283 © Springer Nature Switzerland AG 2021 N. Gupta et al. (eds.), Diffuse Cystic Lung Diseases, Respiratory Medicine, https://doi.org/10.1007/978-3-030-63365-3_15 Chapter 15 Extrapulmonary Manifestations of Diffuse Cystic Lung Diseases Daniel F. Dilling and Stephen J. Ruoss Introduction Previous chapters in this textbook have focused on the respiratory symptoms and pulmonary features of diffuse cystic lung diseases (DCLDs). While the practicing pulmonologist is likely to feel most comfortable with the pulmonary aspects of DCLDs, these diseases often have significant extrapulmonary involvement that war- rants attention and management. Such extrapulmonary aspects of the disease may even overshadow the lung disease with regard to the symptom burden or the need for ongoing testing. In this chapter, we discuss the extrapulmonary aspects in the context of the major DCLDs: Birt-Hogg-Dubé (BHD) syndrome, light chain depo- sition disease (LCDD), lymphocytic interstitial pneumonia/follicular bronchiolitis (LIP/FB), lymphangioleiomyomatosis (LAM), and pulmonary Langerhans cell his- tiocytosis (PLCH). Lymphangioleiomyomatosis (LAM) LAM has been characterized as a low-grade, destructive, metastasizing neoplasm [1] and can occur in patients with tuberous sclerosis complex (TSC-LAM) or in sporadic cases in the absence of TSC (S-LAM). A number of extrapulmonary mani- festations have been described in patients with LAM with varying frequencies D. F. Dilling (*) Division of Pulmonary and Critical Care, Stritch School of Medicine, Loyola University Chicago, Chicago, IL, USA e-mail: ddillin@lumc.edu S. J. Ruoss Division of Pulmonary and Critical Care, Stanford University, Stanford, CA, USA e-mail: ruoss@stanford.edu