Implementable assay for monitoring minimum residual disease after radical treatment for colorectal cancer.

Considering the cost and invasiveness of monitoring postoperative minimal residual disease (MRD) of colorectal cancer (CRC) after adjuvant chemoradiotherapy (ACT), we developed a favorable approach based on methylated circulating tumor DNA to detect MRD after radical resection. Analyzing the public database, we identified the methylated promoter regions of the genes FGD5, GPC6, and MSC. Using digital polymerase chain reaction (dPCR), we termed the "amplicon of methylated sites using a specific enzyme" assay as "AMUSE." We examined 180 and 114 pre- and postoperative serial plasma samples from 28 recurrent and 19 recurrence-free pathological stage III CRC patients, respectively. The results showed 22 AMUSE-positive of 28 recurrent patients (sensitivity, 78.6%) and 17 AMUSE-negative of 19 recurrence-free patients (specificity, 89.5%). AMUSE predicted recurrence 208 days before conventional diagnosis using radiological imaging. Regarding ACT evaluation by the reactive response, 19 AMUSE-positive patients during their second or third blood samples showed a significantly poorer prognosis than the other patients (p = 9E-04). The AMUSE assay stratified four groups by the altered patterns of tumor burden postoperatively. Interestingly, only 34.8% of cases tested AMUSE-negative during ACT treatment, indicating eligibility for ACT. The AMUSE assay addresses the clinical need for accurate MRD monitoring with universal applicability, minimal invasiveness, and cost-effectiveness, thereby enabling the timely detection of recurrences. This assay can effectively evaluate the efficacy of ACT in patients with stage III CRC following curative resection. Our study strongly recommends reevaluating the clinical application of ACT using the AMUSE assay.

Tumor suppressive role of the epigenetic master regulator BRD3 in colorectal cancer.

Bromodomain and extraterminal domain (BET) family proteins are epigenetic master regulators of gene expression via recognition of acetylated histones and recruitment of transcription factors and co-activators to chromatin. Hence, BET family proteins have emerged as promising therapeutic targets in cancer. In this study, we examined the functional role of bromodomain containing 3 (BRD3), a BET family protein, in colorectal cancer (CRC). In vitro and vivo analyses using BRD3-knockdown or BRD3-overexpressing CRC cells showed that BRD3 suppressed tumor growth and cell cycle G1/S transition and induced p21 expression. Clinical analysis of CRC datasets from our hospital or The Cancer Genome Atlas revealed that BET family genes, including BRD3, were overexpressed in tumor tissues. In immunohistochemical analyses, BRD3 was observed mainly in the nucleus of CRC cells. According to single-cell RNA sequencing in untreated CRC tissues, BRD3 was highly expressed in malignant epithelial cells, and cell cycle checkpoint-related pathways were enriched in the epithelial cells with high BRD3 expression. Spatial transcriptomic and single-cell RNA sequencing analyses of CRC tissues showed that BRD3 expression was positively associated with high p21 expression. Furthermore, overexpression of BRD3 combined with knockdown of, a driver gene in the BRD family, showed strong inhibition of CRC cells in vitro. In conclusion, we demonstrated a novel tumor suppressive role of BRD3 that inhibits tumor growth by cell cycle inhibition in part via induction of p21 expression. BRD3 activation might be a novel therapeutic approach for CRC.

Field experiment of a telesurgery system using a surgical robot with haptic feedback.

