Sho Ogata

Purpose This prospective study aimed to compare the diagnostic accuracy of hepatic lesions between contrast-enhanced computed tomography (CE-CT) and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI). We also examined the final diagnosis of equivocal lesions. Methods In each patient undergoing hepatectomy for liver tumors, 2 radiologists (readers A and B) assessed CE-CT and Gd-EOB-MRI. Hepatic lesions were scored as 1, 2, 3, 4, or 5, which corresponded to categorization as benign, probably benign, equivocal, probably malignant, or malignant, respectively. Those scored as 1/2 and 4/5 were defined as benign and malignant, respectively. The lesions left unresected were confirmed as benign when they remained unchanged for ≥ 1 year after hepatectomy. The false-positive rate was defined as the number of lesions finally confirmed as benign among those assessed as malignant preoperatively. Results Among 105 enrolled patients (colorectal liver metastases, 72; hepatocellular carcinoma, 29; other, 4), 886 lesions were recognized on either CT or MRI preoperatively; another 26 lesions were identified only on intraoperative ultrasonography or pathologic examination. The sensitivity of malignant lesion detection was significantly higher for Gd-EOB-MRI than CE-CT for both reader A (90.3% vs. 68.3%; P < 0.001) and reader B (88.1% vs. 70.2%; P < 0.001). The false-positive rate with CE-CT and Gd-EOB-MRI was 2.3% and 3.7%, respectively, for reader A (P = 0.580), and 0.5% and 4.2%, respectively, for reader B (P = 0.033). There were 142 lesions judged as equivocal in at least one of the imaging studies by either reader. Sixty-eight lesions (49%) were recognized as malignant by any of the alternative assessments; among these, 61were confirmed as malignant. Conclusion Gd-EOB-MRI was superior to CE-CT for detecting liver lesions. The false-positive rate was low for both modalities. Equivocal lesions were encountered frequently, but routine use of alternate modalities and evaluation by 2 or more radiologists could enhance the accuracy of diagnosis.

Herein, we report a case of plasmablastic lymphoma (PBL) and diffuse large B-cell lymphoma (DLBCL) that occurred concurrently in the large intestine. An 84-year-old female presented with a palpable rectal tumor and ileocecal tumor observed on imaging analyses. Endoscopic biopsy of both lesions revealed lymphomatous round cells. Hartmann’s operation and ileocecal resection were performed for regional control. The ileocecal lesion consisted of a proliferation of CD20/CD79a-positive lymphoid cells, indicative of DLBCL. In contrast, the rectal tumor showed proliferation of atypical cells with pleomorphic nuclei and abundant amphophilic cytoplasm, with immunohistochemical findings of CD38/CD79a/MUM1/MYC (+) and CD20/CD3/CD138/PAX5 (–). Tumor cells were positive for Epstein-Barr virus– encoded RNA based on in situ hybridization and MYC rearrangement in fluorescence in situ hybridization analysis. These findings indicated the rectal tumor was most likely a PBL. Sequencing analysis for immunoglobulin heavy variable genes indicated a common B-cell origin of the two sets of lymphoma cells. This case report and literature review provide new insights into PBL tumorigenesis.

“Cysts of the ligamentum flavum (cysts‐LF)” is the term for non‐neoplastic cystic lesion involving LF. The aim of the present study was to elucidate the histopathological characteristics and pathogenesis of “cysts‐LF”. Herein, we defined cysts‐LF as spinal cysts containing degenerative LF components. From archival cases, we investigated 18 symptomatic cysts‐LF surgically removed from 18 patients (13 males and five females; median age 68.5 years [range, 42–86 years]). The elastic fibers of LF components in the wall were separated and/or torn, and cyst walls were accompanied by chondroid metaplasia (17 cases), myxoid changes (13 cases), ossification (11 cases), amyloid deposits (14 cases), hemosiderosis (six cases), granular/smudgy calcification (four cases), synovial cell linings (three cases), and severe inflammatory infiltrates (one case). These histologic features of our cysts‐LF were shared by previously reported “cysts‐LF.” Fourteen cysts‐LF demonstrated vascular stenosis/occlusion, and eight showed thick hyalinized vessels, suggesting local circulatory insufficiency. Eight cases (44%) exhibited lipomembranous fat necrosis, accompanied by hyalinized vascular changes (p = 0.003). Ischemic conditions were observed in nearly half of the present cysts‐LF, and may be one of the main contributing factors for the formation of cysts‐LF, via degeneration and cystic changes in the LF.

