Improving recognition of hepatic perivascular epithelioid cell tumor: Case report and literature review

Figure 1 Computed tomography of the liver. A: The entire mass was visualized as low density on non-contrast computed tomography (CT); B: Contrast-enhanced CT showed a strongly enhanced mass in the arterial phase, and the center of the mass was weakly enhanced; the internal component-like structure showed relatively strong enhancement with a blotchy vascular pattern within the tumor (arrowhead) and distorted vessels (arrow); C and D: The portal (C) and late (D) phase CT scans showed washout of the contrast medium, and a portion of the internal area was weakly enhanced.

Figure 2 Magnetic resonance imaging of the liver. A magnetic resonance imaging (MRI) examination was performed on a 1.5 T Achieva Philips device. T1-weighted image (WI): FOV 350, matrix 256 × 204, slice thickness 8 mm, TR 147 ms, TE 2.3/4.6 ms, flip angle 80 degrees; T2-WI: FOV 350, matrix 240 × 196, slice thickness 8 mm, TR 3300 ms, TE 90 ms; T2*-WI: FOV 350, matrix 432 × 346, slice thickness 8 mm, TR 186 ms, TE 8.7 ms, flip angle 60 degrees; Diffusion-WI: FOV 350, matrix 128 × 102, slice thickness 8 mm, TR 1385 ms, TE 70 ms. A: The mass showed ill-defined low signal intensity on the T1-WI; B: There were no decreases in signal intensities in the out-of-phase (B) and in-phase (A) images; C: The mass showed high signal intensity on the T2-WI. The weakly enhanced center of the mass, as shown on computed tomography, was visualized as high signal intensity on the T2-WI, very similar to that observed in the entire mass; D: The mass was also visualized as high signal intensity on the T2*-WI after administration of superparamagnetic iron oxide; E: The mass showed high signal intensity on the diffusion-WI. The apparent diffusion coefficient was 1.491 × 10-3 mm²/s.

Figure 3 Digital subtraction angiography. Arteriography of the celiac artery showed strong enhancement (arrowheads) with thickened and distorted vessels (arrows) fed by the left hepatic artery on A and B.

Figure 4 Microscopic features of the operative specimen. A and C: Show low and high power views, respectively, of the borderline area of the tumor (T) and non-tumor (NT) areas (magnification × 20 and × 200, respectively, hematoxylin eosin staining); B: Shows immunostaining features using an anti-HMB45 antibody (magnification × 20); D: Shows the tumor including fat (magnification × 200; hematoxylin eosin staining).

Figure 5 The annual numbers of reported perivascular epithelioid cell tumor and epithelioid angiomyolipoma cases. PEC: Perivascular epithelioid cell tumor; EAML: Epithelioid angiomyolipoma.