Approach to the diagnosis of cystic lung disease

ANA: antinuclear antibody; BAL: bronchoalveolar lavage; BHD: Birt-Hogg-Dubé; CD1a: CD1 antigen; CVID: common variable immunodeficiency; FLCN: folliculin; GGO: ground glass opacities; HRCT: high resolution computed tomography; LAM: lymphangioleiomyomatosis; LIP: lymphoid interstitial pneumonia; PLCH: pulmonary Langerhans cell histiocytosis; RF: rheumatoid factor; SSA: anti-Ro/SSA antibodies; SSB: anti-La/SSb antiboides; TSC: tuberous sclerosis complex.

* This is a suggested approach to the diagnosis of cystic lung disease identified on HRCT; not all patients with cystic lung disease will fit these categories. Refer to the UpToDate review on the diagnosis of cystic lung disease.

¶ In addition to the typical HRCT features of LAM cysts, pleural fluid is more likely to be associated with LAM than other causes of cystic lung disease and occurs in about 10% of patients. MMPH nodules 2 to 14 mm are seen in up to two-thirds of patients with TSC-LAM, and much less commonly in LAM.

Δ Features of TSC include family history of TSC, facial angiofibromas, hypomelanotic macules, confetti lesions, Shagreen patches, seizures, cognitive impairment. Diagnosis requires review by TSC specialist. Refer to UpToDate reviews on diagnosis of TSC.

◊ Refer to the UpToDate review on diagnosis of LAM.

§ Immunodeficiencies associated with LIP are largely HIV infection and CVID. Refer to UpToDate topic reviews.

¥ Lung biopsy is not helpful to confirm BHD, as histologic changes are nonspecific.