Clinical Approach to Dental Root Canal Filler-Induced Maxillary Sinus Fungal Mass Using Transnasal Endoscopy.

Accidentally extruded root canal filler within the sinuses may induce maxillary sinusitis with fungal mass. The authors describe 2 cases of gutta-percha-induced fungal masses in the left maxillary sinus of 2 women. The lesions were evaluated preoperatively using both computed tomography and magnetic resonance imaging, providing comprehensive insights into the condition. In one patient, the lesion was located such that it could be resected through the middle meatal antrostomy alone. However, the second patient presented with an anteroinferiorly situated lesion that necessitated not only a transnasal approach but also an endoscopic modified medial maxillectomy. Both patients recovered uneventfully after surgery. This case series is the first published report of 2 cases of gutta-percha-induced maxillary sinus fungal masses, with their imaging findings, successfully treated through different routes through transnasal endoscopic surgery. These reports highlight the need for a collaborative approach between dental practitioners and otolaryngologists. In addition to the patient's wishes, surgical interventions must consider the unique characteristics of each case and the potential for collaboration across different medical specialties.

Pulmonary Erdheim-Chester Disease With BRAF-AGAP3 Fusion: Late-Onset Osteolytic Femoral Lesions Despite Long-Term Pulmonary Stabilization With Corticosteroid.

Erdheim-Chester disease (ECD) is a rare inflammatory myeloid neoplasm affecting multiple systems and organs. The patient is a 38-year-old male with ECD complicated with pulmonary and cutaneous manifestations but without bone lesions diagnosed in 2008. Initial treatment with oral and inhaled corticosteroids achieved persistent favorable disease remission. However, atypical late-onset bone lesions developed in the bilateral femur in 2021. Although BRAF-V600E mutation was negative in the lung specimen at diagnosis, the next-generation gene sequence using biopsied bone lesions revealed a rare BRAF-AGAP3 fusion, leading to the administration of trametinib. This is the first report describing ECD harboring BRAF-AGAP3 fusion successfully treated with trametinib. Our case presents a unique clinical course in which late-onset osteolytic bone lesions developed despite a long-term stabilization of pulmonary lesions with low-dose oral and inhaled corticosteroids.

Hyperprogressive disease under anti-PD-1 rechallenge after initial response to anti-PD-1 treatment for non-small cell lung cancer: a case report.

Background: Hyperprogressive disease is an unexpected response pattern observed in immune checkpoint therapy and associated with poor prognosis. The rechallenge of programmed cell death 1/programmed cell death ligand 1 (PD-1/PD-L1) inhibitors can be a treatment option in non-small cell lung cancer (NSCLC) patients who once responded to them. Here, we reported the hyperprogressive phenomenon after PD-1/PD-L1 rechallenge in a patient with NSCLC. Case Description: This case report described a patient with recurrent large cell lung cancer undergoing hyperprogressive disease with pleural and pericardial dissemination shortly after the pembrolizumab rechallenge, although he had a favorable response to the initial pembrolizumab treatment. A lower ratio of CD8+ T cells to Foxp3+ regulatory T cells was distributed in the cell blocks of pleural and pericardial effusion which were taken after hyperprogressive disease, compared to the resected tumor microenvironment. Neutrophil-to-lymphocyte ratio (NLR) was lower in peripheral blood when the disease was controlled and it rose when the disease progressed. Notably, NLR increased dramatically when hyperprogression occurred. Conclusions: For the first time, we reported that a patient who showed a favorable response to initial anti-PD-1 treatment underwent hyperprogressive disease when rechallenging the same immunotherapy. The increased Foxp3+ regulatory T cells in the tumor microenvironment and the longitudinal change of NLRs in peripheral blood were suggested to be associated with hyperprogressive disease.

Lymphangioleiomyomatosis as a potent lung cancer risk factor: Insights from a Japanese large cohort study.

