Lymphangioleiomyomatosis: pathogenesis, clinical features, diagnosis, and management

Abdominal lymphangioleiomyomatosis in a man presenting with gastrointestinal hemorrhage as the first manifestation: a case report

Lymphangioleiomyomatosis (LAM) is a rare, low-grade malignant condition that typically affects women of childbearing age and primarily involves the lungs. While cases involving males and affecting the gastrointestinal tract are exceedingly uncommon. This report discusses an unusual case of abdominal LAM in a male patient with gastrointestinal hemorrhage. The patient, a 70-year-old man, had been experiencing recurrent abdominal pain, occasional black stools, dizziness, and fatigue for over a month before being admitted to the hospital. Diagnostic electronic gastroscopy identified ulcers in the gastric and duodenal bulb with hemorrhage. An abdominal CT scan revealed multiple cystic foci in the retroperitoneum and mesentery, but no masses were found. Despite receiving medical treatment, the patient continued to have black stools and eventually underwent laparoscopic distal subtotal gastrectomy. The pathological results of the excised distal gastric specimens showed LAM-like lesions in the submucosal layer of the pylorus, mesentery of the side of the lesser curvature of the stomach, and small intestine, leading to a diagnosis of abdominal LAM. However, even after the surgery, the patient still experienced recurrent black stools and developed new symptoms of chest tightness and shortness of breath. A follow-up chest CT revealed bilateral pleural effusion and multiple lung cysts, indicating a worsening condition. The patient was then prescribed oral Sirolimus, which resulted in an improvement in symptoms, including black stool, chest tightness, and shortness of breath. This case report provides a detailed account of the progression of an unusual gastrointestinal LAM case and suggests that a combination of surgery and Sirolimus may be effective in managing the condition.

Pulmonary tuberculosis related diffuse cystic lung disease with recurrent pneumothorax mimicking pulmonary lymphangioleomyomatosis in Ethiopia: A review and case report

Millions of individuals worldwide are afflicted by the fatal infectious disease tuberculosis, which accounts for thousands of avoidable deaths. The literature has provided a good description of the clinical manifestation and radiologic features of pulmonary tuberculosis. However, the parenchymal complication of pulmonary tuberculosis presenting as cystic lung disease, has not been widely documented in the literature and is one of the incredibly uncommon causes of diffuse cystic lung disease. It is very uncommon to have a patient with possible pulmonary lymphangioleomyomatosis to be superinfected with bacteriologically confirmed tuberculosis. This report describes a young female patient who was admitted to the hospital, had repeated chest tube insertions and drainage of recurrent spontaneous pneumothoraxes secondary to likely diffuse cystic lung disease related to pulmonary tuberculosis. First, it was thought that the most likely diagnosis was pulmonary lymphangioleomyomatosis. The patient ultimately diagnosed with diffuse cystic lung disease associated with pulmonary tuberculosis as the most likely cause of her clinical presentation considering the high index of suspicion and her sputum gene xpert results. For drug-susceptible tuberculosis, the patient was finally started on anti-tuberculosis medication. She had both clinical and radiological improvement after completion of her anti tuberculosis treatment. Thus, it is reasonable to conclude that tuberculosis may contribute to diffuse cystic lung disease (DCLD) in tuberculosis endemic settings such as Ethiopia, and that appropriate diagnostic efforts should be undertaken to make the diagnosis. A high index of clinical suspicion is crucial to prevent delays in the diagnosis of diffuse cystic lung disease associated with pulmonary tuberculosis.

Nintedanib for patients with lymphangioleiomyomatosis: a phase 2, open-label, single-arm study

BACKGROUND

Lymphangioleiomyomatosis is an ultra-rare disease mainly affecting women of childbearing age. The MILES trial showed the efficacy of sirolimus, an mTOR inhibitor, in stabilising lung function in patients with lymphangioleiomyomatosis. Drug toxicity and development of resistance are potential limitations of therapy with sirolimus. Nintedanib is a multikinase inhibitor that inhibits PDGFR, which is active in human and murine lymphangioleiomyomatosis lesions. We aimed to investigate the activity and safety of nintedanib in patients with lymphangioleiomyomatosis.

METHODS

This phase 2, open-label, single-arm study was conducted at MultiMedica IRCCS, a national referral university centre for rare pulmonary diseases in Milan, Italy. Eligible participants were aged 18 years and older and had sporadic or tuberous sclerosis complex-associated lymphangioleiomyomatosis with progressive pulmonary function decline in the past year despite treatment with sirolimus or treatment naive. Patients received nintedanib 150 mg orally twice per day, with a possible reduction to 100 mg twice per day in case of side-effects or hepatoxicity, for 12 months, followed by a period of 12 additional months without study treatment. The primary endpoint was the change in FEV1 (FEV1 slope in L) over 12 months. This study is registered with ClinicalTrials.gov, NCT03062943.

FINDINGS

From Oct 14, 2016, to Dec 13, 2019, 35 female patients (mean age 50 years [SD 11]) entered the study, 30 of whom were eligible and received nintedanib. After 12 months, 22 patients completed the treatment, 19 of whom also completed the 12 months of follow-up. FEV1 remained stable after one year of treatment (predicted mean difference 0·001 L [95% CI -0·063 to 0·066]; p=0·97). During the 12 months off treatment, a slight decline in FEV1 was observed (predicted mean difference -0·076 L [95% CI -0·149 to -0·004]; p=0·040). The most frequent adverse events were nausea (15 [50%] patients), diarrhoea (eight [26%]), and abdominal pain (two [7%]). No serious adverse events were observed during the treatment period.

INTERPRETATION

Our findings suggest that nintedanib did not improve FEV1, but that the treatment was generally well tolerated. These results might support nintedanib as a second-line therapy in patients not controlled by standard treatment with mTOR inhibitors. Further investigation, such as a non-inferiority trial comparing nintedanib and sirolimus could help to better clarify the role of this drug as a potential alternative treatment.

FUNDING

Boehringer-Ingelheim.

The development for emerging biomarkers of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare, slowly progressing, low-grade metastatic tumor primarily affecting women. Currently, vascular endothelial growth factor-D (VEGF-D) is the only validated diagnostic biomarker, enabling diagnosis of LAM without the need for lung biopsy in appropriate clinical settings. However, VEGF-D concentrations are normal in about 30% of patients, rendering it insufficient for diagnosing all cases of LAM. There remains a need to identify more non-invasive, safe, sensitive, and specific biomarkers associated with LAM. Therefore, it is imperative to explore novel non-invasive, safe, and specific diagnostic methods for LAM. This article aims to review biomarkers associated with LAM, including potential biomarkers newly discovered or showing advancements in classical biomarkers widely used in LAM, and discuss their application in LAM diagnosis, assessment of disease severity, prediction of treatment response, and prognosis. （LAM） 、，。，-D （VEGF-D） ， LAM。， 30% VEGF-D ， LAM 。 LAM 、、。，、 LAM 。 LAM ， LAM ， LAM 、、。.

Pericardial Effusion as a Presentation of Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare, systemic neoplastic disease that primarily affects women of childbearing age. The disease can arise sporadically or in association with tuberous sclerosis. It is characterized by the proliferation of abnormal smooth muscle-like cells, leading to cystic lung destruction, accumulation of chylous fluid, and development of abdominal tumors. The main clinical presentations are pneumothorax and progressive dyspnea on exertion. In some patients, the onset of symptoms occurs while on estrogen replacement therapy or during pregnancy. Since most patients present with common lung symptoms, such as fatigue and dyspnea, LAM is often the last diagnosis to consider. Worsening symptoms with the menstrual cycle can help raise this suspicion. This report describes a case of LAM in which the lack of awareness about this rare disease led to a significant diagnostic delay. A 34-year-old Caucasian woman presented with symptoms of dyspnea and fatigue that began during her second pregnancy, which were initially misinterpreted as obstructive lung disease for three years. As the disease evolved, the development of a pericardial effusion, a rare manifestation of the disease, led to the need to perform computed tomography, revealing multiple thin-walled intrapulmonary cysts with diffuse distribution suggestive of LAM, mediastinal lymphadenopathy, and lymphangioma. Serum vascular endothelial growth factor A levels were normal, and spirometry testing revealed severe airflow obstruction. Based on clinical and imaging findings, a diagnosis of LAM was made. With this article, we intend to raise awareness for the manifestations of this disease and its relation to hormonal changes and review treatment options.

Unsupervised Exercise in Interstitial Lung Disease: A Delphi Study to Develop a Consensus Preparticipation Screening Tool for Lymphangioleiomyomatosis

BACKGROUND

Little research is available to provide practical guidance to health care providers for exercise preparticipation screening and referral of patients with interstitial lung diseases (ILDs), including lymphangioleiomyomatosis (LAM), to participate in remote, unsupervised exercise programs.

RESEARCH QUESTION

What exercise preparticipation screening steps are essential to determine whether a patient with LAM is medically appropriate to participate in a remote, unsupervised exercise program?

STUDY DESIGN AND METHODS

Sixteen experts in LAM and ILD participated in a two-round modified Delphi study, ranking their level of agreement for 10 statements related to unsupervised exercise training in LAM, with an a priori definition of consensus. Additionally, 60 patients with LAM completed a survey of the perceived risks and benefits of remote exercise training in LAM.

RESULTS

Seven of the 10 statements reached consensus among experts. Experts agreed that an in-person clinical exercise test is indicated to screen for exercise-induced hypoxemia and prescribe supplemental oxygen therapy as indicated prior to initiating a remote exercise program. Patients with recent pneumothorax should wait to start an exercise program for at least 4 weeks until after resolution of pneumothorax and clearance by a physician. Patients with high cardiovascular risk for event during exercise, severe resting pulmonary hypertension, or risk for falls may be more appropriate for referral to a rehabilitation center. A LAM-specific remote exercise preparticipation screening tool was developed from the consensus statements and agreed upon by the panelists.

INTERPRETATION

A modified Delphi study approach was useful to develop disease-specific recommendations for safety and preparticipation screening prior to unsupervised, remotely administered exercise in LAM. The primary product of this study is a clinical decision aid for providers to use when medically screening patients prior to participation in the newly launched LAMFit remote exercise program.

Perivascular Epithelioid Cell-Family Tumors in Children, Adolescents, and Young Adults: Clinicopathologic Features in 70 Cases

CONTEXT.—

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors of uncertain histogenesis expressing smooth muscle and melanocytic markers. The clinicopathologic spectrum in young patients is not well documented.

OBJECTIVE.—

To describe a multi-institutional series of PEComas in children, adolescents, and young adults.

DESIGN.—

PEComas, not otherwise specified (NOS); angiomyolipomas (AMLs); lymphangioleiomyomatosis; and clear cell sugar tumors were retrospectively identified from 6 institutions and the authors' files.

RESULTS.—

Seventy PEComas in 64 patients (median age, 15 years) were identified. They were more common in females (45 of 64 patients), occurring predominantly in the kidney (53 of 70), followed by the liver (6 of 70). Thirty-four patients had confirmed tuberous sclerosis complex (TSC), 3 suspected TSC mosaicism, 2 Li-Fraumeni syndrome (LFS) and 1 neurofibromatosis type 1. Most common variants were classic (49 of 70) and epithelioid (8 of 70) AML. Among patients with AMLs, most (34 of 47) had TSC, and more TSC patients had multiple AMLs (15 of 36) than non-TSC patients (2 of 13). Two TSC patients developed malignant transformation of classic AMLs: 1 angiosarcomatous and 1 malignant epithelioid. Lymphangioleiomyomatosis (5 of 70) occurred in females only, usually in the TSC context (4 of 5). PEComas-NOS (6 of 70) occurred exclusively in non-TSC patients, 2 of whom had LFS (2 of 6). Three were malignant, 1 had uncertain malignant potential, and 2 were benign. All 4 PEComas-NOS in non-LFS patients had TFE3 rearrangements.

CONCLUSIONS.—

Compared to the general population, TSC was more prevalent in our cohort; PEComas-NOS showed more frequent TFE3 rearrangements and possible association with LFS. This series expands the spectrum of PEComas in young patients and demonstrates molecular features and germline contexts that set them apart from older patients.

[Highlights 57th SEPAR Congress]

The Spanish Society of Pneumology and Thoracic Surgery (SEPAR) has held its 57th Congress in Valencia from 6 to 8 of June 2024. The SEPAR Congress is the leading meeting for the entire respiratory scientific community, which allows learning about the main scientific advances in this area and provides the ideal situation to create and strengthen ties. This year, under the title "Respiratory Health for everybody", the SEPAR Congress stressed the importance of raising awareness about the importance of caring for and protecting our respiratory system. In this review, we offer a summary of some notable issues addressed in six selected areas of interest: chronic obstructive pulmonary disease (COPD), asthma, interstitial lung diseases (ILDs), pulmonary vascular diseases, sleep and breathing disorders and respiratory physiotherapy.

Repurposing Nitazoxanide for Potential Treatment of Rare Disease Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare genetic lung disease. Unfortunately, treatment with the mTORC1 inhibitor Rapamycin only slows disease progression, and incomplete responses are common. Thus, there remains an urgent need to identify new targets for the development of curative LAM treatments. Nitazoxanide (NTZ) is an orally bioavailable antiprotozoal small molecule drug approved for the treatment of diarrhea caused by Giardia lamblia or Cryptosporidium parvum in children and adults, with a demonstrated mTORC1 inhibitory effect in several human cell lines. NTZ's excellent safety profile characterized by its more than 20 years of clinical use makes it a promising candidate for repurposing. Our rationale for this study was to further investigate NTZ's effect using in vitro and in vivo LAM models and to elucidate the underlying molecular mechanism beyond mTORC1 inhibition. For this purpose, we investigated cell proliferation, cell viability, and changes in protein phosphorylation and expression in primary human cell cultures derived from LAM lung samples before translating our results into a syngeneic mouse model utilizing Tsc2-null cells. NTZ reduced cell growth for all tested cell lines at a dose of about 30 µM. Lower doses than that had no effect on cell viability, but doses above 45 µM lowered the viability by about 10 to 15% compared to control. Interestingly, our western blot revealed no inhibition of mTORC1 and only a mild effect on active ß-Catenin. Instead, NTZ had a pronounced effect on reducing pAkt. In the mouse model, prophylactic NTZ treatment via the intraperitoneal and oral routes had some effects on reducing lung lesions and improving body weight retention, but the results remain inconclusive.

Surgical Management of Solitary Extrapulmonary Lymphangioleiomyomatosis in the Mesentery: A Case Report

Pulmonary lymphangioleiomyomatosis (LAM) is a rare condition characterised by infiltration of the lungs with abnormal smooth muscles and cystic lesions. A rarer form of the condition is extrapulmonary LAM (E-LAM) where the same cystic lesions are found in various organs throughout the body resulting in a variety of symptoms. Given the rarity of E-LAM and the difficulty in diagnosing it, there is little evidence to guide its management both surgically and medically. We describe a case of a 22-year-old female with a nine-month history of abdominal pain found to have a large mesenteric mass during laparoscopy for suspected ovarian torsion. She underwent a laparotomy to exteriorise the mass and dissect it off the mesentery. The mass was removed without compromise to the bowel or mesentery. The patient recovered well without symptoms and was discharged without complications. Histopathology of the mass revealed it to be E-LAM. This case is the first to our knowledge that demonstrates the successful removal of a solitary E-LAM from the mesentery with minimal adverse outcomes and symptomatic relief.

Genetic background of pulmonary (vascular) diseases - how much is written in the codes?

PURPOSE OF REVIEW

To provide a comprehensive overview of the underlying genetic defects of pulmonary (vascular) diseases and novel treatment avenues.

RECENT FINDINGS

Pulmonary arterial hypertension (PAH) is the prime example of a pulmonary vascular disease, which can be caused by genetic mutations in some patients. Germline mutations in the BMPR2 gene and further genes lead to vessel remodelling, increase of pulmonary vascular resistance and onset of heritable PAH. The PAH genes with the highest evidence and strategies for genetic testing and counselling have been assessed and evaluated in 2023 by international expert consortia. Moreover, first treatment options have just arisen targeting the molecular basis of PAH.

SUMMARY

Apart from PAH, this review touches on the underlying genetic causes of further lung diseases including alpha 1 antitrypsin deficiency, cystic fibrosis, familial pulmonary fibrosis and lymphangioleiomyomatosis. We point out the main disease genes, the underlying pathomechanisms and novel therapies trying not only to relieve symptoms but to treat the molecular causes of the diseases.

Machine Learning Model for Predicting Axillary Lymph Node Metastasis in Clinically Node Positive Breast Cancer Based on Peritumoral Ultrasound Radiomics and SHAP Feature Analysis

OBJECTIVE

This study seeks to construct a machine learning model that merges clinical characteristics with ultrasound radiomic analysis-encompassing both the intratumoral and peritumoral-to predict the status of axillary lymph nodes in patients with early-stage breast cancer.

METHODS

The study employed retrospective methods, collecting clinical information, ultrasound data, and postoperative pathological results from 321 breast cancer patients (including 224 in the training group and 97 in the validation group). Through correlation analysis, univariate analysis, and Lasso regression analysis, independent risk factors related to axillary lymph node metastasis in breast cancer were identified from conventional ultrasound and immunohistochemical indicators, and a clinical feature model was constructed. Additionally, features were extracted from ultrasound images of the intratumoral and its 1-5 mm peritumoral to establish a radiomics feature formula. Furthermore, by combining clinical features and ultrasound radiomics features, six machine learning models (Logistic Regression, Decision Tree, Support Vector Machine, Extreme Gradient Boosting, Random Forest, and K-Nearest Neighbors) were compared for diagnostic efficacy, and constructing a joint prediction model based on the optimal ML algorithm. The use of Shapley Additive Explanations (SHAP) enhanced the visualization and interpretability of the model during the diagnostic process.

RESULTS

Among the 321 breast cancer patients, 121 had axillary lymph node metastasis, and 200 did not. The clinical feature model had an AUC of 0.779 and 0.777 in the training and validation groups, respectively. Radiomics model analysis showed that the model including the Intratumor +3 mm peritumor area had the best diagnostic performance, with AUCs of 0.847 and 0.844 in the training and validation groups, respectively. The joint prediction model based on the XGBoost algorithm reached AUCs of 0.917 and 0.905 in the training and validation groups, respectively. SHAP analysis indicated that the Rad Score had the highest weight in the prediction model, playing a significant role in predicting axillary lymph node metastasis in breast cancer.

CONCLUSION

The predictive model, which integrates clinical features and radiomic characteristics using the XGBoost algorithm, demonstrates significant diagnostic value for axillary lymph node metastasis in breast cancer. This model can provide significant references for preoperative surgical strategy selection and prognosis evaluation for breast cancer patients, helping to reduce postoperative complications and improve long-term survival rates. Additionally, the utilization of SHAP enhancing the global and local interpretability of the model.

Immunology and targeted therapy in Castleman disease

INTRODUCTION

Castleman disease (CD) is a benign lymphoproliferative disease causing severe systemic inflammation. Interleukin-6 (IL-6) is a major pathogenesis of multicentric CD (MCD), but only 30-60% of patients respond to IL-6 inhibitors. Novel agents for IL-6 inhibitor-refractory cases are needed. Clinical data and samples are being collected on a large scale and the clinical, pathological, and pathogenetic aspects are being elucidated.

AREAS COVERED

The pathological and clinical classification of CD is outlined. Focusing on idiopathic MCD (iMCD), this review identifies therapeutic targets and summarizes currently recommended drugs and promising therapeutic candidates.

EXPERT OPINION

The pathogenesis of MCD has been implicated in the activation of the Janus kinase (JAK)-transcriptional signaling activator (STAT) 3 pathway and the phosphatidylinositol 3-kinase (PI3K)/Akt/mechanical target of rapamycin (mTOR) signaling pathway. iMCD-TAFRO (thrombocytopenia, anasarca, fever/elevated CRP, reticulin myelofibrosis/renal dysfunction, organ enlargement) is resistant to IL-6 inhibitors, and cyclosporine and mTOR inhibitors are sometimes effective. JAK inhibitors and mTOR inhibitors may be therapeutic agents for iMCD. Recently, we have shown that peripheral helper T (Tph) cell abnormalities are at the core of iMCD pathogenesis. Therapies targeting chemokine (C-X-C motif) ligand 13 (CXCL13) produced by Tph cells and blocking the Tph-CXCL13-B cell pathway may satisfy unmet need in refractory cases.

