Comparative Analysis on Imaging Manifestation and Pathological Features of Renal Epithelioid Angiomyolipoma

objective: To study the imaging features and pathological characteristics of renal epithelioid angiomyolipoma(EAML). Material and Method: Image findings and pathologic features of 7 cases with EAML proved by pathology were retrospectively studied from 2008-2014. Results: There were totally 8 lesions of 7cases, including five lesion extruded of the kidney, 2 lesions grown into renal sinus, 1 lesion simultaneously extruded of the kidney and grown into renal sinus;; Unenhanced CT, three cases showed slightly highdensity, two cases showed iso-density. One case showed hypointense on T1-weighted imagingand hyperintense on T2-weighted imaging;After intravenous enhancement, two cases showed "fast-forward and slow-out" and two cases showed “fast-in and fast-out” on enhanced CT; "Renal cortex lifted sign " may be seen in five case), "Black star sign" could also be found in five cases, "Renal cortex lifted sign" and" black star sign” can be seen simultaneously in 4cases; 2 cases had malignant sign in histologic examination. Histologically, the tumors were predominantly composed of epithelioid cells, smooth muscle, thick-walled blood vessels and adipose tissue. Immunohistochemical study showed that the tumor cells were positive for S-100, vimentin, HMB-45, HHF-35 and CD34. Conclusions: The imaging findings of EAML are multivarious. And it's difficult to distinguish with other diseases. If part of the tumor extrude of the kidney or grow into renal sinus and the lesions are slightly high density or iso-density in plain CT scan, it may be a suggestive diagnosis of EMAL.