BACKGROUND AND OBJECTIVE: Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease associated with the functional tumour suppressor genes TSC1 and TSC2 and causes structural destruction in the lungs, which could potentially increase the risk of lung cancer. However, this relationship remains unclear because of the rarity of the disease. METHODS: We investigated the relative risk of developing lung cancer among patients diagnosed with LAM between 2001 and 2022 at a single high-volume centre in Japan, using data from the Japanese Cancer Registry as the reference population. Next-generation sequencing (NGS) was performed in cases where tumour samples were available. RESULTS: Among 642 patients diagnosed with LAM (sporadic LAM, n = 557; tuberous sclerosis complex-LAM, n = 80; unclassified, n = 5), 13 (2.2%) were diagnosed with lung cancer during a median follow-up period of 5.13 years. All patients were female, 61.5% were never smokers, and the median age at lung cancer diagnosis was 53 years. Eight patients developed lung cancer after LAM diagnosis. The estimated incidence of lung cancer was 301.4 cases per 100,000 person-years, and the standardized incidence ratio was 13.6 (95% confidence interval, 6.2-21.0; p = 0.0008). Actionable genetic alterations were identified in 38.5% of the patients (EGFR: 3, ALK: 1 and ERBB2: 1). No findings suggested loss of TSC gene function in the two patients analysed by NGS. CONCLUSION: Our study revealed that patients diagnosed with LAM had a significantly increased risk of lung cancer. Further research is warranted to clarify the carcinogenesis of lung cancer in patients with LAM.

Two Surgical Cases of Colorectal Cancer in Patients With Immunoglobulin G4-Related Disease.

Immunoglobulin G4-related disease (IgG4RD) is a relatively new disease concept that is most common in Asia. It is a systemic chronic lymphoproliferative disease that is diagnosed by mass formation or thickened lesion, a high serum IgG4 level (≥135 mg/dL), and confirmation of lymphocytes and plasma cells by histopathological examination. The precise mechanism of this disease remains elusive; however, distinguishing IgG4RD from malignancy proves challenging due to its manifestation of swollen lymph nodes and retroperitoneal thickening and fibrosis. Malignancy is also 3.5 times more likely in cases with IgG4RD. In this study, we report two cases of colorectal cancer in patients with IgG4RD who underwent surgery. In both cases, excising the tumor from the retroperitoneal posed a challenge, and swollen lymph nodes were observed without evidence of cancer metastasis. We believe that these are very informative cases, and we report the cases with a literature review of IgG4RD.

The BAP1 nuclear deubiquitinase is involved in the nonhomologous end-joining pathway of double-strand DNA repair through interaction with DNA-PK.

BRCA1-associated protein 1 (BAP1) has emerged as a major tumor suppressor gene in diverse cancer types, notably in malignant pleural mesothelioma (DPM), and has also been identified as a germline cancer predisposition gene for DPM and other select cancers. However, its role in the response to DNA damage has remained unclear. Here, we show that BAP1 inactivation is associated with increased DNA damage both in Met-5A human mesothelial cells and human DPM cell lines. Through proteomic analyses, we identified PRKDC as an interaction partner of BAP1 protein complexes in DPM cells and 293 T human embryonic kidney cells. PRKDC encodes the catalytic subunit of DNA protein kinase (DNA-PKcs) which functions in the nonhomologous end-joining (NHEJ) pathway of DNA repair. Double-stranded DNA damage resulted in prominent nuclear expression of BAP1 in DPM cells and phosphorylation of BAP1 at serine 395. A plasmid-based NHEJ assay confirmed a significant effect of BAP1 knockdown on cellular NHEJ activity. Combination treatment with X-ray irradiation and gemcitabine (as a radiosensitizer) strongly suppressed the growth of BAP1-deficient cells. Our results suggest reciprocal positive interactions between BAP1 and DNA-PKcs, based on phosphorylation of BAP1 by the latter and deubiquitination of DNA-PKcs by BAP1. Thus, functional interaction of BAP1 with DNA-PKcs supports a role for BAP1 in NHEJ DNA repair and may provide the basis for new therapeutic strategies and new insights into its role as a tumor suppressor.

