Microsatellite Instability-high Signet Ring Cell Carcinoma of the Colon Treated With Immunotherapy: Report of a Case.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are attracting increasing attention as a novel and potentially curative therapy for microsatellite instability-high (MSI-H) colorectal cancer (CRC). CASE REPORT: An 80-year-old female visited our hospital with complaints of lower abdominal pain due to bowel obstruction caused by descending colon cancer. After 1 month of metallic stent detention, she underwent radical surgery, although laparotomy showed broad peritoneal dissemination. Based on the genetic finding of MSI-H status, pembrolizumab therapy was administered in two cycles. Unfortunately, the therapy was ineffective, and the patient died after being discharged 5 months after surgery. CONCLUSION: The findings in this case of MSI-H CRC with a poor response to an ICI suggest the importance of confirming HLA status, including beta-2-microglobulin and HLA expression, before starting ICI therapy in cases of MSI-H CRC.

Chronic Appendicitis Caused by a Perforating Fish Bone: Case Report and Brief Literature Review.

BACKGROUND: Appendicitis caused by a foreign body is extremely rare. We report a case of chronic appendicitis caused by a perforating fish bone. CASE REPORT: The patient was a 50-year-old Japanese man. He felt dull lower abdominal pain for 2 months and diagnosed as appendicitis caused by a perforating fish bone. He underwent emergency laparoscopic surgery. The fish bone had perforated through the appendix wall. The fish bone was initially removed followed by laparoscopic appendectomy. Pathological investigation revealed a transmural cut line of approximately 0.5 mm that was surrounded by fibrous tissue with inflammation. CONCLUSION: This is the first reported case of fish bone-induced chronic appendicitis that underwent laparoscopic appendectomy. For optimum outcome, a correct diagnosis based on a detailed consultation and imaging tests, and an operation performed after careful planning are needed.

A rare case of perforation of a colorectal tumor by a fish bone.

The accidental ingestion of foreign bodies is a common clinical issue. While most foreign bodies pass through the gastrointestinal (GI) tract without complications, a few cases unfortunately result in GI perforation. Fish bones are one of the most frequent foreign bodies found in the GI tract, and they are high-risk objects for GI perforation due to their hard and sharp-pointed ends. Here, we present a rare case of a 64-year-old man with perforation of a colorectal tumor by a fish bone. The patient received emergency Hartmann's operation with lymph node dissection. Although the patient experienced recurrence in the liver rather than peritoneal dissemination, systemic chemotherapy was considerably effective, and conversion therapy with hepatectomy was successfully performed; the patient achieved 5-year relapse-free survival after the operation. To our knowledge, this is the first report of the perforation of a GI tumor by a fish bone. This rare case suggests the significant clinical implication that proper preoperative diagnosis and prompt surgical treatment lead to better postoperative outcomes for patients with tumor perforation by a foreign body.

A Case of Mesenteric Desmoid Tumor Causing Bowel Obstruction After Laparoscopic Surgery.

BACKGROUND: A desmoid tumor is a rare neoplasm that is derived from soft tissues. Although it shows benign characteristics pathologically, local recurrence can occur. CASE REPORT: We herein report the case of a patient with an intraabdominal desmoid tumor that developed 3 years after laparoscopic appendectomy for acute appendicitis. A 59-year-old male visited our emergency room with complaints of abdominal pain and fullness. Abdominal computed tomography revealed distention of the small intestine with a point of obstruction by an intraabdominal tumor-like region. Pathological findings showed that the tumor was compatible with desmoid fibromatosis. CONCLUSION: In cases with an intraabdominal tumor after laparoscopic surgery, it is important to consider the possibility of a desmoid tumor, since it is difficult to diagnose it accurately before surgery.

Perirectal abscess with dysuria.

Perirectal abscesses often occur in the dorsal portion of the perirectal tissues. We report a patient who presented with fever, pain on defecation, and dysuria. He was found to have a perirectal abscess in the anterior perineum pressing on the urethra. After emergency surgery to drain the abscess, the symptoms improved.