Steroid receptors in pulmonary lymphangiomyomatosis

Novel developments in the study of estrogen in the pathogenesis and therapeutic intervention of lymphangioleiomyomatosis

OBJECTIVE

This study aimed to enhance the understanding of the role of estrogen in lymphangioleiomyomatosis(LAM) and to conclude the impact of estrogen-altering events on the condition and recent advances in estrogen-based treatments for LAM.

RESULTS

LAM development is strongly linked to mutations in the tuberous sclerosis gene (TSC1/2) and the presence of estrogen. Estrogen plays a significant role in the spread of TSC2-deficient uterine leiomyoma cells to the lungs and the production of pulmonary LAM. Menstruation, pregnancy, estrogen medication, and other events that cause an increase in estrogen levels can trigger the disorder, leading to a sudden worsening of symptoms. Current findings do not support using estrogen-blocking therapy regimens. However, Faslodex, which is an estrogen receptor antagonist, presents new possibilities for future therapeutic approaches in LAM.

CONCLUSION

Estrogen is crucial in the development and spread of LAM. The use of estrogen inhibitors or estrogen receptor antagonists alone does not provide good control of the disease or even poses a greater risk, and the use of a combination of mTOR receptor inhibitors, complete estrogen receptor antagonists, estrogen inhibitors, and autophagy inhibitors targeting important signaling pathways in LAM pathogenesis may be of greater benefit to the patient.

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.

An Evidence-Based Update on the Potential Association between Rheumatoid Arthritis and Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) represents an uncommon disorder characterized by cystic lung destruction and chronic respiratory failure. Lung damage caused by various mechanisms may represent a hypothesis for studying the association between LAM and rheumatoid arthritis (RA), which is the most prevalent autoinflammatory rheumatic disease and may affect the lungs as an extra-articular manifestation. Despite their distinct clinical presentations, the pathophysiology of both disorders includes dysregulated immunological function, abnormal cellular development, and inflammation. Current research suggests a potential relationship between RA and LAM, as some RA patients have been reported to develop LAM. However, the association of RA and LAM raises important therapeutic dilemmas. For this reason, the trajectory of a patient who was identified in our medical records as suffering from both LAM and RA, treated with many novel molecules and biological therapy, but with a negative outcome due to respiratory and multiorgan failure, has been exemplified. The delay in the diagnosis of LAM is due to a correlation between RA and LAM, worsening the vital prognosis and also hindering pulmonary transplantation. In addition, extensive research is essential for understanding the potential connection between these two disorders and discovering any similar mechanisms involved that may underlie their occurrence. This may contribute to the development of new therapeutic options that target shared pathways implicated in the pathogenesis of RA and LAM.

Lymphangioleiomyomatosis: pathogenesis, clinical features, diagnosis, and management

Lymphangioleiomyomatosis (LAM) is a slowly progressive, low-grade, metastasising neoplasm of women, characterised by infiltration of the lung parenchyma with abnormal smooth muscle-like cells, resulting in cystic lung destruction. The invading cell in LAM arises from an unknown source and harbours mutations in tuberous sclerosis complex (TSC) genes that result in constitutive activation of the mechanistic target of rapamycin (mTOR) pathway, dysregulated cellular proliferation, and a programme of frustrated lymphangiogenesis, culminating in disordered lung remodelling and respiratory failure. Over the past two decades, all facets of LAM basic and clinical science have seen important advances, including improved understanding of molecular mechanisms, novel diagnostic and prognostic biomarkers, effective treatment strategies, and comprehensive clinical practice guidelines. Further research is needed to better understand the natural history of LAM; develop more powerful diagnostic, prognostic, and predictive biomarkers; optimise the use of inhibitors of mTOR complex 1 in the treatment of LAM; and explore novel approaches to the development of remission-inducing therapies.

Tuberous sclerosis complex for the pulmonologist

Tuberous sclerosis complex (TSC) is a rare multisystem genetic disorder affecting almost all organs with no sex predominance. TSC has an autosomal-dominant inheritance and is caused by a heterozygous mutation in either the TSC1 or TSC2 gene leading to hyperactivation of the mammalian target of rapamycin (mTOR). TSC is associated with several pulmonary manifestations including lymphangioleiomyomatosis (LAM), multifocal micronodular pneumocyte hyperplasia (MMPH) and chylous effusions. LAM is a multisystem disorder characterised by cystic destruction of lung parenchyma, and may occur in either the setting of TSC (TSC-LAM) or sporadically (S-LAM). LAM occurs in 30–40% of adult females with TSC at childbearing age and is considered a nonmalignant metastatic neoplasm of unknown origin. TSC-LAM is generally milder and, unlike S-LAM, may occur in males. It manifests as multiple, bilateral, diffuse and thin-walled cysts with normal intervening lung parenchyma on chest computed tomography. LAM is complicated by spontaneous pneumothoraces in up to 70% of patients, with a high recurrence rate. mTOR inhibitors are the treatment of choice for LAM with moderately impaired lung function or chylous effusion. MMPH, manifesting as multiple solid and ground-glass nodules on high-resolution computed tomography, is usually harmless with no need for treatment.

Tuberous sclerosis complex is associated with diverse pulmonary manifestations including LAM, multiple micronodular pneumocyte hyperplasia and chylous effusions. LAM occurs in 30–40% of adult females with tuberous sclerosis complex.https://bit.ly/3iLqZ08

[Thoracic endometriosis and lymphangioleiomyomatosis: Coincidence or hormonal rational?]

INTRODUCTION

Lymphagioleiomyomatosis (LAM) and endometriosis are two diseases that occur in young women. The main thoracic complication of both diseases is pneumothorax.

CASE REPORT

We describe the case of a 45-year-old woman who presented with a right-sided pneumothorax. The clinical context and the perioperative findings were suggestive of thoracic endometriosis, while the histology of the pulmonary biopsy and the evolution of her case were in favour of LAM. This presentation indicates the coexistence of the two diseases, which has never previously been described in the literature. The case raises the question as to whether it should be policy to systematically undertake a pulmonary biopsy in cases of thoracic endometriosis.

CONCLUSIONS

LAM and endometriosis are both diseases under hormonal influence. To date, we do not know if there is any direct link between the two diseases or if the presentation that we describe here occurred by chance.