Efficacy of radiation therapy in Japanese patients with positive margins after breast-conserving surgery.

BACKGROUND: Additional surgical resection is recommended after breast-conserving surgery if the surgical margin is pathologically positive. However, in clinical practice, radiation therapy is sometimes used instead for several reasons. Irradiation may be appropriate for some patients, but real-world data is still insufficient to establish it as standard treatment. We retrospectively investigated the status of local control in patients who received irradiation for positive margins. METHODS: We investigated 85 patients with positive margins after curative partial mastectomy who were treated with irradiation instead of additional excision during the period 2006-2013. The patients received whole-breast irradiation (43.2-50 Gy) using photon beams and additional tumour-bed boost (8.1-16 Gy) using electron beams. Intrabreast tumour recurrence was defined as secondary cancer within the ipsilateral conserved breast. Surgical margin was defined as positive if tumour cell exposure was pathologically confirmed on the margin. RESULTS: Seven patients (8.2%) developed intrabreast tumour recurrence during a mean observation period of 119 months. As to components of positive margin, 76 cases were positive for an intraductal component, of which seven (9.2%) developed intrabreast tumour recurrence. Meanwhile, all nine cases positive for an invasive component were free from intrabreast tumour recurrence. Two of the intrabreast tumour recurrence cases seemed to develop new lesions rather than recurrence, considering tumour location. The cumulative incidence of intrabreast tumour recurrence over 10 years was 6.1%. Limited to true recurrence, intrabreast tumour recurrence incidence was 4.9%. CONCLUSION: Our real-world data supports irradiation as an alternative to additional surgical intervention for positive margins after breast-conserving surgery and offers a basis for further research.

NTRK2 expression in gastrointestinal stromal tumors with a special emphasis on the clinicopathological and prognostic impacts.

Gastrointestinal stromal tumors (GISTs) are typically characterized by activating mutations of the KIT proto-oncogene receptor tyrosine kinase (KIT) or platelet-derived growth factor receptor alpha (PDGFRA). Recently, the neurotrophic tyrosine receptor kinase (NTRK) fusion was reported in a small subset of wild-type GIST. We examined trk IHC and NTRK gene expressions in GIST. Pan-trk immunohistochemistry (IHC) was positive in 25 (all 16 duodenal and 9 out of 16 small intestinal GISTs) of 139 cases, and all pan-trk positive cases showed diffuse and strong expression of c-kit. Interestingly, all of these cases showed only trkB but not trkA/trkC expression. Cap analysis of gene expression (CAGE) analysis identified increased number of genes whose promoters were activated in pan-trk/trkB positive GISTs. Imbalanced expression of NTRK2, which suggests the presence of NTRK2 fusion, was not observed in any of trkB positive GISTs, despite higher mRNA expression. TrkB expression was found in duodenal GISTs and more than half of small intestinal GISTs, and this subset of cases showed poor prognosis. However, there was not clear difference in clinical outcomes according to the trkB expression status in small intestinal GISTs. These findings may provide a possible hypothesis for trkB overexpression contributing to the tumorigenesis and aggressive clinical outcome in GISTs of duodenal origin.

Stromal Ki67 Expression Might be a Useful Marker for Distinguishing Fibroadenoma From Benign Phyllodes Tumor of the Breast.

Background. Fibroadenoma (FA) and benign phyllodes tumor (PT) of the breast often have similar appearances on imaging. While an exact diagnosis of biopsy specimens is required to choose adequate treatment, including surgical procedures, it is sometimes difficult to pathologically differentiate these 2 tumors due to histological resemblances. To elucidate markers for distinguishing FA from benign PT, we analyzed clinical samples immunohistochemically. Methods. We retrospectively investigated 80 breast fibroepithelial lesions. As a discovery set, 60 surgical excision samples (30 FA and 30 benign PT) were examined. Twenty biopsy samples (10 FA and 10 benign PT) were examined as a validation set. To determine targets for immunohistochemistry, we first tested some proteins based on previous reports. As a result, Ki67 was chosen for differentiating FA and PT; thus further examinations were conducted with this protein. Results. Among the proteins examined, stromal Ki67 was significantly higher in PT than in FA. Benign PT had significantly higher stromal Ki67 expression both at random and at hotspots (p < .001 and <.001, respectively). The receiver operating characteristic curve analysis identified 3.5% and 8.5% (at random spots and hotspots, respectively) as the optimal cutoff values of stromal Ki67 for distinguishing between these 2 tumors. In the validation cohort employing needle biopsy specimens, we confirmed that these 2 cutoff values properly classified these 2 tumors (p = .043 and .029, respectively). Conclusion.We revealed that stromal Ki67 might be a potential marker for distinguishing FA from benign PT.

