Molecular evidence for multicentric development of thyroid carcinomas in patients with familial adenomatous polyposis

Familial adenomatous polyposis is characterized by multiple colorectal adenomas and an increased incidence of colorectal carcinomas. Patients also develop various extracolonic tumors, of which, thyroid carcinoma is common in young females. The occurrence of multiple carcinomas in one thyroid is frequently observed, although some carcinomas are solitary. To clarify whether each carcinoma develops independently or metastatically spreads from the first one formed, we analyzed the adenomatous polyposis coli (APC) gene mutation in each carcinoma. We found that each carcinoma had a different somatic mutation of the APC gene. This is molecular confirmation for the multicentric development of thyroid carcinomas in familial adenomatous polyposis through biallelic inactivation of the APC gene.

Somatic mutations of LKB1 and beta-catenin genes in gastrointestinal polyps from patients with Peutz-Jeghers syndrome

Peutz-Jeghers syndrome (PJS) is characterized by multiple gastrointestinal hamartomatous polyps, mucocutaneous melanin deposition, and increased risk of cancer, mainly in the gastrointestinal tract. We examined mutations of the LKB1, beta-catenin, APC, K-ras, and p53 genes in 27 gastrointestinal hamartomatous polyps from 10 patients in nine PJS families. Of these hamartomatous polyps, one intestinal polyp had an adenomatous lesion, and one gastric polyp contained adenomatous and carcinomatous lesions. Germ-line mutations of the LKB1 gene were detected in six PJS families. Somatic mutations of the LKB1 gene were found in 5 polyps, whereas loss of heterozygosity (LOH) at the LKB1 locus at 19p was seen in 14 other polyps. In adenomatous lesions microdissected from hamartomatous polyps, both beta-catenin mutation and 19p LOH were detected. Furthermore, a carcinomatous lesion in a gastric hamartomatous polyp was found to contain a mutation of the p53 gene and LOH at the p53 locus in addition to LOH at the LKB1 locus and a beta-catenin mutation. K-ras mutations were detected in a few polyps, whereas no APC mutation or 5q LOH was detected in hamartomatous polyps. These results suggest that gastrointestinal hamartomatous polyps in PJS patients develop through inactivation of the LKB1 gene by germ-line mutation plus somatic mutation or LOH of the unaffected LKB1 allele, and that additional mutations of the beta-catenin gene and p53 gene convert hamartomatous polyps into adenomatous and carcinomatous lesions.

Allelic loss at SMAD4 in polyps from juvenile polyposis patients and use of fluorescence in situ hybridization to demonstrate clonal origin of the epithelium

Juvenile polyposis syndrome (JPS; Online Mendelian Inheritance in Man2 174900) is a rare Mendelian disorder in which individuals have typical hamartomatous polyps within the gastrointestinal tract. The stromal element of the polyps has classically been thought to be the proliferative component, although epithelial malignancies (largely gastrointestinal cancers) occur more frequently than expected in JPS patients. Germ-line mutations in SMAD4 (DPC4) account for about a third of JPS cases. It has been postulated that the apparent paradox of a stromal lesion predisposing to epithelial malignancy can be resolved by the "landscaper" effect: an abnormal stromal environment affects the development of adjacent epithelial cells, and the resulting regeneration of damaged epithelium leads to an increased risk of cancer. We have found allele loss at the SMAD4 locus on 18q in polyps from JPS individuals with a germ-line SMAD4 mutation, showing that SMAD4 is acting as a tumor suppressor gene in JPS polyps, as it does in sporadic cancers of the gastrointestinal tract. Interphase fluorescence in situ hybridization showed deletion of one copy of SMAD4 in the epithelial component of JPS polyps, but not in the inflammatory infiltrate. Fluorescence in situ hybridization also suggested that a single copy of SMAD4 was present in stromal fibroblasts of JPS polyps. Thus, biallelic inactivation of SMAD4 occurs in both the epithelium and some of the stromal cells in these lesions, suggesting a common clonal origin. Epithelial malignancies almost certainly develop in juvenile polyposis through direct malignant progression of the epithelial component of the hamartomas. SMAD4/DPC4 probably acts as a "gatekeeper" tumor suppressor in juvenile polyps, and there is no need to invoke a "landscaper hypothesis."

