000 Cysts in the Lung

  • Cyst is a
    • nonspecific term for a
    • thin-walled (usually <3 mm),
    • well-defined and circumscribed,
    • air containing lesion
    • 1 cm or more in diameter.
      • heterogenous group of disorders characterised by
        • multiple air-filled lucencies
        • surrounded by discrete walls.
    • Diseases
      • Lymphangioleiomyomatosis (LAM),
      • Langerhans cell histiocytosis (PLCH),
      • Birt-Hogg-Dubé syndrome (BHD), and
      • Lymphoid interstitial pneumonia (LIP),
  • Thin walled cysts
    • No central core structures
    • Differential Diagnosis
    • Lymphangioleiomyomatosis (LAM),

      • LAM 
        Ashley Davidoff MD TheCommonvein.net
    • Langerhans cell histiocytosis (PLCH),
    • Pulmonary Langerhans Cell Histiocytosis
      Thiin Walled Bizarre Shaped Upper Lobe Cysts
      Ashley Davidoff MD TheCommonVein.net
      • Langerhans Cell HistiocytosisCT scan shows multiple small cysts sometimes irregular in shape predominantly in the upper lobes. The cysts are round and air filled large and are between 5mm-8mm
    • Birt-Hogg-Dubé syndrome (BHD), and
    • Lymphoid interstitial pneumonia (LIP), although the differential diagnosis can at times expand to encompass other extremely rare etiologies
    • Amyloidosis
    • Light Chain Deposition Disease
    • Neurofibromatosis
  • Less Common
    •  Sjögren syndrome
    •  light chain deposition disease
    •  Ehlers Danlos syndrome type IV
    •  fire-eater’s lung (pneumatoceles)
    •  lymphomatoid granulomatosis
    • neurofibromatosis
    • congenital pulmonary airway (cystic adenomatoid) malformation,
    • smoking related small airways injury [
    • Proteus syndrom
      • Look Alikes
        • Emphysema
          • No wall
          • Central soft tissue elements
        • Blebs
        • Bullae
          •  >1 cm in diameter, bounded by a
          • thin wall (<1 mm)
          • background emphysema
        • Bronchiectasis
          • continuity with airways
        • Honeycombing
          • enlarged airspaces
            • .3 -1.0cms (up to 2.5cms)
          • thick fibrous walls
          • End stage fibrotic disease
          • subpleural
          • stacked
        • Pneumatoceles
          • thin-walled parenchymal cyst
          • Infection
            • bacterial pneumonia eg children
            • PCP  Pneumocystis jirovecii,
            • coccidioidomycosis,
            • hyperimmunoglobulinemia E syndrome,
            • staphylococcal pneumonia
          • Chest Trauma
  • LAM

    • LAM and LYMPHANGIOLEIOMYOMAS in the ABDOMEN
      38-year-old patient with progressive dyspnea and cough
      CXR (scout for CT) shows hyperinflated lungs with increased lung volumes with bilateral and extensive thin-walled cysts surrounded by very little normal lung parenchyma. The cysts are round and thin-walled except for air filled large irregular pocket in the right apex (image 27628/29) . Some of the cysts do not have walls at all and others have an irregular configuration.
      In the abdomen multiple low density lymphangioleiomyomas are present that are due to lymphatic obstruction.
      Ashley Davidoff MD TheCommonVein.net

Upper

The presence of micronodules or cysts excludes a confident diagnosis of UIP.45 On HRCT, micronodules are discrete, round, soft-tissue densities of <3 mm.7 Cysts are low attenuation areas that tend to be round and thin-walled (<2 mm). Cysts in the lung often contain air but may also contain fluid or solid material.7