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Tracheobronchial neoplasia refers to benign or malignant tumors arising from the trachea and main bronchi. Primary tumors are rare (≈2% of all respiratory tract malignancies), but the tracheobronchial tree is frequently affected secondarily by direct extension or metastasis.

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Etiopathogenesis

Benign Neoplasms

Squamous papilloma / Papillomatosis	HPV-related, multiple exophytic lesions, risk of malignant transformation
Hamartoma	Composed of cartilage, fat, connective tissue; often incidental
Lipoma, leiomyoma, fibroma	Rare mesenchymal tumors
Neurogenic tumors (schwannoma, paraganglioma)	Arising from autonomic or paraganglionic tissue

Malignant neoplasms:

Squamous cell carcinoma (SCC)	Most common tracheal malignancy. Associated with smoking. Tends to cause irregular, ulcerated intraluminal mass with early obstruction.
Adenoid cystic carcinoma (ACC)	Second most common. Arises from submucosal glands, often in younger patients. Shows submucosal infiltration with smooth, long-segment concentric narrowing; tends to spread longitudinally along the airway.
Carcinoid tumors	Neuroendocrine origin. Can be typical (low-grade, indolent) or atypical (more aggressive). Commonly endobronchial, causing recurrent pneumonia/atelectasis.
Mucoepidermoid carcinoma	Arises from minor salivary glands in tracheobronchial tree; usually low-grade, lobulated enhancing mass.
Small cell carcinoma	Rare in trachea, more common in bronchi; aggressive, associated with paraneoplastic syndromes.
Metastatic/secondary involvement	From lung, thyroid, esophagus, larynx, or hematogenous spread (renal cell carcinoma, breast, colon)

Clinical Features

Symptoms often appear late due to slow growth and large airway reserve.
Common: cough, wheeze, hemoptysis, stridor, recurrent post-obstructive pneumonia, dyspnea.
SCC: hemoptysis, hoarseness.
ACC: slowly progressive airway obstruction.
Carcinoid: flushing, diarrhea (rare carcinoid syndrome).

Radiology

Chest Radiography

Often nonspecific; may show atelectasis, collapse, or obstructive pneumonia.
Focal airway narrowing sometimes visible.

CT (modality of choice)