CD44-positive Cancer Stem-like Cells as a Potential Source of Peritoneal Metastasis After Surgery.

BACKGROUND/AIM: The role of CD44 in gastric cancer-derived peritoneal metastasis is currently unknown. It was previously shown that viable, tumorigenic cancer cells are spilled into the peritoneal cavity during surgery, providing a potential cause of peritoneal recurrence after surgery. The purpose of this study was to elucidate the mechanism of peritoneal metastasis of gastric cancer through the expression of CD44 and to propose a method for preventing peritoneal recurrence. MATERIALS AND METHODS: Gastric cancer cell line MKN-45 was sorted into CD44+ and CD44- cells and then injected intraperitoneally into NOD/ShiJic-scidJcl mice. Differences in tumor-initiating capacity between the two groups were assessed using in vivo limiting dilution assays. Tumors harvested from both groups were examined for CD44 and ALDH1A1 expression using immunohistochemistry. The effects of CD44 blockade with anti-CD44 antibody on cell invasion and peritoneal metastasis formation in vivo were assessed. RESULTS: CD44+ cells showed significantly higher efficiency in initiating peritoneal tumor than CD44- cells. Blockade of CD44 significantly reduced peritoneal dissemination of CD44+ cells in vivo, indicating that the CD44 function of intraperitoneally disseminated cancer cells helped promote the formation of peritoneal metastasis. The margin of established tumors showed clusters of cells co-expressing CD44 and ALDH1A1. Peritoneally administered CD44- cells resulted in peritoneal metastases consisting of CD44+ and CD44- cancer cells. CONCLUSION: CD44 expressing cells are a potential source of peritoneal metastasis after surgery and could be a promising target for preventing peritoneal recurrence.

Non-occlusive Mesenteric Ischemia with Significant Hyperphosphatemia.

An 86-year-old Japanese woman was referred to our hospital due to the sudden onset of abdominal pain. Abdominal contrast-enhanced computed tomography (CT) revealed no signs of ischemic bowel; however, laboratory investigations revealed metabolic lactic acidosis, elevation of inflammatory markers, and a remarkable elevation in the serum phosphate level. A prompt surgical evaluation revealed non-occlusive mesenteric ischemia (NOMI). Elevated serum phosphate levels may suggest extensive bowel ischemia or infarction, which can lead to a prompt surgical evaluation, even in the absence of specific radiological findings.

Successful treatment of rectal cancer with pelvic abscess using transrectal drainage followed by laparoscopic radical resection: a case report.

The incidence of rectal cancer with a pelvic abscess is rare; hence, treatment strategies are difficult because both malignant and infectious inflammation need to be addressed. Here, we report the case of a 53-year-old man diagnosed with rectal cancer accompanied by a pelvic abscess. We performed transrectal drainage of the abscess, and a transanal rectal drainage tube was inserted into the abscess cavity. His symptoms rapidly improved, and computed tomography showed that the pelvic abscess had disappeared. Six weeks after drainage, radical laparoscopic Hartmann's procedure with resection of the rectal cancer and incision drainage scar was performed. After adjuvant chemotherapy, laparoscopic stoma closure was performed a year after the operation. The patient showed no evidence of cancer recurrence 1.5 years after radical surgery. Transrectal drainage followed by laparoscopic radical resection can be a less invasive and effective treatment for rectal cancer accompanied by a pelvic abscess.

Predictors and clinical impact of postoperative diarrhea after colorectal cancer surgery: a prospective, multicenter, observational study (SHISA-1602).

PURPOSE: Postoperative diarrhea, including high-output stoma (HOS), frequently occurs after colorectal surgery; its risk factors and clinical implications on subsequent complications remain unknown. This study aimed to evaluate the risk factors and clinical implications of postoperative diarrhea after primary colorectal cancer (CRC) surgery. METHODS: This prospective observational study included patients with CRC who underwent radical surgery at six hospitals between June 2016 and December 2017. The patients were categorized into three groups (non-stoma, colostoma, and ileostoma groups). RESULTS: A total of 178 patients participated in the study. In the non-stoma group, the incidence of postoperative diarrhea was 18.4% (27/147). The incidence of HOS was 28.6% (4/14) in the ileostoma group, and 0% in the colostoma group. Multivariable analyses of the incidence of diarrhea in the non-stoma group indicated that habitual smoking and hypertension were significantly associated with postoperative diarrhea (P = 0.012 and P = 0.0274, respectively). Postoperative diarrhea was more likely to occur in patients with rectal cancer than in those with colon cancer (P = 0.0501). In the non-stoma and ileostoma groups, the probability of the occurrence of other complications with Clavien-Dindo (C-D) grades II or higher was significantly higher in patients with C-D grade I diarrhea, including HOS, than in patients without diarrhea (39.3% vs. 14.6%, P = 0.0061). CONCLUSIONS: Smoking and hypertension are the independent predictors of postoperative diarrhea after an elective CRC surgery. Rectal cancer surgery seems to be associated with postoperative diarrhea more than colon cancer surgery does. Mild postoperative diarrhea may lead to more severe complications.

