Background: Recurrence in pleomorphic adenoma (PA) has been debated as a risk factor for malignant transformation (MT). In this study, we investigated whether recurrence is a risk factor for MT, by longitudinally analyzing cases with recurrent PA (RPA), and carcinomas from PA (CXPA) or RPA (CXRPA). Methods: The study population included 24 CXPA, 24 RPA, 6 CXRPA, and 386 PA cases (study period 2010–2018). Time and event data were collected from the medical documents to identify the time–event sequences. Results: The time interval to MT in CXRPA was significant longer than that of benign recurrence (median 342.0 vs. 109.5 months). In CXRPA, the recurrence intervals were not shorter than those in RPA according to recurrence frequency. Crudely, the MT rate was 5.9% among primary cases and 20.0% among recurrent cases. However, the time-adjusted MT rates increased up to 11.4% (incubation time > 60 months) and 20.0% (>120 months) in primary cases, which were not different from recurrent cases. Conclusion: In these longitudinal analyses, we did not find any clinical evidence that recurrence facilitates MT in the background of PA. Instead, a long incubation time seems to be a key factor for MT of underlying RPA.

It remains uncertain how long pure ground-glass nodules (pGGNs) detected on low dose computed tomography (LDCT) should be followed. Further studies with longer follow-up periods are needed to determine the optimal follow-up duration for pGGNs. What is the percentage of enlarging nodules among pGGNs that have remained stable for 10 years? This was a retrospective cohort study originating from subjects with pGGNs detected on LDCT scans between 1997 and 2006, whose natural courses were reported in 2013. We re-analyzed all the follow-up data until July 2022. The study subjects were followed by our institutional guidelines until they were no longer a candidate for definitive treatment. The growth of the pGGNs was defined as an increase in the diameter of the entire nodule by 2 mm or more or the appearance of new solid portions within the nodules. A total of 89 patients with 135 pGGNs were followed for a median of 193 months. Of 135 pGGNs, 23 (17.0%) increased in size, and the median time to the first detection of a size change was 71 months. Of the 23 growing pGGNs, 122 were detected on the first LDCT, and 13 were newly detected on the follow-up CT scan. An increase in size was observed within 5 years in 8 nodules (34.8%), between 5 and 10 years in 12 nodules (52.2%) and after 10 years in 3 nodules (13.0%). Fifteen nodules were histologically confirmed as adenocarcinoma by surgery. Among the 76 pGGNs stable for 10 years, 3 (3.9%) increased in size. Among pGGNs that remained stable for 10 years, 3.9% eventually grew, indicating that some pGGNs can grow even after a long period of stability. We suggest that pGGNs may need to be followed for more than 10 years to confirm growth.

PurposeThe incidence of BRAF V600E mutation in non-small cell lung carcinoma (NSCLC) is lower than 2%, which poses difficulties in finding legitimate patients for targeted therapy. We investigated the predictive factors pertaining to BRAF V600E and the effectiveness of the VE1 antibody as a screening method for patient selection.Materials and MethodsThe study was designed into two steps. In a first group, BRAF-mutated NSCLCs were identified from sequencing data to determine the features of BRAF V600E mutation. The results of the first group helped the collection of adenocarcinomas with a papillary or micropapillary pattern but without EGFR or ALK alterations as a second group so that the frequency of BRAF V600E mutation could be calculated. The sensitivity and specificity of the VE1 were compared with BRAF V600E status. ResultsAmong 39 BRAF-mutated NSCLCs in the first group, 20 (51%) were V600E. BRAF V600E mutation was more common in female patients and showed no significant correlation with smoking status. Nineteen cases were adenocarcinomas without EGFR and ALK alterations. The most common patterns of invasion were papillary and micropapillary along with central fibrosis. The sensitivity and specificity of the VE1 were 90.0% and 92.3%, respectively. In the second group, 6.7% of cases were VE1-positive, indicating that the prevalence was significantly higher than that reported in previous studies (0.3-1.8%). ConclusionBRAF V600E-mutated NSCLCs could be enriched with the application of clinicopathologic parameters, which are not perfect. Therefore, additional VE1 immunohistochemistry may be useful as a screening method.