Background: The Paris System for Reporting Urine Cytology (TPS) recommends diagnostic criteria for urinary tract cytology, focusing primarily on the detection of high‐grade urothelial carcinoma (HGUC) in the lower urinary tract. The second edition of TPS (TPS 2.0), published in 2022, extends these recommendations to the upper urinary tract (UUT); however, there is a lack of comprehensive data on this subject.Methods: In total, 223 consecutive UUT cytology specimens from 137 patients were retrieved and reclassified according to TPS 2.0 criteria and were compared with the original diagnosis based on the conventional system (CS). Histologic follow‐up within a 3‐month period was conducted for 43 patients.Results: Histologic follow‐up revealed 30 HGUCs, five low‐grade urothelial carcinomas (LGUCs), and eight nonneoplastic fibrotic tissues. The risk of high‐grade malignancy for each TPS diagnostic category was 16.7% for nondiagnostic/unsatisfactory, 2.3% for negative for HGUC (NHGUC), 42.1% for atypical urothelial cells, 50.0% for suspicious for HGUC (SHGUC), and 81.8% for HGUC. In all five cases of histologically diagnosed LGUC, the cytologic diagnosis was NHGUC. When SHGUC/HGUC was considered positive, the diagnostic accuracy of TPS had 63% sensitivity, 95% specificity, a 90% negative predictive value, and a 79% positive predictive value, which were better than those of CS. In addition, the TPS indices did not differ significantly between the specimens obtained before and after the application of contrast reagents.Conclusions: TPS implementation improved the accuracy of UUT cytology in predicting histologic HGUC, which was unaffected by the application of contrast reagents. These data indicate the usefulness of TPS for UUT cytology in routine clinical settings.

Inflammatory pseudotumor (IPT) is a benign tumor mass composed of chronic infiltration of inflammatory cells and fibrous tissue. IgG4-RD (related disease) in the hepatobiliary system has been widely recognized and includes IgG4-related hepatic IPT. This report describes a patient with IgG4-related hepatic IPT with sclerosing cholangitis. A 75-year-old woman was admitted to our hospital for the treatment of rectal cancer. Abdominal contrast-enhanced computed tomography revealed a low-density mass, 2.5 cm in diameter, in the left lateral lobe. Magnetic resonance imaging showed that the mass was slightly hypointense on T1-weighted images and slightly hyperintense on T2-weighted images. Based on these results, we made a diagnosis of cholangiolocellular carcinoma, and we performed a left hepatectomy. Histopathological examination showed that the mass was composed of fibrous stroma with dense lymphoplasmacytic infiltration. Immunohistochemically, IgG4-positive plasma cells were observed. The final diagnosis was IgG4-related hepatic IPT with sclerosing cholangitis. IgG4-related IPT is a relatively rare disease that can occur in any organ of the body. Although the accurate diagnosis of IgG4-related hepatic IPT remains difficult, IgG4-RD should be included in the differential diagnosis of liver tumors and histological analysis performed.

Background: Human intestinal spirochetosis (HIS) is an infectious disease of large intestines caused by Brachyspira species, and most HIS cases are asymptomatic or exhibit mild intestinal symptoms. The host reaction to HIS remains unclear, and we examined HIS-related mucosal inflammatory features histologically. Methods: From the archival HIS cases in a single medical center, 24 endoscopically taken specimens from 14 HIS cases (male:female = 10:4; 28–73 yrs) were selected as not containing polypoid or neoplastic lesions. Stromal neutrophils, eosinophils, and mast cells, and intraepithelial neutrophils and eosinophils, (sNeu, sEo, sMast, iNeu, and iEo, respectively) were counted, and the presence or absence of lymphoid follicles/aggregates (LFs) was also examined. Association of the above inflammation parameters and spirochetal infection parameters (such as degrees of characteristic fringe distribution, of spirochetal cryptal invasion, and of spirochetal intraepithelial invasion) were also analysed. Results: iNeu was observed in 29.2%, iEo in 58.3%, and LFs in 50.0% of the specimens. Maximal counts of sNeu, sEo, sMast, iNeu, and iEo averaged 8.4, 21.5, 6.0, 0.5 and 1.5, respectively. Strong correlation between the maximum counts of iNeu and iEo (p < 0.001, r = 0.81), and correlations between those of iEo and sNeu (p = 0.0012, r = 0.62) and between those of iEo and sEo (p = 0.026, r = 0.45) were observed. iNeu was influenced by fringe formation (p < 0.05) and spirochetal crypt involvement (p < 0.05). Conclusions: HIS was accompanied by inflammatory reactions, and among these, mucosal eosinophilic infiltration may be a central indicator and host reaction of HIS.