Estrogen activates pyruvate kinase M2 and increases the growth of TSC2-deficient cells

Lymphangioleiomyomatosis (LAM) is a devastating lung disease caused by inactivating gene mutations in either TSC1 or TSC2 that result in hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1). As LAM occurs predominantly in women during their reproductive age and is exacerbated by pregnancy, the female hormonal environment, and in particular estrogen, is implicated in LAM pathogenesis and progression. However, detailed underlying molecular mechanisms are not well understood. In this study, utilizing human pulmonary LAM specimens and cell culture models of TSC2-deficient LAM patient-derived and rat uterine leiomyoma-derived cells, we tested the hypothesis that estrogen promotes the growth of mTORC1-hyperactive cells through pyruvate kinase M2 (PKM2). Estrogen increased the phosphorylation of PKM2 at Ser37 and induced the nuclear translocation of phospho-PKM2. The estrogen receptor antagonist Faslodex reversed these effects. Restoration of TSC2 inhibited the phosphorylation of PKM2 in an mTORC1 inhibitor-insensitive manner. Finally, accumulation of phosphorylated PKM2 was evident in pulmonary nodule from LAM patients. Together, our data suggest that female predominance of LAM might be at least in part attributed to estrogen stimulation of PKM2-mediated cellular metabolic alterations. Targeting metabolic regulators of PKM2 might have therapeutic benefits for women with LAM and other female-specific neoplasms.

Official American Thoracic Society/Japanese Respiratory Society Clinical Practice Guidelines: Lymphangioleiomyomatosis Diagnosis and Management

BACKGROUND

Lymphangioleiomyomatosis (LAM) is a rare cystic lung disease that primarily affects women. The purpose of these guidelines is to provide recommendations for the diagnosis and treatment of LAM.

METHODS

Systematic reviews were performed to summarize evidence pertinent to our questions. The evidence was summarized and discussed by a multidisciplinary panel. Evidence-based recommendations were then formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation approach.

RESULTS

After considering the panel's confidence in the estimated effects, the balance of desirable (i.e., benefits) and undesirable (i.e., harms and burdens) consequences of treatment, patient values and preferences, cost, and feasibility, recommendations were formulated for or against specific interventions. These included recommendations for sirolimus treatment and vascular endothelial growth factor D testing and recommendations against doxycycline and hormonal therapy.

CONCLUSIONS

Evidence-based recommendations for the diagnosis and treatment of patients with LAM are provided. Frequent reassessment and updating will be needed.

[Pulmonary lymphangioleiomyomatosis: From pathogenesis to management]

INTRODUCTION

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease affecting mainly young women.

BACKGROUND

The respiratory manifestations are characterized by a progressive cystic destruction of the lung parenchyma. Extrapulmonary involvement includes benign renal tumours called angiomyolipomas and abdominal lymphatic masses called lymphangioleiomyomas. At the pathological level, the cellular proliferation found in LAM is in part due to the presence of mutations in the tumour suppressor genes TSC1 and TSC2 (Tuberous Sclerosis Complex). These mutations lead to the activation of the mTOR pathway, which is currently the main therapeutic target. mTOR inhibitors such as sirolimus or everolimus have shown a beneficial effect on the decline in pulmonary function and a reduction of angiomyolipoma size, but are necessary in only some patients.

PERSPECTIVES

LAM cells have migratory properties mediated by the formation of new lymphatic vessels. They are also able to secrete metalloproteases, which enhance their invasiveness. Moreover, the expression of estrogen and progesterone receptors by LAM cells suggests a possible role for sex hormones in the pathogenesis of the disease.

CONCLUSION

A better understanding of mTOR-independent mechanisms would allow the development of novel therapeutic approaches.

Progesterone and estradiol synergistically promote the lung metastasis of tuberin-deficient cells in a preclinical model of lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a female-predominant lung disease that can lead to respiratory failure. LAM cells typically have inactivating tuberous sclerosis 2 (TSC2) mutations, leading to mTORC1 hyperactivation. The gender specificity of LAM suggests that female hormones contribute to disease progression. Clinical findings indicate that estradiol exacerbates LAM behaviors and symptoms. Although hormonal therapy with progesterone has been employed, the benefit in LAM improvement has not been achieved. We have previously found that estradiol promotes the survival and lung metastasis of cells lacking tuberin in a preclinical model of LAM. In this study, we hypothesize that progesterone alone or in combination with estradiol promotes metastatic behaviors of TSC2-deficient cells. In cell culture models of TSC2-deficient LAM patient-derived and rat uterine leiomyoma-derived cells, we found that progesterone treatment or progesterone plus estradiol resulted in increased phosphorylation of Protein Kinase B (Akt) and Extracellular signal-regulated kinases1/2 (ERK1/2), induced the proliferation, and enhanced the migration and invasiveness. In addition, treatment of progesterone plus estradiol synergistically decreased the levels of reactive oxygen species and enhanced cell survival under oxidative stress. In a murine model of LAM, treatment of progesterone plus estradiol promoted the growth of xenograft tumors; however, progesterone treatment did not affect the development of xenograft tumors of Tsc2-deficient cells. Importantly, treatment of progesterone plus estradiol resulted in alteration of lung morphology and significantly increased the number of lung micrometastases of Tsc2-deficient cells compared with estradiol treatment alone. Collectively, these data indicate that progesterone increases the metastatic potential of Tsc2-deficient LAM patient-derived cells in vitro and lung metastasis in vivo. Thus, targeting progesterone-mediated signaling events may have therapeutic benefit for LAM and possibly other hormonally dependent cancers.

Doxiciclina em pacientes com linfangioleiomiomatose: segurança e eficácia no bloqueio de metaloproteinases

OBJETIVO: A linfangioleiomiomatose (LAM) é caracterizada pela presença de cistos pulmonares, cuja formação está associada à hiperreatividade de metaloproteinases de matriz (MMP), principalmente MMP-2 e MMP-9. Objetivamos comparar os níveis dessas MMPs entre pacientes com LAM e controles saudáveis, assim como avaliar, nas pacientes com LAM, a segurança e a eficácia do tratamento com doxiciclina, um potente inibidor de MMPs. MÉTODOS: Estudo clínico prospectivo no qual as pacientes com LAM receberam doxiciclina (100 mg/dia) por seis meses, coletando-se amostras de urina e sangue para a dosagem de MMP-2 e MMP-9 antes e ao final do período. Foram ainda obtidas amostras de 10 mulheres saudáveis. RESULTADOS: De 41 pacientes com LAM que iniciaram o tratamento, 34 concluíram o protocolo. Os níveis de MMP-9 sérica e urinária foram significativamente inferiores no grupo controle (p < 0,0001). Comparando-se os valores antes e após o tratamento, a mediana do nível sérico da MMP-9 reduziu de 919 ng/mL para 871 ng/mL (p = 0,05), enquanto a mediana da dosagem urinária de MMP-9 diminui de 11.558 pg/mL para 7.315 pg/mL (p = 0,10). A mediana da MMP-2 sérica apresentou um decréscimo significativo após o tratamento (p = 0,04). Não foram detectados níveis de MMP-2 urinária. Epigastralgia, náuseas e diarreia foram os efeitos adversos mais prevalentes, e geralmente autolimitados. Apenas 1 paciente interrompeu o tratamento devido a efeitos colaterais. CONCLUSÕES: Pela primeira vez, conseguiu-se evidenciar em pacientes com LAM a redução dos níveis séricos e urinários de MMPs após o uso de doxiciclina, que se mostrou uma medicação segura, com efeitos colaterais leves e toleráveis.

