Anticancer efficacy of monotherapy with antibodies to SIRPα/SIRPß1 mediated by induction of antitumorigenic macrophages.

The interaction of signal regulatory protein α (SIRPα) on macrophages with CD47 on cancer cells is thought to prevent antibody (Ab)-dependent cellular phagocytosis (ADCP) of the latter cells by the former. Blockade of the CD47-SIRPα interaction by Abs to CD47 or to SIRPα, in combination with tumor-targeting Abs such as rituximab, thus inhibits tumor formation by promoting macrophage-mediated ADCP of cancer cells. Here we show that monotherapy with a monoclonal Ab (mAb) to SIRPα that also recognizes SIRPß1 inhibited tumor formation by bladder and mammary cancer cells in mice, with this inhibitory effect being largely dependent on macrophages. The mAb to SIRPα promoted polarization of tumor-infiltrating macrophages toward an antitumorigenic phenotype, resulting in the killing and phagocytosis of cancer cells by the macrophages. Ablation of SIRPα in mice did not prevent the inhibitory effect of the anti-SIRPα mAb on tumor formation or its promotion of the cancer cell-killing activity of macrophages, however. Moreover, knockdown of SIRPß1 in macrophages attenuated the stimulatory effect of the anti-SIRPα mAb on the killing of cancer cells, whereas an mAb specific for SIRPß1 mimicked the effect of the anti-SIRPα mAb. Our results thus suggest that monotherapy with Abs to SIRPα/SIRPß1 induces antitumorigenic macrophages and thereby inhibits tumor growth and that SIRPß1 is a potential target for cancer immunotherapy.

Bone loss over time and risk of osteoporosis in advanced pancreatic cancer.

BACKGROUND: Pancreatic cancer has a high risk of developing osteoporosis. However, the impact of osteoporosis has not been well-studied. This study aimed to evaluate bone loss over time and risk of osteoporosis in patients with advanced pancreatic cancer. METHODS: We retrospectively examined consecutive patients with unresectable pancreatic cancer who had evaluable computed tomography before treatment and at 1-year follow-up. Bone mineral density at the first lumbar vertebra was measured on computed tomography, and osteoporosis was defined as bone mineral density < 135 Hounsfield units. The prevalence and risk factors for osteoporosis, changes in bone mineral density over time and incidence of bone fractures were analyzed. RESULTS: Three hundred eighty patients were included. Osteoporosis was associated with older age, female sex, low body mass index and poor performance status at baseline. A consistent decrease in bone mineral density was observed over time regardless of age, sex or disease status, resulting in an increase in the prevalence of osteoporosis over time (47% at baseline, 79% at 1 year, 88% at 2 years, 89% at 3 years, 95% at 4 years and 100% at 5 years). Changes in bone mineral density from baseline were greater in patients with locally-advanced pancreatic cancer, in those who received modified FOLFIRINOX or S-IROX for more than 3 months, and in those who received radiation therapy. Incident fractures developed in 45 patients (12%) during follow-up. CONCLUSIONS: Osteoporosis and osteoporotic fractures were highly prevalent in patients with advanced pancreatic cancer. This study highlights the importance of screening for osteoporosis in such patients.

Targeting of SIRPα as a potential therapy for Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a rare neoplastic disorder characterized by inflammatory lesions arising from the anomalous accumulation of pathogenic CD1a+ CD207+ dendritic cells (DCs). SIRPα is a transmembrane protein highly expressed in myeloid cells such as DCs and macrophages. Here we show that SIRPα is a potential therapeutic target for LCH. We found that SIRPα is expressed in CD1a+ cells of human LCH lesions as well as in CD11c+ DCs in the spleen, liver, and lung of a mouse model of LCH (BRAFV600ECD11c mouse), in which an LCH-associated active form of human BRAF is expressed in a manner dependent on the mouse Cd11c promoter. BRAFV600ECD11c mice manifested markedly increased numbers of CD4+ T cells, regulatory T cells, and macrophages as well as of CD11c+ MHCII+ DCs in the spleen. Monotherapy with a mAb to SIRPα greatly reduced the percentage of CD11c+ MHCII+ DCs in peripheral blood, LCH-like lesion size in the liver, and the number of CD11c+ MHCII+ DCs in the spleen of the mutant mice. Moreover, this mAb promoted macrophage-mediated phagocytosis of CD11c+ DCs from BRAFV600ECD11c mice, whereas it had no effects on the viability or CCL19-dependent migration of such CD11c+ DCs or on their expression of the chemokine genes Ccl5, Ccl20, Cxcl11, and Cxcl12. Our results thus suggest that anti-SIRPα monotherapy is a promising approach to the treatment of LCH that is dependent in part on the promotion of the macrophage-mediated killing of LCH cells.

