Glycoprotein non-metastatic melanoma protein B promotes tumor growth and is a biomarker for lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare, progressive cystic lung disease affecting almost exclusively female-sexed individuals. The cysts represent regions of lung destruction caused by smooth muscle tumors containing mutations in one of the two tuberous sclerosis (TSC) genes. mTORC1 inhibition slows but does not stop LAM advancement. Furthermore, monitoring disease progression is hindered by insufficient biomarkers. Therefore, new treatment options and biomarkers are needed. LAM cells express melanocytic markers, including glycoprotein non-metastatic melanoma protein B (GPNMB). The function of GPNMB in LAM is currently unknown; however, GPNMB's unique cell surface expression on tumor versus benign cells makes GPNMB a potential therapeutic target, and persistent release of its extracellular ectodomain suggests potential as a serum biomarker. Here, we establish that GPNMB expression is dependent on mTORC1 signaling, and that GPNMB regulates TSC2-null tumor cell invasion in vitro. Further, we demonstrate that GPNMB enhances TSC2-null xenograft tumor growth in vivo, and that ectodomain release is required for this xenograft growth. We also show that GPNMB's ectodomain is released from the cell surface of TSC2-null cells by proteases ADAM10 and 17, and we identify the protease target sequence on GPNMB. Finally, we demonstrate that GPNMB's ectodomain is present at higher levels in LAM patient serum compared to healthy controls and that ectodomain levels decrease with mTORC1 inhibition, making it a potential LAM biomarker.

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.

Case report: If it is not asthma-think of lymphangioleiomyomatosis in younger female patients

Lymphangioleiomyomatosis (LAM) is a rare lung disease predominantly affecting women, and it is characterized by the proliferation of smooth muscle cells and cystic lung destruction. LAM diagnosis is challenging due to varied clinical presentations and resemblance to common conditions such as asthma. We present two female cases where LAM was initially misdiagnosed. Case 1 describes a woman treated for asthma-chronic obstruction pulmonary disease overlap syndrome, while also undergoing treatment with vascular endothelial growth factor (VEGF) inhibitor pazopanib for a retroperitoneal leiomyoma, the latter responding well to treatment. Due to progressive dyspnea, pazopanib-induced pneumonitis was suspected. High-resolution computed tomography (HRCT) showed changes compatible with LAM. A revision of biopsies showed that the leiomyoma was in fact a lymphangioleiomyoma, and VEGF-D was increased. Both supported the LAM diagnosis. Treatment with mTORC1 inhibitor sirolimus was initiated. Case 2 describes a woman, who in resemblance with the woman from case 2 was also suspected of asthma and did not respond clinically to treatment. After several years, HRCT was performed and suspicion of LAM was raised. Transbronchial biopsy and later, an increased VEGF-D supported the LAM diagnosis. As in case 1, treatment with sirolimus was initiated. These cases underscore the importance of reevaluating diagnoses when treatments fail to yield expected results. Improved awareness and early detection of LAM can enhance patient outcomes and life quality. Early LAM diagnosis is vital as mTORC1 inhibitors such as sirolimus can prevent further decline in lung function. Notably, the response of case 2 to pazopanib treatment supports suggestions of its potential as a second-line therapy for perivascular epithelioid cell tumors (PEComas), including LAM.

A chylothorax in a young woman: The difficulties of medical management

Lymphangioleiomyomatosis is a rare pulmonary disease affecting women of childbearing age. Whilst chylothorax is a well-recognized complication of the condition, management strategies aren't well-defined, have low success rates and are often only available at tertiary or specialist centres. We describe a case of a young woman referred to pleural clinic with a chylous effusion found to be secondary to lymphangioleiomyomatosis. Initial medical management was unsuccessful and recurrent drainages caused significant complications. Remission was ultimately achieved with a combination of mTOR inhibitors and interventional radiology techniques.

Lymphangioleiomyomatosis with Tuberous Sclerosis Complex-A Case Study

Lymphangioleiomyomatosis (LAM) is characterized by lung cysts that cause lung deterioration, changes in the lymphatic system, and tumors in the kidneys. It mainly affects women of reproductive age and is a progressive disease. LAM can occur as an isolated disease or coexist with tuberous sclerosis (TSC). The source of LAM cells is unknown. Patients with confirmed LAM should be treated with an mTOR inhibitor, sirolimus, or everolimus. We present a case of LAM with TSC in a patient whose symptoms, including those in the lymph nodes and chyaloperitoneum, mainly concern the abdominal cavity.

Lymphangioleiomyomatosis With Atypical Presentation Following Pneumothorax: A Case Report

Lymphangioleiomyomatosis (LAM) is a rare systemic disease that typically presents like cystic lung disease. High-resolution computed tomography (CT) is the recommended imaging technique, with cysts being the hallmark: typically multiple, well-circumscribed, thin-walled, with a variable diameter (usually <2 cm) and widespread in distribution. The gold standard for diagnosis is a biopsy. LAM should be considered in the differential diagnosis of cystic lung diseases. The authors report a case of LAM presenting with a pneumothorax, which due to its atypical imaging characteristics, mimicked another uncommon cystic disease. A multidisciplinary approach is crucial when dealing with presentations of rare diseases.

Spontaneous Pneumothorax in a Young Female With Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare disorder of abnormal proliferation of smooth muscle-like cells which results in the formation of thin-walled cysts and progressive lung destruction. It commonly presents with progressive dyspnea that is often associated with a history of pneumothorax or chylothorax particularly among females of reproductive age. In this report, we present a case of hydropneumothorax as the initial presentation of LAM in a 33-year-old woman, a rather rare presentation. We also discuss the pathogenetic mechanisms, the diagnosis, and treatment strategies using mTOR inhibitors like sirolimus.

Lymphangioleiomyomatosis: where endocrinology, immunology and tumor biology meet

Abstract

Lymphangioleiomyomatosis (LAM) is a cystic lung disease found almost exclusively in genetic females and caused by small clusters of smooth muscle cell tumors containing mutations in one of the two tuberous sclerosis genes (TSC1 or TSC2). Significant advances over the past 2-3 decades have allowed researchers and clinicians to more clearly understand the pathophysiology of LAM, and therefore better diagnose and treat patients with this disease. Despite substantial progress, only one proven treatment for LAM is used in practice: mechanistic target of rapamycin complex 1 (mTORC1) inhibition with medications such as sirolimus. While mTORC1 inhibition effectively slows LAM progression in many patients, it is not curative, is not effective in all patients, and can be associated with significant side effects. Furthermore, the presence of established and accurate biomarkers to follow LAM progression is limited. That said, discovering additional diagnostic and treatment options for LAM is paramount. This review will describe recent advances in LAM research, centering on the origin and nature of the LAM cell, the role of estrogen in LAM progression, the significance of melanocytic marker expression in LAM cells, and the potential roles of the microenvironment in promoting LAM tumor growth. By appreciating these processes in more detail, researchers and caregivers may be afforded novel approaches to aid in the treatment of patients with LAM.

