Renal angiomyolipoma in association with pulmonary lymphangioleiomyomatosis: forme fruste of tuberous sclerosis?

Individual Copy Number of Ribosomal Genes as a Factor of Mental Retardation and Autism Risk and Severity

Autism is a complex multifactorial developmental disorder characterized by deficits in communication and restricted interests, often followed by mental retardation. Autism spectrum disorders (ASD) are caused by defects in miscellaneous molecular mechanisms, many of which remain unclear. But a considerable part of the known pathways converges on protein synthesis or degradation processes at different stages in the dendrites, laying the foundation for a concept of disturbed “translational homeostasis” or “proteostasis” in autism. The protein synthesis is conducted on ribosomes, cellular organelles consisting from a complex of riboproteins and a ribosomal RNA (rRNA) framework. The rRNA is encoded by ribosomal genes (RG) existing in multiple copies in the genome. The more copies of RG that are contained in the genome, the higher is the peak (maximum possible) ribosome abundance in the cell. A hypothesis is proposed that the RG copy number, through determining the quantity of ribosomes available in the dendrites, modulates the level of local dendritic translation and thus is a factor of risk and severity of a series of neuropsychiatric disorders caused by aberrant dendritic translation. A carrier of very low copy number of ribosomal genes is expected to have a milder form of ASD than a subject with the same epigenetic and genetic background, but a higher ribosomal gene dosage. Various ways of evaluation and testing the hypothesis on clinical material and animal models are suggested.

Analysis of a Mouse Skin Model of Tuberous Sclerosis Complex

Tuberous Sclerosis Complex (TSC) is an autosomal dominant tumor suppressor gene syndrome in which patients develop several types of tumors, including facial angiofibroma, subungual fibroma, Shagreen patch, angiomyolipomas, and lymphangioleiomyomatosis. It is due to inactivating mutations in TSC1 or TSC2. We sought to generate a mouse model of one or more of these tumor types by targeting deletion of the Tsc1 gene to fibroblasts using the Fsp-Cre allele. Mutant, Tsc1^ccFsp-Cre+ mice survived a median of nearly a year, and developed tumors in multiple sites but did not develop angiomyolipoma or lymphangioleiomyomatosis. They did develop a prominent skin phenotype with marked thickening of the dermis with accumulation of mast cells, that was minimally responsive to systemic rapamycin therapy, and was quite different from the pathology seen in human TSC skin lesions. Recombination and loss of Tsc1 was demonstrated in skin fibroblasts in vivo and in cultured skin fibroblasts. Loss of Tsc1 in fibroblasts in mice does not lead to a model of angiomyolipoma or lymphangioleiomyomatosis.

Minireview: Lymphangioleiomyomatosis (LAM): The "Other" Steroid-Sensitive Cancer

Lymphangioleiomyomatosis (LAM) is a devastating rare lung disease affecting primarily childbearing age women in which tumors consisting of abnormal smooth-muscle-like cells grow within the lungs and progressively lead to loss of pulmonary function. LAM cells metastasize to the lungs, predominantly through the lymphatics; however, the source of the LAM cell is still unknown. LAM cells contain inactivating mutations in genes encoding tuberous sclerosis 1 or 2, proteins that normally limit cell growth through suppression of mammalian target of rapamycin complex 1. As of today, sirolimus (an mammalian target of rapamycin complex 1 inhibitor) is the only treatment, available for LAM patients that is approved by the Food and Drug Administration; however, this drug and others in its class provide stabilization but not remission of LAM. One of the biggest problems in treating LAM is that both the origin of the LAM cells and the mechanism of the sexual dimorphism in LAM are still not understood. LAM cells express estrogen and progesterone receptors, and lung function declines during periods of high circulating estrogen levels. Moreover, numerous basic research studies find that estrogen is a key driving force in LAM cell proliferation, migration, and metastasis. In this review, we highlight recent insights regarding the role of steroid hormones in LAM and discuss possible explanations for the profound female sexual dimorphism of LAM.

