Queensland Pulmonary Diagnostics Rachael Kaye & Peter Fooks

Present the

Case of the Month - May

Pulmonary Lymphangioleiomyomatosis (LAM) INTRODUCTION Mrs. X is a 41-year-old female who first noticed mild shortness of breath after running up stairs in May 2012. In May 2013, she noted streaks of blood in her throat, which was initially assumed to be nasal in origin. A nasal steroid spray was prescribed by her GP, without improvement. Five months later, Mrs. X presented to an emergency department after coughing up a mouthful of blood. Investigations showed what was assumed to be blood consolidated in the lower lobe of her left lung, and she was found to have widespread, thin-walled cysts throughout all lung regions (Appendix A, Figure 2a & b). Upon biopsy, the widespread cysts were found to be consistent with lymphangioleiomyomatosis. PATHOPHYSIOLOGY Lymphangioleiomyomatosis (LAM) is a rare and slowly progressive disorder, which primarily targets the lungs, kidneys and lymphatic system [1]. LAM cells are smooth muscle-like cells which originate from angiomyolipomas. These are benign tumours composed of blood vessels, smooth muscle cells and adipose tissue, which commonly occur in the kidneys or uterus of LAM sufferers [2]. Clusters of LAM cells migrate from angiomyolipomas and travel via the lymphatics to the pulmonary veins, whereby they infiltrate the pulmonary microvasculature and alveolar septa. The infiltration of LAM cells in the lungs leads to cystic destruction, airflow obstruction, gas trapping and eventually respiratory failure [3]. EPIDEMIOLOGY LAM occurs almost exclusively in women (3.4-7.8 per million women) [4] and has been reported in patients aged between 12 and 75 yrs. The average age at diagnosis is 35 yrs [5] and is typically delayed by 3-5 yrs from the time of symptom onset due to misdiagnosis as asthma or COPD, which are more common causes of dyspnea [6, 7]. The prognosis of LAM varies, however, the 10 yr survival rate has been estimated to be 80-90% [8]. There are two known ways that LAM may occur: sporadically (SLAM), or genetically (TSC-LAM). While TSC-LAM can be genetically passed on to a male, it is an incredibly rare scenario. The majority of sufferers of TSC-LAM and the entirety of the population with SLAM are female. It is believed that LAM is associated with hormonal changes, specifically oestrogen, and this is why it has a much higher rate of occurrence in pre-menopausal women. A study in the United Kingdom of the LAM-affected population found that of five reported cases of LAM in post-menopausal

women, four of the patients were being treated with hormone replacement therapy [5]. Mrs X is believed to have SLAM as she has no evidence of TSC related disease. AEITOLOGY Inactivation of the TSC1 and/or the TSC2 gene appears to be responsible for the development of LAM in sporadic and TSC associated cases[9]. The TSC1 gene codes for hamartin and the TSC2 gene encodes for tuberin, which together form the hamartin-tuberin complex [10]. This is a critical component in the downstream-regulation of mammalian target of rapamycin (mTOR), which is responsible for increased protein translation, growth factor-independent growth, increased proliferation, increased cell size [11], enhanced cell survival and suppressed autophagy [12, 13]. Mutations of the TSC2 gene are thought to be the cause of LAM in the majority of sporadic and TSC-associated cases [14, 15] and tend to cause a more severe manifestation [16]. CLINICAL PRESENTATION Generally, LAM causes a variety of symptoms including shortness of breath, pneumothorax, haemoptysis and chylothorax (pleural effusion involving chyle), alongside lymphangiomyomas and angiomyolipomas which may be distributed throughout the body. Physical examination can demonstrate an audible crackling in the lungs. The most commonly reported issues experienced are found to be pneumothorax and dyspnoea, though a persistent cough and chest pain are also reported quite frequently [5]. The lymphangiomyomas can be either abnormal solid or cystic changes in the tissue, and in the case of Mrs. X, have caused widespread cystic changes throughout her lungs. They may also be the cause of chylothorax experienced by some LAM patients, as the solid masses may directly impact the integrity of the lymphatic system, essentially causing a leak of chyle into the pleural cavity [17].

s demonstrated it to be lymphatic in nature, demonstrating that she had chylothorax most likely related to her LAM (Appendix B, Figure 4a & b). Mrs. X also complained of a productive

gs, but other than her initial shortness of breath has not reported any other symptoms. Physical examination showed crackles in the left base posteriorly, consistent with her LAM diagnosis. DIAGNOSIS AND MONITORING LAM may be diagnosed based on a combination of patient history, tissue biopsy, lymphoscintigraphy and high resolution CT. Lung tissue biopsy is the current gold standard in the diagnosis of LAM, and reveals spindle shaped LAM cells with eosinophilic cytoplasms and immunoreactivity to smooth muscle actin and HMB-45 antibodies [6]. High resolution CT scans show interstitial changes to the lungs, in particular the presence of parenchymal cysts [18]. Pulmonary function tests (PFTs) are often used to monitor the progression of LAM. Pulmonary function testing in LAM usually demonstrates a FEV1 and DLCO below predicted values, with FVC and TLC generally unaffected [18]. Lung function has been shown to decline at rates of 3-15% per year [19-22].

1/FVC ratio of 68%, with no

apparent change post-bronchodilator. The other notabPFT was that gas transfer was particularly low, at 11.81 ml/min/mmHg (46%

in the left lower lobe (Appendix A, Figure 2a & b). Further investigations showed that there was partial lymphatic duct obstruction, leading to lymphatic dilatation and pooling. The lymphatic pooling correlated to the ground glass changes located in Mrs.

TREATMENT AND MANAGEMENT Treatment options for LAM are currently limited. Treatment involves the use of bronchodilators for the management of airflow obstruction and oxygen therapy for hypoxaemia. Surgical correction of pneumothorax or chylothorax are performed if necessary [6]. Hormone therapy has been trialled to reduce oestrogen levels [5], but has been shown to be ineffective [6]. The recent discovery of the TSC1/TSC2 gene mutations has led to mTOR inhibitors as a target for new therapeutic treatment options. Recent clinical trials have been performed on the mTOR inhibitors everolimus and sirolimus. Everolimus has recently been shown to significantly improve FEV1, FVC and DLCO [23], while sirolimus has been shown to stabilise lung function and prevent progressive decline [24]. More clinical trials are needed to establish the effectiveness and safety of the long term use of mTOR inhibitors as a LAM therapy. Mrs X was involved in a clinical trial investigating the effectiveness of everolimus in LAM. Her lung function was monitored throughout treatment and her full reports can be found in Appendix A, while a summary of her results throughout treatment can be seen below. Four months after starting treatment with everolimus, Mrs. X reported resolution of her shortness of breath and cough. Testing also demonstrated that her gas transfer, which had further declined from her initial presentation of 11.81 ml/min/mmHg (46% predicted) to 10.2 ml/min/mmHg (39% predicted), had improved to 13.9 ml/min/mmHg (53% predicted), with a similar corresponding increase in KCO. Further investigation via lymphoscintigraphy demonstrated significant improvement in the obstruction of the lymphatic system, and there was no evidence of continued lymphatic pooling (Appendix B, Figure 5a & b). CT scans determined there to be significant improvement in the ground glass opacities of Mrs.

in the lungs (Appendix A, Figure 3a & b).

F igure 1 Change in FEV1, FVC, FEV1/FVC, DLCO and KCO with everolimus treatment. Values are expressed as a percentage of predicted for age, sex and height. DISCUSSION

pooling treated by everolimus, as indicated in her follow-up lymphoscintigraphy (Appendix B). CT investigation demonstrated that there were still cystic changes to be found in her lungs, suggesting that the drug did not have an effect on that particular issue (Appendix A). As LAM does not generally affect FVC, it is thought that the increase she saw with treatment is due to the dramatic reduction in lymphatic pooling. It is recommended that she continue her treatment, as well as receiving timely follow-up examinations to track her progress as time goes on. It is important to note that throughout her treatment, Mrs. X performed pulmonary function tests on three separate systems. While all three systems are undergo regular quality control, there is likely to be some difference between them which could affect the results. In future, it would be important for her to perform testing on a single unit consistently, to minimize any potential differences in results due to equipment. CONCLUSION Mrs X presented with shortness of breath, productive cough and haemoptysis. Following lung biopsy she was diagnosed with LAM, a slowly progressive disease characterised by the migration of smooth muscle-like cells to the lungs, causing cystic

resolution CT showed wide spread cysts and ground glass appearance, which correlated with lymphatic pooling shown via lymphoscintigraphy. PFT showed reduced DLCO and borderline airway obstruction. PFT results and lymphatic pooling improved with everolimus treatment, however the improvements in the PFT results were most likely a result of the resolution of lymphatic pooling. Mrs. X should

continue with everolimus treatment, and get regularly monitored to assess her condition as time goes on.

BIBLIOGRAPHY 1. Henske, E.P. and F.X. McCormack, Lymphangioleiomyomatosis a wolf in

The Journal of Clinical Investigation, 2012. 122(11): p. 3807-3816.

2. Henske, E.P., Metastasis of benign tumor cells in tuberous sclerosis complex. Genes, Chromosomes and Cancer, 2003. 38(4): p. 376-381.

3. Kumasaka, T., et al., Lymphangiogenesis-mediated shedding of LAM cell clusters as a mechanism for dissemination in lymphangioleiomyomatosis. The American journal of surgical pathology, 2005. 29(10): p. 1356-1366.

4. Harknett, E., et al., Use of variability in national and regional data to estimate the prevalence of lymphangioleiomyomatosis. QJM, 2011. 104(11): p. 971-979.

5. Johnson, S. and A. Tattersfield, Clinical experience of lymphangioleiomyomatosis in the UK . Thorax, 2000. 55(12): p. 1052-1057.

6. Johnson, S., et al., European Respiratory Society guidelines for the diagnosis and management of lymphangioleiomyomatosis. European Respiratory Journal, 2010. 35(1): p. 14-26.

7. Ryu, J.H., et al., The NHLBI lymphangioleiomyomatosis registry: characteristics of 230 patients at enrollment. American journal of respiratory and critical care medicine, 2006. 173(1): p. 105-111.

8. Johnson, S.R., et al., Survival and disease progression in UK patients with lymphangioleiomyomatosis. Thorax, 2004. 59(9): p. 800-803.

9. Strizheva, G.D., et al., The spectrum of mutations in TSC1 and TSC2 in women with tuberous sclerosis and lymphangiomyomatosis. American journal of respiratory and critical care medicine, 2001. 163(1): p. 253-258.

10. Plank, T.L., R.S. Yeung, and E.P. Henske, Hamartin, the product of the tuberous sclerosis 1 (TSC1) gene, interacts with tuberin and appears to be localized to cytoplasmic vesicles. Cancer research, 1998. 58(21): p. 4766-4770.

11. Malhowski, A.J., et al., Smooth muscle protein-22-mediated deletion of Tsc1 results in cardiac hypertrophy that is mTORC1-mediated and reversed by rapamycin. Human molecular genetics, 2011. 20(7): p. 1290-1305.

12. Parkhitko, A., et al., Tumorigenesis in tuberous sclerosis complex is autophagy and p62/sequestosome 1 (SQSTM1)-dependent. Proceedings of the National Academy of Sciences, 2011. 108(30): p. 12455-12460.

13. Neuman, N.A. and E.P. Henske, Non canonical functions of the tuberous sclerosis complex Rheb signalling axis. EMBO molecular medicine, 2011. 3(4): p. 189-200.

14. Crooks, D.M., et al., Molecular and genetic analysis of disseminated neoplastic cells in lymphangioleiomyomatosis. Proceedings of the National Academy of Sciences of the United States of America, 2004. 101(50): p. 17462-17467.

15. Qin, W., et al., Angiomyolipoma have common mutations in TSC2 but no other common genetic events. PloS one, 2011. 6(9): p. e24919.

16. Dabora, S.L., et al., Mutational analysis in a cohort of 224 tuberous sclerosis patients indicates increased severity of TSC2, compared with TSC1, disease in multiple organs. The American Journal of Human Genetics, 2001. 68(1): p. 64-80.

17. McGrath, E.E., Z. Blades, and P.B. Anderson, Chylothorax: aetiology, diagnosis and therapeutic options. Respiratory medicine, 2010. 104(1): p. 1-8.

18. Avila, N.A., et al., Pulmonary Lymphangioleiomyomatosis: Correlation of Ventilation-Perfusion Scintigraphy, Chest Radiography, and CT with Pulmonary Function Tests. Radiology, 2000. 214(2): p. 441-446.

19. Urban, T., et al., Pulmonary Lymphangioleiomyomatosis: A Study of 69 Patients. Medicine, 1999. 78(5): p. 321-337.

20. Taveira-DaSilva, A.M., et al., DEcline in lung function in patients with lymphangioleiomyomatosis treated with or without progesterone*. Chest, 2004. 126(6): p. 1867-1874.

21. Johnson, S.R. and A.E. Tattersfield, Decline in Lung Function in Lymphangioleiomyomatosis. American Journal of Respiratory and Critical Care Medicine, 1999. 160(2): p. 628-633.

22. Lazor, R., et al., Low initial KCO predicts rapid F EV1 decline in pulmonary Respiratory Medicine, 2004. 98(6): p. 536-541.

23. Avdeev, S., et al., Treatment with low-dose everolimus in patients with sporadic lymphangioleiomyomatosis (LAM). European Respiratory Journal, 2014. 44(Suppl 58): p. P1519.

24. Taveira-DaSilva, A.M., et al., Changes in lung function and chylous effusions in patients with lymphangioleiomyomatosis treated with sirolimus. Annals of internal medicine, 2011. 154(12): p. 797-805.

APPENDIX A HIGH-RESOLUTION CT SCAN PRE- AND POST-EVEROLIMUS TREATMENT

F igure 2a & b High-resolution CT scan performed following patient initial presentation. CT scan shows wide spread thin walled cysts and ground glass appearance of the left lung and right middle lobe which corresponded with lymphoscintographic evidence of pulmonary lymphatic congestion.

F igure 3a & b High-resolution CT scan post-everolimus treatment. The CT scan shows a reduction in ground glass appearance due to resolution of lymphatic pooling. There was no change in cystic appearance following everolimus treatment.

APPENDIX B LYMPHOSCINTIGRAPHY PRE- AND POST-EVEROLIMUS TREATMENT

F igure 4a & b Lymphoscintogram performed following patient initial presentation. Coronal section scan shows evidence of lymphatic pooling (blue) and obstruction around the lower lobe of the left lung, corresponding with CT evidence of LAM.

F igure 5a & b Lymphoscintogram in a coronal view performed post-everolimus treatment, demonstrating significant resolution/improvement of lymphatic pooling and obstruction.

APPENDIX C PULMONARY FUNCTION TESTS PERFORMED THROUGHOUT TREATMENT