Sinusoidal dilatation and congestion in post-transplant liver biopsies from patients presenting with transaminitis

Sinusoidal dilatation and congestion (SDC) in liver biopsy may be obstructive (due to venous outflow impairment) or non-obstructive in nature. The significance of this finding in the post-liver transplant setting remains unexplored.

We herein retrospectively analysed all post-transplant liver biopsies showing SDC and examined histopathological features in detail. Association with transaminitis and concurrent graft rejection was assessed.

A total of 30 post-transplant liver biopsies from 27 patients showed SDC with atrophy of hepatocyte cords (SDC; incidence 7.4%). All patients had transaminitis. Most patients (n=22; 81.5%) were asymptomatic with deranged liver function tests (LFTs) detected during routine follow-up, raising clinical suspicion of graft rejection. SDC was non-obstructive in 19 (70.4%) and obstructive (due to sinusoidal obstruction syndrome (SOS)) in 8 (29.6%) cases. The incidence of SOS was 2%. SDC was mild, moderate and severe in 18 (66.7%), 7 (25.9%) and 2 (7.4%) cases, respectively. Perivenular and centrilobular sinusoidal fibrosis was seen in the obstructive SDC group (n=3, 11.1%). Concurrent graft rejection was present in 7 (25.9%) cases, of which acute cellular rejection comprised 5 (18.5%), and late acute rejection accounted for 2 cases (7.4%). Serum tacrolimus levels ranged from normal (n=14) to below and above normal (n=5 each). Modulation of immunosuppressive therapy led to normalisation of LFTs in one patient.

Obstructive and non-obstructive SDC in post-liver transplant patients presenting with transaminitis mimics graft rejection clinically and may represent a form of drug-induced liver injury. Liver biopsy plays a crucial role in the diagnosis.