The patient was a 74-year-old man. He was referred to our institution due to bloody stool and multiple liver tumors. Close examination revealed primary colon cancer in the splenic flexure of the colon and multiple liver metastases(up to 6.5 cm, 16 in total)in both lobes of the liver, and he was finally diagnosed with transverse colon cancer(cT3N+M1a[H3], cStage Ⅳa). As the liver metastases were unresectable and the primary tumor was not stenosed, the patient was treated with chemotherapy. As RAS/BRAF mutation was negative, the chemotherapy with FOLFOX and panitumumab were administered. After 6 courses of chemotherapy, the primary and metastatic tumors were reduced had shrunk and CEA value had decreased. The liver metastases were concentrated in the right lobe of the liver, and radical resection was considered possible with right lobectomy and partial resection of the left lobe of the liver. As the residual liver fraction was expected to be 33%, one-stage hepatectomy was too risky and the two-stage hepatectomy was chosen. Laparoscopic left hemicolectomy and laparoscopic partial resection of the liver(S3 and S4, 4 tumor resections in total)were performed at the first operation. On postoperative day 8, the percutaneous transhepatic portal vein embolization(PTPE)of the right lobe of the liver was performed, and the expected residual liver fraction was increased to 40% 2 weeks after PTPE. The laparoscopic right lobectomy of the liver was performed on day 20 after PTPE. The patient has had no major complications or recurrences to date. We report a case in which R0 was achieved after aggressive chemotherapy and laparoscopic two-stage hepatectomy.

Para-aortic lymph node metastasis(PALNM)is classified as distant metastasis in colorectal cancer(CRC). Although the benefit of para-aortic lymph node dissection(PALND)for the CRC patients with PALNM suspected radiologically remains controversial, some reports have shown that the survival benefit for PALND in CRC patients with PALNM. Moreover, the report evaluating the extent of PALND showed that the patients treated with radical lymphadenectomy had better prognosis compared to those treated with targeted lymphadenectomy defined as the dissection of only swollen lymph nodes. We have performed the laparoscopic PALND for selected CRC patients with PALNM. Three radical dissections using retroperitoneoscopy have been performed in 9 CRC patients who underwent PALND in the last 6 years. Now, we show one of the effective cases treated with the retroperitoneoscopic radical resection. We additionally mention the effectiveness of the retroperitoneoscopic radical resection for the patients with PALNM. The retroperitoneoscopic resection resulted in more blood loss and longer operative time than laparoscopic resection, however, more lymph nodes were resected. The retroperitoneoscopic radical resection may be the preferable procedure for the CRC patients with PALNM, especially for the patients with multiple or extensively spread PALNM.

A 77-year-old male patient with cT4N1aM1(PUL1), cStage Ⅳ rectal cancer underwent low anterior resection in Y20XX with a plan to perform pneumonectomy after resection of the primary tumor. The pathological diagnosis was pT3N0M1 (PUL1), pStage Ⅳ mucinous adenocarcinoma ly1, v1, pPM0, pDM0. A thoracoscopic left lung S4 segmentectomy was performed Y+2 months later and a thoracoscopic right upper lung partial lobectomy was performed Y+6 months later. However, a small nodule appeared in the lower lobe of the right lung on postoperative follow-up CT and continued to grow, so a partial resection of the lower lobe of the right lung was performed Y+12 months later. However, a 6 mm-sized mass appeared in the left upper lobe of the lung on postoperative follow-up CT, and it continued to grow, so partial resection of the left upper lobe was performed Y+20 months later. Both pathological diagnoses were pulmonary metastasis of rectal cancer. Since the patient had had 3 metastatic recurrences at this point, postoperative adjuvant chemotherapy(S-1)was administered from Y+22 months. Since then, the patient has been alive without metastasis or recurrence, and is still recurrence-free 14 years after the last pneumonectomy.

A 70' woman presented to our hospital complaining of a weight loss and loss of appetite. She was diagnosed with advanced sigmoid colon cancer by colonoscopy, and CT scan showed that the tumor had invaded the bladder and left ovary, and showed enlarged para-aortic lymph nodes. The tumor was large, and it was determined that a total cystectomy was necessary for radical resection, it was decided to perform pre-operative chemotherapy. Because RAS gene has no mutation, the regimen chose mFOLFOX6, in addition to cetuximab. Although Grade 3 neutropenia was observed, there was no appearance of adverse events that were intolerant, and 6 courses were performed. The treatment resulted in a marked reduction of the tumor. An open sigmoid colon resection with bladder wall and left ovarian cyst were performed. Even after the operation, the course was good, and it was discharged from the hospital lightly on the 10th day after the operation. The histopathological diagnosis was moderately differentiated adenocarcinoma, ypT4b(bladder left ovary), ypN0, M0, ypStage Ⅱc, all with negative surgical margins. She remained recurrence-free for 6 months of postoperative follow up. Cetuximab combination regimen was considered to be an effective option.

