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Objectives: Heterotopic ossification (HO), which occurs when bone tissue forms outside the skeleton, is extremely rare in rectal cancer. Adenocarcinoma is the histological type of all reported primary colorectal cancers with HO. However, in the present case, we observed areas of adenocarcinoma with squamous cell carcinoma-like differentiation. Here we conducted histopathological and immunohistochemical analyses to identify the mechanisms of HO development, to differentiate between adenocarcinoma and squamous cell carcinoma-like phenotypes, and to understand the associated prognostic implications., Case Report: A 62-year-old woman was admitted to our hospital with symptoms of intermittent hematochezia without abdominal pain. Colonoscopy revealed stenosis with a protuberant mass in the rectum. Abdominopelvic contrast-enhanced computed tomography showed irregular wall thickness of the rectum, multiple lymph node metastases, and liver metastases. The rectal tumor exhibited calcified deposits with marked hyperintensity. We then performed Hartmann's operation and D3 lymph node resection. The biopsy specimen revealed tubular and solid adenocarcinoma nests and squamous carcinoma-like components over a necrotic extent without secreted mucin. She received chemotherapy (mFOLFOX6 with bevacizumab) as the first option and is alive 5 months after surgery., Conclusion: To the best of our knowledge, this is the first case of heterotopic ossification in a primary rectal cancer with squamous cell carcinoma-like differentiation that was surgically resected. This case suggests that BMP-2 transformed fibroblasts and pluripotent stem cells into osteocytes. We conclude that the squamous cell carcinoma-like lesion was squamous metaplasia of adenocarcinoma., Competing Interests: The authors have no conflicts of interest to declare.

Objectives: We evaluated the clinical outcomes of transumbilical single-incision laparoscopic appendectomy with extracorporeal hand-sewn stump closure in adults., Methods: One-hundred-and-thirty-one consecutive adults with acute appendicitis were treated with the intention of performing transumbilical single-incision laparoscopic appendectomy with extracorporeal hand-sewn stump closure from July 2012 to December 2017. The procedure completion rate and outcomes were examined. To evaluate the risk factors for conversion, the background data were compared between the patients in whom the procedure was completed versus those in whom the procedure was uncompleted., Results: The procedure was completed in 113 of 131 patients (86.3%). Single-site surgery was completed in 117 patients (89.3%). The median operation time was 79 (range 30-270) minutes and median intraoperative blood loss was 10 (range 0-394) ml. Postoperative complications occurred in 17 patients (13.0%). Postoperative hospital stay was 6 (range 1-27) days. The 18 patients in whom the procedure could not be completed comprised four patients in whom the stapler was used for intraabdominal stump closure, and 14 patients who were converted to multiport laparoscopic surgery or open surgery. Multivariate analysis showed that the independent risk factors for conversion were age, preoperative abscess, and peri-appendiceal fat density. Receiver operating characteristic curve analysis showed that the cutoff value of peri-appendiceal fat density for conversion was -40.51 Hounsfield units., Conclusions: Transumbilical single-incision laparoscopic appendectomy with extracorporeal hand-sewn stump closure was safe in adults with acute appendicitis. The risk factors for conversion were age ≥60 years, preoperative abscess, and peri-appendiceal fat density ≥-40.51 Hounsfield units., Competing Interests: The authors declare that they have no conflicts of interest.

Hepatocellular adenoma (HCA) is a benign hepatocyte-derived epithelial tumor. HCA is associated with oral contraceptive use among Caucasian populations. We report a case of hepatocellular adenoma with a pedunculated protuberance and high protein induced by vitamin K absence or antagonist-II (PIVKA-II) levels, which made diagnosis challenging. The patient was a 22-year-old woman. In a medical check-up, a high γ-GTP level was detected and a 115-mm solid mass was found in her lower abdomen via abdominal ultrasonography. A blood test showed a high PIVKA-II level. Abdominal CT showed a tumor in the lower abdomen. Contrast-enhanced CT showed a blood vessel thought to be the left hepatic artery connecting to the mass, and a blood vessel thought to be the left hepatic vein returning from the mass to the inferior vena cava. In EOB-MRI, uneven enhancement was observed after contrast imaging, but washout in the equilibrium phase was unclear. Parenchymal hepatocyte phases showed a pale, non-uniform, high signal. These findings indicated that the tumor was derived from the left lobe of the liver and was suggestive of HCC. Surgical resection was then performed. A pathological examination led to a diagnosis of HCA, corresponding to unclassified HCA. The WHO classification of tumors of the digestive system based on an immunohistological examination includes HNF1α-inactivated HCA, β-catenin-activated HCA, inflammatory HCA, and unclassified HCA. In summary, our patient had a large HCA with pedunculated protrusion into the extrahepatic pelvic cavity. This case was challenging to diagnose because of abnormally high PIVKA-II levels, and it was resected laparoscopically.

Objectives: The correlations of the ratio of long-/short-chain DNA fragments in blood with the existence of cancer and the clinicopathological features of colorectal cancer (CRC) were examined. The potential use of this ratio for diagnostic screening was evaluated., Methods: DNA concentrations were amplified using Alu247 for long-chain DNA fragments and Alu115 for long- and short-chain DNA fragments. The Alu247/115 ratio was calculated for 60 patients with CRC and 24 healthy volunteers. The correlation of the Alu247/115 ratio with clinicopathological variables and the efficacy of this ratio as a tumor marker were examined. The Alu247/115 ratio cut-off value was set using a receiver operating characteristic (ROC) curve., Results: The Alu247/115 ratio was significantly higher in patients with CRC than in healthy volunteers (P<0.001). The Alu247/115 ratio was also significantly higher in patients with Dukes stage A or B CRC than in healthy volunteers (P=0.034) as well as in patients with Dukes C or D CRC than in those with Dukes A or B CRC (P=0.016). Among patients with CRC, the Alu247/115 ratio was significantly higher in those with than without venous invasion (P=0.031). Using the cut-off value set from the ROC curve, the sensitivity of the Alu247/115 ratio was significantly higher than that of the carcinoembryonic antigen level (P=0.004) or the carbohydrate antigen 19-9 level (P<0.001)., Conclusion: Our data suggest that the Alu247/115 ratio is a promising tool for highly sensitive and early detection of CRC., Competing Interests: The authors have no conflicts of interest directly relevant to the content of this article.