Table 2. Comparison between common malignant primary tracheal tumors SCC vs. ACC.

Squamous cell carcinoma (SCC)

Most common primary malignancy of trachea (histology like SCC of lung)

M > F, 60–70 years

90% smokers

Usually exophytic or ulcerative; if membranous tracheal wall involved, consider invasion from primary esophageal tumor

Biologically aggressive, grow rapidly, metastasize early; 30% have synchronous or metachronous malignancies

Usual diagnosis within 4–6 months of symptom onset

Adenoid cystic carcinoma (ACC)

Arise from bronchial glands (histology like salivary glands)

M = F, 40–50 years

No smoking association

Usually exerts mass effect rather than regional invasion; submucosal spread

Slow growth, late recurrences

Usual diagnosis more than 1 year after symptom onset

M, male; F, female.