Evolução da função pulmonar após tratamento com goserelina em pacientes com linfangioleiomiomatose

Nas células musculares lisas atípicas características da linfangioleiomiomatose (LAM) encontram-se receptores de estrogênio e progesterona, de modo que o tratamento anti-hormonal pode ser considerado uma opção, mas ainda com resultados controversos. O objetivo deste trabalho foi avaliar retrospectivamente parâmetros hormonais e espirométricos em nove mulheres com LAM após o tratamento com goserelina por um ano. Houve um aumento médio de 80 mL e 130 mL, respectivamente, em VEF1 e CVF, assim como bloqueio hormonal efetivo. Ainda não se pode excluir um potencial efeito favorável da utilização de análogos de hormônio liberador de gonadotrofina em pacientes com LAM, reforçando a necessidade de ensaios randomizados

Lymphangioleiomyomatosis: what do we know and what are we looking for?

Lymphangioleiomyomatosis (LAM) is a rare disease characterised by proliferation of abnormal smooth muscle-like cells (LAM cells) leading to progressive cystic destruction of the lung, lymphatic abnormalities and abdominal tumours. It affects predominantly females and can occur sporadically or in patients with tuberous sclerosis complex. This review describes the recent progress in our understanding of the molecular pathogenesis of the disease and LAM cell biology. It also summarises current therapeutic approaches and the most promising areas of research for future therapeutic strategies.

Lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare disease that mainly affects women, particularly at fertile age. It is sporadic or associated with tuberous sclerosis complex. It is characterised by an abnormal proliferation of immature smooth muscle cells (SMC), which grow aberrantly in the airway, parenchyma, lymphatics and pulmonary blood vessels and which can gradually lead to respiratory failure. It affects several systems, affecting the lymphatic ganglia and causing abdominal tumours. Given its very low prevalence, a difficult to establish early diagnosis, absence of curative treatment and the difficulty in obtaining information, places LAM under the heading of the so-called Rare Diseases. There is a growing interest in the study of this disease which has led to the setting up of patient registers and an exponential growth in LAM research, both at a clinical level and cellular level.

mTOR activation, lymphangiogenesis, and estrogen-mediated cell survival: the "perfect storm" of pro-metastatic factors in LAM pathogenesis

Research interest in lymphangioleiomyomatosis (LAM) has grown dramatically in the past decade, particularly among cancer biologists. There are at least two reasons for this: first, the discovery in the year 2000 that LAM cells carry TSC2 gene mutations, linking LAM with cellular pathways including the PI3K/Akt/mTOR axis, and allowing the Tuberous Sclerosis Complex (TSC)-regulated pathways that are believed to underlie LAM pathogenesis to be studied in cells, yeast, Drosophila, and mice. A second reason for the rising interest in LAM is the discovery that LAM cells can travel to the lung, including repopulating a donor lung after lung transplantation, despite the fact that LAM cells are histologically benign. This "benign metastasis" underpinning suggests that elucidating LAM pathogenesis will unlock a set of fundamental mechanisms that underlie metastatic potential in the context of a cell that has not yet undergone malignant transformation. Here, we will outline the data supporting the metastatic model of LAM, consider the biochemical and cellular mechanisms that may enable LAM cells to metastasize, including both cell autonomous and non-cell autonomous factors, and highlight a mouse model in which estrogen promotes the metastasis and survival of TSC2-deficient cells in a MEK-dependent manner. We propose a multistep model of LAM cell metastasis that highlights multiple opportunities for therapeutic intervention. Taken together, the metastatic behavior of LAM cells and the involvement of tumor-related signaling pathways lead to optimism that cancer-related paradigms for diagnosis, staging, and therapy will lead to therapeutic breakthroughs for women living with LAM.

Molecular pathology of lymphangioleiomyomatosis and other perivascular epithelioid cell tumors

CONTEXT

Lymphangioleiomyomatosis (LAM) is a cystic lung disease that can be included in the wide group of proliferative lesions named PEComas (perivascular epithelioid cell tumors). These proliferative tumors are characterized by the coexpression of myogenic and melanogenesis-related markers. In all these lesions, genetic alterations related to the tuberous sclerosis complex (TSC) have been demonstrated. Striking improvements in the understanding of the genetic basis of this autosomal dominant genetic disease are coupled to the understanding of the mechanisms that link the loss of TSC1 (9q34) or TSC2 (16p13.3) genes with the regulation of the Rheb/m-TOR/p70S6K pathway. These data have opened a new era in the comprehension of the pathogenesis of LAM and have also suggested new therapeutic strategies for this potentially lethal disease.

OBJECTIVE

To present and discuss the pathologic and molecular features of LAM within the spectrum of PEComas, providing a rational approach to their diagnosis.

DATA SOURCES

The published literature and personal experience.

CONCLUSIONS

The inclusion of LAM within the PEComa category is supported by a variety of biologic data and can significantly help in providing a comprehensive view of this interesting and clinically relevant group of lesions. The demonstration of molecular alterations of the mTOR pathway in LAM and other PEComas represents a rational basis for innovative therapeutic approaches with inhibitors of mTOR signaling.

Smooth muscle-like cells in pulmonary lymphangioleiomyomatosis

Proliferation, migration, and differentiation of smooth muscle (SM)-like lymphangioleiomyomatosis (LAM) cells in the lungs are pathologic manifestations of pulmonary LAM, a rare lung disease predominantly afflicting women and exacerbated by pregnancy. LAM cells form nodules throughout the lung without any predominant localization, but can also form small cell clusters dispersed within lung parenchyma. LAM cells have the appearance of "immature" SM-like cells, irregularly distributed within the nodule in contrast to organized SM cell layers in airways and vasculature. Progressive growth of LAM cells leads to the cystic destruction of the lung parenchyma, obstruction of airways and lymphatics, and loss of pulmonary function. Pathogenetically, LAM occurs from somatic or genetic mutations of tumor suppressor genes tuberous sclerosis complex 1 (TSC1) or TSC2. The TSC1/TSC2 protein complex is an integrator of signaling networks regulated by growth factors, insulin, nutrients, and energy. The observation that the TSC1/TSC2 functions as a negative regulator of the mammalian target of rapamycin (mTOR)/p70 S6 kinase (S6K1) signaling pathway yielded the first rapamycin clinical trial for LAM. Although LAM is a rare lung disease, the elucidation of disease-relevant mechanisms of LAM will provide a better understanding of not only SM-like cell growth, migration, and differentiation in LAM but may also offer insights into other metabolic diseases such as cardiovascular diseases, diabetes, and cancer. In this article, we will summarize the progress made in our understanding of LAM, and we will focus on how dysregulation of TSC1/TSC2 signaling results in abnormal proliferation and migration of SM-like LAM cells.

