Stepwise Incremental Dose Schedule of Sirolimus Is Successfully Tolerated by a Patient With Lymphangioleiomyomatosis Who Was Initially Allergic to mTOR Inhibitors.

Lymphangioleiomyomatosis (LAM) is a rare disease involving the proliferation of LAM cells in the lungs and the axial lymphatic system and mechanistic target of rapamycin (mTOR) inhibitors are the only effective medicines for treating it. Patients suffering from LAM, who are allergic to mTOR inhibitors can be treated by desensitizing them to the medicine. A 39-year-old woman presented with dyspnea caused by chylous pleural effusion, ascites, and retroperitoneal lymphangioleiomyomas. She was diagnosed with LAM based on the presence of LAM cell clusters (LCCs) in chylous pleural effusion and elevated serum vascular endothelial growth factor D (VEGF-D) concentration. She was allergic to cedars and yellowtails. Although she was started on sirolimus for treating LAM, the drug had to be discontinued on day 45 because of the appearance of a skin rash on her trunk. A year later, another oral mTOR inhibitor, everolimus, was initiated but had to be discontinued because of the appearance of cutaneous reactions. Since mTOR inhibitors are the only effective molecular-target medicines for LAM, desensitization to sirolimus was attempted by initiating exposure to sirolimus at a low dose followed by stepwise dose escalation. Eventually, the patient tolerated a dose of 0.5 mg/day of sirolimus, which resulted in a trough concentration of approximately 2 ng/ml in blood, without adverse cutaneous reactions; furthermore, clinically relevant effects were observed as her LAM condition reduced and stabilized. This case study illustrates that mTOR inhibitor therapy for LAM should not be abandoned because of allergic cutaneous reactions. Physicians must find a dose that balances adverse events and therapeutic effects to ensure continued treatment for patients with LAM. Furthermore, the possible mechanisms for mTOR inhibitor-induced cutaneous reactions have been discussed.

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.

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.

Clinical and genetic features of 334 Asian patients with Birt-Hogg-Dubé syndrome (BHDS) who presented with pulmonary cysts with or without a history of pneumothorax, with special reference to BHDS-associated pneumothorax.

BACKGROUND: The clinical pulmonary manifestations and genetic features of Birt-Hogg-Dubé syndrome (BHDS) in Asian patients remained unclear. We aimed to clarify the clinical features of BHDS-associated pneumothorax (PTX) and retrospectively investigate potential contributing factors in the largest Asian cohort to date. METHODS: We reviewed the clinical and genetic data collected in 2006-2017, from the BHDS patients who were Asian and presented with pulmonary cysts with or without a history of PTX. RESULTS: Data from 334 (41.3% males; 58.7% females) patients from 297 unrelated families were reviewed. Among them, 314 (94.0%) patients developed PTX. The median age at the first occurrence of PTX was 32 years, which was significantly lower in males (P = 0.003) and patients without notable skin manifestations (P < 0.001). Seventy-six (24.2%) patients experienced their first PTX episode before the age of 25 years. PTX simultaneously occurred in the bilateral lungs of 37 (11.8%) patients. Among 149 patients who had their first PTX episode at least 10 years before BHDS diagnosis, PTX occurred more frequently in males (P = 0.030) and light smokers than in nonsmokers (P = 0.014). The occurrence of PTX peaked in the early 30s and gradually decreased with age but remained high in females (P = 0.001). We identified 70 unique FLCN germline variants, including duplications (46.4%), substitutions (7.1%), insertions/deletions (30.0%), and variants affecting splicing (12.5%). Approximately 80% of Asian patients suspected of having BHDS could be genetically diagnosed by examining FLCN exons 7, 9, 11, 12, and 13. No apparent genotype-phenotype correlation regarding pulmonary manifestations was identified. CONCLUSIONS: Our findings indicate that sex, smoking history, and skin manifestations at BHDS diagnosis significantly influence the clinical features of BHDS-associated PTX. These findings may contribute to the appropriate management and treatment of BHDS-associated PTX.

