Pulmonary Blastoma
Key Facts
Terminology
Synonyms: Well-differentiated fetal adenocarcinoma, pulmonary embryoma
PB monophasic type (well-differentiated fetal adenocarcinoma): Glandular component recapitulates embryonic development of lung
PB biphasic type: Composed of epithelial glandular component and sarcomatous elements
Clinical Issues
Monophasic pulmonary blastomas have better prognosis
Biphasic pulmonary blastomas behave more aggressively
Tumor size (> 5 cm) linked with poor prognosis
Microscopic Pathology
Glandular component mimics embryologic development of lung between weeks 11-18
Presence of morules
Top Differential Diagnoses
Adenocarcinoma
Absence of intracellular mucin in PB
In carcinosarcoma, glandular epithelial component will not show embryonic features of glandular component of PB
Pleuropulmonary blastoma
Epithelial component is benign
Tumor is pleural-based rather than intraparenchymatous
 Gross photograph of pulmonary blastoma shows an intrapulmonary mass with areas of hemorrhage and necrosis. The tumor in the more viable areas appears light tan in color  . |
 PB shows a complex glandular proliferation with a back-to-back arrangement with little intervening stromal tissue. |
TERMINOLOGY
Abbreviations
Pulmonary blastoma (PB)
Synonyms
Well-differentiated fetal adenocarcinoma
Pulmonary embryoma
Definitions
PB monophasic type (well-differentiated fetal adenocarcinoma)
Glandular component recapitulates embryonic development of lung
PB biphasic type
Composed of epithelial glandular component and sarcomatous elements
CLINICAL ISSUES
Epidemiology
Incidence
Rare tumor that may account for < 1% of all pulmonary neoplasms
Age
Tumor is more common in adults
Presentation
Cough
Hemoptysis
Chest pain
Asymptomatic
Treatment
Surgical approaches
Complete surgical resection
Adjuvant therapy
No specific treatment
Prognosis
Monophasic pulmonary blastomas have better prognosis
Biphasic pulmonary blastomas behave more aggressively
Tumor size (> 5 cm) linked with poor prognosis
MACROSCOPIC FEATURES
General Features
Central or peripheral tumor
Well-circumscribed but not encapsulated
Homogeneous or slightly lobulated cut surface
Tan in color ± areas of necrosis &/or hemorrhage
Tumor size varies from 1-20 cm in diameter
MICROSCOPIC PATHOLOGY
Histologic Features
Glandular component mimics embryologic development of lung between 11-18 weeks
Presence of morules (squamoid foci)
Predominant Pattern/Injury Type
Glandular
Biphasic
Predominant Cell/Compartment Type
Epithelial, glandular
Epithelial, biphasic or mixed
DIFFERENTIAL DIAGNOSIS
Adenocarcinoma
Glandular proliferation of PB recapitulates embryologic development of lung (weeks 11-18)
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