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Benign Respiratory Tract Tumors

Benign Respiratory Tract Tumors

1. Respiratory Tract

A. Tissue examination
B. Most lesions are peripheral
C. Radiographic features- major diagnostic aid
1) Calcification
2) "Popcorn" type
3) Well defined margins
4) Lobulated
5) Growth (?)
6) Wedge resection
7) Frozen section

2. Epithelial tumors

A. Mesodermal tumors
1) Vascular tumors
2) Bronchial tumors
B. Neurogenic tumors
C. Developmental or unknown origin tumors
D. Inflammatory and other pseudo0tumors

3. Tumors of Epithelial origin

A. Papilloma- 5 sib-classifications
1) Solitary benign papilloma
2) Multiple benign papillomas
3) Combined bronchial mucous gland and surface papillary tumor
4) In situ papillary bronchial carcinomas
5) Bronchiolar papillomas
B. Proximal
1) Squamous, stalk
C. Distal
1) Clara cells
D. One of few lesions that can be managed by bronchoscopic resection
E. Recurrence is high
F. Rare malignant transformation

4. Polyps

A. Related to inflammatory polyps or URT
B. Squamous metaplasia; ciliated columnar epithelium and granulation tissue
C. Bronchoscopic removal
D. Tumorlet
1) Epithelial proliferation
2) Originates from Kulchitsky cells
3) Multifocal: < 4 mm; associated with pulmonary fibrosis
4) Form of peripheral carcinoid with rare metastases

5. Tumors of Mesodermal Origin

A. Hemangioma
1) Subglottic area of larynx or upper trachea of infants
2) Airway obstuction
3) Dx: Bronchoscopy
4) Other vascular lesions of skin, mucous membranes
5) Tx: Radiation therapy
B. Lymphangioma
1) Upper airway obstruction in infancy
2) Associated with other lesions- cystic hygroma, hemangioma in the neck
3) Tx: surgical excision

6. Endothelioma

A. More solid
B. Lymphatic or vascular origin
1) Angiomatous formation- may ne found only in lung
C. Most often described in newborns
D. Lethal course over a short period or time
E. Lymphangiomatosis
1) Rare- may be related to tuberous sclerosis
2) Slowly progressive- death within 10 years from pulmonary insufficiency
3) Young females presenting with dyspnea
4) Spontaneous PTX; chylothorax, hemoptysis
F. CXR: fine, multinodular lesions in bases- honeycombing

7. A-V Fistula

A. Lower lobes
B. Associated with hemorrhagic telangiectasia (Rendu-Osler-Weber Syndrome) in 50% of cases
C. R > L shunting PA-PV
1) Cyanosis
2) Clubbing
3) Polycythemia
4) DOE
5) Pulmonary murmur
A. Brain abcess or peripheral embolization
B. Dx: CXR,; pulmonary angiogram
C. Tx: Surgical resection; angiographic embolization A-V Fistula

8. Sclerosing Hemangioma

A. Uncommon; originates from Type II pneumocyte precursors
B. Coin lesion, lower lobes
C. Hemoptysis
D. Associated with hemorrhagic telangiectasia
E. Intravascular Bronchoalveolar Tumor
1) Rare; females < 30 years old
2) Originates from vascular endothelium
3) CXR: multiple pulmonary nodules- incidentally discovered
4) Mild dyspnea
5) Stable, slowly growing metastases reported
6) Tumor considered to be malignant

9. Hemangiopericytoma

A. Solitary, encapsulated, asymptomatic
B. Originates from pericytes associated with pulmonary capillaries
C. Considered malignant
D. Tx: Surgical resection for cure or radiation therapy for palliation

10. Fibroma

A. Mostly tracheobronchial in origin
B. Most common benign tumor of mesodermal origin in adult and pediatric age group
C. Collagenous/ spindle cells- myxomatous/ adipose elements
D. Tx: Bronchoscopic resection if stalk is present vs conservative pulmonary resection

11. Chondroma and Osteochondroma

A. Arise in major bronchi
B. May appear as true enchondrosis of bronchial cartilage
C. Firm, translucent; ossified/ calcified material
D. Second most common mesodermal tumor
E. Carney's triad: associated with extra-adrenal paragangliomas and gastric leiomysarcomas

12. Lipoma

A. Rare, intrabronchial lesion; male predominance
B. Slowly growing, avascular, obstructive, pedunculated
C. Tx: Bronchoscopic removal for small lesions; bronchotomy for larger ones
D. Arise in fat cells
E. Associated with bronchiectasis (chronic obstruction)

13. Leiomyoma

A. Fourth in order of frequency
B. Originates from smooth muscle cells
1) Bronchiolar smooth muscle cells
2) Pulmonary vessels
C. Sx: cough, hemoptysis, pneumonia, bronciectasis
D. 50% intrabronchial- 50% peripheral
E. Can be associated with similar cutaneous lesions
F. Tx: Conservative surgical approach
G. Malignant variant: Leiomyosarcoma

14. Order of Frequency of Mesodermal Tumors

A. Fibroma
B. Chondroma
C. Lipoma
D. Leiomyoma

15. Granular Cell Tumors (Myoblastoma)

A. Previously thought to originate from myoblasts
B. Originates from Schwann cells or histiocytes
C. Arises from the tongue or skin
D. 6% originate endobronchially
E. Tx: Surgical removal with wide margins
1) Bronchoscopic removal associated with recurrence < 8 mm

16. Developmental or Unknown Origin

A. Hamartomas
B. Most common benign tumor of the lung
C. 8% of coin-shaped lesions
D. 0.25% of general population
E. CXR: "Popcorn" lesion
F. Malignant transformation- rare
G. True neoplasm
H. Malignant transformation of the epithelial component
1) Chondromatous hamartoma
2) Adenomatous hamartoma of infancy
3) Pulmonary blastoma

17. Teratoma

A. Rare: 50% are benign
B. Characteristics of all germ layers
C. Must be differentiated from metastatic lesion
1) Testicle
2) Direct invasion from mediastinum

18. Chemodectoma

A. One reported case
B. Arise from chemorecptor cells in the lung

19. Clear Cell (sugar) Tumor

A. Resembles hypernephroma
B. Abundant glycogen content
C. Characteristics of Type II glycogen storage disease

20. Thymoma

A. Ectopic thymus tissue (rare)
B. Intrapulmonary thymoma may be associated with Myasthenia Gravis

21. Inflammatory and Other Pseudotumors

A. Plasma Cell Granulomas (Histiocytoma)
1) Solitary pulmonary nodule
2) May be associated with: systemic disease, plasma protein imbalance, NS local inflammatory reaction
3) Micro: Plasma cells and lymphocytes
4) Local exclusion/ lobotomy- cure
5) May be associated with multiple myeloma or other malignancies
6) Do not confuse with plasmacytoma- a malignant lesion

22. Pseudolymphoma

A. Discrete localization
B. Unilateral
C. Resembles lymphoid interstitial pneumonitis
D. Rare conversion to malignant lymphoma
E. Tx: Lobectomy/ segmental resection with follow-up

23. Xanthoma

A. Post-inflammatory lesion- encapsulated
B. Micro: foam cells
C. Conservative resection
D. No reports of recurrence

24. Amyloid

A. Deposition may be diffuse of localized
B. Occasionally may be obstructive
C. Tx: Bronchoscopic removal/ resection

25. Tracheobronchopathia Osteoplastica

A. Multiple cartilaginous/ osseous projections into lower tracheal lumen
B. Usually found at autopsy
C. Rarely obstructive
D. Tx: Bronchoscopic removal/ tracheal resection

Bronchial Adenomas

26. Most are not benign adenomas but are malignant neoplasms

A. Long natural histories
B. 5% of all primary pulmonary neoplasms
C. Two groups
1) Carcinoid tumors
2) Bronchial mucous gland tumors

27. Classification

A. Carcinoid tumors
1) Typical
2) Atypical
B. Bronchial gland tumors
1) Adenoid cystic carcinoma (Clindroma)
2) Mucoepidermoid carcinoma
3) Bronchial gland adenoma

28. Carcinoid Tumors

A. 85-90% or bronchial adenomas
B. Neuroendocrine tumor from Kulchitsky's cells (argentaffin)
C. APUD tumor
D. Mostly in lobar bronchi (70%); others quote higher incidence in periphery or lung
E. More frequent on right and in lower lobes
F. "Mulberry" lesion
G. Small cell uniform tumor cells in a vascular stroma
H. Atypical carcinoid 10-15%
1) Pleomorphism
2) Nuclear irregularity
3) Increased mitotic activity

29. Atypical carcinoid

A. More active biologic behavior
B. 50-60% lymph node metastases (5-10% with typical carcinoids)
C. 10% distant metastases
D. Poorer prognosis
E. Most patients- 5th to 6th decade; slight female predominance
F. 25-30% asymptomatic- present with abnormal CXR
G. Sx: Cough, hemoptysis, recurrent pneumonitis
1) Carcinoid syndrome- 1-2%; usually associated with metastases
2) Cushing's syndrome; hyperinsulism
H. 60-80% seen bronchoscopically: Biopsy (?)

30. Treatment

A. Resection: lobectomy, pneumonectomy
B. Resect recurrent and metastatic disease
C. Bronchoscopic resection- high rate of recurrence
D. Ten year disease-free interval
1) Typical carcinoids- 85-90%
2) Atypical carcinoids or typical carcinoids with lymph node metastases- 50%

31. Bronchial Gland Tumors

A. Adenoid Cystic Carcinoma (Cylindroma)
1) Occurs in trachea
2) 30% lymph node metastases
3) Submucosal and perineural lymphatic spread
4) Sx: cough, hemoptysis, wheezing, obstructive pneumonitis in 6th decade
5) Tx: wide surgical excision with lymph node dissection- RT palliative
6) 50% long-term survival with wide surgical resection

32. Mucoepidermoid Carcinoma

A. Epidermoid and mucous producing elements
B. Behavioral correlates with microscopic appearance
C. Tx: Complete resection
D. Prognosis
1) Low-grade: good with adequate resection
2) High-grade: poor despite therapy
E. Rare; mainly in lobar/ mainstream bronchi

33. Mixed Tumors

A. Rare; similar to salivary gland tumors
B. Require tracheal reconstruction
C. Bronchial Mucous Gland Adenomas
1) Rare; benign; conservative resection

Extended Outline

1. Benign Tumors of the Lung

A. 5% of all tumors of the tracheobronchial tree
B. most are within lung parenchyma
C. usually asymptomatic unless associated with bronchial obstruction
Classification of benign tumors of the lung and tracheobronchial tree (see chart)

2. Clinical features

A. mode of presentation depends on location and size
B. most are peripheral and found on routine CXR
C. chronic cough and chest pain are most frequent symptoms (40%)
D. central lesions are more likely to be symptomatic
E. diagnosis
1) CXR, CT scan
2) bronchoscopy for central lesions
3) peripheral lesions- needle biopsy, thoracoscopy, open biopsy
4) conservative resection is indicated unless there is a surrounding destructive process
Tumors of epithelial origin

3. Papillomas of the tracheobronchial tree

A. most common laryngeal tumor in children
B. rare in adults
C. single or multiple lesions
D. subclasses
1) solitary benign
2) multiple benign
3) benign combined with bronchial mucous gland and surface papillary tumors
4) papillary bronchial CIS
5) bronchial papillomas
E. Approximately 50% of solitary bronchial papillomas are associated w/ lung carcinoma
Tumors of Mesodermal Origin

4. Hemangioma

A. infrequent in lung, more common in trachea and mainstem bronchi
B. multiple one third of cases
C. 60% of cases are associated with generalized hereditary telangiectasia (Oler-Rendu-Weber disease
D. surgical treatment is conservative resection, YAG laser for endobronchial lesions
5. Hemangiopericytoma
A. may arise anywhere in the body
B. lesions are large and 50 % malignant
C. originate from capillary endothelium
D. centrally located, highly vascular
E. treatment is conservative surgical resection unless malignant

6. Pulmonary Lymphangiomyomatosis

A. extensive hamartomas involving smooth muscle of the lungs, lyphatics, hilar,abdominal and lower cervical lymph nodes
B. progressive disorder of childbearing age females with diffuse interstial proliferation of smooth muscle in the lungs, lymph nodes and thoracic duct
C. lesions can produce SOB, emphysema, pneumothoraces, pulmonary hemorrhage with hemoptysis and chylothorax
D. treatment is conservative surgical resection
Bronchial Tumors

7. Fibroma

A. extremely rare
B. may arise from the peripheral parenchyma of the lung of from the walls of the trachea and bronchi
C. treatment is bronchoscopic removal or YAG laser therapy
Chondroma and Osteochondroma