Analysis of genetic and phenotypic heterogeneity in juvenile polyposis

BACKGROUND

Juvenile polyposis syndrome (JPS) is characterised by gastrointestinal (GI) hamartomatous polyposis and an increased risk of GI malignancy. Juvenile polyps also occur in the Cowden (CS), Bannayan-Ruvalcaba-Riley (BRRS) and Gorlin (GS) syndromes. Diagnosing JPS can be problematic because it relies on exclusion of CS, BRRS, and GS. Germline mutations in the PTCH, PTEN and DPC4 (SMAD4) genes can cause GS, CS/BRRS, and JPS, respectively.

AIMS

To examine the contribution of mutations in PTCH, PTEN, and DPC4 (SMAD4) to JPS.

METHODS

Forty seven individuals from 15 families and nine apparently sporadic cases with JPS were screened for germline mutations in DPC4, PTEN, and PTCH.

RESULTS

No patient had a mutation in PTEN or PTCH. Five different germline mutations were detected in DPC4; three of these were deletions, one a single base substitution creating a stop codon, and one a missense change. None of these patients had distinguishing clinical features.

CONCLUSIONS

Mutations in PTEN and PTCH are unlikely to cause juvenile polyposis in the absence of clinical features indicative of CS, BRRS, or GS. A proportion of JPS patients harbour DPC4 mutations (21% in this study) but there remains uncharacterized genetic heterogeneity in JPS.

Mutational analysis of ligand recognition by tcp, the citrate chemoreceptor of Salmonella enterica serovar typhimurium

The chemoreceptor Tcp mediates taxis to citrate. To identify citrate-binding residues, we substituted cysteine for seven basic or polar residues that are chosen based on the comparison of Tcp with the well-characterized chemoreceptors. The results suggest that Arg-63, Arg-68, Arg-72, Lys-75, and Tyr-150 (and probably other unidentified residues) are involved in the recognition of citrate.

Allelic imbalance at the LKB1 (STK11) locus in tumours from patients with Peutz-Jeghers' syndrome provides evidence for a hamartoma-(adenoma)-carcinoma sequence

Patients with Peutz-Jeghers' syndrome (PJS) develop hamartomatous gastrointestinal polyps and characteristic pigmentation, as a result of germline mutations in the LKB1 gene. The hamartomas in PJS were long considered to be without malignant potential. There is, however, accumulating epidemiological evidence to suggest that PJS predisposes to cancers at several different sites (colon, pancreas, breast, ovary, testis, and cervix), although large enough patient samples are rarely available to prove this. Allelic imbalance [allele loss, loss of heterozygosity (LOH)] has previously been reported in a small number of PJS polyps, suggesting that LKB1 acts as a tumour suppressor in these tumours. This study confirms allelic loss at LKB1 in PJS polyps and shows that LOH also occurs in cancers of the colon, breast, and cervix in PJS patients. Allele loss was additionally found in a colonic adenoma from a PJS patient, strongly suggesting the existence of a hamartoma-(adenoma)-carcinoma sequence in tumourigenesis. These results provide molecular evidence that PJS patients are predisposed to cancers at several sites, as a direct result of selection for loss of the 'wild-type' LKB1 allele in tumours. Given the rare involvement of LKB1 in sporadic cancers, these data also suggest that the indirect effect on cancer risk (or 'bystander effect') proposed for hamartomas in juvenile polyposis does not apply to carcinomas in PJS.