INI1-negative colorectal undifferentiated carcinoma with rhabdoid features and postoperative rapidly growing liver metastases: a case report and review of the literature.

BACKGROUND: Malignant tumors with rhabdoid features are extremely rare. They can occur in various organs, including the gastrointestinal tract, with common clinical features of high malignancy and poor prognosis. CASE PRESENTATION: A 41-year-old man visited our hospital complaining of lower abdominal pain and fever. Computed tomography (CT) revealed two wall-thickening lesions in the rectum and sigmoid colon, with the latter invading the small intestine and abdominal wall. Lymph nodes were swollen in the sigmoid mesocolon and at the roots of the inferior mesenteric artery. Colonoscopy revealed a circular type 3 lesion in the sigmoid colon and a semicircular type 2 lesion in the rectum. Biopsies of the sigmoid colon and rectum lesions revealed poorly and moderately differentiated adenocarcinoma cells, respectively. The sigmoid colon, rectum, invaded small intestine, and abdominal wall were resected; lymph node dissection was also performed. Histopathological finding of the sigmoid colon lesion revealed that the tumor cells had poor connectivity with each other, and each cell had eosinophilic cytoplasm and a polymorphic nucleus. These characteristics are termed rhabdoid features, because the morphology of these cells is similar to that of rhabdomyosarcoma tumor cells. Immunohistochemical examination showed that the tumor cells were positive for both epithelial (cytokeratin AE1/AE3) and mesenchymal cell markers (vimentin); however, they were negative for integrase interactor 1 (INI1). Therefore, the sigmoid colorectal cancer was diagnosed as an INI1-negative undifferentiated carcinoma with rhabdoid features. The patient continued to experience high fever after surgery; thus, we performed an abdominal CT scan that revealed cystic lesions in the liver 4 days after surgery. These were absent in the positron emission tomography (PET)-CT scan performed 14 days before surgery. These tumors grew rapidly, and fine needle aspiration cytology revealed that they were undifferentiated carcinomas compatible with metastatic lesions from the undifferentiated carcinoma with rhabdoid features from the sigmoid colon. Chemotherapy was administered but was not effective. The patient died 60 days after surgery. CONCLUSIONS: INI1-negative colorectal undifferentiated carcinomas with rhabdoid features are extremely rare, have high histological malignancy, and a poor prognosis. Chemotherapy is not effective. Effective systemic therapy is desired.

Successful laparoscopy-assisted repair of a rectovaginal fistula after low anterior resection for rectal cancer: a report of two cases.

BACKGROUND: Rectovaginal fistula (RVF) after low anterior resection for rectal cancer is troublesome and refractory. Although various surgical procedures have been previously described, no definitive procedure has shown a satisfactory outcome. We present two consecutive Japanese patients who underwent successful surgery for an RVF after low anterior resection. CASE PRESENTATION: The patients were two women (61-year-old and a 64-year-old). They were admitted to our hospital with a chief complaint of fecal discharge from the vagina after low anterior resection using the double-stapling technique for rectal cancer. They were diagnosed with RVF. Local surgical procedures, including diverting ileostomy, were unsuccessful in previous hospitals. Therefore, we performed laparoscopy-assisted repair of the RVF. In both patients, laparoscopically robust pelvic adhesions were dissected, and the sigmoid colon was transected at just oral side to the RVF. Thereafter, in combination with a perineal approach, the rectum, along with a previous anastomosis and fistula, were completely removed. Surgeries were completed after vaginal repair, redo coloanal anastomosis, and interposition of the dissected connective tissue. In both patients, the postoperative courses were uneventful. They complained of neither recurrence of any RVF nor fecal incontinence 1 year and 10 months after diverting stoma closure. CONCLUSIONS: A laparoscopy-assisted procedure with reanastomosis and interposition of the perineal connective tissue can be an effective treatment for RVF after low anterior resection for rectal cancer.

