CT chest of a 45-year-old non-smoker female shows multiple bilateral cystic lesions with thin walls randomly distributed in the lung parenchyma, no associated nodules, and bilateral pleural effusions. Renal angiomyolipomas are detected on CT abdomen. The diagnosis is:
- A Langerhans cell histiocytosis (LCH)
- B Lymphoid interstitial pneumonia (LIP)
- C Lymphangioleiomyomatosis (LAM) ✓
- D Birt-Hogg-Dubé syndrome
Correct answer: C. Lymphangioleiomyomatosis (LAM)
Explanation
LAM is a multisystem disease predominantly affecting premenopausal women, characterised by diffuse thin-walled lung cysts (from smooth muscle cell proliferation), bilateral chylous pleural effusions (chylothorax), and renal angiomyolipomas. It is associated with TSC mutations. LCH shows upper lobe-predominant nodules and irregular cysts in smokers. LIP shows cysts and ground-glass opacity in Sjögren's or HIV. Birt-Hogg-Dubé shows lower lobe, subpleural cysts with renal tumours but not AMLs.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.