BRCAness of brain lesions reflects a worse outcome for patients with metastatic breast cancer.

PURPOSE: Breast cancer often metastasizes to the central nervous system. Although the prognosis of brain metastases from breast cancer has been considered poor, and systemic therapy has not contributed to an improved prognosis, newer agents are expected to be more effective. BRCAness is defined as the status of homologous recombination deficiency (HRD) in tumor tissue, regardless of the presence of pathogenic germline BRCA1/2 variants. A study employing next-generation sequencing analysis showed that HRD was found relatively frequently in brain metastases of breast cancer patients. However, there have been no studies evaluating BRCAness in brain metastases of breast cancer with more efficient, rapid, and cost-effective methods. METHODS: We retrospectively investigated 17 brain metastases of breast cancer that were surgically resected at our hospital from January 2007 to December 2022. Of these, samples from 15 patients were evaluable for BRCAness by employing multiplex ligation-dependent probe amplification (MLPA) assay. RESULTS: Of the 15 patients, five patients (33%) had tumors with BRCAness. Clinicopathological factors of patients with brain metastases with BRCAness were not statistically different from those of patients who possessed tumors without BRCAness. Patients with brain metastases with BRCAness had shorter overall survival compared to those without BRCAness (BRCAness, median 15 months (95% CI 2-30) vs. non-BRCAness, median 28.5 months (95% CI 10-60); P = 0.013). CONCLUSION: In this study, we evaluated BRCAness in brain metastases of breast cancer with the MLPA method, and found that about one-third of patients had BRCAness-positive tumors. The analysis of BRCAness using MLPA has the potential for practical clinical use.

Detection of Novel Tyrosine Kinase Fusion Genes as Potential Therapeutic Targets in Bone and Soft Tissue Sarcomas Using DNA/RNA-based Clinical Sequencing.