PURPOSE: To verify the usefulness of haptic feedback in telesurgery and improve the safety of telerobotic surgery. METHODS: The surgeon's console was installed at two sites (Fukuoka and Beppu; 140 km apart), and the patient cart was installed in Fukuoka. During the experiment, the surgeon was blinded to the haptic feedback levels and asked to grasp the intestinal tract in an animal model. The surgeon then performed the tasks at each location. RESULTS: No marked differences in task accuracy or average grasping force were observed between the surgeon locations. However, the average task completion time was significantly longer, and the system usability scale (SUS) was significantly lower rating for remote operations than for local ones. No marked differences in task accuracy or task completion time were observed between the haptic feedback levels. However, with haptic feedback, the organ was grasped with a significantly weaker force than that without it. Furthermore, with haptic feedback, experienced surgeons in robotic surgery tended to perform an equivalent task with weaker grasping forces than inexperienced surgeons. CONCLUSION: The haptic feedback function is a tool that allows the surgeon to perform surgery with an appropriate grasping force, both on site and remotely. Improved safety is necessary in telesurgery; haptic feedback will thus be an essential technology in robotic telesurgery going forward.

Subclonal accumulation of immune escape mechanisms in microsatellite instability-high colorectal cancers.

BACKGROUND: Intratumor heterogeneity (ITH) in microsatellite instability-high (MSI-H) colorectal cancer (CRC) has been poorly studied. We aimed to clarify how the ITH of MSI-H CRCs is generated in cancer evolution and how immune selective pressure affects ITH. METHODS: We reanalyzed public whole-exome sequencing data on 246 MSI-H CRCs. In addition, we performed a multi-region analysis from 6 MSI-H CRCs. To verify the process of subclonal immune escape accumulation, a novel computational model of cancer evolution under immune pressure was developed. RESULTS: Our analysis presented the enrichment of functional genomic alterations in antigen-presentation machinery (APM). Associative analysis of neoantigens indicated the generation of immune escape mechanisms via HLA alterations. Multiregion analysis revealed the clonal acquisition of driver mutations and subclonal accumulation of APM defects in MSI-H CRCs. Examination of variant allele frequencies demonstrated that subclonal mutations tend to be subjected to selective sweep. Computational simulations of tumour progression with the interaction of immune cells successfully verified the subclonal accumulation of immune escape mutations and suggested the efficacy of early initiation of an immune checkpoint inhibitor (ICI) -based treatment. CONCLUSIONS: Our results demonstrate the heterogeneous acquisition of immune escape mechanisms in MSI-H CRCs by Darwinian selection, providing novel insights into ICI-based treatment strategies.

Real-time telementoring with 3D drawing annotation in robotic surgery.

BACKGROUND: In telementoring, differences in teaching methods affect local surgeons' comprehension. Because the object to be operated on is a three-dimensional (3D) structure, voice or 2D annotation may not be sufficient to convey the instructor's intention. In this study, we examined the usefulness of telementoring using 3D drawing annotations in robotic surgery. METHODS: Kyushu University and Beppu Hospital are located 140 km apart, and the study was conducted using a Saroa™ surgical robot by RIVERFIELD Inc. using a commercial guarantee network on optical fiber. Twenty medical students performed vertical mattress suturing using a swine intestinal tract under surgical guidance at the Center for Advanced Medical Innovation Kyushu University. Surgical guidance was provided by Beppu Hospital using voice, 2D, and 3D drawing annotations. All robot operations were performed using 3D images, and only the annotations were independently switched between voice and 2D and 3D images. The operation time, needle movement, and performance were also evaluated. RESULTS: The 3D annotation group tended to have a shorter working time than the control group (25.6 ± 63.2 vs. - 36.7 ± 65.4 min, P = 0.06). The 3D annotation group had fewer retries than the control group (1.3 ± 1.7 vs. - 1.1 ± 0.7, P = 0.006), and there was a tendency for fewer needle drops (0.4 ± 0.7 vs. - 0.5 ± 0.9, P = 0.06). The 3D annotation group scored significantly higher than the control group on the Global Evaluate Assessment of Robot Skills (16.8 ± 2.0 vs. 22.8 ± 2.4, P = 0.04). The 3D annotation group also scored higher than the voice (13.4 ± 1.2) and 2D annotation (16.2 ± 1.8) groups (3D vs. voice: P = 0.03, 3D vs. 2D: P = 0.03). CONCLUSION: Telementoring using 3D drawing annotation was shown to provide good comprehension and a smooth operation for local surgeons.

