Evaluating Cellularity Estimation Methods: Comparing AI Counting with Pathologists' Visual Estimates.

The development of next-generation sequencing (NGS) has enabled the discovery of cancer-specific driver gene alternations, making precision medicine possible. However, accurate genetic testing requires a sufficient amount of tumor cells in the specimen. The evaluation of tumor content ratio (TCR) from hematoxylin and eosin (H&E)-stained images has been found to vary between pathologists, making it an important challenge to obtain an accurate TCR. In this study, three pathologists exhaustively labeled all cells in 41 regions from 41 lung cancer cases as either tumor, non-tumor or indistinguishable, thus establishing a "gold standard" TCR. We then compared the accuracy of the TCR estimated by 13 pathologists based on visual assessment and the TCR calculated by an AI model that we have developed. It is a compact and fast model that follows a fully convolutional neural network architecture and produces cell detection maps which can be efficiently post-processed to obtain tumor and non-tumor cell counts from which TCR is calculated. Its raw cell detection accuracy is 92% while its classification accuracy is 84%. The results show that the error between the gold standard TCR and the AI calculation was significantly smaller than that between the gold standard TCR and the pathologist's visual assessment (p<0.05). Additionally, the robustness of AI models across institutions is a key issue and we demonstrate that the variation in AI was smaller than that in the average of pathologists when evaluated by institution. These findings suggest that the accuracy of tumor cellularity assessments in clinical workflows is significantly improved by the introduction of robust AI models, leading to more efficient genetic testing and ultimately to better patient outcomes.

Radical Resection for Second EGFR-mutated Primary Lung Cancer Following Immune Checkpoint Inhibitor Monotherapy for Stage IV Lung Adenocarcinoma.

A 78-year-old woman with multiple lung nodules, epithelial growth factor receptor (EGFR) exon 20 insertion mutations, and diagnosed with advanced lung adenocarcinoma (cT4N3M1a, stage IVA), was referred to our hospital. She received immune checkpoint inhibitor (ICI) therapy. The therapy showed remarkable antitumor effects; only a single nodule remained in the right upper lobe. The nodule was diagnosed as adenocarcinoma through a biopsy. We subsequently performed right upper lobectomy for multiple primary lung cancer (MPLC). The surgical specimen contained EGFR exon 19 deletion mutations and not exon 20 insertion mutations.

[Chemo-Resistant Breast Carcinoma with Cartilaginous Differentiation Manifestation after Neoadjuvant Chemotherapy-A Case Report].

A 49-year-old woman was admitted to our hospital because of a tumor in her right breast. The tumor was localized to the C area and was approximately 3 cm in size. A right axillary lymphadenopathy was also found. Histopathological examination and needle biopsy of the breast tumor revealed invasive lobular carcinoma, and she was diagnosed with Stage ⅡB triple-negative breast cancer(cT2N1M0). Paclitaxel plus bevacizumab chemotherapy followed by ddAC chemotherapy was administered as neoadjuvant chemotherapy, but the tumor remained stable. Thus, she underwent mastectomy and lymph node dissection. Pathological findings of the resected specimen showed invasive carcinoma with cartilaginous differentiation. She was then treated with capecitabine 15 days after the surgery; however, multiple lung metastases were found on CT after 6 courses. Therefore, she was transferred to another hospital and received other chemotherapies, but died after 5 months.

Possible Pseudo-progression of Non-small Cell Lung Carcinoma in a Patient With Clinical Hyper-progression Associated With Trousseau Syndrome Who Was Treated With Pembrolizumab: A Case Report.

BACKGROUND/AIM: Immune checkpoint inhibitors (ICIs), including nivolumab and pembrolizumab, have recently been shown to have clinical benefits in patients with advanced non-small cell lung cancer (NSCLC). The novel tumour responses to these agents are changing the management of patients with cancer. Pseudo-progression of disease (pseudo-PD), that is, an initial flare followed by shrinkage of the tumour, has been described as a distinctive response to ICIs. However, pseudo-PD manifest initial progression and is difficult to segregate with hyper progressive disease (HPD). We, therefore, analysed a case with pseudo-PD histologically. PATIENTS AND METHODS: A 68-year-old Japanese man with stage IV non-small cell lung carcinoma (NSCLC) was treated by anti-PD-1 antibody (pembrolizumab). Four weeks later after second time treatment with pembrolizumab, the patient showed severe melena followed by Trousseau syndrome and died at day 174 after first treatment by pembrolizumab, suggesting HPD clinically. Primary lesion and metastatic lesions were analysed histologically. RESULTS: Histological analysis revealed that NSCLC cells expressed PD-L1, and CD8+ tumor-infiltrated lymphocytes (TILs) were observed. CD8+ TILs showed higher rates of PD-1 indicating that lesions were of the inflamed type and the case was pseudo-PD. Furthermore, it was found that cancer cells expressed MUC1. CONCLUSION: The clinical appearance of the case was aggressive after treatment by pembrolizumab, and the case seemed to be HPD; however, histological analysis revealed that the case was likely pseudo-PD. Therefore, careful histological evaluation is important when investigating the clinical response to an ICI and mucin expression might be a predictive marker for Trousseau syndrome.

Non-bacterial cystitis with increased expression of programmed death-ligand 1 in the urothelium: An unusual immune-related adverse event during treatment with pembrolizumab for lung adenocarcinoma.

INTRODUCTION: Immune checkpoint inhibitors are now a standard therapeutic option for lung adenocarcinoma. However, Immune checkpoint inhibitors often induce various immune-related adverse events. CASE PRESENTATION: The patient was a 78-year-old woman with lung adenocarcinoma who had a partial response to pembrolizumab. During treatment, she complained of pollakiuria and nocturia with painful micturition. Histological analysis revealed infiltration of CD8-positive and/or TIA-1 cytotoxic granule-associated RNA binding protein-positive lymphocytes and programmed death-ligand 1 expression in the urothelium. A diagnosis of immune-related adverse event cystitis was made based on these clinical and pathological findings. The patient's subjective symptoms and findings on cystoscopy improved dramatically after treatment with prednisolone. CONCLUSION: Immune checkpoint inhibitors-induced cystitis is extremely rare. This report is the first to include an immunohistochemical analysis of the urothelial epithelium in immune-related adverse event cystitis and describes an instructive case.

Association of Epstein-Barr virus with regression after withdrawal of immunosuppressive drugs and subsequent progression of iatrogenic immunodeficiency-associated lymphoproliferative disorders in patients with autoimmune diseases.

Patients with autoimmune diseases (AIDs) may develop lymphoproliferative disorders (LPDs) during treatment with immunosuppressive agents (IS) such as methotrexate (MTX), biological agents, or tacrolimus. Some LPDs in patients with AIDs (AID-LPDs) regress after withdrawal of IS, and a high incidence of Epstein-Barr virus (EBV) positivity in such patients has been reported. To identify characteristics and factors predictive of the response to treatment and disease progression, we retrospectively analyzed clinical and histopathological data for 81 patients with AID-LPDs. Almost all of them (96%) had been treated with MTX. Diffuse large B cell lymphoma was the most common LPD type (61%) and seven patients (9%) had classical Hodgkin lymphoma (CHL). EBV was detected by in situ hybridization with an EBV-encoded small RNA (EBER) probe in 43% of the examined cases. In 59 patients, IS was discontinued as the initial treatment, resulting in regression of LPDs in 69% of them, and multivariate analysis showed that EBER positivity was an independent factor predictive of such regression (p = 0.022). Two-year progression-free survival (PFS) and overall survival for the patients overall were 63% and 83%, respectively. Poor PFS was associated with advanced stage (p = 0.024), worse performance status (PS, p = 0.031), CHL histology (p = 0.013), and reactivation of EBV-related antibodies (p = 0.029). In conclusion, EBV positivity demonstrated using an EBER probe is useful for prediction of successful regression after withdrawal of IS in patients with AID-LPDs. Patients with advanced stage disease, worse PS, CHL histology, or reactivation of EBV-related antibodies should be closely monitored after initial treatment.

Acute progressing hepatic angiosarcoma: An autopsy case report.

A man in his 50s presented with pitting edema of both lower legs and abdominal distension as his chief complaint. His personal medical history and family history were unremarkable, except that he was a heavy drinker consuming 66 g of alcohol per day and a heavy smoker. Blood tests upon admission showed slight hepatic dysfunction, thrombocytopenia, jaundice, hypoalbuminemia, and decreased coagulability. Tumor marker tests showed elevated levels of CA19-9 and PIVKA-II. Contrast-enhanced computed tomography revealed enhancement of multiple masses predominantly in the right lobe of the liver in the early phase, followed by diffuse enhancement of the entire liver in the delayed phase. Hepatic arteriography demonstrated large hemangioma-like lesions corresponding to the masses revealed by computed tomography. That findings seemed to be cotton wool appearance. On magnetic resonance images, there were multiple mass-like lesions that showed homogeneous or heterogeneous low signal intensity on T1-weighted images, and clearly high signal intensity on T2-weighted images. The findings were atypical and no definite diagnosis could be made. Hepatic failure then rapidly worsened, and the patient died on hospital day 20. Autopsy led to the diagnosis of hepatic angiosarcoma.

Campylobacter upsaliensis isolated from a giant hepatic cyst.

Campylobacter upsaliensis is an enteropathogenic bacterium in animals, and is also rarely isolated from humans, where it can cause enteritis and bacteremia. This report describes the first case of isolation of C. upsaliensis from an infected giant hepatic cyst. This bacterium could not be cultured from abscess punctuate in a usual Campylobacter-selection medium (charcoal cefoperazone deoxycholate agar medium), because of high concentration of cefoperazone as a selection agent. It could not identified by matrix-assisted laser desorption ionization-time of flight mass spectrum. Rather, it was identified as C. upsaliensis by whole genome sequencing, including by multilocus sequence typing.

Efficacy and Safety of Complete Endoscopic Resection of Colorectal Neoplasia Using a Stepwise Endoscopic Protocol with SOUTEN, a Novel Multifunctional Snare.

BACKGROUND/AIMS: A multifunctional snare SOUTEN has a sharp tip at the top of the snare loop that enables incision of the mucosa, dissection of the submucosal layer, and snaring of lesion. This study assessed the efficacy and safety of complete endoscopic resection of colorectal neoplasia using SOUTEN. METHODS: We analyzed the rates of gross en bloc resection and complete resections of 108 consecutive tumors from 69 patients resected by precutting endoscopic mucosal resection (precutting), hybrid endoscopic submucosal dissection (hybrid), or conventional endoscopic submucosal dissection (conventional) using SOUTEN. RESULTS: Out of the 108 tumors, 50 were resected by precutting, 27 were resected by hybrid after attempting precutting, and the remaining 31 were resected by conventional after attempting precutting and hybrid resections. The median tumor sizes were 14.5 mm for precutting, 16.4 mm for hybrid, and 21.1 mm for conventional. The success rate of gross en bloc resection and histological complete resection were 100% and 94.0% for precutting, 96.4% and 96.4% for hybrid, and 100% and 100% for conventional method, respectively. No procedure-related complication occurred. CONCLUSION: By using SOUTEN, precutting and hybrid were successfully performed on 10-30 mm tumors with a shorter procedure time than conventional without major complications.

Corticosteroid dose increase is a risk factor for nonalcoholic fatty liver disease and contralateral osteonecrosis of the femoral head: a case report.

BACKGROUND: The incidence of bilateral corticosteroid-induced osteonecrosis of the femoral head (ONFH) is high. Although the precise mechanism of corticosteroid-induced ONFH development is unclear, hepatic enzyme abnormalities such as low activity of hepatic cytochrome P450 3A could be one cause. Herein, we report the case of a patient who developed ONFH in the contralateral hip after the dose of corticosteroids for idiopathic thrombocytopenic purpura was increased. Liver biopsy was done to rule out autoimmune hepatitis. CASE PRESENTATION: A 32-year-old woman had been treated with continuous corticosteroids of up to 10 mg/day for Sjögren's syndrome for 25 years and corticosteroid-induced ONFH in the left side. At age 33, idiopathic thrombocytopenia developed, which was treated by increasing the corticosteroid dose (40 mg/day). Two months later, liver enzyme level began to increase slightly and continued to increase. A year after corticosteroid dose increase, contralateral ONFH developed, and a liver biopsy demonstrated nonalcoholic fatty liver disease (NAFLD). CONCLUSIONS: The current case indicates that corticosteroid dose increase is a potential risk factor for NAFLD and contralateral ONFH. Therefore, it would be useful and important for to screen and monitor patients with hepatic enzyme abnormality for ONFH occurrence.

Histopathological differences of experimental aneurysms treated with bare platinum, fibered, and bioactive coils.

PURPOSE: To evaluate the histopathological features of experimental aneurysms embolized with bare platinum, fibered, and bioactive coils. MATERIAL AND METHODS: Twelve experimental aneurysms were constructed in three swine. The aneurysms were divided into four groups and were embolized using a bare platinum coil alone (P group, n = 2), a bioactive coil alone (B group, n = 2), a combination of fibered and bare platinum coils (F/P group, n = 4) and a combination of fibered and bioactive coils (F/B group, n = 4). Histopathological data for all aneurysms recorded at 63 days were analyzed in terms of neointima formation, fibrosis, foreign-body giant-cell infiltration, and organization. RESULTS: Fibrosis was significantly greater in group B compared with that in group F/P (p = .02).　 Inflammation with foreign-body giant-cell infiltration was significantly greater in groups F/P and F/B compared with that in groups P and B (p = .007). CONCLUSION: The present study revealed that the embolic effect of fibered coils was not a thrombus but instead was a foreign-body response in the chronic phase.

Whole genome analysis of a multidrug-resistant Streptococcus pneumoniae isolate from a patient with invasive pneumococcal infection developing disseminated intravascular coagulation.

Multidrug-resistant Streptococcus pneumoniae strains were isolated from blood and sputum of a patient with disseminated intravascular coagulation in Sapporo city, Japan. These antibiograms were only susceptible to vancomycin, linezolid, daptomycin, some carbapenems, and some fluoroquinolones. Identical antibiograms, serotypes (19F), and sequence types (ST10017) suggested a shared origin of these isolates. Only one ST10017 strain has been isolated in the same city in Japan previously (2014), and the 2014 isolate is still susceptible to macrolides. The whole genome of the blood-derived isolate was sequenced. The strain harbored resistance mutations in parC, gyrA, pbp1a, pbp2a, pbp2b, and pbp2x, and harbored the resistance genes, ermB and tetM. The nucleotide sequences of parC and pbp2x genes of strain MDRSPN001 were clearly different from those of other S. pneumoniae strains and were similar to those of oral streptococci strains. These findings suggest that strain MDRSPN001 has been rapidly and drastically evolving multidrug resistance by gene replacement and accumulation of genes originating from other strains, such as oral streptococci, Streptococcus mitis.

Complete Genome Sequence of Multidrug-Resistant Streptococcus pneumoniae Serotype 19F Isolated from an Invasive Infection in Sapporo, Japan.

Invasive infection of multidrug-resistant Streptococcus pneumoniae is a serious clinical concern. Here, we report the complete genome sequence of a multidrug-resistant S. pneumoniae serotype 19F strain isolated from a patient with an invasive infection in Sapporo, Japan.