Prognostic impact of osteosarcopenia in patients with advanced pancreatic cancer receiving gemcitabine plus nab-paclitaxel.

BACKGROUND: Osteosarcopenia, defined as the combination of osteoporosis and sarcopenia, has recently gained attention as a novel prognostic factor for survival in patients with cancer. This study aimed to evaluate the prognostic impact of osteosarcopenia in metastatic pancreatic cancer (PC). METHODS: We retrospectively investigated consecutive metastatic PC patients receiving first-line gemcitabine plus nab-paclitaxel (GnP). Skeletal muscle index at the third lumbar vertebra and bone mineral density at the first lumbar vertebra were measured using pretreatment computed tomography. Treatment outcomes of osteosarcopenia and non-osteosarcopenia groups were compared and analyzed. Multivariate analysis was performed to identify variables associated with survival. RESULTS: Among 313 patients, osteosarcopenia was present in 59 patients (19%). The osteosarcopenia group was associated with older age, higher proportion of females, worse performance status, and higher modified Glasgow prognostic scores (mGPS). Response rates to chemotherapy, progression-free survival (3.5 months vs. 6.4 months, p < 0.001), and overall survival (5.6 months vs. 13.0 months, p < 0.001) were significantly better in the non-osteosarcopenia group. Osteosarcopenia, performance status of 1-2, mGPS score of 1-2, carcinoembryonic antigen ≥10 ng/mL, and carbohydrate antigen 19-9 ≥ 1000 IU/mL were identified as independent factors predicting shorter survival. Grade 3 or higher anemia and febrile neutropenia occurred more frequently in the osteosarcopenia group. CONCLUSIONS: Osteosarcopenia was associated with poor survival in metastatic PC treated with first-line GnP. Screening for osteosarcopenia may be helpful for better management of metastatic PC.

The impact of osteosarcopenia in patients with unresectable or recurrent biliary tract cancer receiving palliative chemotherapy.

BACKGROUND: Osteosarcopenia is a newly described syndrome that has been reported to be associated with worse outcomes in various types of cancer. However, its impact on survival in biliary tract cancer remains unclear. This study evaluated the impact of osteosarcopenia on survival in patients with unresectable or recurrent biliary tract cancer. METHODS: A total of 306 patients with unresectable or recurrent biliary tract cancer who initiated chemotherapy at our institution between 2015 and 2021 were retrospectively investigated. Skeletal muscle index and bone mineral density were measured using pretreatment cross-sectional computed tomography images. Baseline characteristics and survival outcomes were compared between patients with osteosarcopenia and those without. The Cox proportional hazards regression model was used to identify factors associated with survival. RESULTS: Osteosarcopenia was present in 66 patients (22%) and was associated with older age (74 vs. 69 years, P < 0.001) and female sex (58 vs. 37%, P = 0.003). Patients with osteosarcopenia tended to have worse performance status (P = 0.098), higher modified Glasgow prognostic score (P = 0.082), higher neutrophil to lymphocyte ratio (P = 0.058) and were significantly less likely to receive combination chemotherapy (68 vs. 80%, P = 0.044) than those without. Osteosarcopenia was associated with reduced survival (8.9 vs. 14.0 months, P < 0.001) and was identified as an independent factor predicting shorter survival in multivariate analysis. CONCLUSIONS: Osteosarcopenia was associated with poor survival in unresectable or recurrent biliary tract cancer treated with chemotherapy. This study highlights the potential importance of screening for osteosarcopenia in patients with biliary tract cancer.