Ultra-low dose chest CT with silver filter and deep learning reconstruction significantly reduces radiation dose and retains quantitative information in the investigation and monitoring of lymphangioleiomyomatosis (LAM)

PURPOSE

Frequent CT scans to quantify lung involvement in cystic lung disease increases radiation exposure. Beam shaping energy filters can optimize imaging properties at lower radiation dosages. The aim of this study is to investigate whether use of SilverBeam filter and deep learning reconstruction algorithm allows for reduced radiation dose chest CT scanning in patients with lymphangioleiomyomatosis (LAM).

MATERIAL AND METHODS

In a single-center prospective study, 60 consecutive patients with LAM underwent chest CT at standard and ultra-low radiation doses. Standard dose scan was performed with standard copper filter and ultra-low dose scan was performed with SilverBeam filter. Scans were reconstructed using a soft tissue kernel with deep learning reconstruction (AiCE) technique and using a soft tissue kernel with hybrid iterative reconstruction (AIDR3D). Cyst scores were quantified by semi-automated software. Signal-to-noise ratio (SNR) was calculated for each reconstruction. Data were analyzed by linear correlation, paired t-test, and Bland-Altman plots.

RESULTS

Patients averaged 49.4 years and 100% were female with mean BMI 26.6 ± 6.1 kg/m2. Cyst score measured by AiCE reconstruction with SilverBeam filter correlated well with that of AIDR3D reconstruction with standard filter, with a 1.5% difference, and allowed for an 85.5% median radiation dosage reduction (0.33 mSv vs. 2.27 mSv, respectively, p < 0.001). Compared to standard filter with AIDR3D, SNR for SilverBeam AiCE images was slightly lower (3.2 vs. 3.1, respectively, p = 0.005).

CONCLUSION

SilverBeam filter with deep learning reconstruction reduces radiation dosage of chest CT, while maintaining accuracy of cyst quantification as well as image quality in cystic lung disease.

CLINICAL RELEVANCE STATEMENT

Radiation dosage from chest CT can be significantly reduced without sacrificing image quality by using silver filter in combination with a deep learning reconstructive algorithm.

KEY POINTS

• Deep learning reconstruction in chest CT had no significant effect on cyst quantification when compared to conventional hybrid iterative reconstruction. • SilverBeam filter reduced radiation dosage by 85.5% compared to standard dose chest CT. • SilverBeam filter in coordination with deep learning reconstruction maintained image quality and diagnostic accuracy for cyst quantification when compared to standard dose CT with hybrid iterative reconstruction.

Multinodal Cervical Angiomyomatous Hamartoma

Angiomyomatous hamartoma (AMH) is a rare benign lesion of the lymph nodes. Angiomyomatous hamartoma tends to be found in inguinal lymph nodes, and usually in a single lymph node. We present a rare care case of a 53-year-old presenting with a neck lump, found to be AMH involving multiple lymph nodes in her neck. To our knowledge, this is the first case presenting with multiple nodes in this location. There are a limited number of case reports describing magnetic resonance imaging (MRI) features of AMH lesions located in inguinal and head and neck regions. Our MRI findings revealed the mass had intermediate T1 enhancement, high T2 signal enhancement, and high post-gadolinium enhancement and fat saturation of the lesion. Angiomyomatous hamartoma is a histological diagnosis, distinguished from other similar nodal vascular lesions by a number of key features: including the presence of central nodal distribution, muscular blood vessel walls, adipose tissue, and HMB45 negative staining. Early recognition of this benign lesion may have implications for a patient's clinical course and surgical requirements.

Diffuse Cystic Lung Disease: A Clinical Guide to Recognition and Management

TOPIC IMPORTANCE

Diffuse cystic lung diseases (DCLDs) represent a group of pathophysiologically heterogeneous entities that share a common radiologic phenotype of multiple thin-walled pulmonary cysts. DCLDs differ from the typical fibroinflammatory interstitial lung diseases in their epidemiology, clinical presentation, molecular pathogenesis, and therapeutic approaches, making them worthy of a distinct classification. The importance of timely and accurate identification of DCLDs is heightened by the impact on patient management including recent discoveries of targeted therapeutic approaches for some disorders.

REVIEW FINDINGS

This article offers a practical framework for evaluating patients with DCLD, indicating the most appropriate and current diagnostic and management approaches. We focus on the DCLDs that are most likely to be encountered by practicing pulmonologists: lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis, Birt-Hogg-Dubé syndrome, and lymphoid interstitial pneumonia. Chest CT scan is the most informative noninvasive diagnostic modality to identify DCLDs. Thereafter, instituting a structured approach to high-yield associated factors (eg, medical, social, and family history; renal and dermatologic findings) increases the likelihood of identifying DCLDs and achieving a diagnosis.

SUMMARY

Although the individual diseases that comprise the DCLD family are rare, taken together, DCLDs can be encountered more frequently in clinical practice than commonly perceived. An increased eagerness among general pulmonary physicians to recognize these entities, coupled with a practical and systematic clinical approach to examinations and investigations, is required to improve case findings, allow earlier intervention, and reduce morbidity and mortality.

[Differential diagnosis of cystic and nodular lung diseases]

BACKGROUND

Cystic and nodular lung diseases encompass a broad spectrum of diseases with different etiologies and clinicoradiological presentations. Their differentiation is crucial for patient management but can be complex due to diseases with features of both categories and overlapping radiological patterns.

OBJECTIVE

This study aims to describe the imaging features of cystic and nodular lung diseases in high-resolution computed tomography (CT) in detail-primarily based on their etiology-in order to allow a more accurate differential diagnosis of these diseases.

MATERIALS AND METHODS

A narrative review based on current literature on the topic was conducted from a clinicoradiological perspective.

RESULTS

This paper systematically categorizes the differential diagnosis of cystic and nodular lung disease and provides insights into their radiological patterns and etiologies. It highlights the role of CT in the diagnosis of these diseases and emphasizes the importance of multidisciplinary panels combining expertise from radiology, pulmonology, rheumatology, and pathology.

CONCLUSION

Reliable differential diagnosis of cystic and nodular lung diseases, particularly based on their radiological features alone, remains difficult due to their overlapping and dynamic nature. Multidisciplinary boards should be the clinical standard for accurate work-up of these diseases, as they combine the medical history, symptoms, radiological findings, and, if necessary, histopathological examinations, thus providing a more robust framework for diagnosis and management.

Circulating biomarkers of kidney angiomyolipoma and cysts in tuberous sclerosis complex patients

Patients with tuberous sclerosis complex (TSC) develop multi-organ disease manifestations, with kidney angiomyolipomas (AML) and cysts being one of the most common and deadly. Early and regular AML/cyst detection and monitoring are vital to lower TSC patient morbidity and mortality. However, the current standard of care involves imaging-based methods that are not designed for rapid screening, posing challenges for early detection. To identify potential diagnostic screening biomarkers of AML/cysts, we performed global untargeted metabolomics in blood samples from 283 kidney AML/cyst-positive or -negative TSC patients using mass spectrometry. We identified 7 highly sensitive chemical features, including octanoic acid, that predict kidney AML/cysts in TSC patients. Patients with elevated octanoic acid have lower levels of very long-chain fatty acids (VLCFAs), suggesting that dysregulated peroxisome activity leads to overproduction of octanoic acid via VLCFA oxidation. These data highlight AML/cysts blood biomarkers for TSC patients and offers valuable metabolic insights into the disease.

Clinical Trial Validation of Automated Segmentation and Scoring of Pulmonary Cysts in Thoracic CT Scans

In cystic lung diseases such as lymphangioleiomyomatosis (LAM), a CT-based cyst score that measures the percentage of the lung volume occupied by cysts is a common index of the cyst burden in the lungs. Although the current semi-automatic measurement of the cyst score is well established, it is susceptible to human operator variabilities. We recently developed a fully automatic method incorporating adaptive features in place of manual adjustments. In this clinical study, the automatic method is validated against the standard method in several aspects. These include the agreement between the cyst scores of the two methods, the agreement of each method with independent tests of pulmonary function, and the temporal consistency of the measurements in the consecutive visits of the same patients. We found that the automatic method agreed with the standard method as well as the agreement between two trained operators running the same standard method; both methods obtained the same level of correlation with laboratory pulmonary function tests; the automated method had better temporal consistency than the standard method (p < 0.0001). The study indicates that the automatic method could replace the standard method and provide better consistency in assessing the extent of cystic changes in the lungs of patients.

Effect of mTOR inhibitors on the mortality and safety of patients with lymphangioleiomyomatosis on the lung transplantation waitlist: A retrospective cohort study

BACKGROUND

Although lung transplantation (LTx) is the last resort for patients with end-stage lymphangioleiomyomatosis (LAM), the high waitlist mortality is a source of concern in Japan. Discontinuation of mechanistic target of rapamycin (mTOR) inhibitors prior to LTx is recommended due to the incidence of severe adverse events. Therefore, we hypothesized that mTOR inhibitors may affect the mortality of patients with LAM on the LTx waitlist.

METHODS

We retrospectively compared the characteristics of consecutive patients with LAM on the LTx waitlist who were and were not receiving mTOR inhibitors.

RESULTS

Twenty-nine consecutive patients with LAM who listed our center between January 2004 and December 2021 were selected from the database and enrolled in the present study. Seventeen patients (58.6%) were receiving a mTOR inhibitor, sirolimus (treatment group). During a median listing period of 1277 days, 12 patients (41.4%) were hospitalized, six patients (20.7%) died from disease before LTx, and 15 patients underwent LTx. Among the deceased patients, four patients (66.6%) had pneumothoraces. The waitlist mortality in the treatment group was significantly lower than that in the non-treatment group (p = 0.03). Among the six patients who discontinued sirolimus in the treatment group, four patients (66.6%) were hospitalized with respiratory complications after the discontinuation of sirolimus. No mTOR inhibitor-related complications arose in the treatment group undergoing LTx (n = 7), including those on a reduced sirolimus dose.

CONCLUSIONS

Administration of an mTOR inhibitor until LTx may decrease waitlist mortality. Due to life-threatening events after discontinuing sirolimus pre-LTx, a reduced dose until LTx is permissible.

Lymphangioleiomyomatosis and pregnancy: a mini-review

Lymphangioleiomyomatosis(LAM) is a slow progressive, rare cystic lung disease in women of reproductive age, associated with infiltration of the lung by atypical smooth muscle like cells, leading to the cystic destruction of the lung parenchyma. As LAM exclusively affects women of childbearing age, it can arise or exacerbate during pregnancy. Many patients with LAM are discouraged from pregnancy, although there is not much objective evidence effect on fertility. Patients diagnosed with LAM during pregnancy experience worse outcomes, so the safety of pregnancy is a vexing problem. What was worse, treatment strategies are limited on the effects of LAM on pregnancy outcomes. Pregnancy could be considered in LAM patients. Successful delivery in women with LAM depends on the condition of the LAM, which is in turn dependent on obstetricians and respiratory physicians. In this review, we describe the epidemiology, pathogenesis, diagnosis, clinical features and the treatment strategies of LAM during pregnancy.

Influence of intersignaling crosstalk on the intracellular localization of YAP/TAZ in lung cells

A cell is a dynamic system in which various processes occur simultaneously. In particular, intra- and intercellular signaling pathway crosstalk has a significant impact on a cell's life cycle, differentiation, proliferation, growth, regeneration, and, consequently, on the normal functioning of an entire organ. Hippo signaling and YAP/TAZ nucleocytoplasmic shuttling play a pivotal role in normal development, homeostasis, and tissue regeneration, particularly in lung cells. Intersignaling communication has a significant impact on the core components of the Hippo pathway and on YAP/TAZ localization. This review describes the crosstalk between Hippo signaling and key lung signaling pathways (WNT, SHH, TGFβ, Notch, Rho, and mTOR) using lung cells as an example and highlights the remaining unanswered questions.

A Case Report of Malignant Perivascular Epithelioid Cell Tumors of the Uterus and Literature Review

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal tumors originating from perivascular epithelioid cells. In gynecological system, the uterus is one of the most common sites affected by PEComas. Most PEComas are benign, and patients usually have a good prognosis. However, malignant uterus PEComa is rare, and better comprehensive epidemiological investigations are needed. To date, there are a few reported cases of uterus PEComa. We herein report a rare case of malignant PEComa occurred in the uterine corpus and cervix, possibly accompanied by pulmonary lymphangioleiomyomatosis (PLAM). In addition, 55 cases of malignant uterus PEComa were picked out and collected in the data base of PubMed and Medline. On the one hand, the age of onset, population distribution, clinical manifestations, metastatic sites and routes of metastasis were analysed. On the other hand, a summary of the epidemiology, pathogenesis, diagnosis, and treatments of uterus PEComa was given.

Tuberous sclerosis complex associated lymphangioleiomyomatosis caused by de novo mutation of TSC2 gene in Vietnam: A case report

Lymphangioleiomyomatosis (LAM) represents a rare, insidiously progressive disease of the pulmonary system, marked by cystic degradation of lung tissues leading to respiratory compromise. Pulmonary LAM has been identified as being associated with tuberous sclerosis complex (TSC) in its pulmonary manifestation (TSC-LAM), a multisystem genetic disorder resulting from mutations in either the TSC1 or TSC2 genes. Herein, we describe an early 20s female admitted to the hospital with dyspnea, chest pain, hypopigmented macules, and facial fibroadenomas. She has a medical history of renal angiomyolipomas (ALMs) and pneumothoraces. Diagnosis with LAM was confirmed through high-resolution computed tomography (HRCT) scan and histopathology of lung biopsy. Whole exome sequencing analysis identified a frameshift mutation c.4504del (p.L1502Cfs*74) in the patient's TSC2 gene. This variant was de novo due to its absence in the patient's parents. This is the first report on the clinical and genetic etiology of TSC-LAM in Vietnam.