Uncommon radiologic computed tomography appearances of the chest in patients with lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a rare destructive lung disease characterized by multiple thin-walled pulmonary cysts. The currently proposed diagnostic algorithm emphasizes the characteristic cystic appearance on high-resolution computed tomography (HRCT) so uncommon HRCT appearances present challenges to establishing the proper LAM diagnosis. The objective of this study is to accrue uncommon chest HRCT appearances, determine frequencies in both tuberous sclerosis complex (TSC)-associated LAM (TSC-LAM) and sporadic LAM (S-LAM) patients. 311 females referred to our hospital, including 272 S-LAM patients (mean age 39.2 years) and 39 TSC-LAM patients (mean age 38.3 years), were retrospectively evaluated. We found 2 types of radiologic findings likely to make HRCT cyst appearance atypical: characteristics of the cyst itself and uncommon findings in addition to cysts. We found that approximately 80% of LAM patients, whether TSC-associated or sporadic, showed typical HRCT appearance with mild to severe cystic destruction. The remaining 20% displayed unusual profiles in cyst appearance as well as additional findings aside from cyst: the former includes large cyst, thickened walls, and irregularly shaped whereas the latter includes ground glass attenuation and diffuse noncalcified nodules. It is important to be aware of various radiologic findings that make HRCT cystic appearance atypical of LAM.

5-Hydroxymethylcytosine preferentially targets genes upregulated in isocitrate dehydrogenase 1 mutant high-grade glioma.

Gliomas demonstrate epigenetic dysregulation exemplified by the Glioma CpG Island Methylator Phenotype (G-CIMP) seen in IDH1 mutant tumors. 5-Hydroxymethylcytosine (5hmC) is implicated in glioma pathogenesis; however, its role in IDH1 mutant gliomas is incompletely understood. To characterize 5hmC in IDH1 mutant gliomas further, we examine 5hmC in a cohort of IDH1 mutant and wild-type high-grade gliomas (HGG) using a quantitative locus-specific approach. Regions demonstrating high 5hmC abundance and differentially hydroxymethylated regions (DHMR) enrich for enhancers implicated in glioma pathogenesis. Among these regions, IDH1 mutant tumors possess greater 5hmC compared to wild type. 5hmC contributes to overall methylation status of G-CIMP genes. 5hmC targeting gene body regions correlates significantly with increased gene expression. In particular, a strong correlation between increased 5hmC and increased gene expression is identified for genes highly expressed in the IDH1 mutant cohort. Overall, locus-specific gain of 5hmC targeting regulatory regions and associated with overexpressed genes suggests a significant role for 5hmC in IDH1 mutant HGG.

A Model of Lymphangioleiomyomatosis in a Three-Dimensional Culture System.

BACKGROUND: Lymphangioleiomyomatosis (LAM) is a tumor consisting of benign-looking neoplastic cells, but its wretched clinical outcome often resembles a malignant disease. LAM cell clusters (LCCs), unique microstructures commonly found in LAM-associated chylous effusion, are aggregates of LAM cells rimmed by lymphatic endothelium. LCCs seem to be crucial participants in the dissemination and progression of LAM. METHODS AND RESULTS: LCCs isolated from LAM-associated chylous effusion were embedded in a three-dimensional (3-D) culture gels, and then placed in a humidified CO2 incubator. During serial observations of their morphological changes, we found tube formations with lymphatic endothelial cells when LCCs settled side by side in 3-D gels. On the other hand, when LCCs were embedded separately enough to be isolated at their initial sites of settlement in the gels, each of LCCs gradually broke down, leaving a "cyst-like" hole after 7 days at the site where LCCs initially resided. Finally, we demonstrated that "cyst-like" hole formation in 3-D gels was inhibited with treatment with doxycycline or recombinant human VEGF receptor-3. CONCLUSIONS: We consider that our observation of this sequence in vitro illustrates how LCCs behave in vivo while enacting their important role in the progression of LAM. Our results indicate that the 3-D gel culture system for LCCs is a useful tool for exploring the effects of new therapeutic drugs under conditions when LCCs are constantly available.

Pneumothorax developing for the first time in a 73-year-old woman diagnosed with Birt-Hogg-Dubé syndrome.

Spontaneous pneumothorax in the elderly commonly occurs due to underlying pulmonary diseases, such as chronic obstructive pulmonary disease, interstitial lung disease, lung cancer, etc. A 73-year-old woman developed pneumothorax for the first time that was a clinical clue to a diagnosis of Birt-Hogg-Dubé syndrome (BHDS), an autosomal dominant condition characterized by fibrofolliculomas of the skin, renal tumors and multiple lung cysts predisposing to pneumothorax. Although BHDS patients frequently develop pneumothorax during their twenties to forties, the present case indicates that BHDS should be considered as an underlying cause of pneumothorax in the elderly with undisclosed BHDS.