The relationship between frequencies of extracolonic manifestations and the position of APC germline mutation in patients with familial adenomatous polyposis

BACKGROUND

Familial adenomatous polyposis (FAP) patients develop various extracolonic lesions; however, the relationship between germline mutation of the APC gene and extracolonic manifestations is mostly unknown. To examine the genotype-phenotype relationship, we compared the APC mutation and clinical data.

METHODS

Germline mutations from codon 157 to 1465 of the APC gene were identified in 39 families of FAP and clinical data were collected from 80 patients of these families. Germline mutations were classified into two groups: mutations from exon 4 to 9 (codon 157 to 416, Group 1) and those from exon 10 to 15H (codon 564 to 1465, Group 2). The complication rates of extracolonic manifestations were compared between these two groups.

RESULTS

Frequencies of duodenal polyps and gastric adenomas in Group 2 were higher than those in Group 1 (p < 0.0001 and p < 0.0004, respectively) and development of osteoma was more frequent in Group 2 (p = 0.01). The number of colorectal polyps and retinal pigments also correlated with the germline mutation, which was consistent with previous reports. However, such correlations were less obvious with regard to gastric fundic polyps, desmoid tumors, soft tissue tumors and colorectal cancer.

CONCLUSION

There are two types with regard to extracolonic manifestations of FAP: one is more severely affected according to the position of germline mutation of the APC gene and the other is not affected.

Development of invasive adenocarcinoma in a long-standing diverted ileal J-pouch for ulcerative colitis: report of a case

We report a case of a 50-year-old male with ulcerative colitis who developed well-differentiated adenocarcinoma in the ileal J-pouch, which had been defunctioning for 18 years. The extension of the carcinoma in the pouch suggested that it had recently appeared in the pouch. Monitoring by endoscopic examination and biopsy or pouch excision seems to be an appropriate action if a pouch is out of the fecal stream.

Biliary carcinoembryonic antigen levels can predict metachronous liver metastasis of colorectal cancer

We set out to determine whether carcinoembryonic antigen (CEA) levels in gallbladder bile and serum can predict metachronous liver metastasis of colorectal cancer. At the time of surgery, gallbladder bile and serum were sampled for enzyme immunoassays of CEA. Upper limit (mean +/- 2SD) of the normal range for CEA in bile was established from samples at surgery for nonneoplastic gallbladder disease. In 11 patients with synchronous liver metastases, biliary CEA levels correlated with the size of hepatic lesions. In 49 patients without evident liver metastases at the time of surgery, elevated biliary CEA levels predicted subsequent emergence of metachronous liver metastases with 75% sensitivity, 85% specificity, and 84% accuracy; serum CEA levels were not a reliable predictor. In conclusion, determination of biliary CEA level at the time of colorectal resection shows promise as a way to identify patients at high risk for hepatic recurrence.

Hemodynamic changes around cerebral arteriovenous malformation before and after embolization measured with PET

To estimate the changes in regional cerebral blood flow (rCBF) around cerebral arteriovenous malformation (AVM) before and after embolization, 6 patients with AVM were sequentially examined with positron emission tomography (PET). PET depicted the remodeling of rCBF in the ipsilateral hemisphere of AVM after embolization. Decrease of rCBF in the ipsilateral hemisphere was also detected in patients with focal symptoms before embolization, and improvement of clinical symptoms after embolization corresponded to disappearance of rCBF decrease. PET can detect hemodynamic changes after embolization, and has a possibility to estimate the effect of embolization in patients with AVM.

Correlation between histological differentiation and DNA-synthesizing enzymes in rat colorectal tumors induced with 1, 2-dimethylhydrazine

Thymidylate synthase and thymidine kinase are key enzymes involved in de novo and salvage pathways for pyrimidine nucleotide synthesis. Colorectal carcinogenesis induced with 1,2-dimethylhydrazine in rats enhanced mRNA expression levels of both enzymes, resulting in the increase of both enzyme activities and bromodeoxyuridine-immunoreactive S-phase cells. Poorly and well differentiated adenocarcinomas of the colorectum showed the relative elevation of activities of thymidylate synthase and thymidine kinase, respectively. These results indicate that the relationship between de novo and salvage pathways for pyrimidine nucleotide synthesis may depend on the histopathological grades of cell differentiation.

