Introduction: Posterior cerebral artery (PCA) infarctions are usually small in extent and are thus expected to follow a benign course. Malignant unilateral PCA infarctions have not been previously reported.

Methods: Retrospective review of three cases of unilateral PCA infarction exhibiting malignant progression, with cerebral edema-related mass effect, increased intracranial pressure, and transtentorial herniation.

Results: Patient 1 was successfully managed medically using intravenous hypertonic saline and had a favorable functional outcome. Patients 2 and 3 both underwent decompressive hemicraniectomy after clinical signs of transtentorial herniation developed, and both died in the acute phase from malignant intracranial hypertension. In each instance, PCA occlusion was accompanied by a flow-limiting lesion in the internal carotid or middle cerebral artery.

Conclusions: Congenital and/or acquired variability in the distribution and extent of territory supplied by the PCA may lead to the rare syndrome of malignant PCA infarction. Patients suffering a PCA infarct should be followed closely and offered early surgical decompression in the event of malignant conversion.

Patient Care: This manuscript will have an impact by highlighting a rare clinical entity in malignant PCA infarctions that could benefit greatly from early surgical decompression. It is an atypical syndrome that can occur in patients with certain congenital and acquired vascular risk factors that are discovered via cerebrovascular imaging. Certain patients may benefit in the future from increased scrutiny for malignant conversion of their PCA strokes.

Learning Objectives: 1) Understand the congenital variability in vascular territories supplied by cerebral vessels. 2) Identify risk factors for the development of malignant PCA infarction. 3) Appreciate the need for increased surveillance for malignant conversion of PCA infarctions in patients with certain vascular risk factors. 4) Consider decompressive hemicraniectomy as a life-saving treatment in these rare clinical entities.

References: 1. Arboix A, Arbe G, Garcia-Eroles L, Oliveres M, Parra O, Massons J: Infarctions in the vascular territory of the posterior cerebral artery: clinical features in 232 patients. BMC Res Notes 2011; 4: 329. 2. Kumral E, Bayulkem G, Atac C, Alper Y: Spectrum of superficial posterior cerebral artery territory infarcts. Eur J Neurol 2004; 11: 237-246. 3. Hacke W, Schwab S, Horn M, Spranger M, De Georgia M, von Kummer R: 'Malignant' middle cerebral artery territory infarction: clinical course and prognostic signs. Arch Neurol 1996; 53: 309-315. 4. Rahme R, Curry R, Kleindorfer D, Khoury JC, Ringer AJ, Kissela BM, Alwell K, Moomaw CJ, Flaherty ML, Khatri P, Woo D, Ferioli S, Broderick J, Adeoye O: How Often Are Patients With Ischemic Stroke Eligible for Decompressive Hemicraniectomy? Stroke 2011. 5. Pfefferkorn T, Deutschlaender A, Riedel E, Wiesmann M, Dichgans M: Malignant posterior cerebral artery infarction. J Neurol 2006; 253: 1640-1641. 6. Ntaios G, Spengos K, Vemmou AM, Savvari P, Koroboki E, Stranjalis G, Vemmos K: Long-term outcome in posterior cerebral artery stroke. Eur J Neurol 2011; 18: 1074-1080. 7. Ng YS, Stein J, Salles SS, Black-Schaffer RM: Clinical characteristics and rehabilitation outcomes of patients with posterior cerebral artery stroke. Arch Phys Med Rehabil 2005; 86: 2138-2143. 8. van der Zwan A, Hillen B. Review of the variability of the territories of the major cerebral arteries. Stroke. 1991 Aug;22(8):1078-84. 9. van der Zwan A, Hillen B, Tulleken CA, Dujovny M, Dragovic L. Variability of the territories of the major cerebral arteries. J Neurosurg. 1992 Dec;77(6):927-40. 10. van der Zwan A, Hillen B, Tulleken CA, Dujovny M. A quantitative investigation of the variability of the major cerebral arterial territories. Stroke. 1993 Dec;24(12):1951-9. 11. Vahedi K, Hofmeijer J, Juettler E, Vicaut E, George B, Algra A, Amelink GJ, Schmiedeck P, Schwab S, Rothwell PM, Bousser MG, van der Worp HB, Hacke W: Early decompressive surgery in malignant infarction of the middle cerebral artery: a pooled analysis of three randomised controlled trials. Lancet Neurol 2007; 6: 215-222. 12. Weil AG, Rahme R, Moumdjian R, Bouthillier A, Bojanowski MW. Quality of life following hemicraniectomy for malignant MCA territory infarction. Can J Neurol Sci 2011; 38:434-8. 13. Rahme R, Zuccarello M, Kleindorfer D, Adeoye OM, Ringer AJ. Decompressive hemicraniectomy for malignant MCA territory infarction: is life worth living? J Neurosurg (in press).