Pathology of Invasive Squamous Cell Carcinoma

Abstract

The TNM system of staging of laryngeal carcinoma divides laryngeal tumours into supraglottic, glottic and subglottic.¹ The terms are not used purely as anatomical descriptions, but, more than this, to designate three embryologically distinct regions, each of which gives rise to its own type of neoplasm. Origin of a carcinoma from two adjacent regions is held to indicate “invasion” or “extension” from one of these regions to the other and hence to necessitate a higher, i.e. more serious, grading. The concept of the separate embryological development of the three parts of the larynx is unproven, however. The most frequent site for the localisation of carcinoma is the anterior part of the vocal cords and the diameter of the tumour is usually small. It may be that a similarly small neoplasm happens to arise across the arbitrarily designated boundary of glottis and supraglottis or glottis and subglottis. The behaviour of such a neoplasm is not necessarily more aggressive. Laryngeal neoplasms, however, do possess different innate biological properties of growth activity and aggressiveness, which may be related to original size but cannot be predicted from involvement of more than one region.