Subarachnoid hemorrhage emanating from a ruptured infundibulum: case report and literature review.
BACKGROUND
Infundibula are frequently regarded as incidental anatomical variants that are of no pathogenetic significance.


METHODS
A 51-year-old man presented with a sudden onset of severe occipital headache. Computed tomographic scan revealed a predominantly perimesencephalic pattern of SAH with a slight bias toward the left side. Angiography demonstrated a left PCo-A IF as the sole abnormality. At craniotomy, the left PCo-A IF was found to represent the sole abnormality. The IF was markedly reddened posteriorly, contained a capping clot, and lay immediately adjacent to a mass of xanthochromatous tissue. The PCo-A was hypoplastic and lacked perforating vessels; therefore, the IF base was successfully clipped with a straight Sugita clip parallel to the left ICA. At discharge and at clinical follow-up, our patient was asymptomatic and lacked neurologic signs.


CONCLUSIONS
Infundibula may rarely represent a direct source of rupture and SAH. Exploratory craniotomy is required to establish the diagnosis and to provide definitive treatment. To label a case of SAH as angiogram-negative may be unwise when an IF potentially colocalizes to the SAH source.
Coupe
Nicholas J
NJ
Department of Neurosurgery, North Staffordshire Royal Infirmary, Hartshill, Stoke-on-Trent, Staffordshire, UK.
Athwal
Rupinder K
RK
Marshman
Laurence A G
LA
Brydon
Howard L
HL
D015901:Angiography, Digital Subtraction; D002941:Circle of Willis / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D012422:Rupture, Spontaneous; D013345:Subarachnoid Hemorrhage / Q000473:pathology* / Q000503:physiopathology; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures