Benign Tumors of Lungs Flashcards
Prevelence of benign lung tumors
- uncommon (<1% of all resected lung tumors)
- overall 2-5% of primary lung tumors
General categorization of benign lung tumors
- Based upon location
- Endobronchial
- Parenchymal
- Histology (cell of origin)
Definition of solitary pulmonary nodule (SPN)
Rounded lesion with well-demarcated margins ranging in size from mm-cm
Important considerations during radiolgic evaluation of SPN
- Doubling time
- < 10 days or >450 days most likely benign
- Calcification pattern (benign)
- central
- diffuse
- speckled
- laminar
- popcorn appearance
Calcification of malignant appearing SPN
Eccentric calcifications
CT scanning sensitiviety in determining malignancy for SPN
CT scan (1 mm cuts):
91% sensitive
CT characteristics of malignancy with SPN
- Ill-defined boarders
- Spiculation
- Involvment of bronchi
Efficacy of CT guided core needle biopsy (CNB) of SPN
82% accuracy in providing definitive diagnosis
(FNA 17% accurate)
Sensitivity of PET in distinguishing benign vs. malignant SPN
90% sensitivity when nodule >= 10 mm in size
Glucose avid nodule with SUV >= 2.5 on PET scan has _% of chance of being malignant
>90% chance of malignancy
2 primary indications for sugical excision of SPN
- Nodules > 10 mm with malignant characteristics
- Indeterminate SPN by other means
Lung lesion:
Mixed lesion arising from epithelial and mesodermal cells
Hamartomas
Most common benign lesion of lung (75% of all bening lung tumors)
8% of radiologic “coin lesions”
Characteristics of hamartoma
Slow growing (~3-5 mm/year)
More common men
Usually found in 6-7th decade of life
Peripheral location MC (may occur centrally or endobronchially)
CT appearance of hamartoma
1 - 3 mm smooth, lobulated, well-circumscribed, smoothly marginated, peripheral lesion with mixed fat and smooth tissue attenuation
ID the Lesion:
Lung Harartoma:
1 - 3 mm smooth, lobulated, well-circumscribed, smoothly marginated, peripheral lesion with mixed fat and smooth tissue attenuation
Presence of fatty tissue within SPN lesion highly suggestive of
Lung harmartoma
Present ~ 50% of time
On CXR, popcorn-like calcifications can occur with hemartomas in ~ _% of cases
10-30%
Management of hamartoma
- If stable, observation
- Regular followup and serial imaging essential if lesion not resected
- Rate, but real rate of malignant transformation
- Regular followup and serial imaging essential if lesion not resected
Benign tumors of epithelial origin
- Endobronchial
- Papillomas
- Mucus gland adenoma
- Parenchymal
- Mucinous cystadenoma
- Alveolar adenoma
- Pleomorphic adenoma
Characteristics of papillomas
- Relatively common
- Endobronchial location
- Adults
- Solitary
- Men, 50-60 years, smoker
- Children:
- Multiple
- Vocal cord or tracheal involvement
Histologic characteristics of papillomas
Clara cells
TOC for papillomas
Laser ablation or endoscopic removal
Risk of malignant degeneration
Characteristics of Mucus Gland Adenomas
- Arise from submucosal mucus glands in lobar or segmental bronchi
- Coin like lesions on CT
Tumors of mesodermal origin
- Endobronchial
- Benign endobronchial histiocytoma
- Parenchymal
- Intrapulmonary fibrous tumor
- Hemangioma
- Cavernous hemangioma
- Sclerosing hemangioma
- Pulmonary capillary hemangioma
- Chondroma
- Leiomyoma
Benign tumor arising from visceral pleura, presenting as large, asymptomatic mass
Intrapulmonary fibrous tumor
(aka localized pleural mesothelioma, pleural fibroma, solitary fibrous tumor of pleura)
- Appear to make an obtuse angle with the chest wall, revealing they arise from pleura and not lung on imaging.
- Not associated with asbestos
- Associated with paraneoplastic syndrome: 3-4% of cases
- hyperglycemia (insulin-like substance secreted from tumor)
Benign lung tumor associated with paraneoplastic disorder (hyperglycemia) due to insulin-like hormone secretion
Intrapulmonary fibrous tumor
Presence of _ should raise suspicious of Osler-Weber-Rendu syndrome (hereditary hemorrhagic telangiectasia)
Pulmonary cavernous hemangioma
Presence of pulmonary chrondroma should raise suspicous of __
Carney’s Triad:
- Pulmonary chondroma
- GIST tumor
- Extra-adrenal paraganglioma
Carney’s Triad
- Pulmonary chondroma
- GIST tumor
- Extra-adrenal paraganglioma
- MC in females
Characteristics of leiomyomas
- Can occur endobronchially or in lung parenchyma
- 2% of bening lung lesions
- MC in femals and young adults
- Considered metastasizing when occuring concurrently with uterine leiomyomas
- Can be fatal
TOC for lung leiomyoma
Surgical resection
Chemotherapy
Hormonal manipulation
Benign lung lesion associated wtih multiple myeloma
Nodular amyloid
- 3 cm in size
- esosinophilic deposits with “apple-green birefrigence” on histology
- Long-term followup necessary d/t association with macroglobulinemia and lymphoma
Benign lung lesion with prsence of thymic tissue in intrapulmonary locations
Primary pulmonary thymoma
- Very rare
- Likely d/t embrologic descent of thymic tissue to position more inferior than nl