An 89-year-old woman with an allergy to contrast dye and with a history of cholecystectomy visited emergency department complaining of vomiting and abdominal pain. The diagnosis of adhesive bowel obstruction near terminal ileum was made with plain computed tomography. Although intestinal decompression was attempted with nasogastric tube, followed by intestinal tube, no improvement was achieved, so adhesiolysis was planned. Intraoperatively, an extrinsic mass was detected near the terminal ileum, and ileocecal resection was performed. the pathological diagnosis was low grade appendiceal mucinous neoplasm, and margin was negative. Postoperative course was almost smooth, but due to the pre-existing low activity of daily life, she was transferred to a health facility for recuperation on postoperative day 42. When we diagnose small bowel obstruction near the terminal ileum, we need to keep it in mind that appendiceal tumor is one of the differential diagnoses, although the incidence rate is low.

Signet ring cell carcinoma(SRCC)is a poorly prognostic cancer that primarily arises in the stomach. Its occurrence in the colon is extremely rare, with an incidence rate of 1%. We encountered a case of signet ring cell carcinoma that was considered to originate from the cecum based on clinical course and imaging findings.

Advances in chemotherapy have improved the treatment of highly advanced colorectal cancer. Even patients with unresectable tumors with distant metastases to other organs can now be treated with chemotherapy alone and have a favorable prognosis of several years. However, a complete response to chemotherapy is rare. We report this case because of its rarity, as complete remission was maintained after primary resection and chemotherapy. The patient was a 52-year-old man who was admitted to a local hospital because of abdominal pain and diarrhea that had persisted for more than 1 month. Thoracoabdominal CT revealed lesions in the transverse colon, multiple ring-shaped lesions in the liver, and a mass around the aorta. The diagnosis was unresectable colorectal cancer with multiple liver and periaortic lymph node metastases. The patient underwent primary resection of the colorectal cancer and colostomy due to obstruction caused by the colorectal cancer. After 4 courses, CR and 12 courses of total were administered. The patient received 12 courses of total, followed by maintenance therapy. Currently, 25 months have passed since the start of chemotherapy and the patient is maintaining CR.

A woman in her 60s visited the gynecology department of our hospital with a chief complaint of lower abdominal pain and bloating. Contrast-enhanced CT and MRI of the abdomen revealed an irregularly shaped 10 cm mass in contact with the uterus. Presence of a poorly contrast-enhanced area within the mass led to the diagnosis of uterine sarcoma, and surgical intervention was undertaken. A combined resection of the uterus and bilateral ovaries was performed; however, the tumor was found to be contiguous with the sigmoid mesentery rather than the uterus. Therefore, the sigmoid colon, including the tumor, was resected. No evidence of metastases or peritoneal dissemination was observed. Histopathological examination revealed spindle-shaped cells with strong nuclear atypia. Leiomyosarcoma was diagnosed based on h-caldesmon (+), α-SMA(+), desmin(+), and c-kit(-). One year after surgery, the patient is alive without recurrence.

The case was a 68-year-old woman who presented with a complaint of an abdominal mass. She was diagnosed with the retroperitoneal liposarcoma. In the initial surgery, the primary tumor was resected together with the right colon involved. Since the histological type was the dedifferentiated type, imaging tests were performed every 10 weeks. After all there were seven local recurrences and one recurrence of lung metastasis, and each time the tumor relapsed, a combined resection of surrounding organs were repeated. At the time of the eighth recurrence, she requested chemotherapy. But her illness progressed. Five and a half years after the initial surgery, she passed away. The only effective treatment for retroperitoneal liposarcoma is surgical resection, but the prognosis varies depending on the histological type. The dedifferentiated type is a disease that often has a poor prognosis due to repeated local recurrence and inoperability. In this case, we report with a literature review on a case in which we were able to detect a recurrence in a state that was resectable by performing imaging tests at short intervals for dedifferentiated liposarcoma, and we were able to achieve long-term survival through 8 surgeries.

A 60-year-old male was admitted to the hospital with abdominal pain and diagnosed with microsatellite instability-high (MSI-H)sigmoid colon cancer. Computed tomography revealed an obstructive mass in the sigmoid colon along with swelling of the para-aortic lymph nodes. The patient initially underwent loop transverse colostomy, followed by treatment with the immune checkpoint inhibitor(ICI)pembrolizumab. After 5 courses of ICI, the tumor significantly shrank; therefore, radical resection was performed. The patient has been monitored without adjuvant chemotherapy, and recurrence has not occurred after 1 year. This case shows that ICI may be an effective rescue treatment for colorectal cancer patients with unresectable distant metastasis.

