Diagnosis and differential diagnosis of hepatic graft versus host disease (GVHD).

Graft versus host disease (GVHD) is a common complication following allogeneic hematopoietic cell transplantation (HCT) that typically manifests as injury to the skin, gastrointestinal mucosa, and liver. In some cases, hepatic GVHD may be histologically indistinguishable from other disorders such as infection and drug-induced liver injury (DILI). Additionally, clinical signs and symptoms are frequently confounded by the superimposed effects of pretransplant chemoradiotherapy, immunotherapy (IT) (targeted to the underlying malignancy), GVHD prophylaxis, and infection. Thus, careful attention to and correlation with clinical findings, laboratory values, and histologic features is essential for diagnosis. This review, aimed at the practicing pathologist, will discuss current clinical and histologic criteria for GVHD, the approach to diagnosis of hepatic GVHD, and features helpful for distinguishing it from other entities in the differential diagnosis.