Tissue-Engineered Disease Modeling of Lymphangioleiomyomatosis Exposes a Therapeutic Vulnerability to HDAC Inhibition

Lymphangioleiomyomatosis (LAM) is a rare disease involving cystic lung destruction by invasive LAM cells. These cells harbor loss-of-function mutations in TSC2, conferring hyperactive mTORC1 signaling. Here, tissue engineering tools are employed to model LAM and identify new therapeutic candidates. Biomimetic hydrogel culture of LAM cells is found to recapitulate the molecular and phenotypic characteristics of human disease more faithfully than culture on plastic. A 3D drug screen is conducted, identifying histone deacetylase (HDAC) inhibitors as anti-invasive agents that are also selectively cytotoxic toward TSC2-/- cells. The anti-invasive effects of HDAC inhibitors are independent of genotype, while selective cell death is mTORC1-dependent and mediated by apoptosis. Genotype-selective cytotoxicity is seen exclusively in hydrogel culture due to potentiated differential mTORC1 signaling, a feature that is abrogated in cell culture on plastic. Importantly, HDAC inhibitors block invasion and selectively eradicate LAM cells in vivo in zebrafish xenografts. These findings demonstrate that tissue-engineered disease modeling exposes a physiologically relevant therapeutic vulnerability that would be otherwise missed by conventional culture on plastic. This work substantiates HDAC inhibitors as possible therapeutic candidates for the treatment of patients with LAM and requires further study.

Glutaredoxin-1 promotes lymphangioleiomyomatosis progression through inhibiting Bim-mediated apoptosis via COX2/PGE2/ERK pathway

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a female-predominant interstitial lung disease, characterized by progressive cyst formation and respiratory failure. Clinical treatment with the mTORC1 inhibitor rapamycin could relieve partially the respiratory symptoms, but not curative. It is urgent to illustrate the fundamental mechanisms of TSC2 deficiency to the development of LAM, especially mTORC1-independent mechanisms. Glutaredoxin-1 (Glrx), an essential glutathione (GSH)-dependent thiol-oxidoreductase, maintains redox homeostasis and participates in various processes via controlling protein GSH adducts. Redox signalling through protein GSH adducts in LAM remains largely elusive. Here, we demonstrate the underlying mechanism of Glrx in the pathogenesis of LAM.

METHODS

1. Abnormal Glrx expression in various kinds of human malignancies was identified by the GEPIA tumour database, and the expression of Glrx in LAM-derived cells was detected by real-time quantitative reverse transcription (RT-qPCR) and immunoblot. 2. Stable Glrx knockdown cell line was established to evaluate cellular impact. 3. Cell viability was determined by CCK8 assay. 4. Apoptotic cell number and intracellular reactive oxygen species (ROS) level were quantified by flow cytometry. 5. Cox2 expression and PGE2 production were detected to clarify the mechanism of Bim expression modulated by Glrx. 6. S-glutathionylated p65 was enriched and detected by immunoprecipitation and the direct regulation of Glrx on p65 was determined. 7. The xenograft animal model was established and photon flux was analyzed using IVIS Spectrum.

RESULTS

In LAM, TSC2 negatively regulated abnormal Glrx expression and activation in a mTORC1-independent manner. Knockdown of Glrx increased the expression of Bim and the accumulation of ROS, together with elevated S-glutathionylated proteins, contributing to the induction of apoptotic cell death and inhibited cell proliferation. Knockdown of Glrx in TSC2-deficient LAM cells increased GSH adducts on nuclear factor-kappa B p65, which contributed to a decrease in the expression of Cox2 and the biosynthesis of PGE2. Inhibition of PGE2 metabolism attenuated phosphorylation of ERK, which led to the accumulation of Bim, due to the imbalance of its phosphorylation and proteasome degradation. In xenograft tumour models, knockdown of Glrx in TSC2-deficient LAM cells inhibited tumour growth and increased tumour cell apoptosis.

CONCLUSIONS

Collectively, we provide a novel redox-dependent mechanism in the pathogenesis of LAM and propose that Glrx may be a beneficial strategy for the treatment of LAM or other TSC-related diseases.

Exploring bilateral pneumothorax leading to a rare diagnosis in a young lady

Bilateral pneumothorax is a rare occurrence and vigilant clinical examination is mandatory to suspect that during the presentation. This case illustrates a young lady presented with bilateral pneumothorax, new identification of lung cysts and chylous pleural effusion leading to diagnosis of lymphangioleiomyomatosis.

The benefit of indwelling pleural catheter with ambulatory pneumothorax device and autologous blood patch pleurodesis in lymphangioleiomyomatosis with persistent air leak

We report a 35-year-old woman who presented with dyspnoea and chest pain for 1 week. High-resolution computed tomography (HRCT) thorax revealed bilateral pneumothoraces with diffuse lung cysts. Bilateral intercostal chest tubes were inserted, and there was a persistent air leak (PAL) bilaterally. We performed an autologous blood patch pleurodesis (ABPP) for the left PAL. For the right PAL, she underwent a successful right video-assisted thoracic (VATS) surgery, wedge biopsy, and surgical pleurodesis. Histopathology examination confirmed the diagnosis of lymphangioleiomyomatosis (LAM). The left pneumothorax recurred. An indwelling pleural catheter (Rocket® IPC™; Rocket Medical plc; WASHINGTON) was inserted and the patient was discharged after 1 day with an atrium pneumostat (Pneumostat™; Atrium Medical Corporation, Hudson, NH, USA) chest drain valve. The patient was initiated on Sirolimus 2 mg daily. The left PAL resolved at 6 weeks. This case highlights the benefit of IPC with an ambulatory pneumothorax device in a patient with LAM with PAL.

Lymphangioleiomyomatosis: circulating levels of FGF23 and pulmonary diffusion

OBJECTIVE

Lymphangioleiomyomatosis (LAM) is a rare, destructive disease of the lungs with a limited number of determinants of disease activity, which are a critical need for clinical trials. FGF23 has been implicated in several chronic pulmonary diseases. We aimed to determine the association between serum FGF23 levels and pulmonary function in a cohort of patients with LAM.

METHODS

This was a descriptive single-center study in which subjects with LAM and controls with unreported lung disease were recruited. Serum FGF23 levels were measured in all subjects. Clinical data, including pulmonary function testing, were retrospectively obtained from electronic medical records of LAM subjects. Associations between FGF23 levels and clinical features of LAM were explored via nonparametric hypothesis testing.

RESULTS

The sample comprised 37 subjects with LAM and 16 controls. FGF23 levels were higher in the LAM group than in the control group. In the LAM group, FGF23 levels above the optimal cutoff point distinguished 33% of the subjects who had nondiagnostic VEGF-D levels. Lower FGF23 levels were associated with impaired DLCO (p = 0.04), particularly for those with isolated diffusion impairment with no other spirometric abnormalities (p = 0.04).

CONCLUSIONS

Our results suggest that FGF23 is associated with pulmonary diffusion abnormalities in LAM patients and elicit novel mechanisms of LAM pathogenesis. FGF23 alone or in combination with other molecules needs to be validated as a biomarker of LAM activity in future clinical research.

Systematic Review of Lymphangioleiomyomatosis Outcomes in Pregnancy and a Proposed Management Guideline

OBJECTIVE

 Lymphangioleiomyomatosis (LAM) is a rare, multisystem disease that primarily affects women of reproductive age. Disease progression has been linked to estrogen exposure, and as such many patients are advised to avoid pregnancy. Data are limited regarding the interaction between LAM and pregnancy, and as such we performed a systematic review to summarize available literature reporting outcomes of pregnancies complicated by maternal LAM.

