seen, and were immunoreactive for Melan-A, HMB-45, and α-smooth muscle actin. On the basis of these findings, the patient was diagnosed as having an epithelioid angiomyolipoma.
Conclusions : Epithelioid angiomyolipoma is often difficult to diagnose because of the similarity in its morphology to sarcomatoid renal cell carcinoma and other sarcomas. However, the somewhat characteristic features such as the abundant granular cytoplasm may be helpful to include this tumor in the differential diagnosis, which allowed the performance of an accurate immunohistochemical study to establish a definitive diagnosis.