Frequent mutation of beta-catenin and APC genes in primary colorectal tumors from patients with hereditary nonpolyposis colorectal cancer

Hereditary nonpolyposis colorectal cancer (HNPCC) is characterized by defective DNA mismatch repair, which results in genetic instability of tumors; however, only a few target genes have been recognized. Our previous study detected a low frequency of APC gene mutation (21%) in colorectal tumors from HNPCC patients, in contrast to a high frequency of APC gene alteration (>70%) in non-HNPCC tumors. Because both beta-catenin and ACP gene mutations have recently been shown to activate the same signaling pathway, we analyzed beta-catenin mutation in HNPCC tumors. A notable frequency of beta-catenin gene mutation (43%, 12 of 28) was found to occur in HNPCC colorectal tumors. Beta-catenin mutations were not detected in tumors with APC mutations. All beta-catenin mutations detected in HNPCC tumors existed within the regulatory domain of beta-catenin. Immunohistochemical staining of tumors with this mutation showed accumulation of beta-catenin protein in nuclei. These and previous data from our laboratory suggest that activation of the beta-catenin-Tcf signaling pathway, through either beta-catenin or APC mutation, contributes to HNPCC colorectal carcinogenesis in approximately 65% of cases.

Screening SMAD1, SMAD2, SMAD3, and SMAD5 for germline mutations in juvenile polyposis syndrome

BACKGROUND AND AIMS

Juvenile polyps occur in several Mendelian disorders, whether in association with gastrointestinal cancer alone (juvenile polyposis syndrome, JPS) or as part of known syndromes (Cowden, Gorlin, and Bannayan-Zonana) in association with developmental abnormalities, dysmorphic features, or extraintestinal tumours. Recently, some JPS families were shown to harbour germline mutations in the SMAD4 (DPC4) gene, providing further evidence for the importance of the TGFbeta signalling pathway in colorectal cancer. There remains, however, considerable, unexplained genetic heterogeneity in JPS. Other members of the SMAD family are excellent candidates for JPS, especially SMAD2 (which, like SMAD4, is mutated somatically in colorectal cancers), SMAD3 (which causes colorectal cancer when "knocked out" in mice), SMAD5, and SMAD1.

METHODS

SMAD1, SMAD2, SMAD3, and SMAD5 were screened for germline mutations in 30 patients with JPS and without SMAD4 mutations.

RESULTS

No mutations were found in any of these genes. A G-A C89Y polymorphism with possible effects on protein function was found in SMAD3, but the frequencies of the G and A alleles did not differ between patients with JPS and controls.

CONCLUSIONS

It remains to be determined whether or not this polymorphism is involved in a minor predisposition to colorectal or other carcinomas. SMAD4 may be the only member of the SMAD family which causes JPS when mutant in the germline. The other genes underlying JPS remain to be identified.

Regiocontrolled synthesis of carbocycle-fused indoles via arylation of silyl enol ethers with o-nitrophenylphenyliodonium fluoride

[formula: see text] A new, regiocontrolled synthesis of carbocycle-fused indoles has been developed. The two-step procedure involves first the regiospecific arylation of silyl enol ethers with o-nitrophenylphenyliodonium fluoride (1). Reduction of the nitro group on the aromatic ring with TiCl3 followed by spontaneous condensation of the aniline with the ketone then affords the indole products.

