Mediastinum
Cystic lesions
Bronchogenic cyst


Topic Completed: 3 August 2020

Minor changes: 3 August 2020

Copyright: 2003-2020, PathologyOutlines.com, Inc.

PubMed search: bronchogenic cyst lung[title] pathology

Laurence M. Briski, M.D.
Kristine Konopka, M.D.
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Cite this page: Briski L, Konopka K. Bronchogenic cyst. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mediastinumbronchogenic.html. Accessed October 28th, 2020.
Definition / general
  • Benign congenital malformation of tracheobronchial tree
Essential features
  • Benign congenital malformation arising from abnormal budding of primitive foregut during gestation
  • Occurs in mediastinum, lung, head and neck, skin, abdomen, retroperitoneum
  • Unilocular cyst lined by respiratory type epithelium
  • Cyst wall recapitulates bronchial wall with variable amounts of seromucinous glands, cartilage and smooth muscle
  • Excellent prognosis with complete surgical excision
Terminology
  • Bronchial cyst
  • Noncommunicating bronchopulmonary foregut malformation
ICD coding
  • ICD-10: J98.4 - Other disorders of lung
  • ICD-11: CB40.Y - Other specified diseases of the respiratory system
Epidemiology
Sites
  • Depends on stage of development when malformation occurs
  • Most common in thorax: mediastinum (early in gestation), lung (later in gestation)
  • Ectopic locations: head and neck (usually midline; less commonly lateral or subcutaneous), abdomen, retroperitoneum (Acta Otorhinolaryngol Ital 2009;29:36, Am Surg 2005;71:1034)
Pathophysiology
  • Arises from abnormal budding of primitive ventral foregut
  • Usually occurs between 26 - 40 days of gestation
Etiology
  • No known causes or risk factors
Clinical features
  • Most present with symptomatic disease
    • Approximately 50% present with pain (Lung 2008;186:55, Am Surg 2005;71:1034)
    • Respiratory symptoms (cough, dyspnea, hemoptysis) (Lung 2008;186:55)
    • Respiratory distress may result from tracheal compression
    • Gastrointestinal symptoms (dysphagia, nausea, vomiting)
    • Occasionally fever, other constitutional symptoms or infection
  • Asymptomatic presentation uncommon
    • True prevalence of asymptomatic disease unknown
Diagnosis
Radiology description
Radiology images

Images hosted on other servers:

Fluid filled mediastinal mass

Mediastinal mass with high signal intensity on T1 and T2

Mediastinal bronchogenic cyst

Well circumscribed
intrapulmonary
bronchogenic cyst

Esophageal bronchogenic cyst

Prognostic factors
Case reports
Treatment
  • Complete surgical excision recommended for symptomatic patients
  • Aspiration or ablation for nonresectable lesions / high risk patients (J Bronchology Interv Pulmonol 2015;22:195)
  • Observation acceptable for asymptomatic patients
Clinical images

Images hosted on other servers:

Mediastinal bronchogenic cyst

Submucosal esophageal bronchogenic cyst

Polypoid endobronchial bronchogenic cyst

Gross description
  • Unilocular thin walled cyst with smooth surface
  • Filled with serous or mucinous fluid
  • May be turbid or hemorrhagic if infected or previously aspirated / biopsied
Gross images

Images hosted on other servers:

Unilocular cyst with mucoid material

Microscopic (histologic) description
  • Cyst lined by respiratory type epithelium
    • Ciliated pseudostratified columnar cells
    • Variable numbers of goblet cells
    • Filled with serous or mucinous material
  • Cyst wall components (variable)
    • Seromucinous glands
    • Hyaline cartilage
    • Smooth muscle
  • Changes associated with infection or prior procedure
    • Acute and chronic inflammation with epithelial denudation
    • Hemorrhage with hemosiderin laden macrophages
    • Squamous metaplasia
    • Cholesterol clefts
    • Fibrosis
Microscopic (histologic) images

Contributed by Laurence Briski, M.D.

Unilocular cyst

Recapitulation of bronchial structure

Cyst wall components

Foci of smooth muscle

Ciliated respiratory epithelium

Cytology description
  • Ciliated columnar (respiratory type) epithelial cells
  • Macrophages (and other cystic contents)
  • Acute and chronic inflammatory cells
  • Serous or mucinous material
  • Rarely cartilage or smooth muscle spindle cells
Cytology images

Images hosted on other servers:

Cystic contents (Diff-Quik stain)

Positive stains
Negative stains
Sample pathology report
  • Soft tissue, thorax, excision:
    • Bronchogenic cyst
Differential diagnosis
  • Cystic teratoma:
    • Usually has a solid component
    • Lined by variable mixtures of gastrointestinal, squamous and respiratory epithelium
    • Contains tissues derived from all 3 germ cell layers
    • Some cases contain immature tissues, nuclear atypia or tumor necrosis
  • Thyroglossal duct cyst:
    • Lined by respiratory, cuboidal or squamous epithelium
    • Contains thyroid tissue (follicles) in cyst wall
    • Lacks cartilage and smooth muscle
  • Esophageal duplication cyst:
    • Lined by stratified squamous or gastrointestinal epithelium
    • Contains double smooth muscle layer
    • Attached to esophageal wall
  • Branchial cleft cyst:
    • Typically lined by stratified squamous epithelium
    • Contains lymphoid aggregates with reactive germinal centers
    • Often filled with keratinaceous debris
    • Lacks cartilage and smooth muscle
  • Dermoid cyst:
    • Lined by stratified squamous epithelium
    • Contains hair and skin appendages
    • Filled with keratinaceous or sebaceous material
    • Lacks cartilage and smooth muscle
  • Abscess:
    • No true lining; may contain foci of squamous metaplasia
    • Filled with suppurative inflammation
    • Lacks cartilage and smooth muscle
Board review style question #1

A 1 month old girl presents with acute respiratory distress and failure to thrive. Imaging studies reveal a 3.5 cm cystic mediastinal mass compressing her trachea. The lesion is excised and shown above.

Which of the following statements accurately describes this lesion?

  1. Mature germ cell tumor derived from all 3 germ cell layers
  2. Congenital cyst arising from abnormal budding of the primitive ventral foregut
  3. Congenital cyst derived from remnants of the second branchial apparatus
  4. Congenital cyst derived from the thyroglossal duct
Board review answer #1
B. Congenital cyst arising from abnormal budding of the primitive ventral foregut. The lesion shown is a bronchogenic cyst. Teratomas are mature germ cell tumors derived from all 3 germ cell layers (answer A); branchial cleft cysts are derived from remnants of the second branchial apparatus (answer C); thyroglossal duct cysts are derived from the thyroglossal duct (answer D).

Reference: Bronchogenic cyst

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Board review style question #2
Each of the following immunohistochemical markers may be positive in cystic teratomas of the mediastinum. Which is most reliably negative in bronchogenic cysts and therefore useful in the distinction between these two entities?

  1. TTF1
  2. Cytokeratin 7
  3. Cytokeratin 20
  4. CDX2
Board review answer #2
D. CDX2. Based on one series of 22 bronchogenic cysts, CDX2 was negative in all 22 cases. The other listed immunohistochemical stains had varying levels of positivity in this cohort (from positivity with CK7 in 100% of cases to positivity with TTF1 in 18% of cases) (Am J Clin Pathol 2008;130:265).

Reference: Bronchogenic cyst

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