When to suspect and how to diagnose pulmonary lymphangioleiomyomatosis

Transbronchial lung biopsy for the diagnosis of lymphangioleiomyomatosis: the severity of cystic lung destruction assessed by the modified Goddard scoring system as a predictor for establishing the diagnosis

Background

A guide of patient selection for establishing the diagnosis of lymphangioleiomyomatosis (LAM) by transbronchial lung biopsy (TBLB) has not been established, although the pathological confirmation of LAM by lung biopsy is desirable, particularly when patients have no additional test results except typical findings of computed tomography (CT) of the chest.

Methods

We retrospectively reviewed the medical records of LAM patients who visited at our hospital from January 2010 to September 2018. We found 19 patients who underwent TBLB and collected the following data to investigate which parameters could predict the TBLB diagnostic positivity for LAM: age, degree of exertional dyspnea, pulmonary function test, cystic lung destruction visually assessed by the modified Goddard scoring system (MGS), serum level of vascular endothelial growth factor-D, and TBLB-related data.

Results

The diagnosis of LAM was established by TBLB in 15 of 19 patients (78.9%) and no serious complications occurred. MGS was significantly higher in the TBLB-positive group than the TBLB-negative group. In LAM patients without pulmonary lymphatic congestion on CT (N = 16), multivariable logistic regression analysis revealed that MGS and FEV₁/FVC were independent contributing parameters for TBLB diagnostic positivity. However, the analysis of Bayesian inference demonstrated that MGS is a better predictor than FEV₁/FVC; the probability of establishing diagnosis exceeds 80% if MGS is > 2 (i.e., area of cystic destruction occupies > 25% of lung parenchyma on CT).

Conclusions

MGS may be a helpful and convenient tool to select candidates for TBLB to establish the diagnosis of LAM pathologically.

Lymphangioleiomyomatosis Diagnosis and Management: High-Resolution Chest Computed Tomography, Transbronchial Lung Biopsy, and Pleural Disease Management. An Official American Thoracic Society/Japanese Respiratory Society Clinical Practice Guideline

BACKGROUND

Recommendations regarding key aspects related to the diagnosis and pharmacological treatment of lymphangioleiomyomatosis (LAM) were recently published. We now provide additional recommendations regarding four specific questions related to the diagnosis of LAM and management of pneumothoraces in patients with LAM.

METHODS

Systematic reviews were performed and then discussed by a multidisciplinary panel. For each intervention, the panel considered its confidence in the estimated effects, the balance of desirable (i.e., benefits) and undesirable (i.e., harms and burdens) consequences, patient values and preferences, cost, and feasibility. Evidence-based recommendations were then formulated, written, and graded using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.

RESULTS

For women who have cystic changes on high-resolution computed tomography of the chest characteristic of LAM, but who have no additional confirmatory features of LAM (i.e., clinical, radiologic, or serologic), the guideline panel made conditional recommendations against making a clinical diagnosis of LAM on the basis of the high-resolution computed tomography findings alone and for considering transbronchial lung biopsy as a diagnostic tool. The guideline panel also made conditional recommendations for offering pleurodesis after an initial pneumothorax rather than postponing the procedure until the first recurrence and against pleurodesis being used as a reason to exclude patients from lung transplantation.

CONCLUSIONS

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

Utility of transbronchial biopsy in the diagnosis of lymphangioleiomyomatosis

Pulmonary lymphangioleiomyomatosis (LAM) is a rare cystic lung disease that targets women during their reproductive years. A confident diagnosis can often be based on clinical grounds, but diagnostic certainty requires pathological analysis. Although surgical lung biopsy is considered the gold standard for obtaining tissue in patients with diffuse lung disease, it is also associated with higher morbidity and mortality than alternative, less invasive techniques. The objective of our study was to examine the utility of transbronchial biopsy in the diagnosis of LAM. We conducted two online surveys of over 1,000 LAM patients registered with the LAM Foundation who were accessible by email. Transbronchial biopsy specimens were subsequently collected and reviewed by an expert pathologist to validate the diagnosis. We found that transbronchial biopsy has a yield of approximately 60% in patients with LAM. We conclude that transbronchial biopsy may be a safe and effective method for establishing the diagnosis of LAM, obviating the need for surgical lung biopsy in more than half of LAM patients.

