PMC9813661_01
Abdominal resonance magnetic imaging in February, 2019. (A) White target sign in which the bright central core is surrounded by a peripheral slightly hyperintense halo on T2-weighted images (white arrowheads). (B) Subcapsular lesions on T2-weighted images with capsular retraction (white arrow).
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T2, filled by liquid material and peripheral enhancement by the contrast medium, thus suggesting necrotic content, which would be the first sign that the nodules deserve further investigation (Figure 1). The largest nodule measured 6.3x6.1x4.0 cm, and was located in the liver segment VI.
Histologic findings from the sample obtained through laparoscopic biopsies. (A) Hematoxylin-eosin staining showing cords of epithelioid tumor cells within a characteristic myoid to hyaline matrix. (B) Hematoxylin-eosin staining displaying intracytoplasmic vacuoles. These spaces represent immature vascular lumina and may contain erythrocytes. (C) Immunohistochemistry showing the expression of CD31, an endothelial marker.
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However, the sample already had findings compatible with HEHE such as cords of epithelioid tumor cells, and intracytoplasmic vacuoles containing red blood cells (shown in Figure 2A,2B). Only when the patient was forwarded to our hospital in July 2021 the immunoreaction for CD31 was observed on the same sample from the first liver biopsy (Figure 2C). Additional staining for CD31 was performed, thus confirming the diagnosis (shown in Figure 2C).
Abdominal tomographic findings in May 2020. The tumors were typically seen as multiple hypoattenuating nodules in both hepatic lobes, coalescing to form larger confluent lesions with peripheral or subcapsular distribution (A). In (B), a halo (or target pattern) of enhancement can be seen around a larger lesion (white arrow). In (C,D), capsular retraction can be seen near two subcapsular tumors (white arrowheads). In (E), a portal vein branch tapers and terminates just within the edge of a tumor denoted as "lollipop sign" (black arrow).
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Then, a computerized tomography (CT) was done in May 2020 showing that the tumor located in the liver segment VI had dimensions of 12.9x7.3 cm (shown in Figure 3).
Chest tomographic findings in April 2021. Hyperdense nodules of 7 mm were observed in both lungs (black arrow).
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A chest CT showed 7-mm nodules diffusely distributed in both lungs, associated with longitudinal fissure thickening (shown in Figure 4).
Abdominal resonance magnetic imaging in July 2021. In (A), a T2 axial image shows heterogeneously increased signal intensity, with a white target sign in which the bright central core is surrounded by a peripheral slightly hyperintense halo (white arrow). In (B), the gadolinium-based contrast agent shows lesions with either a peripheral halo or a target-type enhancement pattern, with a thin peripheral hypointense rim (white arrowheads).
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A new MRI showed an enlarged liver, containing infiltrative tumors occupying most parts of the right lobe and part of the liver segment III, causing retraction of the liver capsule on segment VI, similar to the findings observed in the last CT (shown in Figure 5).
Volumetric images obtained from the magnetic resonance imaging in February 2019. The normal liver parenchyma is shown in green whereas the tumors are presented in other colors. Left upper quadrant: axial view. Right upper quadrant: three-dimensional view. Left lower quadrant: coronal view. Right lower quadrant: sagittal view.
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The results are shown in Table 1 and in Figures 6,7. Figures 6,7 show that many nodules coalesced, thus changing the nodules to giant tumors and causing hepatomegaly in this time span.
Weak nuclear immunoreactivity for TFE3 suggesting the presence of the YAP1-TFE3 fusion.
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The tumor cells presented TFE3 immunoreactivity (shown in Figure 8), suggesting the presence of the YAP1-TFE3 fusion, a distinct histological HEHE pattern in which mature lumina and epithelioid eosinophilic cells are observed.