BACKGROUND: Approximately 1% of clinically treatable tyrosine kinase fusions, including anaplastic lymphoma kinase, neurotrophic tyrosine receptor kinase, RET proto-oncogene, and ROS proto-oncogene 1, have been identified in soft tissue sarcomas via comprehensive genome profiling based on DNA sequencing. Histologic tumor-specific fusion genes have been reported in approximately 20% of soft tissue sarcomas; however, unlike tyrosine kinase fusion genes, these fusions cannot be directly targeted in therapy. Approximately 80% of tumor-specific fusion-negative sarcomas, including myxofibrosarcoma and leiomyosarcoma, that are defined in complex karyotype sarcomas remain genetically uncharacterized; this mutually exclusive pattern of mutations suggests that other mutually exclusive driver oncogenes are yet to be discovered. Tumor-specific, fusion-negative sarcomas may be associated with unique translocations, and oncogenic fusion genes, including tyrosine kinase fusions, may have been overlooked in these sarcomas. QUESTIONS/PURPOSES: (1) Can DNA- or RNA-based analysis reveal any characteristic gene alterations in bone and soft tissue sarcomas? (2) Can useful and potential tyrosine kinase fusions in tumors from tumor-specific, fusion-negative sarcomas be detected using an RNA-based screening system? (3) Do the identified potential fusion tumors, especially in neurotrophic tyrosine receptor kinase gene fusions in bone sarcoma, transform cells and respond to targeted drug treatment in in vitro assays? (4) Can the identified tyrosine kinase fusion genes in sarcomas be useful therapeutic targets? METHODS: Between 2017 and 2020, we treated 100 patients for bone and soft tissue sarcomas at five institutions. Any biopsy or surgery from which a specimen could be obtained was included as potentially eligible. Ninety percent (90 patients) of patients were eligible; a further 8% (8 patients) were excluded because they were either lost to follow-up or their diagnosis was changed, leaving 82% (82 patients) for analysis here. To answer our first and second questions regarding gene alterations and potential tyrosine kinase fusions in eight bone and 74 soft tissue sarcomas, we used the TruSight Tumor 170 assay to detect mutations, copy number variations, and gene fusions in the samples. To answer our third question, we performed functional analyses involving in vitro assays to determine whether the identified tyrosine kinase fusions were associated with oncogenic abilities and drug responses. Finally, to determine usefulness as therapeutic targets, two pediatric patients harboring an NTRK fusion and an ALK fusion were treated with tyrosine kinase inhibitors in clinical trials. RESULTS: DNA/RNA-based analysis demonstrated characteristic alterations in bone and soft tissue sarcomas; DNA-based analyses detected TP53 and copy number alterations of MDM2 and CDK4 . These single-nucleotide variants and copy number variations were enriched in specific fusion-negative sarcomas. RNA-based screening detected fusion genes in 24% (20 of 82) of patients. Useful potential fusions were detected in 19% (11 of 58) of tumor-specific fusion-negative sarcomas, with nine of these patients harboring tyrosine kinase fusion genes; five of these patients had in-frame tyrosine kinase fusion genes ( STRN3-NTRK3, VWC2-EGFR, ICK-KDR, FOXP2-MET , and CEP290-MET ) with unknown pathologic significance. The functional analysis revealed that STRN3-NTRK3 rearrangement that was identified in bone had a strong transforming potential in 3T3 cells, and that STRN3-NTRK3 -positive cells were sensitive to larotrectinib in vitro. To confirm the usefulness of identified tyrosine kinase fusion genes as therapeutic targets, patients with well-characterized LMNA-NTRK1 and CLTC-ALK fusions were treated with tyrosine kinase inhibitors in clinical trials, and a complete response was achieved. CONCLUSION: We identified useful potential therapeutic targets for tyrosine kinase fusions in bone and soft tissue sarcomas using RNA-based analysis. We successfully identified STRN3-NTRK3 fusion in a patient with leiomyosarcoma of bone and determined the malignant potential of this fusion gene via functional analyses and drug effects. In light of these discoveries, comprehensive genome profiling should be considered even if the sarcoma is a bone sarcoma. There seem to be some limitations regarding current DNA-based comprehensive genome profiling tests, and it is important to use RNA testing for proper diagnosis and accurate identification of fusion genes. Studies on more patients, validation of results, and further functional analysis of unknown tyrosine kinase fusion genes are required to establish future treatments. CLINICAL RELEVANCE: DNA- and RNA-based screening systems may be useful for detecting tyrosine kinase fusion genes in specific fusion-negative sarcomas and identifying key therapeutic targets, leading to possible breakthroughs in the treatment of bone and soft tissue sarcomas. Given that current DNA sequencing misses fusion genes, RNA-based screening systems should be widely considered as a worldwide test for sarcoma. If standard treatments such as chemotherapy are not effective, or even if the sarcoma is of bone, RNA sequencing should be considered to identify as many therapeutic targets as possible.

Copy number loss of KDM5D may be a predictive biomarker for ATR inhibitor treatment in male patients with pulmonary squamous cell carcinoma.

