Unusual case of bifocal leptomeningeal melanocytoma in the posterior fossa with seeding in the spinal canal.

A 26-year-old man presented with signs of raised intracranial pressure. CT and MRI of the head demonstrated two separate lesions in the posterior fossa. The radiological differential diagnoses included multiple meningiomas, schwannomas, neurofibromas and subependymomas. Both lesions were surgically resected. Histopathological examination revealed localisations of a leptomeningeal melanocytoma. Leptomeningeal melanocytoma is a rare tumour of the central nervous system. Generally, it has a good prognosis if radical resection can be performed. In cases of subtotal resection, adjuvant radiotherapy should be considered. Local recurrences are common. Less frequently, leptomeningeal metastases and, on rare occasions, distant metastases or progression to malignant melanoma have been described. We describe an unusual case with multiple localisations of melanocytoma in the posterior fossa and spinal canal, with the emphasis being on the radiological findings and diagnosis of this rare tumour. After surgery of the brain, this patient was irradiated on the craniospinal axis.

Development of intrahepatic arterial shunts in a transplanted liver: a potential pitfall for Doppler sonography.

We describe the hemodynamic features and anatomic basis of false-negative Doppler sonographic findings compared with angiographic findings in a 42-year-old woman after orthotopic liver transplantation complicated by hepatic artery thrombosis. Complete common hepatic artery thrombosis was demonstrated by Doppler sonography and digital subtraction angiography (DSA) on the first postoperative day. A thrombectomy was performed. DSA on the third day after transplantation again showed occlusion of the left hepatic artery. No perfusion was observed in the left hepatic lobe. Liver function remained normal. Doppler sonography on days 8, 10, and 16 after transplantation demonstrated arterial blood flow in both the right and left lobes of the liver, suggesting patent left and right hepatic arteries. Repeat DSA revealed that the arterial flow in the left lobe depended on large, intrahepatic shunts originating from the right hepatic artery. Apparently, shunts can develop within a few days in a transplanted liver from radiologically undetectable structures into vessel-like channels capable of supplying the entire left hepatic lobe.

A girl without a chiasm: electrophysiologic and MRI evidence for the absence of crossing optic nerve fibers in a girl with a congenital nystagmus.

An otherwise healthy 15-year-old girl with a congenital nystagmus was evaluated at our department using visual evoked potential recording and magnetic resonance imaging. She appears to have the unique isolated inborn absence of the optic chiasm, described only once before in two unrelated girls. Unlike these previously described cases, our patient does not seem to display a see-saw nystagmus.

Muscle computed tomography in adult-onset acid maltase deficiency.

Nine patients with adult-onset acid maltase deficiency (Pompe's disease) were examined clinically and with computed tomography (CT). The CT scan showed early and severe involvement of the muscles of trunk and thighs, with selective sparing of the tensor fasciae latae, short head of biceps femoris, gracilis, and sartorius muscles. Shoulder and leg muscles were less affected. The disease spread over the years from trunk to extremities. Muscle strength and CT findings were positively correlated.