Two Cases of Chronic Gastritis with non-Helicobacter pylori Helicobacter Infection.

Two men, 48 and 54 years of age, were referred for medical checkups without any particular symptoms. Upper gastrointestinal endoscopy showed a normal gastric body, but white marbled appearance in the lesser curvature of the gastric angle and antrum. Biopsy specimens revealed relatively long and tightly coiled organisms. The two patients were diagnosed as having non-Helicobacter pylori helicobacter (NHPH) infection according to the findings of pathological and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses. After triple therapy (amoxicillin, clarithromycin, and rabeprazole), endoscopy showed an improvement of the white marbled lesions and biopsy specimens showed no NHPH. The white marbled appearance limited to the gastric angle and antrum may be a potential characteristic finding of NHPH-infected gastritis.

Cortical bone remodeling in parosteal osteosarcoma mimicking medullary involvement: a case with the difficulty in pre-surgical staging.

Parosteal osteosarcoma (POS) is a low-grade well-differentiated variant of osteosarcoma that affects the metaphyseal surface of a long bone. Although Grade-1 POS sometimes involve the medullary canal, such patients are not at a greater risk of local recurrence or metastases. In this report, we describe a rare case of POS in the right distal femur with an intramedullary sclerotic lesion mimicking medullary involvement caused by secondary remodeling of the underlying cortex of the tumor. A 34-year-old woman complained of having a painful hard mass in her right knee for six months. Imaging studies revealed a broad-based sclerotic mass attached to the cortex of the distal and lateral aspect of the femur, along with an intramedullary lesion. Histopathological examination of a biopsy specimen revealed Grade-1 POS. We diagnosed a medullary involvement and we performed a wide resection, including the intramedullary lesion. Histopathological examination of the resected specimen revealed that the intramedullary lesion only exhibited remodeling of the underlying tumor cortex without tumor cell invasion. To the best of our knowledge, this is the first report of such imaging features and pathological findings in a patient with POS. Our experience with the present patient indicates that good local control and overall prognosis of patients with medullary involvement in Grade-1 POS may be due to the remodeling of the underlying cortex mimicking "medullary involvement." This feature will add to the range of diagnostic difficulty experienced during the preoperative staging of POS.

A p53 gene mutation in malignant fibrous histiocytoma associated with bone infarction.

Transformed sarcomas rarely arise from bone infarct lesions, although the majority of bone sarcomas are primary in origin. However, the pathogenesis of the condition is unknown. In this report, we describe a malignant fibrous histiocytoma with a p53 gene mutation. A 59-year-old woman complained of having pain in her left knee for three months. Plain radiographs of the distal metaphysis of her left femur revealed an ill-defined lytic lesion, which was consistent with a malignant tumor in the infarct lesion. An open biopsy specimen did not show any evidence of malignancy. Immunohistochemical examination of the biopsy specimen failed to show p53 protein-positive cells. However, a mutation in the p53 gene was detected when polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) analysis was performed. A functionally relevant p53 missense mutation in codon 273 of exon 8 [CGT (Arg) -> CAT (His)] was confirmed by direct sequencing. We concluded that this lesion was a malignant bone tumor arising from the bone infarct lesion, and we thus performed a wide resection. The histopathological diagnosis of the resected specimen was that it was a malignant fibrous histiocytoma associated with bone infarction. Immunohistochemistry revealed that the tumor cells were positive for the p53 protein. To our knowledge, our patient is the first patient having a bone infarct-associated sarcoma with a p53 gene mutation. Identification of the p53 mutation helps in diagnosing the malignant transformation of the bone infarct lesion. One pathogenesis of this condition may be a mutation in the p53 gene.

Trans-sacral resection of a solitary fibrous tumor in the pelvis: report of a case.

