Hereditary tyrosinaemia (HT) type 1A.

Two infants, aged 5 and 6 months, with the chronic form of HT Type 1 A were studied with sonography and CT. The imaging findings mirrored the pathological process. The sonographic findings included marked hepatomegaly, the parenchyma being of increased echogenicity due to fibrosis and fatty infiltration, and containing multiple hypoechoic regenerating nodules of varying sizes. There was marked nephromegaly, with uniform thickening of the renal cortices. Apart from the density measurement of the hepatic nodules and the perfusion status of the liver and kidney, no additional information was added by CT imaging. The diagnosis of HT Type 1 A should be excluded in an infant presented with the described typical sonographic features.

Symptomatic third ventricular choroid plexus cysts.

We describe the imaging findings in 3 children with choroid plexus cysts (CPC) at the foramen of Monro. All CPC measured less than 2 cm and produced symptoms of raised intracranial pressure when located at the foramen of Monro where there was obstruction to the cerebrospinal fluid (CSF) flow. Among the imaging studies done on our patients, CPC were depicted best by cranial sonography and CT-ventriculography and missed by standard CT and MRI. Misdiagnosis can lead to inappropriate shunting with adverse effects. Two of our patients had relief of symptoms after resection of the cyst. One patient with inoperable cardiac defects died and had no surgery performed. Serial CT and sonographic studies in this patient showed progression in the size of the cyst and ventriculomegaly. Cranial sonography and CT-ventriculography are the modalities of choice in evaluating ventriculomegaly when the diagnosis of occult obstructive CPC is entertained in children. Cranial sonography is indicated in infants with an open fontanelle and CT-ventriculography is reserved for older children with hydrocephalus which is not responding to shunting.