Predominant germ-line mutation of the hMSH2 gene in Japanese hereditary non-polyposis colorectal cancer kindreds

By means of PCR-SSCP and direct sequencing, we detected 12 germ-line mutations of hMSH2 or hMLH1 in 37 Japanese hereditary non-polyposis colorectal cancer (HNPCC) kindreds, of whom 15 satisfied the Amsterdam and 22 the Japanese criteria. The germ-line mutation detection rate of hMSH2 was much higher than that of hMLH1 (11/37 vs. 1/37). The total mutation detection rate of hMSH2 and hMLH1 in the Amsterdam criteria group was significantly higher than that in the Japanese criteria group (9/15 vs. 3/22). Furthermore, the mean age of the HNPCC patients in the mutation-positive group was lower than that in the mutation-negative one; the rates of both vertical transmission and multiplicity of tumors in the mutation-positive group were higher than those in the mutation-negative one. In addition, the number of patients with microsatellite instability-positive cancers in the mutation-positive group was higher than that in the mutation-negative one. Our results suggest firstly that the hMSH2 gene plays a much more important role than hMLH1 in the carcinogenesis of Japanese HNPCC patients, secondly that the rate of hMSH2 and hMLH1 mutations is high in the kindreds satisfying the Amsterdam criteria and thirdly that both the clinical phenotypes (early onset, vertical transmission and multiplicity of tumors) and the microsatellite instability status are important for the genetic screening of HNPCC.

Efficacy of direct revascularization in adult Moyamoya disease: haemodynamic evaluation by positron emission tomography

To evaluate the efficacy of direct cerebrovascular reconstruction to prevent intracranial bleeding from the point of view of haemodynamic status, we performed positron emission tomography (PET) studies in 5 adult patients with Moyamoya disease before and after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis. Regional cerebral blood flow (rCBF), regional cerebral metabolic rate of oxygen (rCMRO2) and regional oxygen extraction fraction (rOEF) in the MCA territories and regional cerebral blood volume (rCBV) in the striatum were measured before and after STA-MCA anastomosis. Correlation between the change of these PET parameters and post-operative decreased opacification of Moyamoya vessels were analyzed. Pre-operatively, significant elevation of rCBV were observed in the basal ganglia as well as significant reduction of rCBF and elevation of rOEF with reduction of rCMRO2 in the MCA territories, indicating "misery" perfusion in the cerebral hemisphere and blood pooling in the Moyamoya vessels under increased haemodynamic stress. Post-operative PET study showed improvement of misery perfusion and reduction of rCBV in the basal ganglia. Reduction of rCBV in the basal ganglia generally compatible with decreasing Moyamoya vessels on angiographic findings. Our results suggests that direct bypass surgery could have a potential both for decreasing haemodynamic stress on Moyamoya vessels and to improve misery perfusion in the hemisphere.

Higher frequency of Smad4 gene mutation in human colorectal cancer with distant metastasis

We have previously detected an increased frequency of loss of heterozygosity (LOH) on chromosome 18q during progression of colorectal carcinomas. To clarify the target of 18qLOH, mutation of Smad4 and Smad2 genes was analysed in 176 colorectal tumors with different stages, including liver metastasis, from 111 sporadic, 52 familial adenomatous polyposis (FAP) and nine hereditary nonpolyposis colorectal cancer (HNPCC) patients. Mutation of other Smad gene families in the TGF-beta signaling pathway was also examined. Twenty-one Smad4 mutations and one Smad2 mutation were detected, whereas mutation of Smad3, 6 and 7 genes was not detected. Smad4 mutations included seven frameshift, one inframe deletion, four nonsense and nine missense mutations, 95% of which resulted in alteration of Smad4 protein regions included in homo-oligomer and hetero-oligomer formation. Frequencies of tumors with Smad4 mutation were 0/40 (0%) in adenoma, 4/39 (10%) in intramucosal carcinoma, 3/44 (7%) in primary invasive carcinoma without distant metastasis, 6/17 (35%) in primary invasive carcinoma with distant metastasis, and 11/36 (31%) in distant metastasis (metastatic/non-metastatic: P=0.006 approximately 0.01). Loss of the other allele was observed in 19 of 20 (95%) invasive and metastasized carcinomas with Smad4 mutations. In four cases both primary and metastasized carcinomas in the same patients showed the same mutations. The present results suggest that Smad4 gene is one of true targets of 18qLOH, and that its inactivation is involved in advanced stages, such as distant metastasis, in human colorectal carcinogenesis.

