No abstract

This study reports in vivo and in vitro magnetic resonance spectroscopic findings in two cases of central neurocytomas (CNC) confirmed by immunohistochemistry. Volume localized in vivo proton magnetic resonance spectroscopy (MRS) was carried out before surgery using a point resolved spectroscopy (PRESS) sequence with a repetition time of six seconds and an echo time of 135 msec. Normal spectrum was obtained from gray matter from a volunteer for comparison. 1 H and 31 P in vitro MRS studies were carried out at 9.4 T on the extracts prepared from the surgically excised tumors. The in vivo spectra showed prominent glycine (Gly) and choline (Cho) and low N-acetyl aspartate compared to the normal. The Gly peak was assigned using the in vitro studies. These studies showed that the major contribution to the Cho peak observed in vivo is from phosphocholine. A combination of the presence of NAA and an increased Gly in the proton MR spectrum could be a characteristic feature of CNCs, which are rare intraventricular tumors of neuronal origin.

In these situations, it is extremely important for the pathologist to be aware of this entity and to distinguish it from other lesions, like cortical invasion by a meningioma, intraparenchymal meningioma and intracerebral schwannoma, which it may mimic.

No abstract

Posterior fossa tension pneumocephalus (PFTP) is a very rare clinical entity--OFF few case reports available prove how rare. Five patients with PFTP are presented. All were operated on for posterior fossa lesions. One was operated on in the lateral position and the rest in a sitting position. All the patients had postoperative (early) neurological deterioration, and computed tomography (CT) scans revealed PFTP in the left cerebellopontine angle in one case and in the IV ventricle in the rest. Air was aspirated from the posterior fossa in one case. All the cases were electively ventilated for 48-72 h. All the patients had an immediate onset of progressive neurological recovery after early intervention and elective ventilation. One patient died 10 days later because of a recurrence of empyema and the development of meningitis. PFTP is a rare but important complication of posterior fossa surgery. Early intervention and elective ventilation can produce a good recovery.