We report a case of granulocyte-colony stimulating factor(G-CSF)-producing undifferentiated sarcoma of the transverse colon. A 80-year-old woman was referred to our hematology department after visiting her primary physician with chief complaints of decreased appetite and fatigue. An elevated white blood cell count was observed during examination. Further laboratory tests at our hospital revealed an elevated white blood cell count of 95,800/μL and a plasma G-CSF level of 895 pg/mL. The patient was referred to our department after a tumor lesion was found in the transverse colon during computed tomography, and a G-CSF-producing tumor was suspected. Right hemicolectomy was performed for diagnosis and treatment. Pathological examination revealed an undifferentiated sarcoma, and immunostaining results were positive for G-CSF, leading to a diagnosis of a G-CSF-producing undifferentiated sarcoma of the transverse colon.

An 86-year-old man with a 3 months history of weight loss and bloody diarrhea was admitted to our hospital. Endoscopic examination revealed transverse colon cancer, along with numerous polypoid lesions in the stomach, duodenum, colon, and rectum. These findings led to a diagnosis of Cronkhite-Canada syndrome(CCS). Due to advanced colon cancer with stenosis, the patient underwent laparoscopic extended right hemicolectomy of the colon with D3 lymphadenectomy. The patient had no major postoperative complications and was discharged on the 17th postoperative day. Six weeks after surgery, the patient was treated with steroids, which led to an improvement in his symptoms. However, after the steroid dose was reduced, diarrhea worsened and the patient continued to receive treatment. The typical treatment for CSS is medical use of corticosteroids, but there is a timing issue regarding when to perform surgery on a patient with cancer. In this case, we could perform surgery for CCS with advanced colon cancer and safely introduce steroid therapy early after surgery.

To improve the prognosis of lower rectal cancer, our department has implemented total neoadjuvant therapy(TNT), which involves the preoperative administration of chemoradiotherapy combined with systemic chemotherapy. For patients who achieve a clinical complete response(cCR)with TNT, we offer the Watch-and-Wait(W & W)strategy as a treatment option. This approach allows for organ preservation and avoids immediate surgery, provided there is informed consent and strict follow-up. This report presents the case of a 61-year-old male with locally advanced lower rectal cancer who required stoma construction before treatment initiation. The cancer had invaded the prostate and levator ani muscles with lateral lymph node metastasis, causing the patient to experience severe anal pain. TNTs were performed after ileostomy. Post-treatment evaluation revealed cCR, and the patient was subsequently placed under the W & W strategy with strict follow-up. Two years after treatment, stoma closure was performed without recurrence and no significant defecation disorder was observed. Two years and 10 months have passed since treatment, and there are no signs of recurrence or maintenance of cCR.

A woman with rectal cancer underwent a laparoscopic low-anterior resection in 2015. However, in 2017, she was diagnosed with pelvic lymph node recurrence, following which a lateral lymph node dissection was performed. Another bout of pelvic lymph node recurrence was confirmed in 2018, whereupon the lesions were irradiated using radiographs. In 2021, pelvic lymph node swelling was detected, and chemotherapy was initiated. Prior to irradiation, a spacer was installed between the tumor and the gastrointestinal tract, and a heavy particle beam was directed at the lymph nodes in 2022. An increase in the size of the lymph nodes in the right external iliac artery and obturator lymph node regions was confirmed, followed by another dose of heavy particle therapy. Interestingly, no recurrence has been observed till date.

A 65-year-old male was admitted to our hospital with symptoms of perineal redness, fever, and hematuria. CT showed bladder wall thickening and a continuous rectum. Rectal cancer was suspected to have invaded the bladder and caused a urinary tract infection. A laparoscopic transverse colostomy was performed. Subsequent contrast-enhanced CT revealed rectal cancer with multiple liver metastases and abscess formation around the urethra. To control the infection, a laparoscopic low anterior resection with total cystectomy was performed. An ileal conduit was selected for urinary diversion. Six months later, after the colostomy was closed, the patient only required management of the ileal conduit. Chemotherapy for liver metastasis was initiated 10 months after surgery.

A 73-year-old woman was admitted to our hospital with a 5 months history of epigastric discomfort. Abdominal CT performed on admission revealed localized dilation of the small intestine. The patient was diagnosed with subileus and treatment was initiated with fasting and intravenous fluids. An upper gastrointestinal series revealed an apple core sign in the upper jejunum. Double-balloon enteroscopy identified a type 2 tumor in the upper jejunum, which was marked with ink. A biopsy of the tumor revealed a Group 5 tumor, with no distant metastasis. The patient was diagnosed with primary small intestinal cancer. A single-incision laparoscopic surgery was performed. A circumferential tumor was found in the jejunum, 25 cm from the ligament of Treitz, and a partial small intestinal resection was performed. The postoperative pathological results were tub1>tub2, pT3(SS), int, INF β, Ly0, V1a, PN0, pPM0, pDM0, pN0(0/5), with a final diagnosis of pStage Ⅱ. The postoperative course was uneventful, and the patient was discharged on the 15th postoperative day. The patient has been under observation for 1 year and 5 months after surgery without recurrence or the need for postoperative adjuvant chemotherapy.