[Pulmonary lymphangioleiomyomatosis with or without tuberous sclerosis]

INTRODUCTION

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease affecting young women and presenting with recurrent pneumothorax.

BACKGROUND

Other lesions such as chylothorax or renal angiomyolipoma may suggest the diagnosis. The condition is related to a proliferation of abnormal smooth muscle cells staining for the monoclonal antibody HMB45. LAM can appear sporadically or be associated with tuberous sclerosis with abnormalities of the TSC2 suppressor gene. High resolution thoracic CT scanning shows bilateral, thin walled pulmonary cysts. Pulmonary function tests reveal bronchial obstruction and over-inflation with a reduced DLCO being the earliest abnormality.

VIEWPOINT

Although there are non-progressive forms, LAM usually leads to chronic respiratory insufficiency within a few, or ten or so years. In the absence of a controlled clinical trial hormone therapy has not been shown to be effective. Lung transplantation is the last therapeutic resort; recurrences in the transplanted lung have been occasionally reported.

CONCLUSIONS

Analysis of the molecular mechanisms induced by mutations of the TSC2 suppressor gene and the demonstration of the migratory properties of smooth muscle cells, whose origin may be extra-thoracic, reveal new specific antiproliferative therapeutic options.

Molecular pathogenesis of lymphangioleiomyomatosis: lessons learned from orphans

Lymphangioleiomyomatosis (LAM) is a rare progressive cystic lung disease affecting young women. The pivotal observation that LAM occurs both spontaneously and as part of the tuberous sclerosis complex (TSC) led to the hypothesis that these disorders share common genetic and pathogenetic mechanisms. In this review we describe the evolution of our understanding of the molecular and cellular basis of LAM and TSC, beginning with the discovery of the TSC1 and TSC2 genes and the demonstration of their involvement in sporadic (non-TSC) LAM. This was followed by rapid delineation of the signaling pathways in Drosophila melanogaster with confirmation in mice and humans. This knowledge served as the foundation for novel therapeutic approaches that are currently being used in human clinical trials.

Conservative treatment of a mesenteric lymphangiomyomatosis in an 11-year-old girl with a long follow-up period

The authors report the case of a 11-year-old girl admitted for a mesenteric tumor discovered during an appendicectomy. The abdominal Doppler echography and computed tomography (CT) scan showed a 8 x 6 x 7-cm multinodular mass involved in the mesenterium. Biological markers and iodine 131 meta-iodobenzylguanidine (MIBG) scintigraphy results were normal. Percutaneous biopsies were performed. Pathology results showed perilymphatic proliferation of smooth muscle cells leading to cystic lesions. No sign of malignancy was seen. Laparotomy showed a multinodular fixed mass involved from the root of the mesenterium. The superior mesenteric vessels were encircled by the tumor, which could not be resected completely. Partial resection was performed. The pathology and the immunohistochemical tests confirmed the diagnosis of lymphangiomyomatosis. At 21 years of age, she remains asymptomatic. An echography and CT scan showed the mass remaining unchanged in size and echopattern. Lymphangiomyomatosis (LMA) is thought to affect exclusively women in their reproductive life, and the steroid hormones are supposed to play an essential role in the pathology and in the behavior of this condition. Infantile LMA is exceptional. The patient reported is remarkable for her young age, the location of the tumor, her long history, and her benign course. Because the tumor is supposed to be hormone dependent, the surge of oestrogen in this 21-year-old woman may initiate the extensive form of lymphangiomyomatosis with pulmonary involvement, the prognosis of which is extremely poor.

Estradiol and tamoxifen stimulate LAM-associated angiomyolipoma cell growth and activate both genomic and nongenomic signaling pathways

Lymphangioleiomyomatosis (LAM) is a progressive lung disease affecting almost exclusively women. The reasons for this strong gender predisposition are poorly understood. Renal angiomyolipomas occur in 50-60% of sporadic LAM patients. The smooth muscle cells of pulmonary LAM and renal angiomyolipomas are nearly indistinguishable morphologically. Here, we report the first successful cell culture of a LAM-associated renal angiomyolipoma. The cells carried inactivating mutations in both alleles of the TSC2 gene and expressed estrogen receptor , estrogen receptor , and androgen receptor. To elucidate the cellular pathways through which steroid hormones influence LAM pathogenesis, we treated the cells with both estradiol and tamoxifen. Cell growth was stimulated by estradiol, associated with phosphorylation of p44/42 MAPK at 5 min and an increase in c-myc expression at 4 h. Tamoxifen citrate also stimulated cell growth, associated with increased phosphorylation of p44/42 MAPK and expression of c-myc, indicating that tamoxifen has agonist effects on angiomyolipoma cells. This response to tamoxifen in human angiomyolipoma cells differs from prior studies of Eker rat leiomyoma cells, possibly reflecting cell type or species differences in cells lacking tuberin. Our data provide the first evidence that estradiol stimulates the growth of angiomyolipoma cells, that tamoxifen has agonist effects in angiomyolipoma cells, and that estradiol and tamoxifen impact both genomic and nongenomic signaling pathways in angiomyolipoma cells. The responsiveness of angiomyolipoma cells to estradiol may be related to the underlying reasons that LAM affects primarily women.

Linfangioleiomiomatose pulmonar

Linfangioleiomiomatose pulmonar (LAM) é uma doença rara, de etiologia desconhecida, que basicamente afeta mulheres jovens no período fértil de sua vida. Clinicamente, manifesta-se através de dispnéia progressiva, pneumotórax de repetição, tosse seca e, menos freqüentemente, por quilotórax e escarros hemoptóicos. Essas alterações surgem devido à proliferação anormal de células de músculo liso no parênquima pulmonar, linfonodos e em outros tecidos. Mais recentemente, estudos citogenéticos verificaram a presença de mutações do gene TSC-2 em células de angiomiolipoma renal e linfonodos abdominais de pacientes com LAM, indicando uma possível origem para as lesões hamartomatosas da doença. Radiologicamente, caracteriza-se pela presença de infiltrado intersticial reticulonodular e sinais de hiperinsuflação ao radiografia de tórax. Na tomografia computadorizada de alta resolução, cistos de paredes finas, localizados centralmente, são visibilizados por todo o parênquima do pulmão. O ultrassom e a tomografia de abdome podem revelar angiomiolipomas renais e linfonodomegalias retroperitoneais. Meningeomas também podem estar associados, porém a sua presença deve sempre levar à pesquisa de esclerose tuberosa. Funcionalmente, a doença caracteriza-se por um distúrbio ventilatório obstrutivo, de caráter progressivo, com hiperinsuflação pulmonar e diminuição da difusão de monóxido de carbono. Apesar da ausência de comprovação quanto à eficácia, o principal tratamento utilizado ainda é o anti-estrogênico e constitui-se de oofarectomia, progesterona contínua, tamoxifeno e análogos de GnRH. Além desse, a realização de transplantes pulmonares tem elevado para além de dez anos a sobrevida média das pacientes.