Gastric volvulus and giant Bochdalek hernia in an adult patient that were safely repaired by endoscopic reduction and elective laparoscopic surgery.

A Bochdalek hernia (BH) is a congenital abnormality with incomplete closure of the diaphragm. It is usually manifested in infants but rarely in adults. Here, we report an adult patient with gastric volvulus and giant BH that were safely repaired by endoscopic reduction and elective laparoscopic surgery, respectively. A 79-year-old woman presented with left upper abdominal pain but no history of trauma. CT revealed a giant BH with gastric volvulus. After emergency endoscopic reduction of the volvulus, elective laparoscopic repair of the BH was performed. The 8 × 8-cm defect was repaired with interrupted nonabsorbable sutures and a mesh. The patient's postoperative course was uneventful, and no complications or recurrence were observed in the 6 months that followed.

The Elevation in Preoperative Procalcitonin Is Associated with a Poor Prognosis for Patients Undergoing Resection for Colorectal Cancer.

BACKGROUND: Procalcitonin (PCT) is a well-known marker for bacterial infection; however, the clinical significance of PCT in the long-term prognosis after colorectal cancer (CRC) surgery remains unclear. METHODS: This is a retrospective review of 277 patients that underwent CRC surgery to investigate the relationship between preoperative PCT, clinicopathological condition, cancer-specific overall survival (OS), and relapse-free survival (RFS). RESULTS: Median follow-up interval was 5.0 years in all patients. Thirty-six patients developed recurrence, and 46 patients died due to recurrences or metastases of CRC. Preoperative PCT levels were highest in Stage IV patients. The cancer-specific OS in patients with Stage IV/PCT ≤0.05 ng/mL was significantly higher than those with Stage IV/PCT >0.05 ng/mL (3 years survival; 42.3 vs. 14.3%, p = 0.0413). On multivariate analysis, gender, TNM classification, and PCT were identified as significant risk factors for cancer-specific OS in patients with Stage I-III CRC. The cancer-specific OS rate of these patients with PCT ≥0.08 ng/mL, compared with PCT <0.08 ng/mL, was significantly decreased (5 years survival; 59.1 vs. 92.7%, p < 0.0001). TNM classification was finally identified as an independent risk factor for cancer-specific RFS in these patients by multivariate analysis. CONCLUSION: High preoperative PCT values in CRC patients appeared to be associated with poor OS but not RFS following surgical treatments.

Accuracy, criteria, and clinical significance of visual assessment on diffusion-weighted imaging and apparent diffusion coefficient quantification for diagnosing acute appendicitis.

PURPOSE: To assess the accuracy, criteria, and clinical significance of diffusion-weighted imaging (DWI) signal intensity and apparent diffusion coefficient (ADC) quantification for diagnosing acute appendicitis. METHODS: Fifty-one patients with right lower abdominal pain [uncomplicated appendicitis (n = 25), complicated appendicitis (n = 10), and non-appendicitis (n = 16)] who underwent MR examination were enrolled in this retrospective study. Two radiologists independently measured appendiceal diameter and wall thickness. They assessed whether a wall defect, an abscess, extraluminal air, or an appendicolith was present on axial T2WI; evaluated intensity on DWI using a 5-point scale; and determined the ADC values of the appendix and peri-appendiceal tissue. Statistical analysis was performed to assess imaging findings for the diagnosis of appendicitis and complicated appendicitis. Cut-off values were determined using receiver operating characteristic analysis. RESULTS: For diagnosing acute appendicitis, the accuracy improved from 78.4% using only T2WI to 86.3% using combined T2WI and DWI for reader 1 and from 82.4 to 86.3% for reader 2. For the appendix, the cut-off ADC values that diagnosed appendicitis were 1.41 × 10-3 and 1.26 × 10-3 mm2/s with accuracies of 78.4% and 76.5%, respectively. For the peri-appendiceal tissue, these values of 1.03 × 10-3 and 0.91 × 10-3 mm2/s differentiated between uncomplicated and complicated appendicitis with an accuracy of 97.1%. CONCLUSIONS: Combined DWI and T2WI provided high accuracy for diagnosing appendicitis. The inflamed appendix had lower ADC value than the normal appendix. The peri-appendiceal tissue presenting low ADC value was a notable finding of complicated appendicitis.