A 65-year-old woman underwent laparoscopically assisted high anterior resection for sigmoid colon cancer in March 2011. The pathological result was S, type 2, 2.5×2.7 cm, tub2, pSE, pN2(#241 5 pts), ly2, v1, fStage Ⅲb. She received UFT+UZEL for 6 months as postoperative adjuvant chemotherapy. She was followed up, but in February 2017, dynamic-CT showed a 24×15 mm left retroperitoneal recurrence, and in the same area, the left ureter was disrupted and the left renal pelvis was dilated. In March of the same year, she underwent 8 courses of FOLFOX+Pmab therapy, and in August of the same year, she underwent left hemicolectomy with left renal complications due to her PR status. After discharge from the hospital, she underwent another 6 courses of FOLFOX+Pmab therapy. She was switched to oral administration of S-1, which was continued for 1 year. However, in November 2019, a right ovarian metastasis appeared, and right ovarian resection was performed. In July 2022, multiple bilateral lung metastases appeared on a CT scan, and 5 courses of FOLFIRI+Bmab were performed. Subsequently, she was followed up without chemotherapy at her request. Thirteen years after the initial surgery, there has been no apparent recurrence on imaging, and the patient is alive.

An 81-year-old man was suspected of having gastric cancer and liver metastasis based on CT findings at another hospital. Upper gastrointestinal endoscopy revealed a 50 mm ulcerative lesion on the posterior wall of the upper gastric body. A biopsy led to a diagnosis of poorly differentiated adenocarcinoma of the non-solid type(por2). Contrast CT revealed a 25 mm enlarged lymph node in the lesser curvature and a 15 mm solitary liver metastasis in S2. No other distant metastases were found. The preoperative diagnosis was U, Post, Type 2, 50 mm, por2, cT4aN(+)M1(HEP), cStage Ⅳ. Chemotherapy (TS-1, 2 courses)was administered, and stable disease(SD)was observed. Because the disease severity was controlled, laparoscopic total gastrectomy and partial S2 hepatectomy were performed. The pathological findings revealed gastric MiNEN with liver metastasis. After surgery, no chemotherapy was administered. The patient has been under observation for 3 years without any sign of recurrence.

An 83-year-old woman was referred for the surgical treatment of early gastric cancer. FDG-PET/CT showed multiple space-occupying lesions in the spleen with abnormal FDG accumulation. Robot-assisted distal gastrectomy(D1+), Billroth Ⅱ reconstruction, and robot-assisted splenectomy were simultaneously performed for the diagnosis of splenic tumors without any intraoperative complications. Histopathological examination revealed early gastric cancer[M, Less, por+sig>tub2, 27×15 mm, pT1a, N0, M0, pStage ⅠA], and based on the findings of non-caseating granulomas, the multiple splenic tumors were diagnosed as splenic sarcoidosis. Histopathological diagnosis is necessary for the definitive diagnosis of splenic tumors. Although laparoscopic splenectomies have become increasingly common, the safety of robot-assisted splenectomies remains controversial. In the present case, robot-assisted splenectomy was performed safely during the simultaneous resection of gastric cancer, and a histological diagnosis was possible. However, further evidence on the usefulness of robot-assisted splenectomy is required.

A 67-year-old man presented with obstructive jaundice in March 2022 and was diagnosed with borderline resectable pancreatic head cancer. Gemcitabine+nab-paclitaxel(GnP)was started as preoperative chemotherapy, and tumor shrinkage was observed. In August of the same year, he underwent a subtotal stomach-preserving pancreaticoduodenectomy, combined portal vein resection and reconstruction. The pathological evaluation of surgical specimen demonstrated that it was anaplastic pancreatic cancer and he was treated with adjuvant chemotherapy with GnP. In April 2023, a CT scan confirmed that there was no recurrence or metastasis, and the patient was given 20 doses of anticancer drugs over a 6 months period and then stopped taking them. In August of the same year, the chemotherapy was resumed due to the finding of elevated CA19-9. Immediately after the administration, a decrease in CA19-9 was observed, however it rose again in February 2024, and a CT scan indicated tumor recurrence in the residual pancreas. He is currently being followed up on an outpatient basis with S-1 medication. Anaplastic carcinoma has a poor prognosis, but we have experienced a case of long-term survival of approximately 2 years after surgery with multidisciplinary treatment.