STUDY DESIGN

 This was a systematic review including randomized controlled trials, observational studies, systematic reviews, case reports, clinical practice guidelines, and quality improvement studies with full-text manuscripts or abstracts in the English language with primary data on pregnant or postpartum patients with LAM. The primary outcome was maternal outcomes during pregnancy as well as pregnancy outcomes. Secondary outcomes were neonatal outcomes and long-term maternal outcomes. This search occurred in July 2020 and included MEDLINE, Scopus, clinicaltrials.gov, Embase, and Cochrane Central. Risk of bias was ascertained using the Newcastle-Ottawa Scale. Our systematic review was registered with PROSPERO as protocol number CRD 42020191402.

RESULTS

 A total of 175 publications were identified in our initial search; ultimately 31 studies were included. Six (19%) studies were retrospective cohort studies and 25 (81%) studies were case reports. Patients diagnosed during pregnancy had worse pregnancy outcomes compared to those diagnosed with LAM prior to pregnancy. Multiple studies reported a significant risk of pneumothoraces during pregnancy. Other significant risks included preterm delivery, chylothoraces, and pulmonary function deterioration. A proposed strategy for preconception counseling and antenatal management is provided.

CONCLUSION

 Patients diagnosed with LAM during pregnancy generally experience worse outcomes including recurrent pneumothoraces and preterm delivery as compared to patients with a LAM diagnosis prior to pregnancy. Given that there are limited studies available, and that the majority are low-quality evidence and subject to bias, further investigation of the interaction between LAM and pregnancy is warranted to guide patient care and counseling.

KEY POINTS

· Data are limited on the effects of lymphangioleiomyomatosis on pregnancy outcomes.. · We performed a systematic review to summarize pregnancy outcomes complicated by LAM.. · Patients diagnosed with LAM during pregnancy experience worse outcomes..

Estradiol Augments Tumor-Induced Neutrophil Production to Promote Tumor Cell Actions in Lymphangioleiomyomatosis Models

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease caused by smooth muscle cell-like tumors containing tuberous sclerosis (TSC) gene mutations and found almost exclusively in females. Patient studies suggest LAM progression is estrogen dependent, an observation supported by in vivo mouse models. However, in vitro data using TSC-null cell lines demonstrate modest estradiol (E2) responses, suggesting E2 effects in vivo may involve pathways independent of direct tumor stimulation. We previously reported tumor-dependent neutrophil expansion and promotion of TSC2-null tumor growth in an E2-sensitive LAM mouse model. We therefore hypothesized that E2 stimulates tumor growth in part by promoting neutrophil production. Here we report that E2-enhanced lung colonization of TSC2-null cells is indeed dependent on neutrophils. We demonstrate that E2 induces granulopoiesis via estrogen receptor α in male and female bone marrow cultures. With our novel TSC2-null mouse myometrial cell line, we show that factors released from these cells drive E2-sensitive neutrophil production. Last, we analyzed single-cell RNA sequencing data from LAM patients and demonstrate the presence of tumor-activated neutrophils. Our data suggest a powerful positive feedback loop whereby E2 and tumor factors induce neutrophil expansion, which in turn intensifies tumor growth and production of neutrophil-stimulating factors, resulting in continued TSC2-null tumor growth.

Long-term volume reduction in renal angiomyolipomas embolized by gelatin sponge particles with or without supplementary microcoil embolization

OBJECTIVE

To examine the effect of supplementary microcoil embolization on the long-term progression of angiomyolipomas embolized using gelatin sponge particles (GSPs).

METHODS

This retrospective study included 29 unruptured angiomyolipomas in 25 patients, treated by complete embolization and radiological follow-up for ≥3 years. Embolization was performed using GSPs and supplementary microcoils. Supplementary microcoil embolization affecting >90% of the tumor vasculature was defined as microcoil embolization. Tumor volumes pre- and post-embolization were measured by computed tomography or magnetic resonance imaging.

RESULTS

Eleven tumors received supplementary microcoil embolization and 18 tumors did not. Relative tumor reduction at >3 years post-embolization was significantly greater in tumors with supplementary microcoil embolization compared with tumors without microcoil embolization (81% ± 8% vs. 55% ± 29%). Fourteen tumors tended to show volume regrowth and the volumes of the remaining 15 tumors continued to decline. Tumors without supplementary microcoil embolization were more likely to show volume regrowth during follow-up than tumors with supplementary microcoil embolization (78% vs. 0%, respectively).

CONCLUSIONS

When using a combination of GSPs and microcoils, supplementary microcoil embolization should be carried out to ensure maximum long-term reduction in tumor volume in patients with angiomyolipomas.

Lymphangioleiomyomatosis in lymph node cytology: Another "Floating Island" to visit

Lymphangioleiomyomatosis (LAM) is a rare disease with variable presentations. The neoplastic cells in LAM demonstrate a unique and diagnostically important "myomelanocytic" phenotype. Cytologic reports of LAM are infrequent and have not in the past emphasized the floating island pattern in which circumscribed aggregates of lesional cells are rimmed by appliques of flattened endothelium. This case illustrates the cytology of LAM and emphasizes that the floating island cytoarchitectural pattern more classically associated with entities such as hepatocellular carcinomas may be seen in cytological preparations of LAM at unanticipated body sites.

Determinants of Progression and Mortality in Lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis is a progressive diffuse cystic lung disease with approximately 85% survival at 10 years. The determinants of disease progression and mortality after the introduction of sirolimus therapy and vascular endothelial growth factor D (VEGF-D) as a biomarker have not been well defined.

RESEARCH QUESTION

Which factors, including VEGF-D and sirolimus therapy, influence disease progression and survival prognosis in patients with lymphangioleiomyomatosis?

STUDY DESIGN AND METHODS

The progression dataset and the survival dataset included 282 and 574 patients, respectively, from Peking Union Medical College Hospital, Beijing, China. A mixed-effects model was used to compute the rate of decline in FEV₁, and generalized linear models were used to identify variables affecting FEV₁ decline. A Cox proportional hazards model was used to explore the association between clinical variables and the outcomes of death or lung transplantation in patients with lymphangioleiomyomatosis.

RESULTS

VEGF-D levels and sirolimus treatment were associated with FEV₁ changes and survival prognosis. Compared with patients with VEGF-D of < 800 pg/mL at baseline, patients with VEGF-D of ≥ 800 pg/mL lost FEV₁ faster (SE, -38.86 mL/y; 95% CI, -73.90 to -3.82 mL/y; P = .031). The 8-year cumulative survival rates of patients with VEGF-D of ≥ 2,000 pg/mL and < 2,000 pg/mL were 82.9% and 95.1%, respectively (P = .014). The generalized linear regression model also demonstrated the benefit of delaying the decline of FEV₁ by 65.56 mL/y (95% CI, 29.06-102.06 mL/y) in patients treated with sirolimus compared with those without sirolimus (P < .001). The 8-year risk of death was reduced by 85.1% (hazard ratio, 0.149; 95% CI, 0.075-0.299) after sirolimus treatment. After inverse treatment probability weighting, the risks of death in the sirolimus group were reduced by 85.6%. CT scan results of grade III severity were associated with worse progression than results of grades I or II severity. Patients with baseline FEV₁ of 70% predicted or St. George's Respiratory Questionnaire Symptoms domain 50 or higher predicted a higher risk of worse survival.

INTERPRETATION

Serum VEGF-D levels, a biomarker of lymphangioleiomyomatosis, are associated with disease progression and survival. Sirolimus therapy is associated with slower disease progression and better survival in patients with lymphangioleiomyomatosis.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT03193892; URL: www.

CLINICALTRIALS

gov.

Late diagnosis of tuberous sclerosis complex in a 40-year-old female presenting with abdominal pain: a case report

Tuberous sclerosis (TS) is a rare autosomal-dominant neurocutaneous disorder that is characterized by hamartomas affecting a variety of organs, including the brain, heart, kidneys, skin, lungs, and liver. TS can emerge in a wide variety of clinical and phenotypic forms at any age, all with varying degrees of severity, and is brought on by mutations in the tumor suppressor genes TSC1 or TSC2. This case report is about a 40-year-old female with facial angiofibromas and abdominal symptoms who was referred to the radiology department of our hospital for ultrasonography of the abdomen, which revealed echogenic mass lesions/angiomyolipomas in bilateral kidneys. Subsequent contrast-enhanced computed tomography of the abdomen revealed large fat-attenuating mass lesions which were confirmed to be angiomyolipomas. Similarly, noncontrast computed tomography of the head showed multiple calcified nodules/tubers in subependymal, subcortical, and cortical locations of the brain. High-resolution computed tomography of the chest showed multiple cystic lesions in bilateral lungs suggestive of lymphangioleiomyomatosis. The aim of this case report is to highlight the late presentation of tuberous sclerosis complex.

Lymphangioleiomyomatosis: Searching for potential biomarkers

Background

Vascular endothelial growth factor-D (VEGF-D) is the most commonly used biomarker for diagnosing lymphangioleiomyomatosis (LAM). However, lung biopsy is often necessary as well; therefore, defining new biomarkers for LAM is crucial. The aim of this study was to describe the diagnostic accuracy of a variety of biomarkers.

Methods

We assessed 13 analytes in serum related to extracellular matrix remodeling, lymphatic involvement and angiogenesis in a cohort of patients with LAM, comparing them with patients with other cystic lung diseases (OCLD) and healthy women. A scoring method based on the cut-point of each VEGF-D and metalloproteinase-2 (MMP-2) was used to evaluate the diagnostic performance of the marker combination.

Results

A total of 97 subjects were recruited: 59 (61%) LAM patients, 18 (19%) OCLD patients, and 20 (20%) healthy female controls. MMP-2 was the only extracellular matrix remodeling biomarker able to differentiate LAM patients from OCLD and healthy patients. Serum MMP-2 was higher in LAM patients [median 578 (465-832) ng/ml] than in patients with OCLD and healthy controls [medians 360 (314-546) and 427 (365-513) ng/ml, respectively (p < 0.0001)]. The area under ROC curve (AUC) of MMP-2 was 0.785 and that of VEGF-D 0.815 (p = 0.6214). The sensitivity/specificity profiles of each biomarker (54/92% for MMP-2, 59/95% for VEGF-D) yielded a composite score (-6.36 + 0.0059 × VEGF-D + 0.0069 × MMP-2) with higher accuracy than each component alone (AUC 0.88 and sensitivity/specificity 79/87%).

Conclusion

Combining MMP-2 and VEGF-D may increase diagnostic accuracy for LAM.

Lymphangioleiomyomatosis: a metastatic lung disease

Lymphangioleiomyomatosis (LAM) is a rare disease affecting women, caused by somatic mutations in the TSC1 or TSC2 genes, and driven by estrogen. Similar to many cancers, it is metastatic, primarily to the lung. Despite its monogenetic nature, like many cancers, LAM is a heterogeneous disease. The cellular constituents of LAM are very diverse, including mesenchymal, epithelial, endothelial, and immune cells. LAM is characterized by dysregulation of many cell signaling pathways, distinct populations of LAM cells, and a rich microenvironment, in which the immune system appears to play an important role. This review delineates the heterogeneity of LAM and focuses on the metastatic features of LAM, the deregulated signaling mechanisms and the tumor microenvironment. Understanding the tumor-host interaction in LAM may provide insights into the development of new therapeutic strategies, which could be combinatorial or superlative to Sirolimus, the current U.S. Food and Drug Administration-approved treatment.

Spectrum of germline and somatic mitochondrial DNA variants in Tuberous Sclerosis Complex

Tuberous Sclerosis Complex (TSC) is caused by loss of function variants in either TSC1 or TSC2 and is characterized by broad phenotypic heterogeneity. Currently, there is limited knowledge regarding the role of the mitochondrial genome (mtDNA) in TSC pathogenesis. In this study, we aimed to determine the prevalence and spectrum of germline and somatic mtDNA variants in TSC and identify potential disease modifiers. Analysis of mtDNA amplicon massively parallel sequencing (aMPS) data, off-target mtDNA from whole-exome sequencing (WES), and/or qPCR, revealed mtDNA alterations in 270 diverse tissues (139 TSC-associated tumors and 131 normal tissue samples) from 199 patients and six healthy individuals. Correlation of clinical features to mtDNA variants and haplogroup analysis was done in 102 buccal swabs (age: 20-71 years). No correlation was found between clinical features and either mtDNA variants or haplogroups. No pathogenic variants were identified in the buccal swab samples. Using in silico analysis, we identified three predicted pathogenic variants in tumor samples: MT-ND4 (m.11742G>A, p. Cys328Tyr, VAF: 43%, kidney angiomyolipoma), MT-CYB (m.14775T>C, p. Leu10Pro, VAF: 43%, LAM abdominal tumor) and MT-CYB (m.15555C>T, p. Pro270Leu, VAF: 7%, renal cell carcinoma). Large deletions of the mitochondrial genome were not detected. Analysis of tumors from 23 patients with corresponding normal tissue did not reveal any recurrent tumor-associated somatic variants. The mtDNA/gDNA ratio between tumors and corresponding normal tissue was also unchanged. Overall, our findings demonstrate that the mitochondrial genome is highly stable across tissues and within TSC-associated tumors.

Dysregulated lipid metabolism in lymphangioleiomyomatosis pathogenesis as a paradigm of chronic lung diseases

A chronic inflammatory condition characterizes various lung diseases. Interestingly, a great contribution to inflammation is made by altered lipids metabolism, that can be caused by the deregulation of the mammalian target of rapamycin complex-1 (mTORC1) activity. There is evidence that one of mTOR downstream effectors, the sterol regulatory element-binding protein (SREBP), regulates the transcription of enzymes involved in the de novo fatty acid synthesis. Given its central role in cell metabolism, mTOR is involved in several biological processes. Among those, mTOR is a driver of senescence, a process that might contribute to the establishment of chronic lung disease because the characteristic irreversible inhibition of cell proliferation, associated to the acquisition of a pro-inflammatory senescence-associated secretory phenotype (SASP) supports the loss of lung parenchyma. The deregulation of mTORC1 is a hallmark of lymphangioleiomyomatosis (LAM), a rare pulmonary disease predominantly affecting women which causes cystic remodeling of the lung and progressive loss of lung function. LAM cells have senescent features and secrete SASP components, such as growth factors and pro-inflammatory molecules, like cancer cells. Using LAM as a paradigm of chronic and metastatic lung disease, here we review the published data that point out the role of dysregulated lipid metabolism in LAM pathogenesis. We will discuss lipids' role in the development and progression of the disease, to hypothesize novel LAM biomarkers and to propose the pharmacological regulation of lipids metabolism as an innovative approach for the treatment of the disease.

Generation of Pmel-dependent conditional and inducible Cre-driver mouse line for melanocytic-targeted gene manipulation

Conditional and inducible gene targeting using Cre/loxP-mediated recombination is a powerful reverse genetics approach used to study spatiotemporal gene functions in specified cell types. To enable temporal gene manipulation in the melanocyte lineage, we established a novel inducible Cre-driver mouse line by targeting an all-in-one tetracycline/doxycycline (Dox)-inducible Cre expression cassette into the Pmel locus (Pmel^{P2A-TetON3G-TRE3G-iCre} ), a gene locus preferentially expressed in pigment cells. By crossing these Cre-driver mice with a strong Cre-reporter mouse line, Gt(ROSA)26Sor^{tm9(CAG-tdTomato)Hze} , we show the effectiveness of the Pmel^{P2A-TetON3G-TRE3G-iCre} mouse line in facilitating Dox-inducible Cre/loxP recombination in a wide variety of pigment cell lineages including hair follicle melanocytes and their stem cells. Furthermore, to demonstrate proof of concept, we ablated Notch signaling postnatally in the Pmel^{P2A-TetON3G-TRE3G-iCre} mice. In agreement with the previously reported phenotype, induced ablation of Notch signaling in the melanocyte lineage resulted in premature hair graying, demonstrating the utility of the Pmel^{P2A-TetON3G-TRE3G-iCre} allele. Therefore, the Pmel^{P2A-TetON3G-TRE3G-iCre} mouse line is suitable for assessing gene functions in melanocytes using an in vivo inducible reverse genetics approach. Furthermore, we unexpectedly identified previously unrecognized PMEL-expressing cells in non-pigmentary organs in the mice, suggesting unanticipated functions of PMEL other than melanosome formation.

Lung transplantation for lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease, associated with respiratory symptoms of dyspnea and spontaneous pneumothorax, along with various extra-thoracic manifestations. Often a progressive disease, albeit slowly, patients can develop chronic and severe respiratory failure and require supplemental oxygen. Lung transplantation (LTX) can offer improved duration and quality of life for patients with end-stage lung disease due to LAM. There are several unique considerations for LTX in LAM patients, and disease-specific complications of LAM prior to LTX can affect management decisions. Furthermore, there are several possible post-transplant issues specific to LAM. In this review, we discuss evaluation and management, disease-specific complications (both pre- and post-transplant), and outcomes for LAM patients undergoing lung transplantation.

Pulmonary lymphangioleiomyomatosis and renal angiomyolipoma in a patient with systemic lupus erythematosus: A case report

BACKGROUND

The co-incidence of systemic lupus erythematosus (SLE) and tuberous sclerosis with pulmonary lymphangioleiomyomatosis (LAM) and renal angiomyolipoma (AML) is rare. In such patients, the rupture of renal AML may result in fatal circumstances, but this may be preventable.

METHODS

A 22-year-old Asian woman with SLE was admitted to our hospital with severe left-flank pain. Imaging studies showed the bilateral rupture of multiple renal AMLs.

RESULTS

The patient underwent emergency selective transcatheter embolization (TE) of the left renal artery. After TE and massive hydration, the patient complained of dyspnea and postembolization syndrome with fever. The chest computed tomography (CT) revealed pulmonary LAM, pulmonary edema with bilateral pleural effusions, and pneumonic consolidation. After the emergency procedure, the patient was treated with intravenous administration of antibiotics, diuretics, and nonsteroidal anti-inflammatory drugs for 10 days. The patient recovered favorably and was discharged 20 days after the treatment. She was diagnosed with renal AML and pulmonary LAM along with facial angiofibromas as well as tuberous sclerosis complex (TSC), although she had no TSC1 or TSC2 gene mutations.

CONCLUSION

Although rare, SLE may coexist with TSC, along with LAM and AML, with a risk of AML rupture. The activation of the mTOR signaling pathway is shared between SLE and TSC. Thus, in patients with SLE, clinicians should consider imaging studies, such as kidney sonography and chest CT, to screen for possible manifestation of AML and LAM.

Bioinformatics analysis of inflammation and oncology in pulmonary lymphangioleiomyomatosis

This study investigates the molecular markers and biological pathways of pulmonary lymphangioleiomyomatosis. We analyzed 2 gene expression profiles in the gene expression omnibus Gene Expression Omnibus database for normal lung tissue and lymphangioleiomyomatosis and identified differential expressed genes in pulmonary lymphangioleiomyomatosis. Ninety-one differentially expressed genes were identified, including 36 upregulated genes and 55 downregulated genes. Hub genes and pathogenic pathways associated with disease development were subsequently identified by enrichment analysis and protein-protein interaction network. Analysis showed that differential expressed genes are mainly involved in the biological behavior of tumor cell proliferation and invasion as well as the inflammatory response. We have identified 10 hub genes in the protein-protein interaction network. Hub genes play an important role in the proliferation and inflammatory response involved in tumor cell proliferation. This study deepens the understanding of lymphangioleiomyomatosis disease and provides a biological basis for further clinical diagnosis and treatment.

Prophylactic renal artery embolization before pregnancy in patients with lymphangioleiomyomatosis and renal angiomyolipoma

OBJECTIVE

Pregnant patients with lymphangioleiomyomatosis (LAM) and renal angiomyolipomas (AMLs) require care for both renal AMLs and pulmonary dysfunction because AMLs can grow and rupture during pregnancy, potentially causing hemorrhagic shock and fetal death. This study examined whether prophylactic transcatheter arterial embolization (TAE) could prevent the pregnancy-associated growth and rupture of renal AMLs in patients with LAM.

METHODS

This retrospective study included five women with 14 renal AMLs (initial diameter, ≥2 cm) first encountered between September 2010 and August 2015 who subsequently became pregnant. Seven tumors in five patients were embolized, and seven tumors in two patients were not treated. Changes in the volume of each tumor were evaluated.

RESULTS

Untreated tumors were much more likely to grow than embolized tumors both during pregnancy (100% vs. 0%) and at the first follow-up visit after delivery (100% vs. 14%). One untreated hypervascular tumor grew rapidly during pregnancy to 409% of the pretreatment volume. No tumor ruptured.

CONCLUSIONS

Prophylactic pre-pregnancy TAE decreased the growth and bleeding of renal AMLs during pregnancy in patients with LAM. TAE can be recommended for hypervascular tumors before pregnancy regardless of the size of the aneurysm.

Unusual case of uterine intravascular leiomyomatosis with lymphatic spread to pelvic lymph nodes

Intravascular leiomyomatosis is a rare disease characterized by extension of benign smooth muscle proliferation into uterine and pelvic vessels. The involved vessels are almost always veins and rarely lymphatics. Intraarterial growth has not been described. Intravascular leiomyomatosis can show different morphologic features that are commonly described in leiomyomas. The differential diagnosis includes endometrial stromal sarcoma, lymphangioleiomyomatosis and leiomyosarcoma. Immunohistochemistry is helpful to establish a correct diagnosis. The condition is histologically benign; however, these lesions can spread by the venous system into the inferior vena cava, heart, and lungs. Treatment of this condition is surgical. The spread of intravenous leiomyomatosis exclusively by uterine lymphatics to the pelvic lymph nodes has not been previously reported.

Soluble Immune-Related Proteins as New Candidate Serum Biomarkers for the Diagnosis and Progression of Lymphangioleiomyomatosis

Background

The goal of this study was to analyze serum from lymphangioleiomyomatosis (LAM) patients and healthy controls to identify novel biomarkers that could shed light on disease diagnosis and pathogenesis.

Methods

From April 2017 to October 2019, qualified serum samples were obtained to explore differences in 59 immune proteins between 67 LAM patients and 49 healthy controls by the Luminex method.