Frequency of undiagnosed cystic lung disease in patients with sporadic renal angiomyolipomas

OBJECTIVE

The aim of this study was to assess the frequency of undiagnosed cystic lung lesions suggestive of pulmonary lymphangioleiomyomatosis (LAM) in patients who received a diagnosis of sporadic renal angiomyolipomas (AMLs).

METHODS

We conducted a retrospective review of CT scans of the chest or abdomen for cystic lung lesions on 176 adult patients who received a diagnosis of sporadic renal AML during a 10-year period, 1997 to 2006, and comparison with chest CT scans of 176 control subjects without renal AML but matched for age, sex, and smoking history. Patients presenting with suspected or known pulmonary LAM and those with underlying tuberous sclerosis were excluded.

RESULTS

Sporadic renal AML was diagnosed in 176 patients with a median age of 58 years (range, 20-91 years), the majority of whom were women (81.8%). Renal tumor was an incidental finding on imaging studies for most patients (90.3%). Nineteen patients (10.8%) had one or more cystic lung lesions and included nine patients (5.1%) with four or more cysts, all of whom were women. In comparison, eight control subjects (4.6%) had one to three cystic lung lesions and none of them exhibited four or more cysts. None of the patients with renal AML and cystic lung lesions, including six women with 10 or more cysts, had undergone an evaluation of their cystic lung disease.

CONCLUSIONS

We conclude that a significant portion of women with sporadic renal AMLs exhibit cystic lung lesions suggestive of pulmonary LAM but may remain undiagnosed. Coexistence of pulmonary LAM should be considered in women incidentally found to have sporadic renal AMLs.

Recognition of tuberous sclerosis in adult women: delayed presentation with life-threatening consequences

BACKGROUND

Tuberous sclerosis complex (TSC) is associated with tumor development in the brain, retina, kidney, skin, heart, and lung. Seizures, intellectual disability, and characteristic skin lesions commonly manifest in early childhood, but some findings, notably renal angiomyolipomas and pulmonary lymphangioleiomyomatosis (LAM), emerge later, placing adults with undiagnosed TSC at increased risk for morbidity and mortality.

OBJECTIVE

To describe the clinical presentation and severity of TSC in adult women.

DESIGN

Retrospective cohort study.

SETTING

National Institutes of Health Clinical Center, Bethesda, Maryland, 1995 to 2010.

PATIENTS

79 women aged 18 years or older who were enrolled in an observational cohort study of TSC to evaluate disease manifestations.

MEASUREMENTS

History, physical examination, pulmonary function testing, chest radiography, abdominal computed tomography, high-resolution chest computed tomography, and brain magnetic resonance imaging were used to evaluate patients.

RESULTS

Among the 45 patients who received a diagnosis of TSC in adulthood, 21 presented with symptoms due to LAM, 19 with renal angiomyolipomas, and 10 with seizures. Of the 45 patients, 30 met clinical criteria for TSC in childhood that remained undiagnosed for a median of 21.5 years and 15 were older than 18 years before meeting the clinical criteria for TSC. Patients diagnosed in adulthood and those diagnosed in childhood had similar occurrences of pneumothorax, shortness of breath, hemoptysis, nephrectomy, and death.

LIMITATION

No men were included in the study, and selection was biased toward patients having pulmonary LAM.

CONCLUSION

Women who received a TSC diagnosis in adulthood had minimal morbidity during childhood but were still at risk for life-threatening pulmonary and renal manifestations.

PRIMARY FUNDING SOURCE

Intramural Research Program, National Institutes of Health, National Heart, Lung, and Blood Institute.