A limited number of patients with lung squamous cell carcinoma (SCC) benefit clinically from molecular targeted drugs because of a lack of targetable driver alterations. We aimed to understand the prevalence and clinical significance of lysine-specific demethylase 5D (KDM5D) copy number loss in SCC and explore its potential as a predictive biomarker for ataxia-telangiectasia and Rad3-related (ATR) inhibitor treatment. We evaluated KDM5D copy number loss in 173 surgically resected SCCs from male patients using fluorescence in situ hybridization. KDM5D copy number loss was detected in 75 of the 173 patients (43%). Genome-wide expression profiles of the transcription start sites (TSSs) were obtained from 17 SCCs, for which the cap analysis of gene expression assay was performed, revealing that upregulated genes in tumors with the KDM5D copy number loss are associated with 'cell cycle', whereas downregulated genes in tumors with KDM5D copy number loss were associated with 'immune response'. Clinicopathologically, SCCs with KDM5D copy number loss were associated with late pathological stage (p = 0.0085) and high stromal content (p = 0.0254). Multiplexed fluorescent immunohistochemistry showed that the number of tumor-infiltrating CD8+ /T-bet+ T cells was lower in SCCs with KDM5D copy number loss than in wild-type tumors. In conclusion, approximately 40% of the male patients with SCC exhibited KDM5D copy number loss. Tumors in patients who show this distinct phenotype can be 'cold tumors', which are characterized by the paucity of tumor T-cell infiltration and usually do not respond to immunotherapy. Thus, they may be candidates for trials with ATR inhibitors.

IgG4-related mastitis characterized by skin thickening of the breast: a case report.

BACKGROUND: IgG4-related diseases are characterized by marked infiltration and IgG4-positive plasma cells and fibrosis, and involve multiple organs. However, IgG4-related mastitis is rare. We report a case of mastitis associated with IgG4-related disease. CASE PRESENTATION: A 78-year-old woman visited our hospital with a complaint of multiple subcutaneous nodules. A biopsy of a dorsal subcutaneous mass was performed but did not yield a definitive diagnosis. However, blood tests showed a high level of IgG4, thus she was referred to the department of collagen disease for further examination. Computed tomography (CT) showed a thickening of the skin of the right breast, and the patient was referred to our department. On physical examination, a large area of thickened skin was observed in the right breast without inflammatory breast cancer-like redness, and no mass was palpable. A needle biopsy was performed on an indistinct hypoechoic area in the breast, and she was diagnosed with mastitis associated with IgG4-related disease. Systemic steroid therapy was then administered and the symptoms of multiple skin nodules and mastitis improved. CONCLUSIONS: We reached the diagnosis based on a biopsy of the mammary gland enabling the patient to begin treatment for IgG4-related disease. This case was characterized by breast skin thickening, which is different from inflammatory breast cancer.

The Impact of FGFR3 Alterations on the Tumor Microenvironment and the Efficacy of Immune Checkpoint Inhibitors in Bladder Cancer.

BACKGROUND: Currently, only limited knowledge is available regarding the phenotypic association between fibroblast growth factor receptor 3 (FGFR3) alterations and the tumor microenvironment (TME) in bladder cancer (BLCA). METHODS: A multi-omics analysis on 389 BLCA and 35 adjacent normal tissues from a cohort of OMPU-NCC Consortium Japan was retrospectively performed by integrating the whole-exome and RNA-sequence dataset and clinicopathological record. A median follow-up duration of all BLCA cohort was 31 months. RESULTS: FGFR3 alterations (aFGFR3), including recurrent mutations and fusions, accounted for 44% of non-muscle invasive bladder cancer (NMIBC) and 15% of muscle-invasive bladder cancer (MIBC). Within MIBC, the consensus subtypes LumP was significantly more prevalent in aFGFR3, whereas the Ba/Sq subtype exhibited similarity between intact FGFR3 (iFGFR3) and aFGFR3 cases. We revealed that basal markers were significantly increased in MIBC/aFGFR3 compared to MIBC/iFGFR3. Transcriptome analysis highlighted TIM3 as the most upregulated immune-related gene in iFGFR3, with differential immune cell compositions observed between iFGFR3 and aFGFR3. Using EcoTyper, TME heterogeneity was discerned even within aFGFR cases, suggesting potential variations in the response to checkpoint inhibitors (CPIs). Among 72 patients treated with CPIs, the objective response rate (ORR) was comparable between iFGFR3 and aFGFR3 (20% vs 31%; p = 0.467). Strikingly, a significantly higher ORR was noted in LumP/aFGFR3 compared to LumP/iFGFR3 (50% vs 5%; p = 0.022). This trend was validated using data from the IMvigor210 trial. Additionally, several immune-related genes, including IDO1, CCL24, IL1RL1, LGALS4, and NCAM (CD56) were upregulated in LumP/iFGFR3 compared to LumP/aFGFR3 cases. CONCLUSIONS: Differential pathways influenced by aFGFR3 were observed between NMIBC and MIBC, highlighting the upregulation of both luminal and basal markers in MIBC/aFGFR3. Heterogeneous TME was identified within MIBC/aFGFR3, leading to differential outcomes for CPIs. Specifically, a favorable ORR in LumP/aFGFR3 and a poor ORR in LumP/iFGFR3 were observed. We propose TIM3 as a potential target for iFGFR3 (ORR: 20%) and several immune checkpoint genes, including IDO1 and CCL24, for LumP/iFGFR3 (ORR: 5%), indicating promising avenues for precision immunotherapy for BLCA.