A 24-year-Old woman with recurrent pneumothoraces

Lymphangioleiomyomatosis (LAM) is an abnormal proliferation of smooth muscle-like cells and may occur sporadically or in association with tuberous sclerosis complex. Patients are typically female, nonsmoking and may have cystic lung disease with pneumothorax. Diagnosis can be made by compatible imaging findings with a history of tuberous sclerosis complex, or in conjunction with vascular endothelial growth factor-D 800 pg/ml or greater, a highly specific finding. Sirolimus is first line treatment for LAM.

Diagnosis of cystic lung diseases: a position statement from the UK Cystic Lung Disease Rare Disease Collaborative Network

BACKGROUND

Rare cystic lung diseases are increasingly recognised due the wider application of CT scanning making cystic lung disease management a growing part of respiratory care. Cystic lung diseases tend to have extrapulmonary features that can both be diagnostic but also require surveillance and treatment in their own right. As some of these diseases now have specific treatments, making a precise diagnosis is crucial. While Langerhans cell histiocytosis, Birt-Hogg-Dubé syndrome, lymphoid interstitial pneumonia and lymphangioleiomyomatosis are becoming relatively well-known diseases to respiratory physicians, a targeted and thorough workup improves diagnostic accuracy and may suggest other ultrarare diseases such as light chain deposition disease, cystic pulmonary amyloidosis, low-grade metastatic neoplasms or infections. In many cases, diagnostic information is overlooked leaving uncertainty over the disease course and treatments.

AIMS

This position statement from the Rare Disease Collaborative Network for cystic lung diseases will review how clinical, radiological and physiological features can be used to differentiate between these diseases.

NARRATIVE

We highlight that in many cases a multidisciplinary diagnosis can be made without the need for lung biopsy and discuss where tissue sampling is necessary when non-invasive methods leave diagnostic doubt. We suggest an initial workup focusing on points in the history which identify key disease features, underlying systemic and familial diseases and a clinical examination to search for connective tissue disease and features of genetic causes of lung cysts. All patients should have a CT of the thorax and abdomen to characterise the pattern and burden of lung cysts and extrapulmonary features and also spirometry, gas transfer and a 6 min walk test. Discussion with a rare cystic lung disease centre is suggested before a surgical biopsy is undertaken.

CONCLUSIONS

We suggest that this focused workup should be performed in all people with multiple lung cysts and would streamline referral pathways, help guide early treatment, management decisions, improve patient experience and reduce overall care costs. It could also potentially catalyse a national research database to describe these less well-understood and unidentified diseases, categorise disease phenotypes and outcomes, potentially leading to better prognostic data and generating a stronger platform to understand specific disease biology.

Familial pulmonary cysts: A clue to diagnose Birt-Hogg-Dubé syndrome: A case report and literature review

Birt-Hogg-Dubé syndrome (BHD) is an inherited autosomal dominant condition caused by germline mutations in the FLCN gene, mapped to chromosome 17p11.2. Typical manifestations include pulmonary cysts, spontaneous pneumothorax, fibrofolliculomas, and kidney neoplasms. This report details the case of a 56-year-old female non-smoker diagnosed with multiple pulmonary cysts, presenting with a history of recurrent spontaneous pneumothorax. A computed tomography (CT) scan of her daughter revealed similar pulmonary cysts, raising suspicion of BHD. Further abdominal enhanced CT revealed a left renal tumour and cutaneous fibrofolliculomas on her daughter's neck. Consequently, whole-exome sequencing confirmed an FLCN germline mutation in the patient and three relatives, establishing a diagnosis of BHD. This case highlights the importance of familial pulmonary cysts as a clue for diagnosing BHD, providing crucial insights into comparable clinical presentations.

Clinical, tomographic and functional comparison of sporadic and tuberous sclerosis complex-associated forms of lymphangioleiomyomatosis: a retrospective cohort study

Background

Lymphangioleiomyomatosis (LAM) is a rare disease that can occur sporadically (S-LAM) or associated with the tuberous sclerosis complex (TSC-LAM). The natural history of LAM is not completely understood, including whether there is a difference between the clinical courses of the two forms. This study aimed to compare the clinical, functional and tomographic features between S-LAM and TSC-LAM, and evaluate the annual rates of change in lung function.

Methods

This retrospective cohort study included patients with LAM followed up between 1994 and 2019. Clinical, functional and imaging variables were evaluated, and the lung cysts were automatically quantified. Quality of life and predictors of lung function impairment were accessed, and the annual rate of lung function decline was compared between S-LAM and TSC-LAM.

Results

Of the 107 patients included, 77 had S-LAM and 30 had TSC-LAM. Although patients with TSC-LAM had a higher prevalence of renal angiomyolipomas and neurological and dermatological manifestations, pulmonary function tests were similar. Patients with S-LAM had a greater rate of forced expiratory volume in 1 s decline and a higher extent of cysts. Pneumothorax, desaturation in the 6-minute walking test and a higher extent of lung cysts were predictors of functional impairment. A greater impact on vitality and emotional health was observed in the TSC-LAM.

Conclusion

Greater functional decline and a higher cystic extension were found in patients with S-LAM. Our study provides a broad clinical, functional and tomographic characterisation of patients with LAM, adding valuable information to the existing evidence to better understand the two forms of the disease.

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.

[Genetic diffuse cystic lung disease in adults]

Multiple cystic lung diseases comprise a wide range of various diseases, some of them of genetic origin. Lymphangioleiomyomatosis (LAM) is a disease occurring almost exclusively in women, sporadically or in association with tuberous sclerosis complex (TSC). Patients with LAM present with lymphatic complications, renal angiomyolipomas and cystic lung disease responsible for spontaneous pneumothoraces and progressive respiratory insufficiency. TSC and LAM have been ascribed to mutations in TSC1 or TSC2 genes. Patients with TSC are variably affected by cutaneous, cognitive and neuropsychiatric manifestations, epilepsy, cerebral and renal tumors, usually of benign nature. Birt-Hogg-Dubé syndrome is caused by mutations in FLCN encoding folliculin. This syndrome includes lung cysts of basal predominance, cutaneous fibrofolliculomas and various renal tumors. The main complications are spontaneous pneumothoraces and renal tumors requiring systematic screening. The mammalian target of rapamycin (mTOR) pathway is involved in the pathophysiology of TSC, sporadic LAM and Birt-Hogg-Dubé syndrome. MTOR inhibitors are used in LAM and in TSC while Birt-Hogg-Dubé syndrome does not progress towards chronic respiratory failure. Future challenges in these often under-recognized diseases include the need to reduce the delay to diagnosis, and to develop potentially curative treatments. In France, physicians can seek help from the network of reference centers for the diagnosis and management of rare pulmonary diseases.