Vascular endothelial growth factors C and D induces proliferation of lymphangioleiomyomatosis cells through autocrine crosstalk with endothelium

Lymphangioleiomyomatosis (LAM) is a potentially fatal lung disease characterized by nodules of proliferative smooth muscle-like cells. The exact nature of these LAM cells and their proliferative stimuli are poorly characterized. Herein we report the novel findings that the lymphangiogenic vascular endothelial growth factors (VEGF) C and D induce LAM cell proliferation through activation of their cognate receptor VEGF-R3 and activation of the signaling intermediates Akt/mTOR/S6. Furthermore, we identify expression of the proteoglycan NG2, a marker of immature smooth muscle cells, as a characteristic of LAM cells both in vitro and in human lung tissue. VEGF-C-induced LAM cell proliferation was in part a result of autocrine stimulation that resulted from cross talk with lymphatic endothelial cells. Ultimately, these findings identify the lymphangiogenic VEGF proteins as pathogenic growth factors in LAM disease and at the same time provide a novel pharmacotherapeutic target for a lung disease that to date has no known effective treatment.

Lymphatic involvement in lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a rare, multisystem disease affecting primarily premenopausal women. The disease is characterized by cystic lung disease, at times leading to respiratory compromise, abdominal tumors (in particular, renal angiomyolipomas), and involvement of the axial lymphatics (e.g., adenopathy, lymphangioleiomyomas). Disease results from the proliferation of neoplastic cells (LAM cells), which, in many cases, have a smooth muscle cell phenotype, express melanoma antigens, and have mutations in one of the tuberous sclerosis complex genes (TSC1 or TSC2). In the lung, LAM cells found in the vicinity of cysts are, at times, localized in nodules and may be responsible for cyst formation through the production of proteases. Lymphatic channels, expressing characteristic lymphatic endothelial cell markers, are found within the LAM lung nodules. LAM cells may also be localized within the walls of the axial lymphatics, and, in some cases, penetrate the wall and proliferate in the surrounding adipose tissue. Consistent with extensive lymphatic involvement in LAM, the serum concentration of VEGF-D, a lymphangiogenic factor, is higher in LAM patients than in healthy volunteers.

[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.

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.

Segmental tuberous sclerosis presenting as unilateral facial angiofibromas

Tuberous sclerosis (TSC) is an autosomal dominant inherited disorder with cutaneous lesions of ash leaf hypopigmented macules, shagreen patches, periungual fibromas, facial angiofibromas, forehead fibrous plaques, confetti hypopigmentation, and poliosis. Multiple facial angiofibromas are a pathognomonic feature of TSC. Unilateral facial angiofibromas, however, represent a rare variant of TSC, as only 6 cases are reported in the literature. We describe a case of a 52-year-old man who presented with unilateral facial angiofibromas and poliosis without other features of TSC.

Pulmonary lymphangioleiomyomatosis and multiple hepatic angiomyolipomas in a man

Pulmonary lymphangioleiomyomatosis (LAM) is an uncommon disease that to this point has been known to occur exclusively in reproductive women. To our knowledge, only one case of pulmonary LAM that was proven pathologically has been reported in a genotypical and phenotypical man. Multiple occurrence of hepatic angiomyolipomas is also rare, and only six cases have been found in the literature. Here, we report a biological and phenotypical man who had pulmonary LAM and multiple hepatic angiomyolipomas, leading to a presumptive diagnosis of tuberous sclerosis. This unusual presentation further broadens the wide spectrum of various clinicopathological aspects of pulmonary lymphangioleiomyomatosis and hepatic angiomyolipoma. Here, we emphasize that multiple hepatic angiomyolipomas should be distinguished from hepatic tumors, particularly in an endemic area for hepatocellular carcinoma. Further, pulmonary lymphangioleiomyomatosis can be a cause of cystic pulmonary disease even in a man.

Contemporary diagnosis and management of renal angiomyolipoma

PURPOSE

We present a comprehensive resource that summarizes contemporary advances relevant to the clinical management of renal angiomyolipoma.

MATERIALS AND METHODS

A MEDLINE search was done using the key words angiomyolipoma, hemangioma or lipoma and kidney neoplasm, and therapeutic embolization. References from these articles were reviewed to identify additional relevant source material. We identified 13 series published since 1986 comprising 336 patients as well as 24 reports of therapeutic embolization for angiomyolipoma, comprising 76 patients. To our knowledge we report the largest compilation series to date.