In vivo antitumor function of tumor antigen-specific CTLs generated in the presence of OX40 co-stimulation in vitro.

Adoptive cell transfer (ACT) is an emerging and promising cancer immunotherapy that has been improved through various approaches. Here, we described the distinctive characteristics and functions of tumor Ag-specific effector CD8+ T-cells, co-cultured with a tumor-specific peptide and a stimulatory anti-OX40 antibody, before being used for ACT therapy in tumor-bearing mouse recipients. Splenic T-cells were obtained from wild-type FVB/N mice that had been injected with a HER2/neu (neu)-expressing tumor and a neu-vaccine. The cells were then incubated for 7 days in vitro with a major histocompatibility complex (MHC) class I peptide derived from neu, in the presence or absence of an agonistic anti-OX40 monoclonal antibody, before CD8+ T cells were isolated for use in ACT therapy. The proliferative ability of OX40-driven tumor Ag-specific effector CD8+ T-cells in vitro was less than that of non-OX40-driven tumor Ag-specific effector CD8+ T-cells, but they expressed significantly more early T-cell differentiation markers, such as CD27, CD62L and CCR7, and significantly higher levels of Bcl-2, an anti-apoptotic protein. These OX40-driven tumor Ag-specific effector CD8+ T-cells, when transferred into tumor-bearing recipients, demonstrated potent proliferation capability and successfully eradicated the established tumor. In addition, these cells exhibited long-term antitumor function, and appeared to be established as memory T-cells. Our findings suggest a possible in vitro approach for improving the efficacy of ACT, which is simple, requires only a small amount of modulator, and can potentially avoid several toxicities associated with co-stimulation in vivo.

ABCG2 expression in colorectal adenocarcinomas may predict resistance to irinotecan.

Irinotecan is a key drug for patients with advanced and recurrent colorectal carcinoma. However, the efficacy of irinotecan is not sufficient; partly, as there is no useful marker to predict chemosensitivity to the drug. The aim of the present study was to evaluate whether the expression levels of adenosine triphosphate-binding cassette sub-family G (WHITE) member 2 (Junior blood group) (ABCG2) in primary colorectal tumors predict chemoresistance to irinotecan. Using the resected primary tumor specimens of 189 patients with colorectal cancer, the association between the immunohistochemical expression of ABCG2 protein and the results of the collagen gel droplet embedded culture drug sensitivity test, performed to evaluate the chemosensitivity to SN-38 (an active metabolite of irinotecan), was investigated. Among the 189 patients, 17 received irinotecan-based chemotherapy, and their responses and progression-free survival (PFS) were analyzed. The tumors of patients with increased ABCG2 expression accounted for 60% of the tumors examined, and were significantly more resistant to SN-38, compared with patients with low ABCG2 expression (P<0.001). In a multivariate logistic regression analysis, increased expression of ABCG2 protein was an independent and significant predictor of resistance to SN-38, increasing the risk of resistance by 12-fold. Increased expression of ABCG2 and a low sensitivity to SN-38 was significantly associated with resistance to irinotecan-based chemotherapy (P=0.01 and 0.028, respectively). The median PFS of patients with increased expression of ABCG2 was significantly shorter, compared with patients with low expression levels of ABCG2 (104 vs. 242 days; P=0.047). The increased immunohistochemical expression of ABCG2 in primary tumors may be a useful predictive biomarker of resistance to irinotecan-based chemotherapy for patients with recurrent or metastatic colorectal cancer.

Perioperative Adiponectin Measurement is Useful for Prediction of Postoperative Infection in Patients with Colorectal Cancer.

