A CT of the chest shows multiple bilateral cysts of variable size, thin-walled, without nodules or ground-glass change, in a 35-year-old woman with spontaneous pneumothorax and chylothorax. What is the most likely diagnosis?

• A Lymphoid interstitial pneumonia (LIP)
• B Birt-Hogg-Dubé syndrome
• C Pulmonary Langerhans cell histiocytosis (PLCH)
• D Lymphangioleiomyomatosis (LAM) ✓

Explanation

LAM affects women of reproductive age and presents with diffuse, uniform bilateral thin-walled pulmonary cysts (without nodules), recurrent spontaneous pneumothorax, and chylothorax (due to lymphatic obstruction by smooth muscle proliferation). HRCT showing diffuse thin-walled cysts with no other abnormality in a young woman is virtually diagnostic. Birt-Hogg-Dubé also shows bilateral lung cysts but associated with renal tumours and fibrofolliculomas. PLCH shows irregular stellate cysts with nodules in upper lobe predominance in smokers. LIP shows bilateral cysts but with ground-glass opacity and interstitial infiltrates, commonly in Sjögren syndrome or HIV.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.