Renal angiomyolipoma in association with pulmonary lymphangioleiomyomatosis

The authors report on a premenopausal female hemodialysis patient with relapsing pneumothorax, in whom the diagnosis of pulmonary lymphangioleiomyomatosis (LAM) was made. Ten years earlier, she had retroperitoneal bleeding from a kidney tumor corresponding to an angiomyolipoma (AML). The association between renal AML and pulmonary LAM is reviewed. Renal AML represents the most frequent extrapulmonary manifestation of pulmonary LAM. It is found in 32% to 60 % of cases in which a systematic search with abdominal computed tomography (CT) scan is done. The latter approach is advised to help avoid complications caused by renal AML. Therapeutic recommendations for renal AML are based on tumor size or presence of symptoms. Conversely, premenopausal women presenting with AML should be investigated for associated pulmonary LAM with high-resolution CT scan. Because LAM is very likely estrogen dependent, one of the several proposed antiestrogen therapies should be considered. Finally, there is significant overlap between renal AML, pulmonary LAM, and tuberous sclerosis. The latter should therefore be actively searched for in case of either AML or LAM.

Tissue inhibitor of metalloproteinase-3 downregulation in lymphangioleiomyomatosis: potential consequence of abnormal serum response factor expression

Pulmonary lymphangioleiomyomatosis (LAM) is characterized by abnormal smooth muscle-like cell proliferation leading to tissue destruction and cyst formation. We demonstrate that serum response factor (SRF), a critical smooth muscle transcription factor, is overexpressed in LAM cells. To determine whether abnormal SRF levels might have a pathogenic role in LAM, we transfected SRF into mouse lung fibroblasts and performed a cDNA array analysis. High SRF level upregulated the expression of matrix metalloproteinase (MMP)-2 and MMP-14, two MMPs previously shown to be increased in LAM. In addition, SRF down-regulated tissue inhibitor of metalloproteinase (TIMP)-3, one of their inhibitors. TIMP-3 inhibition was further confirmed by reverse transcriptase/polymerase chain reaction, immunoblotting, and immunostaining of human lung fibroblasts transfected with SRF fused to DsRed2 (a red variant of green fluorescent protein). To determine the in vivo significance of our findings, we immunostained 12 LAM cases for TIMP-3. In eight of them, TIMP-3 was ubiquitously present in normal lung parenchyma, but it was absent in LAM lesions. In the remaining cases, including two out of five normal control lungs, the antibody immunoreacted exclusively with elastin, probably due to suboptimal tissue processing. Because timp-3-null mice develop spontaneous emphysema, our findings suggest that SRF-mediated TIMP-3 inhibition might contribute to the tissue damage seen in LAM.

Pulmonary lymphangioleiomyomatosis: a case report with immunohistochemical details and DNA analysis

A 47-year-old woman is presented with pulmonary lymphangioleiomyomatosis (PLAM) involving the bilateral lung and slight pulmonary function abnormality. Computed tomography scan showed bilateral microcyst formation in the lung. Histologically, proliferating spindle shaped cells with centrilobular emphysema were main findings. Immunohistochemically, these proliferating spindle shaped cells were positive for alpha-smooth muscle actin, desmin, vimentin, HMB45, estrogen receptor and progesterone receptor, but negative for S-100, cytokeratin. Single strand conformation polymorphism (SSCP) and DNA analysis for tuberous sclerosis 1 and 2 showed no significant abnormality.

High levels of exhaled nitric oxide (NO) and NO synthase III expression in lesional smooth muscle in lymphangioleiomyomatosis

Smooth-muscle proliferation is the hallmark of lymphangioleiomyomatosis (LAM). Although little is known about the pathogenesis of LAM, nitric oxide (NO) is a key regulator of smooth-muscle proliferation. NO is linked to the pathogenesis of other lung diseases such as asthma, in part by the finding of higher-than-normal levels of exhaled NO. If NO were involved in the abnormal smooth-muscle proliferation in LAM, we reasoned that exhaled NO from individuals with LAM would also differ from that of healthy control subjects. To evaluate this hypothesis, we studied exhaled NO in individuals with LAM in comparison with healthy and asthmatic women using a chemiluminescent NO analyzer. Women with LAM had higher exhaled NO than did healthy women but lower than asthmatic women (NO [parts per billion] median (25 to 75%): LAM 8 [7 to 15] [n = 28], control 6 [5 to 8] [n = 21], asthma 14 [8 to 25] [n = 22]; Kruskal-Wallis P < 0.001). Immunohistochemical studies on formalin-fixed, paraffin-embedded sections of surgical and autopsy material from lungs of individuals with LAM showed diffuse NO synthase III (NOSIII) expression in the lesional smooth muscle of LAM similar to that in the vascular endothelium. NOSIII expression was limited to the vascular endothelium and bronchial smooth muscle in healthy control lungs. The increased NO and the presence of NOSIII expression in lesional smooth muscle warrants further study into the potential role for NO in the pathogenesis of LAM.

Clinical experience of lymphangioleiomyomatosis in the UK

BACKGROUND

Lymphangioleiomyomatosis is a rare lung disease that affects only women. No controlled trials of management have been performed and, until such data are available, management must be based on clinical experience. This study provides data on the natural history of lymphangioleiomyomatosis in the UK and compares this with experience from other centres.

METHODS

We tried to identify all cases of lymphangioleiomyomatosis in the UK over a five year period by contacting all chest physicians. Cases were confirmed by lung biopsy or history and high resolution computed tomographic (CT) scanning. Details of disease and management were obtained from hospital notes.