Telesurgery and telesurgical support using a double-surgeon cockpit system allowing manipulation from two locations.

BACKGROUND: Although several studies on telesurgery have been reported globally, a clinically applicable technique has not yet been developed. As part of a telesurgical study series conducted by the Japan Surgical Society, this study describes the first application of a double-surgeon cockpit system to telesurgery. METHODS: Surgeon cockpits were installed at a local site and a remote site 140 km away. Three healthy pigs weighing between 26 and 29 kg were selected for surgery. Non-specialized surgeons performed emergency hemostasis, cholecystectomy, and renal vein ligation with remote assistance using the double-surgeon cockpits and specialized surgeons performed actual telesurgery. Additionally, the impact of adding internet protocol security (IPsec) encryption to the internet protocol-virtual private network (IP-VPN) line on communication was evaluated to address clinical security concerns. RESULTS: The average time required for remote emergency hemostasis with the double-surgeon cockpit system was 10.64 s. A non-specialized surgeon could safely perform cholecystectomy or renal vein ligation with remote assistance. Global Evaluative Assessment of Robotic Skills and System Usability Scale scores were higher for telesurgical support-assisted surgery by a non-specialized surgeon using the double-surgeon cockpits than for telesurgery performed by a specialized surgeon without the double-cockpit system. Adding IPsec encryption to the IP-VPN did not have a significant impact on communication. CONCLUSION: Telesurgical support through our double-surgeon cockpit system is feasible as first step toward clinical telesurgery.

Clinicopathological features of appendiceal goblet cell adenocarcinoma in Japan: a multicenter retrospective study.

PURPOSE: In the 5th edition of the World Health Organization classification, appendiceal goblet cell adenocarcinoma (GCA) is categorized separately from neuroendocrine tumors and other appendiceal adenocarcinomas. We clarified the clinicopathological characteristics of Japanese appendiceal GCA. METHODS: We designed a retrospective multicenter cohort study and retrieved the data of patients with appendiceal neoplasms and histologically diagnosed appendiceal goblet cell carcinoid (GCC) treated from January 2000 to December 2017 in Japan. The available GCC slides were reviewed and diagnosed with a new grading system of GCA. RESULTS: A total of 922 patients from 43 institutions were enrolled; of these, 32 cases were patients with GCC (3.5%), and 20 cases were ultimately analyzed. The 5-year survival rate was 61.4% (95% confidence interval: 27.4-83.2), and the median survival time was 93.1 months. For peritoneal metastasis, regional lymph node metastasis was a significant factor (p = 0.04), and Grade 3 was a potential factor (p = 0.07). No peritoneal metastasis was observed in either T1/2 patients (n = 2) or Grade 1 patients (n = 4). We were unable to detect any significant factors associated with regional lymph node metastasis. CONCLUSION: For peritoneal metastasis, regional lymph node metastasis was a significant factor, and Grade 3 was a potential factor.

Clinical significance of signal regulatory protein alpha (SIRPα) expression in esophageal squamous cell carcinoma.

Signal regulatory protein alpha (SIRPα) is a type I transmembrane protein that inhibits macrophage phagocytosis of tumor cells upon interaction with CD47, and the CD47-SIRPα pathway acts as an immune checkpoint factor in cancers. This study aims to clarify the clinical significance of SIRPα expression in esophageal squamous cell carcinoma (ESCC). First, we assessed SIRPα expression using RNA sequencing data of 95 ESCC tissues from The Cancer Genome Atlas (TCGA) and immunohistochemical analytic data from our cohort of 131 patients with ESCC. Next, we investigated the correlation of SIRPα expression with clinicopathological factors, patient survival, infiltration of tumor immune cells, and expression of programmed cell death-ligand 1 (PD-L1). Overall survival was significantly poorer with high SIRPα expression than with low expression in both TCGA and our patient cohort (P < .001 and P = .027, respectively). High SIRPα expression was associated with greater depth of tumor invasion (P = .0017). Expression of SIRPα was also significantly correlated with the tumor infiltration of M1 macrophages, M2 macrophages, CD8+ T cells, and PD-L1 expression (P < .001, P < .001, P = .03, and P < .001, respectively). Moreover, patients with SIRPα/PD-L1 coexpression tended to have a worse prognosis than patients with expression of either protein alone or neither. Taken together, SIRPα indicates poor prognosis in ESCC, possibly through inhibiting macrophage phagocytosis of tumor cells and inducing suppression of antitumor immunity. Signal regulatory protein alpha should be considered as a potential therapeutic target in ESCC, especially if combined with PD-1-PD-L1 blockade.