RESULTS

Angiomyolipoma is generally benign, although an uncommon subtype (epithelioid angiomyolipoma) may behave more aggressively. Tuberous sclerosis associated angiomyolipoma tends to be larger, multiple and more likely to cause spontaneous hemorrhage than the sporadic entity. Tumors that hemorrhage tend to be larger. Computerized tomography or magnetic resonance is usually sufficient for diagnosis. Biopsy is rarely useful. Primary indications for intervention include symptoms such as pain or bleeding or suspicion of malignancy. Prophylactic intervention is justifiable for large tumors, in females of childbearing age or in patients in whom followup or access to emergency care may be inadequate. Recent advances that have affected management include improved understanding of tuberous sclerosis complex and angiomyolipoma genetics, the identification of molecular markers that facilitate histopathological diagnosis, and the refinement of embolization and partial nephrectomy techniques.

CONCLUSIONS

Although some cases of angiomyolipoma may require complete nephrectomy, most can be managed by conservative nephron sparing approaches. Ongoing research into the molecular biology and clinical behavior of angiomyolipoma may improve our ability to manage these lesions.

Nephron-sparing nephrectomy for giant renal angiomyolipoma associated with lymphangioleiomyomatosis

Renal angiomyolipomas are benign tumors known to occur sporadically and in association with genetic syndromes, including tuberous sclerosis and lymphangioleiomyomatosis. Surgical removal or radiographic embolization of angiomyolipomas larger than 4 cm is usually indicated because of an increased risk of spontaneous hemorrhage. We describe successful nephron-sparing surgery for a giant angiomyolipoma and discuss relevant management issues in a patient with lymphangioleiomyomatosis who had previously undergone bilateral pulmonary transplantation.

Giant angiomyolipoma associated with marked pulmonary lesions suggesting lymphangioleiomyomatosis in a patient with tuberous sclerosis

The association between Tuberous Sclerosis (TS) and Angiomyolipoma (AML) is well known. A patient with TS and giant AML mimicking Renal Cell Carcinoma (RCC), measuring 29 x 18 x 11 cm, weighing 4700 gr is presented. Imaging studies revealed coexistent pulmonary lymphangioleiomyomatosis and concurrent renal and pulmonary involvement is extremely rare in patients in TS. We believe that the growth potential of this hamartomatous lesion may reach to a life threatening size.

Renal angiomyolipoma associated with micronodular pneumocyte hyperplasia of the lung with tuberous sclerosis

Tuberous sclerosis complex is an autosomal-dominant disorder characterized by the triad of mental retardation, epilepsy and adenoma sebaceum. Micronodular pneumocyte hyperplasia is a rare but distinctive pulmonary epithelial lesion, usually associated with tuberous sclerosis. To the authors' knowledge, the relationship between renal angiomyolipoma and micronodular pneumocyte hyperplasia in cases of tuberous sclerosis has not received attention in the urological literature. The case of a woman with renal angiomyolipomas associated with micronodular pneumocyte hyperplasia of the lung with tuberous sclerosis is reported here.

Pulmonary lymphangioleiomyomatosis in a man

Pulmonary lymphangioleiomyomatosis (LAM) is an uncommon disease reported to occur exclusively in women. We describe a phenotypically normal man with pulmonary LAM. Fluorescence in situ hybridization (FISH) studies performed on the lung biopsy confirmed a normal XY genotype. Our patient also had stigmata of tuberous sclerosis complex (TSC), including facial angiofibromas and renal angiomyolipoma. Immunohistochemical stains of both LAM and renal angiomyolipoma showed positive immunoreactivity for hamartin (TSC1) and loss of immunoreactivity for tuberin (TSC2). Loss of heterozygosity (LOH) for TSC2 was further demonstrated in the renal angiomyolipoma. Coupled with the results of immunostains, these findings are consistent with TSC2 mutation.