Allelic imbalance at the LKB1 (STK11) locus in tumours from patients with Peutz-Jeghers' syndrome provides evidence for a hamartoma-(adenoma)-carcinoma sequence

Patients with Peutz-Jeghers' syndrome (PJS) develop hamartomatous gastrointestinal polyps and characteristic pigmentation, as a result of germline mutations in the LKB1 gene. The hamartomas in PJS were long considered to be without malignant potential. There is, however, accumulating epidemiological evidence to suggest that PJS predisposes to cancers at several different sites (colon, pancreas, breast, ovary, testis, and cervix), although large enough patient samples are rarely available to prove this. Allelic imbalance [allele loss, loss of heterozygosity (LOH)] has previously been reported in a small number of PJS polyps, suggesting that LKB1 acts as a tumour suppressor in these tumours. This study confirms allelic loss at LKB1 in PJS polyps and shows that LOH also occurs in cancers of the colon, breast, and cervix in PJS patients. Allele loss was additionally found in a colonic adenoma from a PJS patient, strongly suggesting the existence of a hamartoma-(adenoma)-carcinoma sequence in tumourigenesis. These results provide molecular evidence that PJS patients are predisposed to cancers at several sites, as a direct result of selection for loss of the 'wild-type' LKB1 allele in tumours. Given the rare involvement of LKB1 in sporadic cancers, these data also suggest that the indirect effect on cancer risk (or 'bystander effect') proposed for hamartomas in juvenile polyposis does not apply to carcinomas in PJS.

Somatic mutation of the APC gene in thyroid carcinoma associated with familial adenomatous polyposis

We report the existence of both germline and somatic mutations of the APC gene in thyroid carcinomas from familial adenomatous polyposis (FAP) patients. One papillary thyroid carcinoma from a 210-year-old woman, with germline mutation of the APC gene (TCA to TGA at codon 1110), showed a somatic mutation of AAAAC deletion between codons 1060 and 1063. Another somatic mutation of CAG to TAG at codon 886 was also found in one of multiple thyroid carcinomas from a 26-year-old woman with attenuated FAP and germline mutation at codon 175 (C deletion). This is the first evidence that total absence of the normal function of the APC gene is involved in development of thyroid carcinomas in FAP.

Effects of 5-fluorouracil derivative UFT on thymidylate synthetase and thymidine kinase in rat colorectal tumors

BACKGROUND

Thymidylate synthetase and thymidine kinase are key enzymes involved in de novo and salvage pathways for pyrimidine nucleotide synthesis, respectively.

MATERIALS AND METHODS

Weekly injections of 1,2-dimethyl-hydrazine induced high incidence of colorectal adenocarcinomas in rats.

RESULTS

An increased activity of thymidylate synthetase was found in the poorly differentiated adenocarcinomas of the chemically induced rat colorectal tumors. Six-week oral administration of 1-(2-tetrahydrofuryl)-5-fluorouracil in combination with uracil (UFT) reduced the total number of colorectal tumors, with the reduction of thymidylate synthetase activity in the poorly-differentiated type, though the mRNA expression of thymidylate synthetase and thymidine kinase differed little between the groups with or without UFT treatment.

CONCLUSIONS

These results indicate that the long-term oral administration using UFT suppresses colorectal carcinogenesis and the growth of the poorly-differentiated type tumors.