Radiomics Texture Analysis for the Identification of Colorectal Liver Metastases Sensitive to First-Line Oxaliplatin-Based Chemotherapy.

OBJECTIVE: The aim of this study was to develop a radiomics-based prediction model for the response of colorectal liver metastases to oxaliplatin-based chemotherapy. METHODS: Forty-two consecutive patients treated with oxaliplatin-based first-line chemotherapy for colorectal liver metastasis at our institution from August 2013 to October 2019 were enrolled in this retrospective study. Overall, 126 liver metastases were chronologically divided into the training (n = 94) and validation (n = 32) cohorts. Regions of interest were manually segmented, and the best response to chemotherapy was decided based on Response Evaluation Criteria in Solid Tumors (RECIST). Patients who achieved clinical complete and partial response according to RECIST were defined as good responders. Radiomics features were extracted from the pretreatment enhanced computed tomography scans, and a radiomics score was calculated using the least absolute shrinkage and selection operator regression model in a trial cohort. RESULTS: The radiomics score significantly discriminated good responders in both the trial (area under the curve [AUC] 0.8512, 95% confidence interval [CI] 0.7719-0.9305; p < 0.0001) and validation (AUC 0.7792, 95% CI 0.6176-0.9407; p < 0.0001) cohorts. Multivariate analysis revealed that high radiomics scores greater than - 0.06 (odds ratio [OR] 23.803, 95% CI 8.432-80.432; p < 0.0001), clinical non-T4 (OR 6.054, 95% CI 2.164-18.394; p = 0.0005), and metachronous disease (OR 11.787, 95% CI 2.333-70.833; p = 0.0025) were independently associated with good response. CONCLUSIONS: Radiomics signatures may be a potential biomarker for the early prediction of chemosensitivity in colorectal liver metastases. This approach may support the treatment strategy for colorectal liver metastasis.

Indications for laparoscopic surgery for older rectal cancer patients with comorbidities.

PURPOSE: Given the lack of safety studies concerning laparoscopic surgery for rectal cancer in patients ≥ 80 years old with comorbidities, we sought to investigate this in the current study. METHODS: Between 2012 and 2019, 24 patients ≥ 80 years old underwent laparoscopic surgery for rectal cancer without preoperative treatment. These patients were divided into those with [comorbidity(+) group, n = 13] and without [comorbidity(-) group, n = 11] comorbidities. The preoperative nutritional status and ASA classification, postoperative complications, time to oral diet, and length of hospital stay were evaluated in each group. RESULTS: In the comorbidity(+)/comorbidity(-) groups, the average age was 85.9/84.1 years old, respectively. The major comorbidities were heart disease including atrial fibrillation and valvular disorder. The average PNI and CONUT scores in the comorbidity(+)/comorbidity(-) groups were 44.7/44.2 an 3.1/2.2, respectively. Planned surgical procedures were completed in all patients. Postoperative complications occurred in 2/3 cases in the comorbidity(+)/comorbidity(-) groups, respectively, and the average time to oral diet was 3.8/3.7 days, while the average length of hospitalization after surgery was 15.2/16.5 days, respectively. In the comorbidity(+) group, there was no exacerbation of comorbidities in any cases. CONCLUSION: The safety of laparoscopic surgery is acceptable among older rectal cancer patients with comorbidities.