A current viewpoint of lymphangioleiomyomatosis supporting immunotherapeutic treatment options

Lymphangioleiomyomatosis (LAM) leads to hyperproliferation of abnormal smooth muscle cells in the lungs, associated with diffuse pulmonary parenchymal cyst formation and progressive dyspnea on exertion. The disease targets women of child-bearing age. Complications include pneumothoraces and chylous pleural effusions. Ten-year survival is estimated at 70%, and lung transplantation remains the only validated treatment. It has been observed that LAM cells express markers associated with melanocytic differentiation, including gp100 and MART-1. Other melanocytic markers have also been observed. The same proteins are targeted by T cells infiltrating melanoma tumors as well as by T cells infiltrating autoimmune vitiligo skin, and these antigens are regarded as relatively immunogenic. Consequently, vaccines have been developed for melanoma targeting these and other immunogenic melanocyte differentiation proteins. Preliminary data showing susceptibility of LAM cells to melanoma derived T cells suggest that vaccines targeting melanosomal antigens can be successful in treating LAM.

Transbronchial Biopsy Interpretation in the Patient With Diffuse Parenchymal Lung Disease

Context.—The most common lung tissue samples seen by pathologists worldwide are obtained with the flexible bronchoscope. Specimens taken for examination of diffuse or multifocal parenchymal lung abnormalities pose special challenges for the general surgical pathologist, and these challenges are often compounded by high clinical expectations for accurate and specific diagnosis.

Objective.—To present and discuss the most common histopathologic patterns and diagnostic entities seen in transbronchial biopsy specimens in the setting of diffuse or multifocal lung disease. Specifically, acute lung injury, eosinophilic pneumonia, diffuse alveolar hemorrhage, chronic cellular infiltrates, organizing pneumonia, alveolar proteinosis, sarcoidosis, Wegener granulomatosis, intravenous drug abuse-related microangiopathy, Langerhans cell histiocytosis, and lymphangioleiomyomatosis are presented. Clinical and radiologic context is provided for the more specific diagnostic entities.

Data Sources.—The published literature and experience from a consultation practice.

Conclusions.—The transbronchial biopsy specimen can provide valuable information for clinical management in the setting of diffuse or multifocal lung disease. Computed tomographic scans are useful for selecting appropriate patients to undergo biopsy and in limiting the differential diagnosis. Knowledge of the clinical context, radiologic distribution of abnormalities, and histopathologic patterns is essential. With this information, the surgical pathologist can substantially influence the diagnostic workup and help guide the clinician to an accurate clinical/radiologic/pathologic diagnosis.

Thoracoscopy and transplantation: a new attractive tool

BACKGROUND

Transplanted patients on immunosuppressive treatment have an increased risk of infections or neoplasms. Transplantation candidates with infection or a suspected malignancy are excluded from transplantation. In patients already transplanted, thoracoscopy can resolve complications or treat the pulmonary pathology without compromising the precarious existing reactive equilibrium. These patients require an approach that is as least traumatic as possible.

METHODS

From September 1991 to December 2000, of 2068 videothoracoscopic procedures carried out at our hospital, 2 were in patients who had undergone transplantation and 3 in candidates for kidney, liver, and bone marrow transplantation. Starting from our personal experience in videothoracoscopy as a diagnostic and therapeutic approach, the possibilities of the method in the field of transplantation are reported by a review of the literature carried out by consulting the reference systems of the most important data banks.

CONCLUSIONS

In our experience, videothoracoscopy had a major impact on the management of candidates for transplant, because it allowed us to rule out or treat conditions that would have determined exclusion from a transplant program. In transplanted patients, videothoracoscopy allows a correct diagnosis and treatment with minimal trauma.