Torsion of a mesenchymal hamartoma of the liver in a 1-year-old boy.

We report a case of a one-year-old boy who was referred to our clinic suspected of having acute abdomen. On physical examination, the abdomen was soft, diffusely tender with weak peristalsis. Ultrasonography and MRI of the right hemiabdomen demonstrated a well-defined, solid, expansive formation with slightly lobulated contours and an interspersed inhomogeneous structure with overall dimensions of 59 × 45 × 50 mm. After midline laparotomy was performed, a cystic tumor was found, twisted around a pedicle which was arising from the falciform ligament and it measured 5-6 cm in diameter. The tumor appeared to be necrotic. The mass was ligated and extirpated on the pedicle and sent for histopathological analysis. After the surgery, the boy was hemodynamically stable, without respiratory complications and all laboratory findings were within normal limits. Histopathological analysis showed that the tumor was composed of mesenchymal stroma with sparse glimpses of hepatocytes and bile ducts with partly cystic changes lined by orderly epithelium. Given the clinical data, histology and immunohistochemistry analysis (alpha-fetoprotein, CK8/18, hepatocyte, desmin and CD31) a diagnosis of a twisted mesenchymal hamartoma of the liver was made.