Mutations in the tuberous sclerosis complex gene TSC2 are a cause of sporadic pulmonary lymphangioleiomyomatosis

Lymphangioleiomyomatosis (LAM) is a progressive and often fatal interstitial lung disease characterized by a diffuse proliferation of abnormal smooth muscle cells in the lungs. LAM is of unusual interest biologically because it affects almost exclusively young women. LAM can occur as an isolated disorder (sporadic LAM) or in association with tuberous sclerosis complex. Renal angiomyolipomas, which are found in most tuberous sclerosis patients, also occur in 60% of sporadic LAM patients. We previously found TSC2 loss of heterozygosity in 7 of 13 (54%) of angiomyolipomas from sporadic LAM patients, suggesting that LAM and TSC could have a common genetic basis. In this study, we report the identification of somatic TSC2 mutations in five of seven angiomyolipomas from sporadic LAM patients. In all four patients from whom lung tissue was available, the same mutation found in the angiomyolipoma was present in the abnormal pulmonary smooth muscle cells. In no case was the mutation present in normal kidney, morphologically normal lung, or lymphoblastoid cells. Our data demonstrate that somatic mutations in the TSC2 gene occur in the angiomyolipomas and pulmonary LAM cells of women with sporadic LAM, strongly supporting a direct role of TSC2 in the pathogenesis of this disease.

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.

Molecular analysis of clonality of sporadic angiomyolipoma

Angiomyolipoma, which consists of three intimately intermixed components, smooth muscle, blood vessels, and adipose tissue, is variably considered a hamartoma, a choristoma or a true neoplasm. This study has investigated the clonality of sporadic angiomyolipomas in seven women, each with a single lesion, by determining the pattern of X-chromosome inactivation. Polymerase chain reaction (PCR) amplification of the highly polymorphic human androgen receptor gene (HUMARA) was performed on the DNA extracted from the paraffin-embedded lesional tissue microdissected to sample the admixed smooth muscle and blood vessel component (SMC/BV) and the adipose tissue component. All seven patients were heterozygous for HUMARA polymorphism upon amplification of undigested DNA from non-lesional tissue and were therefore informative for further analysis. In all patients, lesional DNA, representative of the components, was predigested with HpaII restriction enzyme for amplification of the methylated allele. In six patients, the lesions were clonal, while in one, polyclonal. The polyclonal lesion was small and had less than 20 per cent SMC/BV component. Microdissected SMC/BV component was clonal in 6/7 lesions; the scanty SMC/BV in the remaining lesion did not yield amplifiable DNA. Microdissected adipose tissue was polyclonal in all seven lesions. Angiomyolipomas are three clonal lesions due to a clonal smooth muscle cell and blood vessel component, while the polyclonal adipose tissue is probably metaplastic or reactive.

Tuberous sclerosis complex consensus conference: revised clinical diagnostic criteria

At the recent tuberous sclerosis complex consensus conference, the clinical diagnostic criteria for tuberous sclerosis complex were simplified and revised to reflect both new clinical information about tuberous sclerosis complex and an improved understanding of the disorder derived from molecular genetic studies. Based on this new information, some clinical signs once regarded as pathognomonic for tuberous sclerosis complex are now known to be less specific. No single sign is present in all affected patients, and there is no proof that any single clinical or radiographic sign is absolutely specific for tuberous sclerosis complex. Accordingly, the clinical and radiographic features of tuberous sclerosis complex have now been divided into major and minor categories based on the apparent degree of specificity for tuberous sclerosis complex of each feature. A definitive diagnosis of tuberous sclerosis complex now requires two or more distinct types of lesions, rather than multiple lesions of the same type in the same organ system. Although diagnosis on purely clinical grounds can continue to be difficult in a few patients, there should be little doubt about the diagnosis for those individuals who fulfill these strict criteria. Couples with more than one child with tuberous sclerosis complex, no extended family history, and no clinical features of tuberous sclerosis complex are more likely to have germline mosaicism for tuberous sclerosis than nonexpression of the mutation. Germline mosaicism, while fortunately rare, will not be suspected from either diagnostic criteria or molecular testing until a couple has multiple affected children. Genetic counseling for families with one affected child should include a small (1% to 2%) possibility of recurrence, even for parents who have no evidence of tuberous sclerosis complex after a thorough diagnostic evaluation.