Frequent nuclear ß-catenin expression in pulmonary enteric-type adenocarcinoma according to the current World Health Organization criteria.

Based on the current World Health Organization classification criteria, five of 3895 consecutive cases of surgically resected primary lung carcinomas (0.13%) categorized as enteric-type were analyzed. Three cases completely comprised tumor cells that resemble colorectal adenocarcinoma, while the other two cases exhibited features of conventional adenocarcinomas admixed with enteric components. Immunohistochemically, all patients expressed at least three of the five intestinal markers: CDX2, CK20, HNF4α, MUC2, and SATB2. None of the patients expressed TTF-1 and NKX3.1. Three cases showed nuclear accumulation of ß-catenin, indicating activation of the Wnt/ß-catenin signaling pathway; APC mutations were detected in one of these cases. TP53 mutations were detected in three cases. Mutated EGFR or ALK fusions were not detected. Our study demonstrates that pulmonary enteric-type adenocarcinomas share immunohistochemical features and genetic alterations with colorectal adenocarcinomas, which are characterized by frequent activation of the Wnt/ß-catenin signaling pathway and a lack of actionable mutations.

Clinicopathological Impacts of Expression of Neuronal Markers in Lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a tuberous sclerosis complex (TSC)-associated tumor, characterized by the expression of neural crest lineages including neuronal markers. Neural crest cells can differentiate into multiple cell types that contribute to tissues associated with TSC-related tumors, and TSC-related tumors could be specifically associated with distinct neural crest subtypes. This study aimed to clarify the clinicopathological effects of expression of neuronal markers in LAM. Lung tissues from 40 patients with LAM (of whom 13, 1, and 26 had undergone lung transplantation, lobectomy, and partial lung resection, respectively) were immunohistochemically analyzed. All patients were women, and their median age was 36 years (range: 24-62 y). All patients who underwent lung transplantation or lobectomy were classified as LAM histologic score (LHS)-3, whereas those who underwent partial lung resection were classified as LHS-1. LAM cells expressed peripherin (65%), and neuron-specific ßIII-tubulin (43%). A comparison of the early (LHS-1) and advanced (LHS-3) stages of LAM revealed that neuron-specific ßIII-tubulin was significantly expressed in the early stage of LAM ( P = 0.0009). Neuron-specific ßIII-tubulin-positive LAM was associated with younger age ( P < 0.0001), the coexistence of renal angiomyolipoma ( P = 0.027), and the absence of retroperitoneal LAM ( P = 0.045). Furthermore, based on the expression levels of immunohistochemical markers in LAM, 2 distinct clusters with different expression levels of neuronal markers were observed. Approximately 40% to 60% of patients with LAM expressed neuron-specific ßIII-tubulin and peripherin. Neuronal expression may be associated with disease severity.

Multiple bronchiolar adenomas/ciliated muconodular papillary tumors of the bilateral lung with tumor budding and potential malignant transformation into squamous cell carcinoma: a case report and literature review.