Use of 123I-IMP brain SPET to predict outcome following STA-MCA bypass surgery: cerebral blood flow but not vasoreactivity is a predictive parameter

Superficial temporal artery - middle cerebral artery (STA-MCA) bypass surgery might improve the cerebral blood flow (CBF) but fail to reduce the risk of post-surgical events such as ischaemic stroke. In this study, we studied retrospectively whether the risk of post-surgical events corresponded to the change in resting CBF and/or the change in vasoreactivity observed before and after STA-MCA surgery using N-isopropyl-I-123-p-iodoamphetamine (123I-IMP) brain single-photon emission tomography (SPET). 123I-IMP brain SPET images obtained at rest and following acetazolamide challenge both before and after STA-MCA surgery were studied in 30 patients. Resting CBF was estimated semiquantitatively using the resting count ratios of the middle cerebral artery (MCA) area to the cerebellum. Acetazolamide c hallenge was assumed to result in an average increase in flow of 40% in the cerebellum. The vasoreactive response was then estimated as the ratio of the change in counts (acetazolamide - rest) to the resting cerebellar counts multiplied by 1.4. We classified 14 patients (50.5 +/- 19.3 years) into group I, who h a change in their resting CBF from before to after surgery of >10%, and 16 patients (54.0 +/- 18.8 years) into group II, who had a change in their resting CBF from before to after surgery of ¿leq10%. Oxygen-15 positron emission tomography (PET) studies were performed in five patients from group I and five patients from group II. One post-surgical event occurred in group I while there were eight post-surgical events in group II (P<0.05). Resting CBF improved by 20.4% +/- 7.5% in group I and by 0.9% +/- 6.9% in group II patients after surgery (P<0.001). No significant difference in the improvement in vasoreactivity was observed between group I patients (32.6% +/- 17.7%) and group II patients (24.6% +/- 15.6%) following surgery. Patients in the group I PET subset showed normalization of oxygen extraction fraction (OEF) from 0.59 +/- 0.09 before surgery to 0.46 +/- 0.06 after surgery (P<0.05), while patients in the group II PET subset showed no statistical difference in OEF before surgery (0.58 +/- 0.14) and after surgery (0.54 +/- 0.05). We conclude that the outcome of STA-MCA bypass surgery can be predicted by the improvement in resting CBF but not by the improvement in vasoreactivity.

Endosaccular embolization for internal carotid artery aneurysms at the c3 portion

SUMMARY

Direct surgery for the aneurysms at the C3 portion of the internal carotid artery (ICA) requires relatively complicated procedures. We present three patients with this aneurysm who underwent endovascular embolization. The remodelling technique was utilized in two of these patients with unruptured aneurysms. Sufficient obliteration was achieved in every case. Endovascular embolization may be an important alternative for ICA C3 aneurysms.

Spinal Dural AVF Two Cases with MRI Follow-up

SUMMARY

Spinal dural arteriovenous fistula (d-AVF) is one of the arteriovenous malformations that are treatable by surgery or embolization. We present two cases treated by embolization and stress the necessity of early diagnosis and treatment, and the usefulness of T2WI on MRI for follow-up after embolization. One was a 51-year-old man who presented with gait disturbance and sphincter dysfunction. MRI revealed diffuse swelling on T1WI, and intramedullary high signal intensity on T2WI. A spinal d-AVF was found through tiny radicullomeningeal arteries via the right Th12 intercostal artery that drained into engorged retromedullary veins. The spinal d-AVF was embolized with 50% NBCA. Six months after the embolization, he was able to go back to his job, T2WI showed disappearance of the high signal intensity, which was confirmed at angiography one year after the embolization. The other case was a 62-year-old man who presented with sensory disturbance and gait disturbance. MRI showed the same findings, without the flow voids on them in case 1. The high signal area in the central spinal cord was thought to be syringomyelia, in which a syrinx-subarachnoid shunt was tried in vain. On the surface of the spinal cord, abnormally engorged and tortuous vessels were found. The syrinx was not confirmed. An angiogram showed a spinal d-AVF fed by the radicullomeningeal artery through a common trunk of the Th11/12 intercostal arteries with drainage into the retromedullary vein. The spinal d-AVF was embolized. Six months after the embolization, T2WI showed a decrease of high intensity areas. Early diagnosis and treatment are important for the prognosis of spinal d-AVF. T2WI may be the best way to check for recurrence.