Renal angiomyolipomas, cysts, and cancer in tuberous sclerosis complex

Tuberous sclerosis is a multisystem syndrome characterized by neurological symptoms and tumors in multiple organs, including kidney, brain, skin, eyes, heart, and lung. The kidney and brain are the two most frequently affected organs in TSC, and renal disease is a leading cause of death in TSC patients. Three types of tumors occur in TSC kidneys: (1) angiomyolipomas, which are benign tumors composed of smooth muscle, fat, and vessels; (2) epithelial cysts; and (3) malignant tumors. This review focuses on the clinical, pathological, and molecular features of these tumors.

[Lymphangioleiomyomatosis and tuberous sclerosis: a casual association or a causative one?]

Lymphangioleiomyomatosis (LAM) is a rare lung disease that mainly affects women of childbearing age. Pulmonary disease that is indistinguishable from LAM appears in 1% of patients with tuberous sclerosis (TS). At present we can not say whether we are looking at an association of two rare diseases or at a single disease with different clinical profiles. To date, open lung biopsy has been required for definitive diagnosis. We report the case of a women with TS and LAM in whom a diagnosis of pulmonary involvement was based on clinical signs and high resolution computerized tomography of the chest.

Evidence that lymphangiomyomatosis is caused by TSC2 mutations: chromosome 16p13 loss of heterozygosity in angiomyolipomas and lymph nodes from women with lymphangiomyomatosis

Lymphangiomyomatosis (LAM) is a rare disease, of unknown etiology, affecting women almost exclusively. Lung transplantation is the only consistently effective therapy for LAM. Microscopically, LAM consists of a diffuse proliferation of smooth muscle cells. LAM can occur without evidence of other disease (referred to as "sporadic LAM") or in association with tuberous sclerosis complex (TSC). TSC is an autosomal dominant tumor suppressor gene syndrome characterized by seizures, mental retardation, and tumors in the brain, heart, skin, and kidney. Renal angiomyolipomas occur in approximately 50% of sporadic LAM patients and in 70% of TSC patients. Loss of heterozygosity (LOH) in the chromosomal region for the TSC2 gene occurs in 60% of TSC-associated angiomyolipomas. Because of the similar pulmonary and renal manifestations of TSC and sporadic LAM, we hypothesized that LAM and TSC have a common genetic basis. We analyzed renal angiomyolipomas, from 13 women with sporadic LAM, for LOH in the regions of the TSC1 (chromosome 9q34) and TSC2 (chromosome 16p13) genes. TSC2 LOH was detected in seven (54%) of the angiomyolipomas. We also found TSC2 LOH in four lymph nodes from a woman with retroperitoneal LAM. No TSC1 LOH was found. Our findings indicate that the TSC2 gene may be involved in the pathogenesis of sporadic LAM. However, genetic transmission of LAM has not been reported. Women with LAM may have low-penetrance germ-line TSC2 mutations, or they may be mosaic, with TSC2 mutations in the lung and the kidney but not in other organs.

Lung transplantation for lymphangioleiomyomatosis

BACKGROUND

Lymphangioleiomyomatosis is a rare disease of unknown origin that usually leads to progressive deterioration of lung function and eventual death from respiratory failure. It occurs in women of reproductive age and people with tuberous sclerosis. Lung transplantation is a recent therapeutic approach.

METHODS

We conducted a retrospective study by questionnaire of 34 patients, treated at 16 transplantation centers, who underwent lung transplantation for end-stage lymphangioleiomyomatosis between 1983 and 1995.