Outcomes of lung oligometastasis in pancreatic cancer.

OBJECTIVE: Pancreatic cancer with lung oligometastasis may have favourable overall survival. The aim of this study was to evaluate outcomes of pancreatic cancer with lung oligometastases including both synchronous and metachronous metastases. METHODS: Consecutive pancreatic cancer patients with lung metastasis treated at our institution between February 2015 and December 2021 were identified from our prospectively maintained database. Clinical characteristics and outcomes were compared and analysed according to the extent of lung metastases. Predictors for overall survival were analysed using the Cox proportional hazards model. RESULTS: A totoal of 171 patients were included (oligometastasis/polymetastasis/multi-organ metastasis: 34/50/87). Patients with oligometastases were more likely to undergo surgical resection (41% vs. 0% vs. 2%) and showed a longer median overall survival (41.3 vs. 17.6 vs. 13.1 months) compared with those with other types of metastases. Oligometastasis (hazard ratio, 0.43; 95% confidence interval, 0.24-0.76; P = 0.004) was identified as an independent factor predicting favourable overall survival in patients with lung-only metastasis. Disease status (synchronous vs. metachronous) was not associated with survival in patients with oligometastasis (29.4 vs. 41.3 months, P = 0.527) and polymetastasis (17.9 vs. 16.7 months, P = 0.545). Selected patients who underwent surgical resection showed a median overall survival of 52.7 months. CONCLUSIONS: Patients with lung oligometastases presented a favourable prognosis. Surgical resection in selected patients was associated with a long median overall survival.

Clinical Outcomes of Patients With Osteosarcoma Experiencing Relapse or Progression: A Single-institute Experience.

BACKGROUND: Patients with osteosarcoma who experience relapse or progression [R/P] have a poor prognosis. METHODS: Data from 30 patients who experienced R/P among 59 with a diagnosis of high-grade osteosarcoma, who were younger than 40 years old between 2000 and 2019, were retrospectively analyzed to identify prognostic and therapeutic factors influencing their outcomes. RESULTS: The 5-year overall survival [OS] rates after the last R/P of patients experiencing first [n=30], second [n=14], and third [n=9] R/P were 50.3%, 51.3%, and 46.7%, respectively. Multivariate analysis did not identify any independent risk factors affecting OS. The 5-year PFS rate of the 30 patients after first R/P was 22.4%, and multivariate analysis identified histologic subtype and curative local surgery as independent risk factors influencing PFS. Long [>6 mo] partial response was observed in three patients treated using temozolomide+etoposide, irinotecan+carboplatin, or regorafenib. CONCLUSIONS: OS rate in the patients with osteosarcoma experiencing R/P included in this study was markedly higher than that reported previously, mainly due to the surgical total removal of tumors, even after subsequent R/P. The recent establishment of salvage chemotherapy or molecular targeted therapy may also increase survival rates in a subgroup of patients.

Long-term outcomes of duckbill-type anti-reflux metal stents versus conventional covered metal stents in reinterventions after covered biliary metal stent dysfunction in unresectable pancreatic cancer.