Metastatic leiomyosarcoma to the thyroid is an extremely rare occurrence, and only 18 cases have been reported. Here, we report a case of a 37-year-old woman who presented with multiple masses on the scalp. Excisional biopsy was done and the mass revealed fascicles of smooth muscle fibers which showed positive staining for smooth muscle actin, thus confirming the diagnosis of leiomyosarcoma. The patient was also found to have a 0.9 cm mass within the left thyroid. Fine-needle aspiration was done and the cytological smear showed hypercellular spindle cell clusters with hyperchromatic and large nuclei. Normal thyroid follicular cells were found within or around tumor cells. In this report, we present the cytologic findings of metastatic leiomyosarcoma to the thyroid and offer differential diagnoses of the aspirated spindle cells.

Purpose: Claudin 18.2 (CLDN18.2) and fibroblast growth factor receptor 2b (FGFR2b) have recently emerged as promising therapeutic targets for advanced gastric cancer (GC). Before integrating CLDN18.2 and FGFR2b into routine practice, for optimal treatment planning, it is important to consider whether there exists an overlap between these biomarkers. Materials and Methods: We evaluated CLDN18.2 expression in many patients with GC (n=1,538) using tissue microarrays that had been previously used to evaluate FGFR2b overexpression. We investigated the overlap between CLDN18.2 and FGFR2b expression and evaluated the clinicopathological features and prognostic implications of CLDN18.2 expression. Results: The CLDN18.2 positivity rates at 50% and 75% cutoffs were 34.7% and 24.4%, respectively. Heterogeneous expression was identified in 335 (23.5%) of 1426 cases with multiple tissue microarray cores. FGFR2b positivity at >0% cutoff was identified in 47 (3.1%) patients with more marked intratumoral heterogeneity than that observed with CLDN18.2. CLDN18.2 positivity (59.6%) in FGFR2b-positive GCs was significantly higher than that (33.9%) in FGFR2b-negative GCs (P<0.001). Concurrent FGFR2b-and CLDN18.2-positive GCs accounted for 1.8% of all patients, and FGFR2b-positive tumor cells were also positive for CLDN18.2 in approximately 75% of these cases. CLDN18.2 positivity was associated with poorly differentiated histology (P<0.001) and advanced pT and pN stages (P<0.03), but not with overall survival. Conclusions: CLDN18.2 and FGFR2b were significantly associated with each other, suggesting a considerable overlap. This finding may have important clinical implications on the optimal treatment strategy for CLDN18.2-positive GC.

Despite atezolizumab plus bevacizumab being a standard treatment for advanced hepatocellular carcinoma (HCC), a significant proportion of patients do not achieve durable benefit. This study aimed to identify predictive biomarkers for this therapy by investigating the role of immune activation within the tumor microenvironment (TME). We characterized the intratumoral TME of patients with advanced HCC treated with atezolizumab plus bevacizumab using single cell transcriptomics on pretreatment tumor biopsies from 12 patients. To complement and support these findings, we integrated our single cell data with publicly available bulk RNA-sequencing data from independent clinical trial cohorts. Patients who responded to combination therapy with atezolizumab plus bevacizumab demonstrated an immune-activated TME, marked by enhanced cytotoxicity and a tumor-specific T cell response. These patients also exhibited an increased proportion of inflammatory cytokine-enriched tumor-associated macrophage clusters with stronger interactions with T cells, an increased population of conventional dendritic cells, and activated antigen-presenting function in tumor endothelial cells. When publicly available bulk RNA-sequencing data from independent clinical trial cohorts were analyzed, these immune activation features were associated with improved progression-free survival (median 10.8 months, 95% CI: 7.3-not reached versus 5.5 months, 95% CI: 4.0-6.7; p <0.001). These findings suggest that the existence of an activated immune TME before treatment is crucial for a favorable clinical response in patients with HCC treated with atezolizumab plus bevacizumab. Only a subset of patients with HCC benefit from combination therapy with atezolizumab plus bevacizumab, limiting its clinical utility. In this study, we used single cell RNA analysis to identify TME features associated with a clinical response to this therapy. Our findings suggest that a pre-existing immune-activated TME is crucial for predicting the response to atezolizumab plus bevacizumab. Specifically, features such as enhanced T cell cytotoxicity, inflammatory cytokine-enriched macrophage clusters, active antigen presentation in endothelial cells, and an increased presence of dendritic cells may aid patient selection and inform therapeutic strategies.