Subglottic carcinoma: review of a series and characterization of its patterns of spread.

The rarity of primary subglottic malignancies, along with the varied definitions of the anatomic confines of this region, have limited our understanding of the patterns of tumor spread within the subglottis. We conducted a retrospective chart review to analyze clinical and pathologic data in patients with subglottic carcinoma. A pattern of disease progression was identified, which is defined by the cartilaginous laryngeal framework, with the fibroelastic barriers susceptible to tumor invasion. We conclude that although cartilaginous laryngeal structures are preserved until late in the disease course, the ability of tumors to invade the fibroelastic membranes provides them with an insidious means of escape. Specifically, tumor progression occurs primarily within the paraglottic space and extralaryngeal compartments; the potential for mucosal spread is limited. The lack of mucosal disease in patients whose cartilaginous laryngeal structures are intact may present a facade of normality in patients with advanced disease, and perhaps delay the early diagnosis of subglottic malignancies by physical and radiologic examination.