Periodic changes of the pulsatility index of the cerebral artery by transcranial Doppler sonography as a clue for leptomeningeal carcinoma: a report of two cases

摘要

Leptomeningeal carcinomatosis (LC) results from the diffuse infiltration of leptomeninges by malignant cells originating from an extra-meningeal primary tumor site. It has been reported that the incidence of LC was 4-15% in patients with solid carcinomatosis, and the common causes of LC are breast cancer, lung cancer, and malignant melanoma. Patients with LC can present various neurological symptoms and signs depending on the site of leptomeningeal invasion. The diagnosis of LC, however, can sometimes be difficult and challenging. It typically requires the demonstration of malignant cells in cerebrospinal fluid (CSF) which may require several lumbar punctures. MRI, especially gadolinium-enhanced MRI may play an important role in supporting the diagnosis of LC patients with negative cytology in CSF. However, to our knowledge, there have been no reports on the periodic changes of the pulsatility index (PI) of the cerebral artery by transcranial Doppler sonography (TCD) in patients with LC. We report the cases of two patients who complained of headache without positive neurological signs and who visited the outpatient department. The MRIs showed no positive results. Both were found to have a periodically changing PI of the cerebral artery, detected by TCD monitoring, indirectly reflecting periodic intracranial pressure change. This prompted us to perform a lumbar puncture for each patient. As a result, we found LC from lung cancer, as demonstrated by CSF cytology and chest CT. We speculated that TCD monitoring may be helpful in LC diagnose but still need further research.