HNF 1 alpha mutated hepatic adenoma

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HNF 1 alpha mutated hepatic adenomas are a genetic and pathologic subtype of hepatic adenoma. Their appearance and prognosis are different from other subtypes.

Epidemiology

They are the second most common (30-35%) hepatic adenoma, after the inflammatory subtype. They occur only in female patients, most with a history of oral contraceptive (OCP) use.

Clinical presentation

May develop right upper quadrant pain from intratumoral hemorrhage.

Radiographic features

This subtype of adenoma is multiple in ~50%.

MRI
  • T1: isointense or  hyperintense relative to liver
  • T1 C+ (Gd):
    • moderate arterial phase enhancement (less than inflammatory subtype)
    • less likely to have persistent enhancement on portal venous and delayed phases, cf. inflammatory subtype
  • IP/OP: hypointensity on the out-of-phase sequence
  • T2: isointense to mildly hyperintense

Treatment and prognosis

If imaging shows a hepatic adenoma, then patients usually stop OCPs and the lesions regresses.

If it does not regress, then one treatment pathway suggests:

  • ≥5 cm: resection (hepatic adenomas larger than 5 cm are at increased risk of hemorrhage)
  • <5 cm: biopsy

Tissue diagnosis then confirms or changes the adenoma subtype. If HNF 1 alpha mutated pathologic subtype, then:

  • clinical and imaging follow up of any remaining adenomas until menopause
  • resection or thermal ablation of enlarging adenomas that grow >5 cm
  • genetic counseling if there is hepatic adenomatosis, familial history of hepatic adenoma, or MODY3 (mature onset diabetes of the young, type 3)

There is also a very small risk that a hepatic adenoma may develop into a hepatocellular carcinoma (HCC).

Differential diagnosis