[The Efficacy of topo â -pS10 Expression in Gastric Cancer as a Predictive Biomarker for Irinotecan Use].

BACKGROUND: Though irinotecan is commonly used for treating advanced gastric cancer, there is no predictive biomarker to date. We have studied the resistant mechanism for irinotecan and found that phosphorylation of serine 10 residue of topoisomerase Ⅰ(topo Ⅰ)is an important step for irinotecan resistance. We have developed an immunohistochemical staining-based biomarker; topo Ⅰ-pS10, for predicting irinotecan efficacy. PURPOSE: The purpose of this study is to test the accuracy of topo Ⅰ-pS10 immunohistochemical staining in gastric cancer clinical samples. METHODS: In this study we performed 2 sets of tests. In the training set, we stained 79 gastric cancer clinical samples which efficacy of irinotecan was measured by succinate dehydrogenase inhibition(SDI)test. In the validation set, we used 27 gastric cancer clinical samples which irinotecan was used and the efficacy was known. RESULTS: Training set: From the ROC curve the cut-off point was set at 35% positive nuclei. Sixty three cases were positive with topo Ⅰ-pS10 in the nuclei. With the result of irinotecan SDI, the sensitivity was 76.6% and the positive predictive value was 92.5%. This result showed that topo Ⅰ-pS10 positive case does not respond to irinotecan. Validation set: In this set, the sensitivity was 82.4% and the positive predictive value was 82.4%. CONCLUSION: topo Ⅰ-pS10 staining can be used as a predictive biomarker for irinotecan for gastric cancer patients.

Skeletal Muscle Loss After Esophagectomy Is an Independent Risk Factor for Patients with Esophageal Cancer.

BACKGROUND: Postoperative changes in skeletal muscle and their influence on outcomes after esophagectomy for patients with esophageal cancer have not been fully investigated. This study aimed to confirm that postoperative skeletal muscle decrease influences long-term patient outcomes. METHODS: Data were collected from 218 patients who underwent curative esophagectomy for esophageal cancer whose data were available before and 6 months after surgery. The skeletal muscle index (SMI) was measured at the level of the L3 vertebrae, and the postoperative change in the SMI compared with preoperative values was calculated as the delta SMI. RESULTS: The mean SMI value was - 11.64%, and the median delta SMI value was - 11.88%. The first and third quartiles were defined as cutoffs, and 218 patients were classified as the mild-loss group (54 patients), moderate-loss group (110 patients), and severe-loss group (54 patients). The patients with a more severely reduced SMI had a worse prognosis (5-year overall survival rates: mild loss, 66.6%; moderate loss, 58.8%; and severe loss, 48.5%; p = 0.0314). This correlation between reduced SMI and prognosis also was observed for the patients with preoperative sarcopenia (p < 0.0001), but not for those without preoperative sarcopenia. CONCLUSIONS: Postoperative reduced SMI and worse prognosis were significantly associated in esophageal cancer patients.

Postoperative C-reactive protein/albumin ratio is a biomarker of risk of recurrence and need for adjuvant chemotherapy for stage III colorectal cancer.

