"Extra-cranial proximal pica aneurysm - a rare and surreptious cause of posterior fossa sah: case report and review of literature".

BACKGROUND: Extra-cranial posterior inferior cerebellar artery (PICA) aneurysms are rare with only 22 cases been reported so far. Intra-dural type of extra-cranial PICA aneurysm is even rarer with few case reports available. We report a previously unreported type of proximal PICA aneurysm in which the PICA aneurysm had intra-dural location at the C2 vertebral level. CASE DESCRIPTION: A 51 year old gentleman presented with sub-arachnoid haemorrhage and intra-ventricular haemorrhage, predominantly involving the fourth ventricle and had no focal neurological deficit. CT angiogram was negative however a dedicated four vessel angiogram demonstrated an abnormal extracranial origin of right PICA at C1-C2 level, with associated aneurysm in its proximal segment. A C1 posterior arch excision with partial C2 laminectomy and clipping of the aneurysm was done. CONCLUSION: Aneurysm associated with extracranial intra-dural PICA origin is a rare cause of SAH, and may not be detected with CT angiography. Such cases often require dedicated four vessel angiography, with careful study for any possibility of extra-cranial aneurysm. This variant has important surgical implication and requires preservation of the Lateral spinal artery (LSA-PICA communication), and that such aneurysm approached only with posterior cervical exposure without the need of a craniotomy. Such cases remind us the need to have an in-depth understanding of the variations of the posterior circulation.

Topographic, histological and molecular study of aberrant crypt foci identified in human colon in different clinical groups.

BACKGROUND/AIMS: Aberrant crypt foci (ACF) are early microscopic lesions of the colonic mucosa, which can be detected by magnified chromoendoscopy. Herein, we have investigated whether ACF identified in different clinical groups can be differentiated based on their characteristics. METHODS: Macroscopically unremarkable mucosal flaps were collected from 270 fresh colectomies and divided into 3 clinical groups: colorectal carcinoma (group A), disease controls having known pre-neoplastic potential (group Bc), and disease controls without risk of carcinoma development (group Bn). Topographic and histologic analysis, immunohistochemistry, and molecular studies (high-resolution melt curve analysis, real-time polymerase chain reaction, and Sanger sequencing) were conducted for certain neoplasia-associated markers. RESULTS: ACF were seen in 107 cases, out of which 72 were left colonic ACF and 35 right colonic ACF (67.2% vs. 32.7%, P=0.02). The overall density of left colonic ACF was 0.97/cm, which was greater than the right colonic ACF density of 0.81/cm. Hypercrinia was present in 41 out of 72 left colonic ACF and in 14 out of 35 right colonic ACF (P=0.01). Immunohistochemical expression of p53 was also greater in left colonic ACF than in right colonic ACF (60.5% vs. 38.2%, P=0.03). However, ACF identified among the 3 clinical groups did not show any distinguishing topographic, histological, or genetic changes. CONCLUSIONS: Left colonic ACF appear to be high-risk based on their morphological and prototypic tumor marker signature. ACF identified in different clinical groups do not show significant genotypic or topographic differences. Further detailed genetic studies are required to elucidate them further.