BACKGROUND: The use of duckbill-type anti-reflux metal stents (DMS) in reinterventions after covered metal stent (CMS) dysfunction has been reported in patients with distal malignant biliary obstruction (MBO). However, the superiority of DMS over conventional CMS (c-CMS) has not been established. Therefore, we conducted this retrospective study to evaluate the long-term efficacy and safety of DMS as a second stent in comparison with c-CMS. METHODS: We investigated consecutive patients with distal MBO due to unresectable pancreatic cancer who underwent reintervention after dysfunction of initial biliary CMS at our institution. We compared causes of recurrent biliary obstruction (RBO), time to RBO (TRBO), adverse events (AEs), and reintervention rates of DMS and c-CMS in this stenting. RESULTS: A total of 76 patients were included (DMS 41 and c-CMS 35). While overall RBO rates were similar between the two groups (46% vs. 63%, p = 0.172), RBO due to non-occlusion cholangitis tended to be less frequent in the DMS group than in the c-CMS group (2% vs. 14%, p = 0.089). Median TRBO was significantly longer in the DMS group (286 days vs. 112 days, p = 0.029). DMS was identified as the only significant risk factor for TRBO (hazard ratio, 0.52; p = 0.044). Overall AE rates were significantly lower in the DMS group (2% vs. 23%, p = 0.010), with non-occlusion cholangitis being the most common AE in the c-CMS group. Endoscopic reintervention was successfully performed in all patients in both groups, despite failed stent removal in 15% of patients in DMS group. CONCLUSIONS: DMS was associated with a significantly longer TRBO and lower rate of AEs compared with c-CMS in reinterventions after initial CMS dysfunction. DMS may be preferable to c-CMS as a second stent after biliary CMS dysfunction.

Outcomes after partially covered self-expandable metal stent placement for recurrent duodenal obstruction.

BACKGROUND: Outcomes of partially covered self-expandable metal stents (SEMS) as an additional stent after recurrent duodenal obstruction (RDO) have not been elucidated. In this study, we compared outcomes of partially covered and uncovered SEMS placement after RDO in patients with malignant duodenal obstruction and explored factors affecting re-recurrent obstruction and overall survival in this population. METHODS: We conducted a retrospective study of patients undergoing SEMS placement for RDO at a cancer institute in Japan from July 2014 to June 2021. Clinical variables and outcomes of patients undergoing partially covered and uncovered SEMS placement were compared. RESULTS: Sixty-one patients underwent SEMS placement after RDO, for which the COMVI stent was used in 38 cases and uncovered stents were used in 23 cases. Stent ingrowth was the most common cause of RDO (51.4%). Stent migration only occurred after partially covered stent placement (20% vs. 0%, p = 0.018). Choice of SEMS had no impact on time to re-RDO (median 2.8 vs. 4.1 months, p = 0.776) or overall survival (median 2.6 vs. 2.4 months, p = 0.703). Median overall survival was longer in patients receiving chemotherapy after second stenting (4.6 vs. 1.8 months, p < 0.001) and shorter in those with early RDO, regardless of the SEMS used. Use of the partially covered stent had no impact on survival or time to RDO. CONCLUSIONS: While outcomes after partially covered SEMS placement for RDO were not significantly different from uncovered SEMS, migration remains a concern when they are used as a second stent. Chemotherapy after second stenting was associated with longer overall survival but not with longer time to re-RDO.

The landscape of genetic aberrations in myxofibrosarcoma.

Myxofibrosarcoma (MFS) is a rare subtype of sarcoma, whose genetic basis is poorly understood. We analyzed 69 MFS cases using whole-genome (WGS), whole-exome (WES) and/or targeted-sequencing (TS). Newly sequenced genomic data were combined with additional deposited 116 MFS samples. WGS identified a high number of structural variations (SVs) per tumor most frequently affecting the TP53 and RB1 loci, 40% of tumors showed a BRCAness-associated mutation signature, and evidence of chromothripsis was found in all cases. Most frequently mutated/copy number altered genes affected known disease drivers such as TP53 (56.2%), CDKN2A/B (29.7%), RB1 (27.0%), ATRX (19.5%) and HDLBP (18.9%). Several previously unappreciated genetic aberrations including MUC17, FLG and ZNF780A were identified in more than 20% of patients. Longitudinal analysis of paired diagnosis and relapse time points revealed a 1.2-fold mutation number increase accompanied with substantial changes in clonal composition over time. Our study highlights the genetic complexity underlying sarcomagenesis of MFS.

Long-term Outcomes in Asymptomatic Ulcerative Colitis Diagnosed During Screening Colonoscopy.