BACKGROUND: Adjuvant chemotherapy is generally recommended for patients with stage III colorectal cancer. Even with adjuvant chemotherapy, 20-30% of such patients develop recurrences; the risk factors for recurrence are currently unclear. The preoperative systemic inflammation index has been linked to poor prognoses in patients with colorectal cancer; however, the relationship between postoperative systemic inflammation index and recurrence is unclear. We aimed to evaluate the association between preoperative and postoperative systemic inflammation indexes and recurrence in patients with stage III colorectal cancer. METHODS: The following laboratory data of 133 patients with stage III colorectal cancer were analyzed: preoperative and postoperative C-reactive protein/albumin ratios (CAR); neutrophil to lymphocyte ratios (NLR); and platelet to lymphocyte ratios (PLR) and their relationships with recurrence analyzed. RESULTS: The optimal cutoff values for systemic inflammation indexes were determined by examining receiver operating characteristic curves. Multivariate analyses indicated that N-stage, postoperative complications, preoperative NLR, and postoperative CAR were independent predictors of recurrence-free survival (RFS). Postoperative CAR was also an independent predictor of overall survival (OS). Patients with postoperative CAR ≥ 0.035 who did not receive adjuvant chemotherapy had shorter RFS and OS than those who did. There were no significant differences in RFS and OS between patients with postoperative CAR < 0.035 who did and did not receive adjuvant chemotherapy. CONCLUSIONS: Postoperative CAR is strongly associated with poor prognosis in patients with stage III colorectal cancer and is a useful biomarker for determining whether adjuvant chemotherapy should be administered.

Effect of EGFR and p-AKT Overexpression on Chromosomal Instability in Gastric Cancer.

BACKGROUND: Molecular profiling in gastric cancer (GC) is important for diagnosis and treatment. In this study, we investigated signal transduction pathways that might induce chromosomal instability in GC. METHODS: Epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and p-AKT expression were analyzed using immunohistochemistry, and chromosomal instability was assessed by DNA aneuploidy using laser scanning cytometry, in a total of 202 GC cases. RESULTS: The rate of EGFR expression and p-AKT expression was 70.3 and 34.2 %, respectively, in GC patients. In total, 57.5 % of GC patients exhibited DNA aneuploidy, and p-AKT positively correlated with EGFR and HER2 (p = 0.0127 and p = 0.00031, respectively). Patients with EGFR overexpressing GC showed shorter disease-specific survival than the other cases (hazard ratio 2.00, 95 % confidence interval 1.19-3.53; p = 0.0104). Moreover, EGFR and p-AKT expression was significantly correlated with DNA aneuploidy (p = 0.0002 and p = 0.0302, respectively). CONCLUSIONS: Our data showed that both EGFR and p-AKT overexpression were clearly associated with DNA aneuploidy. Aneuploidy could be a useful marker for therapies that target EGFR.

Molecular mechanisms regulating the hormone sensitivity of breast cancer.

Breast cancer is a heterogeneous disease. Approximately 70% of breast cancers are estrogen receptor (ER) positive. Endocrine therapy has dramatically improved the prognosis of ER-positive breast cancer; however, many tumors exhibit de novo or acquired resistance to endocrine therapy. A thorough understanding of the molecular mechanisms regulating hormone sensitivity or resistance is important to improve the efficacy of and overcome the resistance to endocrine therapy. The growth factor receptor signaling pathways, particularly the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway can mediate resistance to all forms of endocrine therapy. In contrast, FOXA1 transcription factor is a key determinant of ER function and endocrine response. Intriguingly, a link between hormone resistance induced by the PI3K/Akt/mTOR pathway and the function of FOXA1 has been suggested. In this review, we focus on the PI3K/Akt/mTOR pathway and functions of FOXA1 in terms of the molecular mechanisms regulating the hormone sensitivity of breast cancer.

Breast mucoepidermoid carcinoma with a rare CRTC3-MAML2 fusion.

Mucoepidermoid carcinoma is the most prevalent malignancy in the salivary gland and is sporadic in the breast. Here, we report a case of breast mucoepidermoid carcinoma with a rare CREB-regulated transcription coactivator 3-mastermind-like transcriptional coactivator 2 (CRTC3-MAML2) fusion. A 23-year-old female was admitted to our hospital with a left breast palpable mass. Histologic findings of the core-needle biopsy indicated breast cancer. The section revealed a squamoid tumor-cell proliferation with enlarged nuclei and eosinophilic cytoplasm among smaller intermediate cells and abundant cystic spaces containing secretory materials. The features were compatible with mucoepidermoid carcinoma in low-grade, confirmed by detecting the CRTC3-MAML2 fusion using reverse transcription polymerase chain reaction and direct sequencing. We only administered tamoxifen postoperatively without other adjuvant therapy because her tumor partially expressed hormonal receptors. No signs indicate a recurrence or metastasis in our over 3 year follow-up. The genetic analysis helps in definitively diagnosing breast mucoepidermoid carcinoma, and the treatment strategy should be considered based on the histologic findings.

