Melissa L. Rosado-de-Christenson, MD, FACR

Axial HRCT shows typical findings of LAM characterized by diffuse bilateral thin-walled air-filled pulmonary cysts image of uniform size, with small foci of intervening normal lung image.

Coronal HRCT shows the typical distribution of cysts in LAM. Although the upper lung cysts image are larger than those in the lower image, there is no preferential upper or lower lung involvement.


Abbreviations and Synonyms

  • Lymphangioleiomyomatosis (LAM)

    • Synonym: Lymphangiomyomatosis

  • Tuberous sclerosis complex (TSC)


  • Proliferation of atypical smooth muscle cells in lungs and thoracic & retroperitoneal lymphatics


General Features

  • Best diagnostic clue

    • Woman of childbearing age; progressive dyspnea

      • Radiography: Large volumes, reticular opacities, chylothorax, or spontaneous pneumothorax

      • CT: Diffuse bilateral thin-walled air-filled cysts with intervening normal lung

  • Patient position/location: Diffuse bilateral pulmonary involvement

  • Size: Variable cyst sizes ranging from 2-5 mm, but larger cysts ranging from 6-12 mm may also occur

  • Morphology: Spherical cysts with smooth thin walls

CT Findings

  • Lung

    • Diffuse bilateral thin-walled cysts with normal intervening lung

      • Relative sparing of lung apices & lung bases

      • Visualization of lung cysts in patients with normal or near-normal radiographs

    • Pulmonary involvement may be initially mild but becomes profuse & severe as disease progresses

    • Variable cyst sizes, typically 2-5 mm, but larger cysts 6-10 mm & dominant cysts also observed

      • Typically smaller cysts in early disease and larger cysts in late disease

    • Typically round cysts; ovoid & polygonal cysts; polygonal cysts more common in severe disease

    • Cyst walls range from barely perceptible to 2-4 mm in thickness

  • Pleura

    • Pleural effusion; chylothorax

      • Rarely exhibits fat attenuation

    • Pneumothorax

    • Hydropneumothorax

  • Other

    • Lymphadenopathy; thoracic, abdominal, pelvic

    • Renal angiomyolipomas in 20-54%

Radiographic Findings

  • Lung

    • Normal or increased lung volumes

    • Diffuse bilateral symmetric reticular opacities

    • Radiographs may appear normal in spite of involvement with cystic disease

  • Pleura

    • Pneumothorax in 39-53%

    • Pleural effusion in 10-20%; unilateral or bilateral

Imaging Recommendations

  • Best imaging tool

    • HRCT is more sensitive than radiography

    • Extent of disease correlates with expiratory volumes and diffusion capacity

  • Protocol advice: Coronal reformations help confirm diffuse cephalocaudal pulmonary involvement

  • Screening recommendations

    • Women with TSC: Once after age of 18

    • Women with unexplained recurrent pneumothorax

    • Women with little or no tobacco use who have diagnosis of primary spontaneous pneumothorax (or emphysema)


Langerhans Cell Histiocytosis

  • M = F; smokers

  • Upper lung predominant involvement

  • Small cysts of variable sizes, some with bizarre shapes

  • Thin & nodular irregular cyst walls

  • Associated small irregular pulmonary nodules

Centrilobular Emphysema

  • Smokers, occurs in both males and females

  • Upper lobe predominant involvement

  • Centrilobular lucencies with imperceptible walls; visualization of central lobular artery

Lymphocytic Interstitial Pneumonia (LIP)

  • Adult women; 50-60 years of age

  • Immunosuppression, Sjögren syndrome

  • Thin-walled air-filled lung cysts of various sizes

  • Ground-glass opacity & poorly defined nodules

Tracheobronchial Papillomatosis

  • Males; history of laryngeal papillomatosis

  • Thick- or thin-walled cysts of variable shapes

  • Association with pulmonary & tracheal nodules

Idiopathic Pulmonary Fibrosis

  • Adult men; over 65 years of age

  • Low lung volumes; peripheral lower lung involvement

  • Honeycomb subpleural cysts of variable size

  • Architectural distortion & traction bronchiectasis

Sep 20, 2016 | Posted by in RESPIRATORY IMAGING | Comments Off on Lymphangioleiomyomatosis

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