Results

We characterized 22 serum immune proteins that were differentially expressed in LAM patients compared with healthy people. Fifty-nine proteins were then classified into eight categories according to their biological function, and the results showed that LAM patients displayed significantly higher levels of growth factors (p = 0.006) and lower levels of costimulatory molecules (p = 0.008). LAG-3 was not only likely to have better predictive value than VEGF-D but also showed a significant difference between patients without elevated VEGF-D and healthy people. IL-18 was positively correlated with lung function and six-minute walk test (6MWT) distance and negatively correlated with St. George’s Respiratory Questionnaire (SGRQ) score and pulmonary artery systolic pressure (PASP), which suggested that IL-18 was related to disease severity. PD-1 was significantly different between patients with pneumothorax and/or chylothorax and those without complications.

Conclusion

We performed a large-scale serum immune factor analysis of LAM. Our study provides evidence that LAG-3 may be a novel candidate serum biomarker for the diagnosis of LAM. Future independent validation in prospective studies is warranted.

Lung-selective mRNA delivery of synthetic lipid nanoparticles for the treatment of pulmonary lymphangioleiomyomatosis

Safe and efficacious systemic delivery of messenger RNA (mRNA) to specific organs and cells in vivo remains the major challenge in the development of mRNA-based therapeutics. Targeting of systemically administered lipid nanoparticles (LNPs) coformulated with mRNA has largely been confined to the liver and spleen. Using a library screening approach, we identified that N-series LNPs (containing an amide bond in the tail) are capable of selectively delivering mRNA to the mouse lung, in contrast to our previous discovery that O-series LNPs (containing an ester bond in the tail) that tend to deliver mRNA to the liver. We analyzed the protein corona on the liver- and lung-targeted LNPs using liquid chromatography-mass spectrometry and identified a group of unique plasma proteins specifically absorbed onto the surface that may contribute to the targetability of these LNPs. Different pulmonary cell types can also be targeted by simply tuning the headgroup structure of N-series LNPs. Importantly, we demonstrate here the success of LNP-based RNA therapy in a preclinical model of lymphangioleiomyomatosis (LAM), a destructive lung disease caused by loss-of-function mutations in the Tsc2 gene. Our lung-targeting LNP exhibited highly efficient delivery of the mouse tuberous sclerosis complex 2 (Tsc2) mRNA for the restoration of TSC2 tumor suppressor in tumor and achieved remarkable therapeutic effect in reducing tumor burden. This research establishes mRNA LNPs as a promising therapeutic intervention for the treatment of LAM.

Cross talk between LAM cells and fibroblasts may influence alveolar epithelial cell behavior in lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a female-specific cystic lung disease in which tuberous sclerosis complex 2 (TSC2)-deficient LAM cells, LAM-associated fibroblasts (LAFs), and other cell types infiltrate the lungs. LAM lesions can be associated with type II alveolar epithelial (AT2) cells. We hypothesized that the behavior of AT2 cells in LAM is influenced locally by LAFs. We tested this hypothesis in the patient samples and in vitro. In human LAM lung, nodular AT2 cells show enhanced proliferation when compared with parenchymal AT2 cells, demonstrated by increased Ki67 expression. Furthermore, nodular AT2 cells express proteins associated with epithelial activation in other disease states including matrix metalloproteinase 7, and fibroblast growth factor 7 (FGF7). In vitro, LAF-conditioned medium is mitogenic and positively chemotactic for epithelial cells, increases the rate of epithelial repair, and protects against apoptosis. In vitro, LAM patient-derived TSC2 null cells cocultured with LAFs upregulate LAF expression of the epithelial chemokine and mitogen FGF7, a potential mediator of fibroblast-epithelial cross talk, in a mechanistic target of rapamycin (mTOR)-dependent manner. In a novel in vitro model of LAM, ex vivo cultured LAM lung-derived microtissues promote both epithelial migration and adhesion. Our findings suggest that AT2 cells in LAM display a proliferative, activated phenotype and fibroblast accumulation following LAM cell infiltration into the parenchyma contributes to this change in AT2 cell behavior. Fibroblast-derived FGF7 may contribute to the cross talk between LAFs and hyperplastic epithelium in vivo, but does not appear to be the main driver of the effects of LAFs on epithelial cells in vitro.

Leiomyomatosis-like lymphangioleiomyomatosis: A case report of the colonic manifestation of tuberous sclerosis

INTRODUCTION

Tuberous sclerosis complex is an inherited multisystemic disorder with manifestations in various organ systems as a result of a mutation of 1 of 2 tumor suppressor genes, tuberous sclerosis complex-1 or tuberous sclerosis complex-2. Perivascular epithelioid cell tumors have been shown to be associated with these gene mutations and include a variety of tumors such as angiomyolipomas and lymphangioleiomyomatosis.

PATIENT CONCERNS

In this report, we present a case of a 28-year-old woman presenting with symptoms of severe abdominal pain and nausea with a medical history of cardiac rhabdomyoma, adenoma sebaceum, Ash leaf spots, bilateral renal angiomyolipomas, and retinal hamartoma, which are manifestations of tuberous sclerosis complex. The patient was operated twice for colonic perforations in the rectosigmoid and ileocecal regions where the pathologic examination revealed multiple tumoral lesions in both specimens.

DIAGNOSIS

The tumor consisted of a myomatous component where the nodules were composed of spindle cells with fascicular array, and a lymphangiomatous component where epithelioid cells could be observed. Immunohistochemically, smooth muscle markers (desmin and SMA) were positive and the epithelioid component showed HMB-45 positivity. A diagnosis of leiomyomatosis-like lymphangioleiomyomatosis was established due to its morphological and immunohistochemical features, the presence of the tumor in multiple foci, and widespread lymphovascular invasion.

INTERVENTIONS

The patient had a perforation in her bowel twice during the hospital stay and underwent Hartmann operation and ileocecal resection in 2 different surgical operations.

OUTCOMES

After the second operation the patient developed fever and was diagnosed with SARS-CoV-2 infection. No other complication was observed during her stay and the patient's follow-up was unremarkable.

CONCLUSION

Perivascular epithelioid cell tumors are associated with tuberous sclerosis and can rarely appear in the colon. Therefore, lymphangioleiomyomatosis should be in the differential diagnosis in a tuberous sclerosis patient presenting with a colonic tumor.

Recurrent pneumothoraces with diffuse small ground-glass and solid nodules

Multifocal micronodular pneumocyte hyperplasia (MMPH) is the lesser known pulmonary manifestation of tuberous sclerosis. It manifests radiologically as diffuse small ground-glass and solid nodules. Accurate diagnosis is essential as it can be mistaken for miliary tuberculosis or malignant lesions which necessitates specific treatment. Constellation of radiological features such as multicentric disease at onset and stability over time can help to distinguish MMPH from its differentials. Histologically, MMPH is characterized by hamartomatous proliferation of type II pneumocytes with a lack of high nuclear to cytoplasmic ratio. MMPH confers a benign prognosis unlike its differentials. Therefore, accurate diagnosis is paramount in ensuring appropriate care is delivered. Here, we describe the radiological and histological features of MMPH in a patient with genetically proven tuberous sclerosis complex and co-existing lymphangioleiomyomatosis.

A rare lung disease diagnosed by CT in a young pregnant woman

Lymphangioleiomyomatosis (LAM) is an unusual lung disease which can be diagnosed by its characteristic appearance on a high-resolution CT, and may not always require a biopsy.