Background: Bronchiolar adenoma (BA)/ciliated muconodular papillary tumor (CMPT) is a rare lung tumor characterized by ciliated, mucous and basal cells. Recently, some cases of driver mutations or malignant transformations have been reported. However, the nature of BA/CMPT remains controversial. Here, we report a case of bilateral pulmonary multiple BAs with tumor budding and squamous metaplasia. Case Description: A 55-year-old man presented with multiple small nodules in the lower lobes of the bilateral lungs on physical examination 7 years prior. During the past 3 years of regular follow-up, some nodules had slightly enlarged. Because the nodules were mostly solid, the patient underwent video-assisted thoracoscopic segmentectomy of the left lower lung. A postoperative pathological diagnosis of BA was made. In all lesions, the fusion and mutation of major driver genes were not detected by next-generation sequencing (NGS). No recurrence or metastasis was observed after 37 months of follow-up. Notably, all five resected lesions were BA/CMPT, and one lesion was accompanied by squamous metaplasia and tumor budding. Conclusions: Our report found that BA/CMPT with squamous metaplasia and tumor budding has the potential to transform into lung squamous cell carcinoma, expanding its connection with malignant transformation. Smoking may be one of the risk factors. We also found that BA/CMPT can be multiple lesions rather than a solitary lesion.

Stepwise progression of invasive mucinous adenocarcinoma based on radiological and biological characteristics.

INTRODUCTION: Invasive mucinous lung adenocarcinoma (IMA) has unique radiological findings and pathological characteristics. IMA is classified into solitary and pneumonic types; however, it is unclear whether these are biologically identical. METHODS: A single-center retrospective analysis was performed for 70 IMA patients (solitary type [n = 38] and pneumonic type [n = 32]) who underwent pulmonary resection between January 2010 and December 2018. We compared clinical and biological characteristics between the two types. RESULTS: The frequencies of genetic alternations such as EGFR, KRAS, BRAF, GNAS, ERBB2, TP53, NRG1, and MET were not different. Immunohistochemically, expression of MUC1 was significantly more common in the pneumonic type (5.0% versus 20.0%, p = 0.01) and diffuse MUC6 positive in the solitary type (39.0% versus 13.0%, p = 0.02). We further classified solitary types into those with or without ground-glass opacity (GGO) and pneumonic types into those with or without crazy-paving appearance (CPA), and evaluated their surgical outcomes. Five-year overall survival and relapse free survival rates were 95.8%/86.6%, 64.3%/70.7%, 74.6%/68.9%, and 50.0%/28.6% in patients with solitary type with GGO, solitary type without GGO, pneumonic type without CPA, and pneumonic type with CPA, respectively. CONCLUSIONS: There were no differences in genetic alternations; however, mucin expression pattern was different. Surgical outcomes were different according to the presence of GGO in the solitary type and the presence of CPA in the pneumonic type. These findings suggested a stepwise progression from solitary to pneumonic IMA.

Long-term effect of letrozole on metastatic uterine smooth muscle tumors of uncertain malignant potential: A case report.

A 48-year-old woman underwent total abdominal hysterectomy and right salpingo-oophorectomy and was initially diagnosed with a uterine leiomyoma and right ovarian cystadenoma. After 4 years, multiple pulmonary metastases were identified, and treatment with gonadotropin-releasing hormone agonists was started, but stopped later due to disease progression. The patient developed dyspnea and underwent right upper lobectomy. The histopathological findings were consistent with those of pulmonary metastases secondary to a uterine smooth muscle tumor of uncertain malignant potential. Slow disease progression after a poor response to adriamycin and hormone receptor positivity led to the start of letrozole. Letrozole induced spontaneous regression of the pulmonary metastases, and about 2 years into the treatment, sustained response was achieved with minimal side effects. This may be the first case supporting the long-term efficacy and safety of letrozole in the management of adriamycin-resistant lung metastases of uterine smooth muscle tumors of uncertain malignant potential.