Contributed by Nancy McLaughlin1, MD, PhD, FRCS(C), France Berthelet2, MD, MSc, Michel W. Bojanowski1, MD, FRCS(C)
1Division of Neurosurgery, Department of Surgery, and 2Department of Pathology
Centre Hospitalier de l'Université de Montréal - Hôpital Notre-Dame, Montreal, QC, Canada
Presentation and examination
A 30-year-old male, previously in good health, presented an acute loss of consciousness. He had complained about frequent headaches for the last 6 months and noticed a right-hearing impairment for several weeks. While waiting in the gastroscopic suite for the evaluation of a recent pyrosis, the patient experienced an acute loss of consciousness. Being comatose and posturing, he was rapidly intubated. After undergoing an initial CT, the patient was transferred to our institution. On his arrival, the patient remained comatose despite the administration of osmotic agents. A neurological examination revealed equal and reactive pupils, no right corneal reflex and no gag reflex. Nociceptive stimulation evoked bilateral decerebration movements and Babinski signs. Cerebral CT revealed an extra-axial hypodense lesion (Figures 1 and 2) with a cystic component located on the right cerebellopontine angle (CPA). The lesion measured more than 5 cm in its largest diameter and exerted a mass effect on the brain stem. The fourth ventricle was displaced with no associated hydrocephalus. No acute intratumoral or intracystic hemorrhage was documented. A heterogeneous enhancement was documented on contrast cerebral CT (Figure 3 and 4). The patient was urgently taken to the operating room to remove the mass.
Operative procedure and post-operative course
An extended subtotal tumor resection was performed through a right retrosigmoid suboccipital craniotomy and partial C1 laminectomy. The mass was heterogeneous with some regions well vascularized and others cystic. No intratumoral hematoma was identified intraoperatively. The patient was then sent to the surgical intensive unit postoperatively.
A few hours after surgery, the patient moved purposely upper and lower extremities. On post-operative (PO) day 2, the patient could open his eyes and obey to simple commands. The patient was extubated on PO day 4. The next day, a thorough neurological examination revealed hypoesthesia in the territory of the ophthalmic branch of the right trigeminal nerve and right-sided hypoacousia. Facial and lower cranial nerves function was intact. The patient made a remarkable recovery and was discharged on PO day 14. Post-operative MRI revealed a small tumor residue for which the patient was subsequently oriented towards radiosurgery.
The tissue presented moderate cellularity characterized by areas of dense fusiform cells alternating with loose microcystic-like areas(Figure 5) that were traversed by sclerotic blood vessels. In some areas nuclei were arranged in defined palisades with no well-formed Verocay bodies. Intratumoral blood vessels were numerous, sclerotic and surrounded by hemosiderin. An exuberant lymphoplasmacytic infiltrate was found in many areas, revealing the presence of an unusual significant inflammatory reaction. In areas adjacent to the inflammatory infiltrate, an important intratumoral edema was observed (Figure 6).
What is the diagnosis?