Treatment goals in ulcerative colitis have shifted from clinical remission to mucosal healing, and more recently, to histological remission.1,2 Treating patients with healed mucosae has been shown to be beneficial.3 Clinical, endoscopic, and histological findings do not necessarily correlate with each other.4.

Standardization of evaluation method and prognostic significance of histological response to preoperative chemotherapy in high-grade non-round cell soft tissue sarcomas.

BACKGROUND: Preoperative chemotherapy is widely applied to high-grade localized soft tissue sarcomas (STSs); however, the prognostic significance of histological response to chemotherapy remains controversial. This study aimed to standardize evaluation method of histological response to chemotherapy with high agreement score among pathologists, and to establish a cut-off value closely related to prognosis. METHODS: Using data and specimens from the patients who had registered in the Japan Clinical Oncology Group study, JCOG0304, a phase II trial evaluating the efficacy of perioperative chemotherapy with doxorubicin (DOX) and ifosfamide (IFO), we evaluated histological response to preoperative chemotherapy at the central review board. RESULTS: A total of 64 patients were eligible for this study. The percentage of viable tumor area ranged from 0.1% to 97.0%, with median value of 35.7%. Regarding concordance proportion between pathologists, the weighted kappa coefficient (κ) score in all patients was 0.71, indicating that the established evaluation method achieved substantial agreement score. When the cut-off value of the percentage of the residual tumor area was set as 25%, the p-value for the difference in overall survival showed the minimum value. Hazard ratio of the non-responder with percentage of the residual tumor < 25%, to the responder was 4.029 (95% confidence interval 0.893-18.188, p = 0.070). CONCLUSION: The standardized evaluation method of pathological response to preoperative chemotherapy showed a substantial agreement in the weighted κ score. The evaluation method established here was useful for estimating of the prognosis in STS patients who were administered perioperative chemotherapy with DOX and IFO. TRIAL REGISTRATION: UMIN Clinical Trials Registry C000000096. Registered 30 August, 2005 (retrospectively registered).

Early-onset pancreatic cancer: Clinical characteristics and survival outcomes.

BACKGROUND: Early-onset pancreatic cancer (≤50 years, EOPC) is uncommon. This study aims to characterize the clinical and survival characteristics of EOPC in comparison to late-onset pancreatic cancer (>50 years, LOPC). METHODS: We retrospectively investigated consecutive PC patients treated at our institution between 2010 and 2019. We analyzed and compared clinicopathological characteristics, treatments, and outcomes of EOPC and LOPC. RESULTS: Of 1646 PC patients identified (768 resectable/borderline resectable; 248 locally advanced; 630 metastatic), 127 (8%) had EOPC. Current smoking and heavy drinking were associated with EOPC. EOPC presented at a more advanced stage and had higher neutrophil-to-lymphocyte ratios than LOPC. Survival outcomes were similar between the two groups, both in the entire cohort and in each resectability group. In patients undergoing resection, EOPC tended to have a higher N stage (p = 0.099) and had a higher pathological stage (stage IV, 20% vs. 7%, p = 0.005) and a lower rate of macroscopically curative resection (80% vs. 93%, p = 0.006). Liver recurrence was more commonly observed in EOPC (42% vs. 23%, p = 0.015). In the metastatic cohort, combination chemotherapy regimens were more frequently administered in EOPC as first-line treatment (79% vs. 64%, p = 0.028). Both median PFS (4.4 vs. 5.3 months, p = 0.647) and OS (11.5 vs. 9.5 months, p = 0.183) were not significantly different between the two groups. CONCLUSIONS: EOPC presented with a more aggressive tumor biology. Survival outcomes were similar to LOPC due to more intensive treatment.

Biliary balloon dilator impaction in a non-dilated bile duct with anatomical variations: a case report.