Solitary fibrous tumors (SFTs) develop most commonly in the pleura, although they have occasionally been reported to arise in the pelvic cavity. We report a case of an SFT presenting as a painless nodule in the pelvis of a 56-year-old woman. Histologically, the tumor was composed of spindle-shaped cells arranged without pattern, with short and narrow fascicles and interspersed bundles of thick collagen, and numerous blood vessels with a focally hemangiopericytoma-like appearance. Immunohistochemically, the tumor cells strongly expressed vimentin, CD34, and bcl-2. The tumor was excised via a trans-sacral approach, without preoperative transcatheter embolization, and the patient remains well more than 2 years after her operation. To our knowledge, this is the first case of an SFT in the pelvis, which was excised completely via a trans-sacral approach.

Immunohistochemical characterization of pyrimidine synthetic enzymes, thymidine kinase-1 and thymidylate synthase, in various types of cancer.

Thymidine kinase-1 (TK-1) and thymidylate synthase (TS) are key enzymes for salvage and de novo pyrimidine synthesis, respectively. Numerous studies have suggested that increased TS levels are associated closely with resistance to fluoropyrimidine-based chemotherapy. TAS-102 is a novel drug containing trifluorothymidine, which is phosphorylated by TK-1 to its active monophosphated form, that in turn can inhibit TS. TAS-102 has been shown to exhibit antitumor activity in fluoropyrimidine-resistant human cancer cells. TAS-102 is currently undergoing clinical trials for use in gastrointestinal cancers. In the present study, we used immunohistochemistry to investigate the expression of TK-1 and TS in various types of cancer. TK-1 and TS expression was markedly different between cancer types. High TK-1 expression was detected prominently in gastrointestinal adenocarcinomas and esophageal and uterine squamous cell carcinomas. Gastrointestinal adenocarcinomas and squamous cell uterine carcinomas were often accompanied by high TS expression, indicating activation of pyrimidine synthesis through both the salvage and de novo pathways. These results led us to consider that TAS-102 may also be effective for esophageal and uterine squamous cell carcinomas, as well as for gastrointestinal adenocarcinomas, even in fluoropyrimidine-resistant cases with high TS expression. In contrast, thyroid papillary carcinomas, lung adenocarcinomas, hepatocellular carcinomas, pancreatic ductal carcinomas, and renal cell carcinomas, which exhibit low TK-1 expression, may be resistant to TAS-102. In non-small cell lung cancers, high TK-1 expression was demonstrated in squamous cell carcinomas, but not in adenocarcinomas. This result suggests that TAS-102 efficacy and the pyrimidine synthetic pathway may differ depending on histological type. Our results indicate that administration of TAS-102 could be selected on the basis of the immunohistochemical evaluation of TK-1 and TS.

Tall cell variant of papillary thyroid carcinoma: Its characteristic features demonstrated by fine-needle aspiration cytology and immunohistochemical study.

Tall cell variant (TCV) of papillary thyroid carcinoma is a rare tumor, which is usually associated with poor outcome, and pathologists often face the dilemma of proper diagnosis of TCV, not only by cytology but also histology. To allow surgeons to determine aggressiveness of the tumor before operation, it is important for pathologists to detect tall cell features correctly by fine-needle aspiration cytology (FNAC). However, the current criteria and definition of TCV are still controversial and confounded by another problem, the differential diagnosis from poorly differentiated thyroid carcinoma (PDC).In this report, we describe two cases of TCV and present characteristic FNAC findings. The tumor cells had a peculiar shape, which included tall, columnar, and oxyphilic cytoplasm with "eccentric," basally located nuclei. We propose new terms for these cells, such as "tail-like cells" or "tadpole cells."In the surgically-resected specimens, both cases exhibited remarkable extrathyroidal invasion accompanying prominent vascular invasions. They showed high Ki-67 (MIB-1) labeling index by immunohistochemistry, which indicated a higher proliferation activity of TCV than conventional form of papillary thyroid carcinoma.Furthermore, we discuss in this report the problematic issue of differential diagnosis of TCV from PDC and oxyphilic papillary thyroid carcinoma.