Pathology of hereditary renal cell carcinoma syndromes: Tuberous sclerosis complex (TSC)

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disease characterized by hamartomatous tumors involving multiple organs such as the brain, skin, heart, lung and kidney. TSC is caused by inactivating mutations in TSC1/TSC2, which encodes hamartin and tuberin, respectively, and forms a complex that regulates mechanistic target of rapamycin complex 1 (mTORC1), resulting in cell overgrowth and oncogenesis. Since a leading cause of morbidity and mortality in TSC relates to chronic kidney disease and the ability to preserve renal function, this review describes the important pathologic findings in TSC-associated renal neoplasms and their correlating sporadic counterparts. The most common renal tumor in TSC patients are AMLs, followed by a heterogeneous spectrum of renal epithelial tumors, which may provide clues to establishing a diagnosis of TSC.

Diagnostic value of serum vascular endothelial growth factor-D in Korean patients with lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a rare multisystemic disorder characterized by the proliferation of abnormal smooth muscle-like cells. Although serum vascular endothelial growth factor-D (VEGF-D) is currently used as a diagnostic biomarker for LAM, its diagnostic value in Korean patients is unclear.

OBJECTIVES

To evaluate the diagnostic value of serum VEGF-D for LAM in Korean patients.

DESIGN

A multicenter prospective cohort study.

METHODS

Serum samples were prospectively collected from five medical institutions, from patients with LAM (n = 40) and controls (n = 24; healthy participants = 3, other cystic lung diseases = 13, idiopathic pulmonary fibrosis = 4, idiopathic nonspecific interstitial pneumonia = 4). Serum VEGF-D levels were measured using the enzyme-linked immunosorbent assay, and the diagnostic value was evaluated using receiver operating characteristic (ROC) curve analysis.

RESULTS

The mean age of patients with LAM was 44.5 years, and all were female (controls: 47.8 years; female: 70.8%, p < 0.001). The serum VEGF-D levels were significantly higher in patients with LAM than those in the control group (median: 708.9 pg/mL vs 325.3 pg/mL, p < 0.001). In the ROC curve analysis, serum VEGF-D levels showed good predicting performance for LAM diagnosis (area under the curve = 0.918) with an optimal cut-off value of 432.7 pg/mL (sensitivity = 85.0%, specificity = 87.5%). When 800 pg/mL was used as the cut-off value, the specificity of serum VEGF-D for LAM diagnosis increased to 100.0%.

CONCLUSION

Our results suggest that serum VEGF-D may be a useful biomarker for diagnosing LAM in Korean patients, similar to previous reports.

A case report of lymphangioleiomyomatosis with retroperitoneal masses in pregnancy

Background

Lymphangioleiomyomatosis (LAM) is a rare, gradually advancing tumor of unknown origin. It is distinguished by the anomalous proliferation of pulmonary smooth muscle cells and predominantly manifests in women of childbearing age. In this study, we aim to present a noteworthy case of LAM accompanied by lymphangioleiomyoma in the retroperitoneal space during pregnancy, a scenario susceptible to misdiagnosis.

Case presentation

A 31-year-old woman, facing an unintended pregnancy, presented during the 13th week with a cystic-solid mass exhibiting abundant blood signals in the pelvic cavity, as revealed by routine obstetrical ultrasound. Concurrently, her chest CT disclosed diffuse thin-walled cavities in both lungs. Despite the absence of clinical symptoms, the patient abandoned pregnancy and underwent a complete curettage. However, 24 days post-operation, she was readmitted for further assessment, revealing an enlargement of the mass encompassing the abdominal aorta and inferior vena cava, along with compression on the middle and lower segments of the ureter. After a multi-disciplinary discussion and patient explanation, an exploratory laparotomy was performed, resulting in the complete removal of the tumor. Intraoperative pathological examination and immunohistochemical staining indicated a retroperitoneal mass devoid of malignant evidence. The comprehensive morphologic and immunophenotypic features substantiated the diagnosis of lymphangioleiomyomatosis. The postoperative course was uneventful, culminating in the patient's discharge.

Conclusion

The consideration of Lymphangioleiomyomatosis (LAM) with a retroperitoneal tumor is crucial in the differential diagnosis of pelvic and abdominal masses. The preoperative diagnosis of this tumor poses a challenge, as ultrasound or CT scans may not yield definitive results. Accurate diagnosis necessitates not only a pathological examination of the retroperitoneal mass but also the correlation with the patient's chest High-Resolution Computed Tomography (HRCT) findings and corresponding clinical manifestations. Optimal management involves radical surgery, with surgeons comprehensively factoring in both fetal and maternal conditions when formulating a treatment plan.

Hyperactive mTORC1 in lung mesenchyme induces endothelial cell dysfunction and pulmonary vascular remodeling

Lymphangioleiomyomatosis (LAM) is a progressive cystic lung disease caused by tuberous sclerosis complex 1/2 (TSC1/2) gene mutations in pulmonary mesenchymal cells, resulting in activation of the mechanistic target of rapamycin complex 1 (mTORC1). A subset of patients with LAM develop pulmonary vascular remodeling and pulmonary hypertension. Little, however, is known regarding how LAM cells communicate with endothelial cells (ECs) to trigger vascular remodeling. In end-stage LAM lung explants, we identified EC dysfunction characterized by increased EC proliferation and migration, defective angiogenesis, and dysmorphic endothelial tube network formation. To model LAM disease, we used an mTORC1 gain-of-function mouse model with a Tsc2 KO (Tsc2KO) specific to lung mesenchyme (Tbx4LME-Cre Tsc2fl/fl), similar to the mesenchyme-specific genetic alterations seen in human disease. As early as 8 weeks of age, ECs from mice exhibited marked transcriptomic changes despite an absence of morphological changes to the distal lung microvasculature. In contrast, 1-year-old Tbx4LME-Cre Tsc2fl/fl mice spontaneously developed pulmonary vascular remodeling with increased medial thickness. Single-cell RNA-Seq of 1-year-old mouse lung cells identified paracrine ligands originating from Tsc2KO mesenchyme, which can signal through receptors in arterial ECs. These ECs had transcriptionally altered genes including those in pathways associated with blood vessel remodeling. The proposed pathophysiologic mesenchymal ligand-EC receptor crosstalk highlights the importance of an altered mesenchymal cell/EC axis in LAM and other hyperactive mTORC1-driven diseases. Since ECs in patients with LAM and in Tbx4LME-Cre Tsc2fl/fl mice did not harbor TSC2 mutations, our study demonstrates that constitutively active mTORC1 lung mesenchymal cells orchestrated dysfunctional EC responses that contributed to pulmonary vascular remodeling.