BACKGROUND: While techniques for extracting large stones from dilated bile ducts are increasing, options for small stones impacted in non-dilated bile ducts are limited. CASE PRESENTATION: We report the case of an impacted biliary balloon dilator in a choledocholithiasis patient with a non-dilated bile duct and multiple anatomical variations, including low insertion of the cystic duct. After unsuccessful attempts with a stone extraction basket and balloon, a biliary balloon dilator with a sharp catheter tip was advanced into the bile duct. The balloon could not be removed from the bile duct even when deflated. The duodenoscope fell back into the stomach, causing the shaft of the dilator to break near the ampulla. We then removed the broken tip with a snare, which caused the balloon sheath to separate from the shaft and remain in the bile duct. Finally, we removed the sheath with rat-tooth forceps, leading to successful extraction of the stone-and-balloon complex. CONCLUSIONS: The exceedingly rare possibility of balloon impaction should be kept in mind when using biliary balloon dilators in non-dilated bile ducts.

Treatment outcomes of nanoliposomal irinotecan as second-line chemotherapy after gemcitabine and nab-paclitaxel in metastatic and recurrent pancreatic cancer.

BACKGROUND: To compare the treatment outcomes of nanoliposomal-irinotecan (nal-IRI) plus fluorouracil and leucovorin (5-FU/LV) and modified FOLFIRINOX (mFFX) as second-line treatment after gemcitabine with nab-paclitaxel (GnP) for metastatic and recurrent pancreatic cancer. METHODS: We retrospectively analyzed consecutive patients with metastatic or recurrent pancreatic cancer treated with nal-IRI plus 5-FU/LV or mFFX after first-line GnP treatment between March 2014 and October 2021 in our hospital. Patient characteristics, treatment outcomes and adverse events were extracted for comparison. RESULTS: Two hundred sixteen patients were included (nal-IRI plus 5-FU/LV/mFFX: 50/166). Patients in the nal-IRI plus 5-FU/LV group were older, had poorer ECOG PS, and a higher rate of peritoneal metastasis than those in the mFFX group. Median overall survival was 9.5 and 9.8 months (P = 0.97), respectively, and the median progression-free survival was 4.5 vs 4.8 months (P = 0.61), respectively. Anorexia, fatigue and peripheral neuropathy were more common in the mFFX group, but there was no difference in grade 3/4 adverse events between the two groups. CONCLUSIONS: There was no significant difference in efficacy between nal-IRI plus 5-FU/LV and mFFX after GnP. Nal-IRI plus 5-FU/LV appears to be a viable alternative to mFFX as second-line treatment after GnP.

Improvement of Bone Marrow Necrosis by Tyrosine Kinase Inhibitor Substitution in a Pediatric Patient With Philadelphia Chromosome-positive Acute Lymphoblastic Leukemia.

Bone marrow necrosis (BMN) describes necrosis of the myeloid tissues without cortical bone involvement. Imatinib, a tyrosine kinase inhibitor, can trigger BMN during the treatment of malignant disease. In such cases, it is necessary to reduce imatinib dose or discontinue its administration, which could influence treatment outcomes. Here, we report a 6-year-old boy with Philadelphia chromosome-positive acute lymphoblastic leukemia, who developed BMN in response to imatinib. We replaced imatinib with dasatinib, and necrotic lesions gradually disappeared and were never exacerbated. In Philadelphia chromosome-positive acute lymphoblastic leukemia with BMN, tyrosine kinase inhibitor replacement may allow continued chemotherapy without intensity reduction.

Intensive Multimodal Therapy Combined With Long-term Temozolomide and Etoposide Treatment for Recurrent Osteosarcoma to the Liver and Stomach.

The prognosis of patients with osteosarcoma recurring at extrapulmonary/extraosseous sites, especially those with unresectable tumors, is generally dismal due to high resistance to chemotherapy. The present study describes a pediatric patient with osteosarcoma recurring to the liver and stomach. Complete remission was achieved by long-term systemic chemotherapy with temozolomide+etoposide, local irradiation of the stomach, and radical surgical removal of multiple liver metastases following percutaneous transhepatic portal embolization. Second-line multimodal therapy, consisting of salvage chemotherapy and curative local treatment of metastases, may enhance disease-free survival of patients with osteosarcoma experiencing relapse to uncommon sites.

