Synopsis
extramedullary hematopoiesis (74%), including both myelopoiesis and erythropoiesis
portal and lobular inflammation mild-to-absent in 95% of cases
lobular cholestasis (from mild to moderate) with predominantely canalicular pattern (84%).
bile ducts hypoplastic (32%) but not absent or reduced in numbers.
mild focal ductular proliferation (18%)
portal fibrosis or pericellular fibrosis (30%; advanced in 8%).
Idiopathic (49%),
Secondary
hypopituitarism (16%)
biliary atresia (8%)
Alagille syndrome (6%)
bile salt defects (6%)
other entities (5%)
Of note, the biopsy findings did not readily distinguish between the different etiologies with the exception that bile duct hypoplasia was more common in cases of hypopituitarism. A pan-hypopituitarism is the most common recognizable clinical association with neonatal giant cell hepatitis.
References
Neonatal giant cell hepatitis: histological and etiological findings. Torbenson M, Hart J, Westerhoff M, Azzam RK, Elgendi A, Mziray-Andrew HC, Kim GE, Scheimann A. Am J Surg Pathol. 2010 Oct;34(10):1498-503. PMID: 20871223