Safety and efficacy of cryobiopsy for the diagnosis of lymphangioleiomyomatosis compared with forceps biopsy and surgical lung biopsy

BACKGROUND

Transbronchial lung forceps biopsy (TBFB) is recommended before a surgical lung biopsy (SLB) when a definitive diagnosis of lymphangioleiomyomatosis (LAM) is required for patients without any additional confirmatory features. Transbronchial lung cryobiopsy (TBCB) has been suggested as replacement test in patients considered eligible to undergo SLB for the diagnosis of interstitial lung diseases. The efficacy and safety of TBCB were compared with that of TBFB and SLB in the diagnosis of LAM.

METHODS

A retrospective analysis was conducted on 207 consecutive patients suspected with LAM in the First Affiliated Hospital of Guangzhou Medical University from 2005 to 2020.

RESULTS

The difference in diagnostic rate of patients suspected with LAM between TBCB (20/30, 66.7%) and TBFB (70/106, 66.0%) groups was not significant (p = 0.949). One patient performed TBCB with negative pathological results could be diagnosed exclusively after SLB. LAM diagnosis was confirmed by surgical pathological findings in 3 TBFB-negative patients. More patients with minimal cystic profusion were diagnosed with LAM by TBCB (5/19, 26.3%) and SLB (11/39, 28.2%) than by TBFB (3/61, 4.9%) (TBCB vs TBFB: p = 0.04, SLB vs TBFB, p < 0.001). The difference between the severity of cystic lung disease in patients diagnosed with LAM through TBCB and SLB was not significant (p > 0.05). One pneumothorax, 8 mild bleeding and 1 moderate bleeding were observed in TBCB. One pneumothorax, 15 mild bleeding and 1 moderate bleeding occurred after TBFB.

CONCLUSION

Compared to TBFB, TBCB is safe and effective in diagnosing LAM at a higher diagnostic rate in patients with minimal cystic profusion.

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.

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 βIII-tubulin (43%). A comparison of the early (LHS-1) and advanced (LHS-3) stages of LAM revealed that neuron-specific βIII-tubulin was significantly expressed in the early stage of LAM ( P = 0.0009). Neuron-specific βIII-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 βIII-tubulin and peripherin. Neuronal expression may be associated with disease severity.

A remote monitoring-enabled home exercise prescription for patients with interstitial lung disease at risk for exercise-induced desaturation

RATIONALE

Alternatives to center-based pulmonary rehabilitation are needed to improve patient access to this important therapy. A critical challenge to overcome is how to maximize safety of unsupervised exercise for at-risk patients. We investigated if a novel remote monitoring-enabled mobile health (mHealth) program is safe, feasible, and effective for patients who experience exercise-induced hemoglobin desaturation.

METHODS

An interstitial lung disease (ILD) commonly associated with pronounced exercise desaturation was investigated - the rare, female-predominant ILD lymphangioleiomyomatosis (LAM). Over a 12-week program, hemoglobin saturation (SpO2) was continuously recorded during all home exercise sessions. Intervention effects were assessed with 6-min walk test (6MWT), maximal cardiopulmonary exercise test (CPET), lower extremity computerized dynamometry, pulmonary function tests, and health-related quality of life (QoL) surveys. Safety was assessed by blood biomarkers of systemic inflammation and cardiac wall stress, and incidence of adverse events.

RESULTS

Fifteen LAM patients enrolled and 14 completed the intervention, with high adherence to aerobic (87 ± 15%) and strength (87 ± 12%) training components. An innovative characterization of exercise training SpO2 revealed that while mild-to-moderate desaturation was common during home workouts, participants were able to self-adjust exercise intensity and supplemental oxygen levels to maintain recommended exercise parameters. Significant improvements included 6MWT distance (+36 ± 34 m, p = 0.003), CPET time (p = 0.04), muscular endurance (p = 0.008), QoL (p = 0.009 to 0.03), and fatigue (p = 0.001 to 0.03). Patient acceptability and satisfaction indicators were high, blood biomarkers remained stable (p > 0.05), and no study-related adverse events occurred.

CONCLUSION

A remote monitoring-enabled home exercise program is a safe, feasible, and effective approach even for patients who experience exercise desaturation.

Lost in translation: a neglected mTOR target for lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a cystic lung disease of women resulting from mutations in tuberous sclerosis complex (TSC) genes that suppress the mammalian target of rapamycin complex 1 (mTORC1) pathway. mTORC1 activation enhances a plethora of anabolic cellular functions, mainly via the activation of mRNA translation through stimulation of ribosomal protein S6 kinase (S6K1)/ribosomal protein S6 (S6) and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1)/eukaryotic translation initiation factor 4E (eIF4E). Rapamycin (sirolimus), an allosteric inhibitor of mTORC1, stabilises lung function in many but not all LAM patients and, upon cessation of the drug, disease progression resumes. At clinically tolerable concentrations, rapamycin potently inhibits the ribosomal S6K1/S6 translation ribosome biogenesis and elongation axis, but not the translation 4E-BP1/eIF4E initiation axis. In this mini-review, we propose that inhibition of mTORC1-driven translation initiation is an obvious but underappreciated therapeutic strategy in LAM, TSC and other mTORC1-driven diseases.

Identification of common genetic features and pathways involved in pulmonary lymphangioleiomyomatosis and ER-positive breast cancer

Accumulating evidence suggests that patients with pulmonary lymphangioleiomyomatosis (PLAM) have a markedly higher prevalence of breast cancer (BC) than the general population. However, the underlying pathophysiological mechanisms remain unclear. Therefore, in this study, we employed a bioinformatics approach to understand the association between PLAM and estrogen receptor (ER)-positive BC. The PLAM (GSE12027) and ER-positive BC (GSE42568, GSE29044, and GSE29431) datasets were obtained from the Gene Expression Omnibus database, and GEO2R was used to identify common differentially expressed genes (DEGs) between them. Functional annotation was performed, and a protein-protein interaction (PPI) network was constructed. Hub genes were identified and verified using western blotting and immunohistochemistry. We conducted an immune infiltration analysis; based on the results, selected 102 common DEGs for follow-up analysis. Functional analyses revealed that the DEGs were mostly enriched in cell proliferation, gene expression regulation, and tumor-related pathways. Four hub genes-ESR1, IL6, PLA2G4A, and CAV1-were further analyzed, and CAV1 was revealed to be associated with clinical outcomes and immune infiltration in ER-positive BC. This study proposes a common, possible pathogenesis of PLAM and ER-positive BC. These common pathways and pivotal genes may provide new directions for further mechanistic studies.

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

Lymphangioleiomyomatosis (LAM) is an ultra-rare, slowly progressive neoplastic cystic disease, belonging to the group of PEComas. It can occur sporadically or associated to tuberous sclerosis complex disease and affects mainly women in child-birth age. Dyspnoea is the most frequent symptom referred to the time of diagnosis, however spontaneous pneumothorax may be a typical presentation associated to extrathoracic manifestations, such as renal angiomyolipomas. In the last decade, important advances in understanding molecular mechanisms underlying the LAM pathogenesis have been reached. It has allowed to obtain improvements in the research of novel biomarkers, treatment and a better management of the disease.