RESULTS

The 50 patients who fitted the diagnostic criteria for lymphangioleiomyomatosis had a median age at onset of 35 years (range 22-50). Five presented when postmenopausal (four taking hormone replacement therapy). Pneumothorax and dyspnoea were the most common presenting features. Extrapulmonary presentations included renal angiomyolipomas (3) and lymphangiomyomas (2). Only half the patients were assessed for renal angiomyolipoma and six were identified. Thirty patients had had one or more pneumothoraces, of which two thirds recurred if treated conservatively. Chylous effusions occurred in 11 patients, five requiring surgery. Pregnancy was uncommon once the diagnosis was made (n=7), but was associated with an increase in complications. Half the patients were taking a beta agonist and many showed a bronchodilator response in the laboratory. Thirty six patients had received hormone treatment.

CONCLUSIONS

Our UK five year period prevalence was one per 1.1 million population. Since prophylactic interventions are sometimes indicated for renal angiomyolipoma, these data suggest that screening for angiomyolipoma, ideally by CT scanning, may be underused. Patients need to be aware of the increase in complications associated with pregnancy. Recurrence rate of pneumothorax was high in those not treated surgically. Hormone treatment was used variably and controlled trials are needed to determine their role and the optimum duration and dose.

Lymphangioleiomyomatosis (LAM): a review of clinical and morphological features

A review is presented of the clinical and morphological manifestations of lymphangioleiomyomatosis (LAM), a systemic disorder of unknown etiology that affects women. The clinical features include dyspnea, hemoptysis, recurrent pneumothorax, chylothorax, and chylous ascites. It is characterized by: 1) proliferation of abnormal smooth muscle cells (LAM cells) in pulmonary interstitium and along the axial lymphatics of the thorax and abdomen; 2) thin-walled pulmonary cysts, and 3) a high incidence of angiomyolipomas. The pulmonary cystic lesions have a characteristic appearance on high resolution computed tomography. The most specific method for diagnosing LAM is lung biopsy to demonstrate the presence of LAM cells, either by their characteristic histological appearance or by specific immunostaining with HMB-45 antibody. LAM cells differ in several important respects from the types of smooth muscle cells normally present in lung. Their reactivity with HMB-45 antibody is localized in stage I and stage II melanosomes. LAM cells show additional evidence of incomplete melanogenesis, and the significance of these observations remains to be determined. Two types of LAM cells are recognized: 1) small, spindle-shaped cells that are centrally located in the LAM nodules and are highly immunoreactive for matrix metalloproteinase-2 (MMP-2), its activating enzyme (MT-1-MMP), and proliferating cell nuclear antigen (PCNA), and 2) large, epithelioid cells that are distributed along the periphery of the nodules and show a high degree of immunoreactivity with HMB-45 antibody and with antibodies against estrogen and progesterone receptors. Types of treatment used for LAM include oophorectomy, administration of Lupron or progesterone and in very severe cases, pulmonary transplantation (following the onset of respiratory insufficiency, not relieved by O(2)).

Downregulation of estrogen and progesterone receptors in the abnormal smooth muscle cells in pulmonary lymphangioleiomyomatosis following therapy. An immunohistochemical study

Immunohistochemical and confocal microscopic studies were made on lung tissue from 10 women with lymphangioleiomyomatosis (LAM) to evaluate the distribution of estrogen receptors (ER) and progesterone receptors (PR) in the abnormal smooth muscle cells (LAM cells) that characterize this disorder. PR and ER were localized mainly in the nuclei of large, epithelioid LAM cells, in five patients in whom tissues were obtained before treatment. However, the reaction for PR and ER was essentially negative in similarly processed tissues from five patients studied after receiving hormonal therapy (progesterone and tamoxifen). In the untreated group, staining for ER and PR colocalized with that for HMB-45, but not with that for membrane type-1 matrix metalloproteinase (MT-1-MMP), which we have shown to be localized in proliferating LAM cells. These observations demonstrate that PR and ER are selectively expressed in a subpopulation of LAM cells that are larger in size, have a limited ability to proliferate, and do not produce MT-1-MMP, the enzyme that activates MMP-2 (which is secreted by LAM cells and is capable of lysing elastin and collagens). ER and PR in LAM cells appear to be downregulated by hormonal therapy.

Frequent estrogen and progesterone receptor immunoreactivity in renal angiomyolipomas from women with pulmonary lymphangioleiomyomatosis

OBJECTIVE

To determine whether renal angiomyolipomas from women with pulmonary lymphangioleiomyomatosis (LAM) express estrogen receptor (ER) and progesterone receptor (PR).

DESIGN

Retrospective study of archival tissue.

PATIENTS

Twelve women with LAM and angiomyolipomas.

SETTING

Fox Chase Cancer Center.

INTERVENTIONS

ER and PR expression was studied using immunohistochemistry. The hormonal status of the patients at the time of resection of the angiomyolipoma was determined.

RESULTS

Ten of the angiomyolipomas had ER immunoreactivity (83%), and all 12 had PR immunoreactivity (100%). The ER and PR positivity was in the smooth muscle component of the angiomyolipomas only. For five women, pulmonary LAM specimens were also available; two were ER positive (40%), and all five were PR positive (100%). All four angiomyolipomas from women receiving progesterone therapy were ER and PR positive. One tumor from a woman receiving tamoxifen was ER negative and strongly PR positive. One woman was pregnant; her tumor was ER and PR positive.

CONCLUSIONS

ER and PR expression is frequent in renal angiomyolipoma cells from women with LAM. PR was more consistently present than ER in angiomyolipomas and in LAM. Our data suggest that angiomyolipoma growth could be affected by hormonal factors. If the growth of LAM-associated angiomyolipomas slows during hormonal therapy, there are two potential implications for LAM patients: first, angiomyolipoma size could serve as a measurable indication of response to hormonal therapy; and second, surgical removal of angiomyolipomas might be avoided in some cases.

Pulmonary lymphangioleiomyomatosis. A study of 69 patients. Groupe d'Etudes et de Recherche sur les Maladies "Orphelines" Pulmonaires (GERM"O"P)