Interleukin-6 mediates PSAT1 expression and serine metabolism in TSC2-deficient cells

Tuberous sclerosis complex (TSC) and lymphangioleiomyomatosis (LAM) are caused by aberrant mechanistic Target of Rapamycin Complex 1 (mTORC1) activation due to loss of either TSC1 or TSC2 Cytokine profiling of TSC2-deficient LAM patient-derived cells revealed striking up-regulation of Interleukin-6 (IL-6). LAM patient plasma contained increased circulating IL-6 compared with healthy controls, and TSC2-deficient cells showed up-regulation of IL-6 transcription and secretion compared to wild-type cells. IL-6 blockade repressed the proliferation and migration of TSC2-deficient cells and reduced oxygen consumption and extracellular acidification. U-¹³C glucose tracing revealed that IL-6 knockout reduced 3-phosphoserine and serine production in TSC2-deficient cells, implicating IL-6 in de novo serine metabolism. IL-6 knockout reduced expression of phosphoserine aminotransferase 1 (PSAT1), an essential enzyme in serine biosynthesis. Importantly, recombinant IL-6 treatment rescued PSAT1 expression in the TSC2-deficient, IL-6 knockout clones selectively and had no effect on wild-type cells. Treatment with anti-IL-6 (αIL-6) antibody similarly reduced cell proliferation and migration and reduced renal tumors in Tsc2 ^+/- mice while reducing PSAT1 expression. These data reveal a mechanism through which IL-6 regulates serine biosynthesis, with potential relevance to the therapy of tumors with mTORC1 hyperactivity.

Histamine signaling and metabolism identify potential biomarkers and therapies for lymphangioleiomyomatosis

Inhibition of mTOR is the standard of care for lymphangioleiomyomatosis (LAM). However, this therapy has variable tolerability and some patients show progressive decline of lung function despite treatment. LAM diagnosis and monitoring can also be challenging due to the heterogeneity of symptoms and insufficiency of non-invasive tests. Here, we propose monoamine-derived biomarkers that provide preclinical evidence for novel therapeutic approaches. The major histamine-derived metabolite methylimidazoleacetic acid (MIAA) is relatively more abundant in LAM plasma, and MIAA values are independent of VEGF-D. Higher levels of histamine are associated with poorer lung function and greater disease burden. Molecular and cellular analyses, and metabolic profiling confirmed active histamine signaling and metabolism. LAM tumorigenesis is reduced using approved drugs targeting monoamine oxidases A/B (clorgyline and rasagiline) or histamine H1 receptor (loratadine), and loratadine synergizes with rapamycin. Depletion of Maoa or Hrh1 expression, and administration of an L-histidine analog, or a low L-histidine diet, also reduce LAM tumorigenesis. These findings extend our knowledge of LAM biology and suggest possible ways of improving disease management.

Efficacy of Sirolimus Treatment in PEComa-10 Years of Practice Perspective

Perivascular epithelioid cell tumors (PEComa) represent a family of rare mesenchymal tumors resultant from deregulation in mTOR pathway activity. The aim of this study is to evaluate the long-term efficacy of targeted PEComa treatment. We reviewed all consecutive patients with PEComa who started systemic treatment with sirolimus in our reference sarcoma center between January 2011 and August 2020. Histopathology of PEComa was reviewed and confirmed in all cases by a designated sarcoma pathologist. Any surviving progression-free patients were censored at the last follow-up (31 March 2021). Survival curves were calculated according to Kaplan-Meier method and compared with the log-rank test or a Cox proportional hazard model. Fifteen (12 females and 3 males) consecutive PEComa patients were treated. The median age of patients treated systemically was 50 years. Median progression-free survival (PFS) was 4.9 months (95% CI: 3.8-NA) for first-line chemotherapy and was not reached (95% CI: 42.0-NA) for sirolimus as first-line therapy. There was one objective response (OR) in the chemotherapy group. The OR rate reached 73% (11/15 cases) for sirolimus regardless of the treatment line. All patients archived disease control. Three patients died due to disease progression after 55, 32, and 32 months since metastatic disease diagnosis. After a median follow-up of 55.7 (range: 3.2-220) months, the 5 yr OS was 65% (CI 95% 39-100). Our study is the largest single-institution report on PEComa systemic targeted therapy and fills the gap in the field of advanced PEComa care since the FDA/EMEA approval of sirolimus.

Sirolimus Suppresses Phosphorylation of Cofilin and Reduces Interstitial Septal Thickness in Sporadic Lymphangioleiomyomatosis

Sporadic lymphangioleiomyomatosis (S-LAM) is a rare lung disease characterized by the proliferation of smooth muscle-like LAM cells and progressive cystic destruction. Sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, has a proven efficacy in patients with LAM. However, the therapeutic mechanisms of sirolimus in LAM remain unclear. We aimed to evaluate sirolimus-related lung parenchymal changes and the potential effect in LAM cells and modulating pathological cystic destruction. Lung specimens were examined for histopathological changes by HMB45 staining and compared the LAM patients treated with and without sirolimus. We detected the overexpression of mTOR, HMB45, and phosphorylation of cofilin (p-cofilin) in LAM patients. Sirolimus showed efficacy in patients with LAM, who exhibited a reduced expression of mTOR and p-cofilin as well as reduced interstitial septal thickness. In addition, sirolimus suppresses mTOR and p-cofilin, thus suppressing the migration and proliferation of LAM cells isolated from the patient's lung tissue. This study demonstrates that interstitial septal thickness, as determined by histological structural analysis. Sirolimus effectively reduced the expression of p-cofilin and interstitial septal thickness, which may be a novel mechanism by sirolimus. Moreover, we develop a new method to isolate and culture the LAM cell, which can test the possibility of medication in vitro and impact this current study has on the LAM field. The development of approaches to interfere with mTOR-cofilin1-actin signaling may result in an option for S-LAM therapy.

Desaturation-Distance Ratio During Submaximal and Maximal Exercise Tests and Its Association With Lung Function Parameters in Patients With Lymphangioleiomyomatosis

Background: The desaturation-distance ratio (DDR), the ratio of the desaturation area to the distance walked, is a promising, reliable, and simple physiologic tool for functional evaluation in subjects with interstitial lung diseases. Lymphangioleiomyomatosis (LAM) is a rare neoplastic condition frequently associated with exercise impairment. However, DDR has rarely been evaluated in patients with LAM. Objectives: To assess DDR during maximal and submaximal exercises and evaluate whether DDR can be predicted using lung function parameters. Methods: A cross-sectional study was conducted in a cohort of women with LAM. The 6-min walking test (6MWT) and the incremental shuttle walking test (ISWT) were performed, and DDR was obtained from both tests. The functional parameters were assessed at rest using spirometry and body plethysmography. The pulmonary function variables predictive of DDR were also assessed. Results: Forty patients were included in this study. The mean age was 46 ± 10 years. Airway obstruction, reduced DLCO, and air trapping were found in 60, 57, and 15% of patients, respectively. The distance walked and the DDR for the 6MWT and ISWT were, respectively, 517 ± 65 and 443 ± 127 m; and 6.6 (3.8-10.9) and 8.3 (6.2-12.7). FEV1 (airway obstruction) and reduced DLCO and RV/TLC (air trapping) were independent variables predictive of DDR during exercises field tests [DDR6MWT = 18.66-(0.06 × FEV1%pred)-(0.10 × DLCO%pred) + (1.54 × air trapping),R adjust 2 = 0.43] and maximal [DDRISWT = 18.84-(0.09 × FEV1%pred)-(0.05 × DLCO%pred) + (3.10 × air trapping),R adjust 2 = 0.33]. Conclusion: Our results demonstrated that DDR is a useful tool for functional evaluation during maximal and submaximal exercises in patients with LAM, and it can be predicted using airway obstruction, reduced DLCO, and air trapping.

