Among 11 PEN/portal hemorrhagic edema cases, the histology of 5 patients (cases 3, 5, 12, 15, and 1 C4d-negative case) was PEN (Table 3). PEN included portal hemorrhage, mild to moderate portal neutrophilic infiltration, perivenular endothelialitis without significant perivenular necrosis, and focal periportal necrosis (Fig. 3A)..