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disorder of unknown cause characterized by peribronchial, perivascular, and perilymphatic proliferation of abnormal smooth muscle cells leading to cystic lesions. The hypothesis of hormonal dependence and the effectiveness of hormonal therapy have not yet been demonstrated conclusively, and the prevalence of extrathoracic manifestations and the survival of patients with LAM are somewhat contradictory. A multicentric retrospective study was conducted in an attempt to describe better the initial features, the diagnostic procedures, the associated lesions, and, above all, the management and course of LAM in a large homogeneous series of 69 stringently selected patients, with a majority of cases diagnosed since 1990. The aim of the study, based on a review of the literature, also was to provide a comprehensive view of this uncommon disease. The clinical features were in keeping with previous studies, but we found that exertional dyspnea and pneumothorax were the most common features, and chylous involvement was less frequent. LAM was diagnosed after menopause in about 10% of cases. The onset of LAM occurred during pregnancy in 20% of cases, and a clear exacerbation of LAM was observed in 14% of cases during pregnancy. Pulmonary LAM was diagnosed on lung histopathology in 83% of cases, but renal angiomyolipoma, observed in 32% of our patients, may be a useful diagnostic criterion when associated with typical multiple cysts on chest CT scan or with chylous effusion. Chest CT scan was more informative than chest X-ray (normal in 9% of cases), and may be indicated in spontaneous pneumothorax or renal angiomyolipoma in women of childbearing age. About 40% of the patients had a normal initial spirometry, while an obstructive ventilatory defect (44%), a restrictive ventilatory defect (23%), was observed in other patients. Initial diffusing capacity for carbon monoxide was frequently decreased (82%). Hormonal therapy was administered in 57 patients, but a clear > or = 15% improvement of FEV1 was observed in only 4 evaluable patients, treated with tamoxifen and progestogens (n = 2), progestogen (n = 1), and oophorectomy (n = 1). Probably 1 of the most urgent needs for clinical research in LAM is to test the currently available hormonal treatments in the context of international multicenter prospective controlled studies. Pleurodesis was performed in 40 patients. Lung transplantation was performed in 13 patients, 7.8 +/- 5.2 years after onset of LAM, in whom the mean FEV1 was 0.57 +/- 0.15 L. After a follow-up of 2.3 +/- 2.2 years, 9 patients were alive. Mean follow-up from onset of disease to either death or closing date was 8.2 +/- 6.3 years. Overall survival was better than usually reported in LAM, and Kaplan-Meier plot showed survival probabilities of 91% after 5 years, 79% after 10 years, and 71% after 15 years of disease duration.

[Pulmonary lymphangioleiomyomatosis: an often fortuitous diagnosis. A case report]

INTRODUCTION

Lymphangioleiomyomatosis is an uncommon disorder of unknown origin, which exclusively occurs in women of reproductive age. The condition is characterized by proliferation of immature smooth muscle cells throughout the lungs, i.e., in the peribronchial, perilymphatic, and perivascular areas. This results in obliteration of the respiratory tract and in the development of cysts. Lymphangioleiomyomatosis has a poor prognosis due to both numerous lung complications and progression of the disease to respiratory failure.

EXEGESIS

We report the case of a patient in whom lymphangioleiomyomatosis was fortuitously diagnosed from chest CT scan, itself performed for the diagnosis of pulmonary embolism. This case is therefore of particular interest.

CONCLUSION

Our results suggest that the prevalence of lymphangioleiomyomatosis is probably underestimated due to its clinical latency and the absence of specific laboratory tests. Therefore, the development of non-invasive radiological methods should permit early diagnosis of the disease.

Rare pulmonary manifestations of tuberous sclerosis in children

Tuberous sclerosis is one of the rare neurocutaneous syndromes and may involve organs other than skin and brain. Pulmonary involvement is uncommon and predominantly affects women of childbearing age. Those affected present with dyspnea or spontaneous pneumothorax from cystic or fibrous degeneration of the lung. Males are affected very rarely. This paper describes another manifestation of pulmonary involvement in tuberous sclerosis, namely, recurrent intrapleural cysts in a young boy.

When to suspect and how to diagnose pulmonary lymphangioleiomyomatosis

The objective of this study was to present clinical and radiological data of eight women with histologically proven lymphangioleiomyomatosis (LAM) diagnosed between 1984 and 1994, and to suggest a diagnostic strategy when LAM is suspected. A review of case reports, including results of biopsies, lung function and radiological procedures was undertaken. The mean age of the women at start of symptoms was 36 years, and the mean age at time of diagnosis 42 years. The most frequent presenting complaint was dyspnea, either in conjunction with pneumothorax (3), chylothorax (2) or on exertion (2). All patients had airflow limitation and markedly reduced gas transfer. Five patients had 16 episodes of pneumothorax. In seven patients multiple cysts were observed on the surface of the lung during thoracotomy while computerized tomography (CT) scans revealed numerous cysts evenly distributed throughout the lung parenchyma. The procedures that confirmed the diagnosis included transbronchial lung biopsy (4), open lung biopsy (2), thoracoscopy (1), thoracotomy (3) and autopsy (1). Three specimens had to be revised before the histological diagnosis was confirmed. It was concluded that the important clues to a diagnosis of LAM are recurrent episodes of pneumothoraces in fertile women, progressive air-flow limitation, markedly reduced gas transfer and characteristic findings on thoracic CT scans. A specific request to the pathologist to stain lung tissue specimens for smooth muscle cells is mandatory.

Immunohistological detection of estrogen and progesterone receptors in multiple and well differentiated leiomyomatous lung tumors in women with uterine leiomyomas (so-called benign metastasizing leiomyomas). A report on 5 cases

Seventy-four cases of so-called "benign metastasizing uterine leiomyomata" are reported in the literature. In these cases, well differentiated, leiomyomatous lung tumors developed, usually after a period of several years. Histologically, these tumors appear to be benign. We report on five more such cases in which we investigated the contents of estrogen and progesterone receptors in the pulmonary tumors by immunohistological procedures. All the lung tumors exhibited a high content of progesterone receptors, and in 4 out of the 5 cases a high estrogen receptor content was also found. Modern immunohistological techniques permit the investigation of routinely fixed tissue blocks, and it is thus recommended that the contents of these hormone receptors should be determined in well differentiated, leiomyomatous lung tumors from women. This would both provide information on the pathogenesis of these tumors and establish a basis for possible later institution of hormone treatment. It is likely that the majority of these lung tumors are in fact metastases of extremely well differentiated leiomyosarcomas of the uterus. The possibility that lung tumors of this type may constitute a small group that develop in situ as hormone-sensitive proliferations cannot, however, be fully excluded.

Pulmonary tuberous sclerosis

We describe the clinical presentation, pulmonary function tests, chest radiograph, and computed tomography findings, response to hormonal treatment, and duration of survival of nine patients with pulmonary involvement in tuberous sclerosis complex with follow-up over an average of 17 years (range, 1 to 35 years) since diagnosis. All patients were female, and the average age at onset of symptoms was 16 years (range, 3 months to 39 years); pulmonary symptoms did not develop until an average age of 33 years (range, 22 to 46 years). There was an average delay of 8 years before the correct diagnosis was made. The most common presenting clinical features were seizures, pneumothorax, bleeding into a renal angiomyolipoma, dyspnea, and typical skin changes. Pulmonary function tests commonly demonstrated obstruction to airflow and reduced single-breath diffusing capacity. Chest radiograph and computed tomography characteristically demonstrated diffuse interstitial infiltrates with cystic changes. Two asymptomatic patients with mild pulmonary involvement have remained in stable condition without hormonal therapy. The remaining seven patients had moderate to severe airflow obstruction; of these, five underwent hormonal therapy. Three patients had a clinical response to treatment. Two patients who did not receive hormonal treatment died of progressive respiratory failure. Most patients with pulmonary involvement in tuberous sclerosis have a slowly declining clinical course. Although the available data are limited, they suggest that a trial of hormonal therapy is recommended both for symptomatic patients and for those with declining pulmonary function. Tuberous sclerosis complex should be suspected in all patients with the diagnosis of lymphangioleiomyomatosis.