RESULTS

Of the 34 patients, 27 received single-lung transplants; 6, bilateral transplants; and 1, a heart-lung transplant. As of August 31, 1995, the actuarial survival calculated by the Kaplan-Meier method was 69 percent after one year and 58 percent after two years. Eighteen patients were alive 33 +/- 20 months (range, 3 to 74) after transplantation. Forced expiratory volume in one second increased from 24 +/- 12 percent of the predicted value before transplantation to 48 +/- 16 percent six months after transplantation. Five early deaths (within one month) were due to hemorrhage (in one patient), acute lung injury (in three), and dehiscence of the bronchial anastomosis (in one). Eleven late deaths (after one month) were due to infections (in eight patients), bronchiolitis obliterans (in two), and metastatic nephroblastoma (in one). Disease-associated problems were extensive pleural adhesions in 18 patients, leading to moderate-to-severe intraoperative hemorrhage in 4; pneumothorax in the native lung after single-lung transplantation in 6 patients; postoperative chylothorax in 3; and recurrent lymphangioleiomyomatosis in the allograft in 1 patient, who died of disseminated aspergillosis.

CONCLUSIONS

Although disease-related complications are frequent, lung transplantation can be a valuable therapy for patients with end-stage lymphangioleiomyomatosis.

Multicentric renal angiomyolipoma associated with pulmonary lymphangioleiomyomatosis: case report, with histologic, immunohistochemical, and DNA content analyses

A 26-year-old pregnant woman presented with pulmonary lymphangioleiomyomatosis (LAM) and multicentric angiomyolipoma (AML) involving the left kidney and perirenal lymph nodes. In both tumors, smooth muscle cells were the predominant component. Immunohistochemically, these cells stained for vimentin, smooth muscle actin, desmin, and HMB-45. Estrogen receptors were weakly positive in LAM and negative in AML. Progesterone receptors were negative for both lesions. DNA content analysis studies showed the renal AML to be diploid with a minor aneuploid component, the lymph node AML aneuploid, and the LAM diploid. The diagnostic and prognostic significance of hormonal studies and DNA content analysis are discussed.

Extrapulmonary lymphangioleiomyomatosis and lymphangiomatous cysts in tuberous sclerosis complex

OBJECTIVE

To describe the clinical manifestations, imaging findings, and histologic features of extrapulmonary lymphangioleiomyomatosis (LAM) in the tuberous sclerosis complex (TSC).

DESIGN

We retrospectively reviewed institutional medical records since 1940 to identify patients with TSC and extrapulmonary LAM.

MATERIAL AND METHODS

Of 403 patients with TSC, 3 had pulmonary and extrapulmonary LAM and retroperitoneal lymphangiomatous cysts. The clinical, imaging, and histologic features of these three patients were summarized, including analysis of biopsy specimens by conventional histology, immunohistology, radiolabeled ligand-binding assays, and tissue culture.

RESULTS

The three young women had characteristic dermatologic findings of TSC and pulmonary LAM. Two patients were of normal intelligence, and one had a recent history of contraceptive use. All three patients had intra-abdominal lymphangiomatous cysts, uterine LAM, and renal angiomyolipomas. Renal and uterine biopsy specimens demonstrated positive immunostaining for melanoma-related antigens and expression of estrogen and progesterone receptors by ligand-binding assay and immunohistology. Cells cultured from LAM tissue of one of the patients exhibited a mitogenic response to estradiol.

CONCLUSION

Clinically significant extrapulmonary LAM is a rare manifestation of TSC and may occur in women with this disease who also have pulmonary LAM. The clinical features of these patients confirm the importance of sex steroids in the development of these lesions. Immunohistochemical findings suggest that LAM and angiomyolipomas have a neuroectodermal origin. The development of lymphangiomatous cysts in these patients is probably due to smooth muscle proliferation in lymph vessels, which can result in lymphatic obstruction.

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.