A 4 and a half years old male child presented to our hospital for abdominal swelling.

The child occasionally felt stomach ache that was relieved for no reason.

The child showed no obvious tenderness and rebound.

He was born as a premature baby in the 32nd week of his mother's pregnancy.

His medical history included inguinal hernia on 2 sides, but he had only received an operation for the left inguinal hernia.

No family or genetic history was found.

Physical examination of this child showed that the abdomen was obviously bulging.

The mass could be touched below umbilicus about 3 fingers.

There were no other positive signs.

The results of laboratory tests were almost normal, including alpha-fetoprotein (AFP) level.

The Child–Pugh score was less than 5.

Abdominal ultrasonography showed an uneven lesion in the liver and a diagnosis of HB was considered.

Enhancement computed tomography (CT) scanning showed a large mass in the left upper abdomen and left lobe of the liver with an irregular edge.

The size of the mass was 12.3 × 10.2 × 7.2 cm (Fig.1).

There was an uneven nodular shadow and the edge was obvious when the mass was enhanced.

Calcification and an expanded bile duct were not observed.

The left branch of the portal was pressed and the distant part was shown to be unclear.

Abnormal was not observed in the right branch.

According to the medical history, the diagnosis of HB was considered.

We did not recommend a biopsy to the patient because it might cause bleeding and tumor diffusion.

An operation was necessary.

The patient underwent DVSS surgery with sufficient preparation.

Exploration showed an extrahepatic 12 × 10 cm mass in the left lobe of the liver (Fig.2).

After the operation, the sample was split.

The edge of the tumor was clear but no envelope.

Tremelloid mesenchyme was seen on the section (Fig.2C).

The pathological examination showed that the sample was grey red and 14 × 13 × 7 cm in size.

The color of the section was grey red and grey white.

MHL was diagnosed (Fig.3).

Immunohistochemistry results (Fig.4) were the following: mesenchymal CD34 (+), D2–40 (+), S-100 (-), SMA (+), CD7 (-), epithelium CK19 (+), AFP (-), HCG (-).

After 9 days of recovery, the patient returned home without complications.

A follow-up examination, which included blood routine, liver renal function, coagulation routine, and ultrasound scan at 30 days, did not show any abnormality.

No adverse or unanticipated event was presented.