BACKGROUND: Adiponectin (ADN) is a key molecule associated with obesity and metabolic syndrome, and functions as an immunomodulator. We have shown that the ADN ratio (i.e., postoperative ADN/preoperative ADN) can predict infection after gastrectomy in patients with gastric cancer . In the present study, we evaluated whether the ADN ratio could reliably predict the incidence of postoperative infection in patients undergoing colorectal cancer surgery. METHODS: We retrospectively analyzed 131 consecutive patients who underwent colorectal cancer surgery and measured their preoperative and postoperative ADN values. The outcome was postoperative infection, including surgical site and remote infections. The association between the ADN ratio and postoperative infection was assessed using logistic regression models. For the ADN ratio and other significant predictors, we conducted receiver operating characteristics (ROC) analyses. RESULTS: Forty-nine patients (37.4 %) experienced postoperative infections. Logistic regression analysis indicated that the ADN ratio was most significantly associated with postoperative infection [odds ratio per one standard deviation (1 SD) decrease 0.36; 95 % confidence interval 0.18-0.71] even after adjustment for diabetes, type of surgery, blood loss, C-reactive protein level, and preoperative ADN level. History of type 2 diabetes mellitus also significantly predicted postoperative infection (odds ratio per 1 SD increase 2.93; 95 % confidence interval 1.03-8.38). When predicting postoperative infection, the area under the ROC curve for the ADN ratio (0.707) was comparable to that for blood loss (0.698; p = 0.975). CONCLUSIONS: ADN ratio is a clinically useful predictor of postoperative infection in patients undergoing colorectal cancer.

Pyomyositis at the surgical site in a patient with chronic myeloid leukemia: a case report and literature review.

BACKGROUND: Pyomyositis is a rare, subacute, deep pyogenic infection of the muscle tissue. This disease has been previously described in patients that were immunocompromised due to a hematological malignancy. CASE PRESENTATION: A 68-year-old man with a history of chronic myeloid leukemia was treated with imatinib. He was diagnosed with ascending colon cancer and underwent curative surgery. His postoperative course was uneventful, and he was healthy at 6 months after surgery, allowing for reinitiation of imatinib therapy. After the reinitiation of therapy, a computed tomography (CT) scan revealed a mass shadow in the right iliopsoas muscle. This lesion was clinically diagnosed as recurrent colon cancer with an abscess, which was resected surgically. A pathological examination uncovered both edema and inflammation. Two months after the second surgery, imatinib therapy was reinitiated; however, he again developed painful swelling and erythema in his right thigh. A CT scan revealed a similar shadow as described previously. He was then diagnosed with pyomyositis; he underwent incisional drainage and was administered linezolid. Following the treatment for pyomyositis, there was no cancer recurrence or evidence of any recurrent pyomyositis. CONCLUSIONS: Findings from this case suggest that both undergoing surgery and receiving imatinib therapy may modulate an individual's immune response, whereby the surgical site becomes more prone to infection and may predispose an individual to pyomyositis. The case report is followed by a discussion of the literature regarding this disease, including potential risk factors and the underlying pathogenesis.

[Clinical Evaluation of Hyperthermic Intraperitoneal Chemotherapy(HIPEC)in Colorectal Cancer Patients at High Risk of Peritoneal Recurrence].

PURPOSE: We herein report the clinical outcomes of hyperthermic intraperitoneal chemotherapy(HIPEC)in patients at high risk of colorectal peritoneal metastasis. PATIENTS AND METHODS: We enrolled 21 patients with advanced colorectal cancer who were received HIPEC between 2009 and 2014. Retrospectively, we evaluated the short-term and long-term outcomes of these cases. RESULTS: We performed HIPEC for 12 patients with primary cancer and 9 with recurrent cancer. Perioperative complications characteristic of HIPEC did not occur. Seventeen patients(81%)had postoperative recurrence, 5 of whom had a peritoneal recurrence, and all of them already had synchronous peritoneal metastasis at the time of HIPEC. Patients with a higher peritoneal cancer index(PCI)had a tendency towards a higher rate of peritoneal recurrence than those with a lower PCI(11[median]vs 4; p=0.08).

Prognostic impact of CD10 expression in clinical outcome of invasive breast carcinoma.