Fatal pulmonary embolism after surgery for small intestinal necrosis caused by idiopathic portal vein thrombosis: a case report.

BACKGROUND: Portal vein thrombosis (PVT) and venous thromboembolism (VTE) both result from partial or complete occlusion of a blood vessel by a blood clot. The prognosis of PVT is generally good; however, PVT with VTE, including pulmonary embolism (PE), has a high mortality rate. We report here a case of PE after surgery for small intestinal necrosis caused by idiopathic PVT. CASE PRESENTATION: A 69-year-old female attended our hospital with a chief complaint of upper abdominal discomfort, and was diagnosed with necrosis of the small intestine as a result of unexplained PVT. She underwent partial resection of the small intestine. On the second postoperative day, she suffered from respiratory distress and went into cardiopulmonary arrest. The patient recovered following cardiopulmonary resuscitation, but PE was detected. Extracorporeal veno-arterial cardiopulmonary resuscitation and anticoagulation therapy were initiated immediately and the thrombus was aspirated as much as possible. Two days later, extracorporeal veno-arterial cardiopulmonary resuscitation was withdrawn and anticoagulation therapy was continued. The patient subsequently recovered with no neurological damage and was discharged on day 26 after the above procedure. CONCLUSIONS: Idiopathic PVT is often associated with VTE, and a prompt diagnosis and intervention may result in a good prognosis.

A rare case of liver regenerative and non-neoplastic lesion resembling a well-differentiated hepatocellular carcinoma.

BACKGROUND: Nodular regenerative hyperplasia (NRH) is a rare disease that presents pathologically as diffuse hepatic nodules without fibrous septa. It is believed to be caused by vasculopathy against a background of various systemic diseases, such as hematologic, autoimmune, and drug-induced diseases, with various symptoms. In spite of the recent imaging advances, various atypical cases of nodular lesions are observed in daily clinical practice. Cases that do not completely meet these criteria are referred to as -like or -similar lesions in clinical situations, making it difficult to understand their pathogenesis. We present a case in which two hepatic nodular lesions were noted and difficult to differentiate from malignancy preoperatively. The lesions were laparoscopically resected and a pathological diagnosis with non-neoplastic liver regenerative nodules resembling NRH was made. CASE PRESENTATION: A 49-year-old man with no alcohol or drug intake and no past medical history was identified as having liver tumors on screening examination without any symptoms. Contrast-enhanced computed tomography (CT) showed two hepatic tumors; approximately 2-cm tumors at S7 and S8. Gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) revealed fat inclusions in their contents. Ethoxybenzyl (EOB) uptake was also observed during the hepatobiliary phase. Based on preoperative examinations, we suspected well-differentiated hepatocellular carcinoma (HCC) and performed laparoscopic S7/8 partial resection for these lesions. Macroscopically, the resected specimens showed a non-cirrhotic yellowish-cut surface containing brownish, ill-defined lesions with irregular borders. Microscopically, these lesions showed zonal necrosis, congestion, and aggregation of hemosiderin-laden macrophages around the central vein. In these areas, the fatty deposition of hepatocytes was lower than that in the surrounding background hepatocytes. Histopathologically, neither neoplastic nor hyperplastic lesions were observed, and he was diagnosed as regenerative hepatic change with centrilobular necrosis. CONCLUSIONS: Considering the pathological results, these lesions were thought to be a type of NRH-like lesion with possible hepatic vessel disorder. However, the lesion's cause and classification was difficult to determine. The accumulation of these regenerative changes accompanying fatty liver is needed to clarify the mechanism and its clinical significance.