Background: Human intestinal spirochetosis (HIS) is an infectious disease of large intestines caused by Brachyspira species, and most HIS cases are asymptomatic or exhibit mild intestinal symptoms. The host reaction to HIS remains unclear, and we examined HIS-related mucosal inflammatory features histologically. Method: From the archival HIS cases in a single medical center, 24 endoscopically taken specimens from 14 HIS cases (M:F = 10:4; 28-73 yrs) were selected as not containing polypoid or neoplastic lesions. Stromal neutrophils, eosinophils, and mast cells, and intraepithelial neutrophils and eosinophils, (sNeu, sEo, sMast, iNeu, and iEo, respectively) were counted, and the presence or absence of lymphoid follicles/aggregates (LFs) was also examined. Association of the above inflammation parameters and spirochetal infection parameters (such as degrees of characteristic fringe distribution, of spirochetal cryptal invasion, and of spirochetal intraepithelial invasion) were also analysed. Results: iNeu was observed in 29.2%, iEo in 58.3%, and LFs in 50.0% of the specimens. Maximal counts of sNeu, sEo, sMast, iNeu, and iEo averaged 8.4, 21.5, 6.0, 0.5 and 1.5, respectively. Strong correlation between the maximum counts of iNeu and iEo (p < 0.001, r = 0.81), and correlations between those of iEo and sNeu (p = 0.0012, r = 0.62) and between those of iEo and sEo (p = 0.026, r = 0.45) were observed. iNeu was influenced by fringe formation (p < 0.05) and spirochetal crypt involvement (p < 0.05). Conclusions: HIS was accompanied by inflammatory reactions, and among these, mucosal eosinophilic infiltration may be a central indicator and host reaction of HIS.

Human intestinal spirochetosis (HIS), one of the zoonoses, is caused by colonization by Brachyspira species bacteria within the large intestine. Histologic diagnosis of HIS is usually established by finding “fringes” on the colonic surface epithelium in biopsy specimens. However, its histologic characteristics, especially beneath the colonic mucosa, have not been elucidated. The present study was designed to examine the histologic characteristics of HIS in operatively resected specimens. We reviewed operatively resected (colectomy or appendectomy) specimens obtained in six consecutive years at a single medical center. HIS was diagnosed histologically by finding “fringes”. Immunohistochemical study using anti-Treponema pallidum antibody, which cross-reacts with Brachyspira, was additionally performed. A total of 848 (M:F = 477:371; median age, 59 years; 12–94 years) colectomy and/or appendectomy cases were examined, and the seven cases (0.8%) diagnosed as having HIS were all male (1.5% of male cases). Four HIS cases (0.8% of 508 colectomy cases (1.4% of 285 male-cases)) were colectomy cases with cancers, and the other three (0.9% of 340 appendectomy cases (1.6% of 192 male-cases)) were appendectomy cases for acute appendicitis. Our study revealed (1) a heterogeneous distribution of diagnostically important “fringes” within the large intestine, (2) an ileal presence of Brachyspira, (3) superficial location of HIS-related findings among anatomical wall layers, and (4) the presence of Brachyspira or its derivatives within macrophages in the lamina propria and immune apparatus (lymphoid follicles in superficial wall structures (lamina propria or submucosa) and lymph nodes). Investigation using operatively resected specimens might help elucidate the characteristics of HIS. Brachyspira may have immunogenicity in humans.