PMC6791257_01
The explant liver from our patient with OTC deficiency contains a hepatocellular adenoma. (a) The tumor is a well-circumscribed, soft, tan nodule (shown by arrows), measuring 2.0 cm. (b) At low power magnification, the nodule is homogeneous without thick fibrous bands (H&E, 40x). (c) The background liver shows glycogen changes with clear to pink cytoplasm and distinct cell membrane (H&E, 200x). (d) The nodule is composed of hepatocytes with normal N/C ratios (H&E, 100X). (e) Reticulin stain highlights the normal reticulin framework and shows the hepatocellular plates of overall 1-2 cells in thickness (200x). (f) Immunostaining for HepPar1 shows diffuse immunoreactivity (200x).
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fig1
No other masses or lesions were identified (Figure 1(a)). Histologically, in multiple areas of the liver parenchyma, hepatocytes were mildly enlarged and swollen, with clear and pale cytoplasm and distinct, enhanced cell borders, consistent with glycogen changes (Figure 1(b) and 1(c)). The nodule was composed of clusters of hepatocytes forming cords of 1-2 cells thick, with normal nuclear to cytoplasmic ratio and bland-appearing nuclei (Figure 1(d)). Reticulin stain did not show abnormal hepatocellular network (Figure 1(e)). The lesional cells were immunoreactive to HepPar1, confirming hepatocytic origin (Figure 1(f)).
The hepatocellular adenoma is further subtyped as beta-catenin activated HCA. (A) Immunostaining for glutamine synthetase shows diffuse reactivity within the tumor (200x), (B) beta-catenin immunostain is negative for nuclear staining (400x). Intracytoplasmic globules in focal areas of the hepatocellular adenoma are observed. (C) PAS-D stain highlights small PAS positive and diastase resistant cytoplasmic globules (400x). These globules are immunoreactive with alpha-1-antitrypsin (D) but not alpha-1-antichymotrypsin (E) (400x).
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fig2
Instead, it showed a diffuse heterogeneous cytoplasmic staining pattern (Figure 2(a)) that is commonly seen in beta-catenin activated subtype HCA and HCC. Interestingly, beta-catenin immunostain was negative for aberrant nuclear staining (Figure 2(b)). These globules were immunoreactive to alpha-1-antitrypsin but not alpha-1-antichymotrypsin (Figures 2(c)-2(e)), confirming that they are alpha-1-antitrypsin globules.