Retroperitoneal Lympathic Malformations as First Presentation of Lymphangioleiomyomatosis

Teaching Point: This case highlights the extrapulmonary lymphatic abnormalities that may be associated with pulmonary lymphangioleiomyomatosis.

A 47-Year-Old Woman With Pulmonary Nodules and Facial Hemispasms

CASE PRESENTATION

A 47-year-old woman visited her primary physician for a health check, and some radiographic abnormalities were detected. She was referred to our division for further management. In recent years, she had become conscious of occasional facial hemispasms. She denied respiratory symptoms, smoking, alcohol consumption, and any particle inhalation. She had undergone oophorectomy and platinum-based chemotherapy because of ovarian cancer (serous cystadenocarcinoma stage Ⅰa) at the age of 29 years, with no recurrence for 17 years. The patient was diagnosed with rheumatoid arthritis (RA) 5 years before being seen by us and had been treated with bucillamine. No signs of RA progression were evident, and the only used antirheumatic drug was bucillamine. The patient had no history of use of immune-modulating drugs or immunosuppressants. No previous chest radiographs or CT had been performed.

Feasibility and Long-Term Efficacy of PEComa Treatment-20 Years of Experience

Perivascular epithelioid cell tumors (PEComas) represent a family of rare mesenchymal neoplasms, some of which are malignant. There are no specific management guidelines for PEComas, and factors correlating with the disease course are not well defined. This analysis aimed to describe the outcomes of PEComa patients treated radically, including those treated exclusively in the national reference sarcoma center. The secondary aim of the study was to analyze factors associated with PEComa treatment efficacy. We performed an analysis of 27 patients subsequently treated radically for PEComa between 1999 and 2019 who were in follow-up in the national sarcoma reference center. The proportional-hazards model was used to compare the risk of death. The median age at diagnosis was 45 (21–67) years, and 67% of patients were female. The median follow-up period was 68 months (95% CI: 39–101). At the time of analysis, eleven patients (40.7%) experienced progression of the disease and four (14.8%) died. Surgery in the reference sarcoma center was associated with a longer disease control (log-rank p < 0.001). The 5-year-OS rate was 88% (95% CI: 74–100) for the whole analyzed group. We concluded that PEComa treatment should be managed in reference sarcoma centers by a multidisciplinary tumor board with an experienced surgical team. Microscopically radical resection is associated with a longer disease-free survival. Patients requiring long-term follow-ups as late recurrence may be expected.

Spindle cell lesion on fine needle aspiration as an initial step for diagnosis of lymphangioleiomyomatosis: Report of a rare case

Lymphangioleiomyomatosis (LAM) is a rare systemic disease of women of reproductive age characterized by proliferation of abnormal smooth muscle like cells (LAM cells). Patients with LAM characteristically present with chronic dyspnea and cough and less commonly with spontaneous pneumothorax. Manifestation of extrapulmonary LAM as an initial presenting symptom is rare with a renal angiomyolipoma and lymphangioleiomyoma being most common. Although histologic findings of LAM are well-described, the cytological features; however, have been described only in few case reports, which focus on pulmonary LAM. Here, we report a case where initial diagnosis of LAM was made on pelvic "lymph node" fine needle aspiration (FNA) and biopsy in otherwise asymptomatic 25-year-old female, leading to further investigation and detection of developing cystic lung lesions. FNA cytology from the pelvic "lymph node" yielded proliferation of spindle cells without cytologic atypia. This case presented both clinical and histopathologic challenge, requiring clinical correlation and immunohistochemical staining for diagnosis. While rare, it is important to consider LAM in the differential diagnosis of spindle cell lesions in aspirate from nodules around vascular bundles in women of reproductive age even without history of lung lesion.

Connectivity Map Analysis of a Single-Cell RNA-Sequencing -Derived Transcriptional Signature of mTOR Signaling

In the connectivity map (CMap) approach to drug repositioning and development, transcriptional signature of disease is constructed by differential gene expression analysis between the diseased tissue or cells and the control. The negative correlation between the transcriptional disease signature and the transcriptional signature of the drug, or a bioactive compound, is assumed to indicate its ability to “reverse” the disease process. A major limitation of traditional CMaP analysis is the use of signatures derived from bulk disease tissues. Since the key driver pathways are most likely dysregulated in only a subset of cells, the “averaged” transcriptional signatures resulting from bulk analysis lack the resolution to effectively identify effective therapeutic agents. The use of single-cell RNA-seq (scRNA-seq) transcriptomic assay facilitates construction of disease signatures that are specific to individual cell types, but methods for using scRNA-seq data in the context of CMaP analysis are lacking. Lymphangioleiomyomatosis (LAM) mutations in TSC1 or TSC2 genes result in the activation of the mTOR complex 1 (mTORC1). The mTORC1 inhibitor Sirolimus is the only FDA-approved drug to treat LAM. Novel therapies for LAM are urgently needed as the disease recurs with discontinuation of the treatment and some patients are insensitive to the drug. We developed methods for constructing disease transcriptional signatures and CMaP analysis using scRNA-seq profiling and applied them in the analysis of scRNA-seq data of lung tissue from naïve and sirolimus-treated LAM patients. New methods successfully implicated mTORC1 inhibitors, including Sirolimus, as capable of reverting the LAM transcriptional signatures. The CMaP analysis mimicking standard bulk-tissue approach failed to detect any connection between the LAM signature and mTORC1 signaling. This indicates that the precise signature derived from scRNA-seq data using our methods is the crucial difference between the success and the failure to identify effective therapeutic treatments in CMaP analysis.

Two most common diagnoses among myriads of cystic lung diseases

BACKGROUND

Diffuse cystic lung diseases are a group of heterogeneous pathophysiological processes and include neoplastic, inflammatory, and infectious etiologies. This manuscript focuses on manifestations of pulmonary Langerhans cell histiocytosis (PLCH) and lymphangioleiomyomatosis (LAM). Description of the cases: Three female patients with LAM and one with PLCH are described. Stress dyspnea was a key symptom. There were similar cyst patterns in more than one lung lobe with a slow, progressive course. Histopathology confirmed the LAM diagnosis resulting from the nodular proliferate and the cyst wall that strongly expressed Human Melanoma Black-45 (HMB-45). A typical constellation for PLCH was demonstrated in high-resolution computed tomography (HRCT). It was found to be disseminated and relatively thick-walled cysts, mainly in the upper and middle parts. An individualized therapy was applied. Three patients with mild symptoms were followed up, including HRCT evaluations. Sirolimus was administered to one patient with a severe manifestation of LAM.

CONCLUSION

LAM and PLCH are rare. High-resolution computed tomography is an essential diagnostic tool. Lung emphysema as misdiagnosis should be avoided. The characteristics of pulmonary cysts, the cyst's wall regularity, and identification of associated pulmonary lesions, should be evaluated. A promising new therapy concept are mTOR inhibitors are, especially in LAM. The most important recommendation in PLCH is the cessation of cigarette smoking. HIPPOKRATIA 2021, 25 (2):83-86.