LETTER TO EDITOR
Year : 2001 | Volume
: 11 | Issue : 1 | Page : 41--42
Department of Radiodiagnosis, JLN Hospital, Bhilai, India
M K Dwivedi
Department of Radiodiagnosis, JLN Hospital, Bhilai
|How to cite this article:|
Dwivedi M K. Mesenchymal hamartoma.Indian J Radiol Imaging 2001;11:41-42
|How to cite this URL:|
Dwivedi M K. Mesenchymal hamartoma. Indian J Radiol Imaging [serial online] 2001 [cited 2019 Jun 26 ];11:41-42
Available from: http://www.ijri.org/text.asp?2001/11/1/41/28312
Mesenchymal hamartoma is an uncommon benign lesion arising from the mesenchyme of the portal tract. It consists of a mixture of mesenchymal tissue and bile ducts and is considered a developmental anomaly rather than a true neoplasm . It commonly presents as a painless abdominal mass before the age of two years. Because mesenchymal hamartoma is a benign lesion with excellent prognosis, distinguishing it from other liver masses is important.
A two-years-old girl presented with an abdominal mass with loss of appetite, vomiting and low-grade fever for five days. Ultrasound examination showed a well-defined round lesion, measuring 7.8 x 8.0 cm. in size in the epigastric region, having mixed echotexture but predominantly hypoechoic with central cystic areas. It was causing compression of the liver, which was otherwise normal [Figure 1]. The gall bladder was normal and the portal vein and common bile duct was not visualized. CT showed a well-defined round mass measuring 9.8 x 6.8 cm. abutting the undersurface of the liver. The mass was predominantly solid with areas of decreased attenuation centrally with septae [Figure 2]. Compression of the left and right lobes of the liver by the mass was seen and it showed normal parenchymal attenuation. CECT scan showed enhancement of the mass [Figure 3]. The rest of abdominal viscera were normal. Ultrasound guided fine needle aspiration cytology was performed and showed fascicles of spindle cells in a myxoid background. Few vascular fragments and a few clusters of benign ovoid cells were seen suggestive of mesenchymal hamartoma.
In 1956, Edmondson classified the tumor as mesenchymal hamartoma using the term hamartoma first coined by Albrech  implying a developmental anomaly rather than a true neoplasm. The mass arises from the indigenous mesoderm within the portal tracts. Mesenchymal hamartoma accounts for 3% of all childhood tumors. It is usually a slow growing tumor and is most common before the age of two. Rapid enlargement may result from rapid fluid collection in the cyst. Mass effect from bulky tumors may cause respiratory distress or lower limb swelling.
Most mesenchymal hamartomas are located within the right lobe of liver. The mass may blend with the adjacent liver, may be encapsulated or may be attached to the liver by a pedicle . Mesenchymal hamartomas are usually large; the tumor cut surface shows either mesenchymal predominance (solid component) or a cystic predominance (cystic component). Sonography is very informative and should be the primary screening technique. It reveals a large intra-abdominal mass, predominantly cystic with multiple, thin, echogenic septae in contact with normal liver parenchyma. The tumor may be more solid with small cysts surrounded by thick echogenic septae. The intrahepatic biliary radicals are normal.
CT supports the sonographic findings confirming the extent of the mass and its relationship to the adjacent structures. On CT, mesenchymal hamartoma usually appears as well defined mass with central area of low attenuation with internal septae . The solid component of the lesion may be more predominant with multiple small cysts giving the lesion a "swiss-cheese" appearance.  The mass is usually large and well demarcated from normal liver exhibiting predominantly cystic lobules . MRI appearance depends on the mesenchymal or cystic predominance. Lesions of mesenchymal predominance are hypointense on T1W. Cystic predominant lesions are of variable intensity on T1W and hyperintense on T2W images.
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