Molecular Features and Clinical Management of Hereditary Pancreatic Cancer Syndromes and Familial Pancreatic Cancer.

Hereditary pancreatic cancers are caused by several inherited genes. Familial pancreatic cancer is defined as pancreatic cancer arising in a patient with at least two first-degree relatives with pancreatic cancer in the absence of an identified genetic cause. Hereditary pancreatic cancer syndromes and familial pancreatic cancers account for about 10% of pancreatic cancer cases. Germline mutations in BRCA1, BRCA2, ATM, PALB2, CDKN2A, STK11, and TP53 and mismatch repair genes (MLH1, MSH2, MSH6, PMS2, and EPCAM) are among the well-known inherited susceptibility genes. Currently available targeted medications include poly (ADP-ribose) polymerase inhibitors (PARP) for cases with mutant BRCA and immune checkpoint inhibitors for cases with mismatch repair deficiency. Loss of heterozygosity of hereditary pancreatic cancer susceptibility genes such as BRCA1/2 plays a key role in carcinogenesis and sensitivity to PARP inhibitors. Signature 3 identified by whole genome sequencing is also associated with homologous recombination deficiency and sensitivity to targeted therapies. In this review, we summarize molecular features and treatments of hereditary pancreatic cancer syndromes and surveillance procedures for unaffected high-risk cases. We also review transgenic murine models to gain a better understanding of carcinogenesis in hereditary pancreatic cancer.

Multiple non-polypoid mucosal Schwann cell hamartomas presenting as edematous and submucosal tumor-like lesions: a case report.

BACKGROUND: Mucosal Schwann cell hamartomas are rare neurogenic tumors which present most commonly in the distal colon. They are usually discovered as small, single polyps in asymptomatic patients. CASE PRESENTATION: An asymptomatic 64-year-old man was referred to us after a 12 mm subepithelial lesion was discovered incidentally on screening colonoscopy. Follow-up colonoscopy conducted 2 months later revealed that the tumor had disappeared, leaving multiple edematous, submucosal tumor-like elevations presenting as skip lesions throughout the sigmoid colon. Lesions had elongated pits on magnifying endoscopy and were limited to the first layer on endoscopic ultrasound. Biopsies revealed unclearly delineated foci of spindle-shaped cells limited to the lamina propria. On immunohistochemistry, all lesions were positive for S-100 protein and negative for CD34, CD56, and neurofilament protein. The patient was diagnosed with multiple mucosal Schwann cell hamartomas of the sigmoid colon. He remains asymptomatic after 18 months of follow-up, but the lesions have also remained unchanged. CONCLUSION: We report a case of multiple non-polypoid mucosal Schwann cell hamartomas. Endoscopic findings may assist in the differential diagnosis, particularly when presenting as non-polypoid, submucosal tumor-like lesions.

Simultaneous gastric cancer and breast cancer metastases to the stomach with lymph node collision tumor: a case report.

BACKGROUND: While double primary cancers are common in breast cancer patients, co-existence of primary gastric cancer and gastric metastases of breast cancer is exceedingly rare. CASE PRESENTATION: A 51-year-old woman receiving chemotherapy for breast cancer presented with melena and presyncope. A circumferential thickening of the pylorus and small submucosal tumor-like lesions in the gastric fundus and corpus were confirmed on endoscopy. Immunohistochemistry of biopsies revealed that the former was composed of poorly differentiated gastric cancer cells, while the latter were breast cancer metastases. Distal gastrectomy was performed. Pathological evaluation of the resected specimen revealed gastric adenocarcinoma in the pyloric lesion and breast countless cancer metastases throughout the remainder of the stomach, with positive margins. One lymph node had evidence of both stomach cancer and breast cancer metastases, forming a collision tumor. Despite a successful surgery, the patient died 6 months later due to progression of breast cancer. CONCLUSION: We report a case of synchronous primary gastric adenocarcinoma and gastric metastases of breast cancer. Inter-disciplinary collaboration is crucial in determining the optimal treatment in double cancers.