Relation of pulmonary lymphangio-leiomyomatosis to use of the oral contraceptive pill and fertility in the UK: a national case control study

BACKGROUND

Pulmonary lymphangioleiomyomatosis is a rare progressive disease of unknown aetiology affecting premenopausal women. Since the oral contraceptive pill has been implicated in its pathogenesis, a case control study was carried out to determine whether women with the disease were more likely to have taken the oral contraceptive pill, and whether the disease was associated with other conditions related to sex hormones including pregnancy, parity, and fibroids.

METHODS

All chest physicians in the UK were asked for details of all live patients with pulmonary lymphangioleiomyomatosis; the patient's family doctor was then asked for four age and sex matched control subjects from their patient register. Details of lifetime use of the oral contraceptive pill, pregnancy, parity, history of fibroids, and smoking were obtained from cases and controls. Relative odds of exposure to potential risk factors were estimated by conditional logistic regression.

RESULTS

Medical details were obtained from all 23 cases of lymphangioleiomyomatosis identified; questionnaires were completed by 21 cases (one by proxy) and by 46 matched controls of mean (SD) age 43 (10) and 44 (11) years, respectively. The patients had a mean age of 34 (9) years at onset of symptoms and a median (range) time of 2 (0-29) years from onset of symptoms to diagnosis. Compared with control subjects, cases did not differ in the use of the oral contraceptive pill (odds ratio (OR) 0.39, 95% CI 0.09 to 1.68), diagnosis of fibroids (OR 3.12; 95% CI 0.52 to 18.7), age of menarche, menstrual history, or lifetime smoking. They were, however, less likely to have been pregnant (OR 0.14, 95% CI 0.03 to 0.71) or to have had children (OR 0.13, 95% CI 0.03 to 0.67). More pregnancies had ended in spontaneous abortion (28% v 8%) but the proportion of women undergoing spontaneous abortion was similar in cases and controls (OR 2.13, 95% CI 0.47 to 9.3).

CONCLUSIONS

This study does not support the hypothesis that use of the oral contraceptive pill is causally associated with the development of pulmonary lymphangioleiomyomatosis. Sex hormones may be involved, however, since patients were less likely to have been pregnant or to have had children, and tended to have had more spontaneous abortions and an increased incidence of fibroids.

Coexisting lymphangioleiomyomatosis and bilateral angiomyolipomas in a patient with tuberous sclerosis

A patient with tuberous sclerosis and known bilateral angiomyolipomas presented with a complete pneumothorax prior to scheduled renal surgery. Evaluation revealed the presence of pulmonary lymphangioleiomyoma, an unusual entity known to coexist with tuberous sclerosis. Pulmonary decortication and conservative renal surgery resulted in a satisfactory long-term result.

Pulmonary lymphangioleiomyomatosis

This paper reports a case of a 50 yr old premenopausal woman with pulmonary lymphangioleiomyomatosis. This asymptomatic woman was found to have 'pulmonary nodules' on routine chest x-ray simulating metastatic lesions. The final diagnosis was possible after pathological examination of the lung biopsy specimens. This case is atypical for 3 reasons: firstly, the patient's age was 50, unusually old for this tumor; secondly, she was asymptomatic; and finally, the pulmonary imaging findings revealed bilateral nodular lesions in contrast to the usual reticular pattern.

Lymphangiomyomatosis and angiomyolipoma: closely related entities characterized by hamartomatous proliferation of HMB-45-positive smooth muscle

Angiomyolipoma is a hamartomatous condition which can occur as a component of the tuberous sclerosis complex. Lymphangiomyomatosis, another hamartomatous lesion occurring predominantly in the lungs, has long been suspected to be related to angiomyolipoma and tuberous sclerosis because of occasional clinical associations. We undertook this study to provide further support for the close relationship between these two entities. Five cases of lymphangiomyomatosis and 20 case of angiomyolipoma were retrieved for histological review and immunohistochemical studies. The antibodies used were anti-muscle specific actin (HHF-35), anti-desmin (D33) and anti-melanoma (HMB-45). Lesions featuring smooth muscle proliferation were used as controls. The proliferated smooth muscle cells in both lymphangiomyomatosis and angiomyolipoma were much plumper and paler or even clear, when compared with the deeply eosinophilic cytoplasm of the normal spindly smooth muscle cells and those of leiomyomas. Their nuclei were round to oval and pale rather than elongated and dark. Cells with bizarre nuclei were commoner in angiomyolipoma (18/20 cases) than lymphangiomyomatosis (1/5). In 12 cases of angiomyolipoma there were foci indistinguishable from lymphangiomyomatosis, i.e. plump spindle cells arranged in short fascicles around ramifying endothelium-lined spaces. All five cases of lymphangiomyomatosis stained for muscle-specific actin, desmin and HMB-45. For angiomyolipomas, the positivity rates for these markers were: 20/20, 17/20 and 18/20, respectively, including one case that was negative for both desmin and HMB-45. The various smooth muscle proliferations and tumours selected as controls were uniformly HMB-45 negative. The distinctive cytological features, morphological overlap and immunophenotypic profile all support a close relationship between lymphangiomyomatosis and angiomyolipoma, which probably represent different morphological manifestations of hamartomatous proliferation of a peculiar form of HMB-45-positive smooth muscle.

Pulmonary lymphangiomyomatosis. Follow-up and long-term outcome with antiestrogen therapy; a report of eight cases

Lymphangiomyomatosis is a rare disease which affects young women of childbearing age. Eight women with pulmonary LAM were treated with antiestrogen therapy and were monitored by blood estrogen measurements along with clinical hypoestrogenic symptoms. Treatment ranged from three to nine years. The response to therapy was evaluated by the clinical course, chest x-ray films, pulmonary function tests and overall long-term outcome. Three patients died of respiratory failure after three, five and nine years of treatment. Of the five patients remaining alive, respiratory function deteriorated in four cases, after a transient period of mild improvement lasting three years in two cases. The last patient appeared stable after three years of follow-up. Time course ranged from 4 to 17 years. However, without a control group, we cannot determine whether or not the apparent improvement of the natural time course was due to the hormonal treatment.