BACKGROUND: Early diagnosis and treatment for breast cancers has greatly improved in recent years, however, subset of this disease with early recurrence have remained to be unpredictable. Several studies has addressed that strong CD10 expression in tumor stroma is associated with poor survival rate of breast cancers, but no correlation between CD10 expression and disease-free survival has been elucidated yet. For these reasons, this study with modified immunohistochemical (IHC) staining evaluated the expression of CD10 in invasive breast carcinomas (IBCs) and analyzed correlations between CD10 expression on tumor cells, stromal cells and myeloid-like cells with clinicopathological parameters and recurrence status. METHOD: IHC staining method was performed on formalin-fixed paraffin-embedded sections of 73 cases of primary IBCs, with record of pathological characteristics of subjects followed up from 1998 to 2007. RESULTS: Stromal CD10 expression was observed in 39/73 cases (53.4 %) with strong expression in 41.0 %. Three cases stained positive for myeloid-like cells and five for carcinomatous cells, of which 6 cases had recurrence and/or regional LN status. Stromal CD10 expression was significantly higher in the unfavorable group (69.6 %; 16/23 cases) compared with the favorable group (32.1 %; 9/28 cases) (p = 0.048). The levels of CD10 expression showed significant difference among clinical outcomes (recurrence or non-recurrence), independent of regional LN status (p = 0.034), histology type (p = 0.044), ER status (p = 0.042), PgR status (p = 0.039), Her2 status (p = 0.038) and Ki67 index (p = 0.036) (partial Pearson correlations). Cox proportional-hazards regression showed that risk factors for disease-free survival were stromal CD10 expression [CD10±, CD10+ versus CD10++; p = 0.003; HR 2.824 (1.427-5.591)]; regional LN status [N0, N1, N2, versus N3; p = 0.004; HR 2.107 (1.262-3.517)] and PgR status [negative versus positive, p = 0.006, HR 0.172 (0.049-0.596)]. CONCLUSION: CD10 expression on stroma with or without other positive tumor cells and/or myeloid-like cells may function as a powerful prognostic factor for IBC disease-free survival rates, predicting of potential recurrence. It can be determined by a simple modified IHC staining method, which is independent of other prognostic morphologic markers and biomarkers in IBC.

Successful surgical approach for a patient with encapsulating peritoneal sclerosis after hyperthermic intraperitoneal chemotherapy: a case report and literature review.

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is a rare surgical complication that can occur after intraperitoneal treatment. It is also a serious and potentially fatal complication of continuous ambulatory peritoneal dialysis. The present report describes a case of surgically treated EPS that probably occurred as a complication of hyperthermic intraperitonal chemotherapy (HIPEC). CASE PRESENTATION: A 39-year-old man required sigmoidectomy for serosal invasive advanced sigmoid colon cancer. HIPEC with oxaliplatin, 5-fluorouracil and mitomycin C were given as adjuvant therapy. Subsequently, intestinal obstruction developed at 15 months postoperatively, and the patient was hospitalized. Abdominal computed tomography showed a dilated small intestine enveloped by a thickened membrane. We found no evidence of peritoneal recurrence, but exploratory surgery revealed EPS, probably caused by HIPEC. We peeled the capsule off of the intestine. The patient's postoperative course was uneventful, and sufficient nutritional intake after surgery was noted. Seven months after surgery, he is well with no recurrence. CONCLUSION: The surgical treatment via peritonectomy and enterolysis for postoperative EPS appears safe and effective. A diagnosis of EPS should be considered when intestinal obstruction does not show improvement with conservative treatment in patients who have undergone HIPEC, provided the possibility of peritoneal cancer recurrence is excluded.

Magnetic resonance imaging shrinkage patterns following neoadjuvant chemotherapy for breast carcinomas with an emphasis on the radiopathological correlations.

Preoperative neoadjuvant chemotherapy (NAC) is considered to be the standard treatment for locally-advanced breast carcinomas. Obtaining precise information regarding the tumor extent and distribution by imaging modalities to assess the success of breast-conserving surgery following NAC is extremely important. Analysis of the detailed radiopathological correlation of magnetic resonance imaging (MRI) following NAC has not been reported previously. The MRI and histopathological shrinkage patterns of residual breast carcinomas in 27 consecutive cases were analyzed following NAC and classified into five categories: Types I and II (concentric shrinkage with and without surrounding lesions, respectively); type III (shrinkage with residual multinodular lesions); type IV (diffuse contrast enhancement in whole quadrant); and non-visualization. The present study clearly demonstrated that the most common MRI shrinkage pattern was type I (11 cases), followed by type II and non-visualization, and the most common histopathological shrinkage pattern was type II (11 cases), followed by type III (8 cases). The concordance rate between MRI and pathological patterns was 48% and the worst concordance MRI pattern was type I. MRI is considered to be a useful method for evaluation of the residual carcinoma following NAC. However, the concordance rate was low in the MRI pattern I cases and tiny foci of residual carcinoma were present in half of the non-visualization cases, as shown by MRI. Therefore, the tumor extent must be completely resected for patients who undergo NAC, and postoperative radiation may be important for preventing local recurrence of breast carcinoma.