Current role of computed tomography imaging in the evaluation of cartilage invasion by laryngeal carcinoma.

OBJECTIVES: To evaluate thyroid, arytenoid, and cricoid cartilage invasion on computed tomography (CT) imaging in patients undergoing total laryngectomy for both primary and recurrent laryngeal carcinoma. Secondary endpoint was to compare laryngeal cartilage invasion between primary and recurrent tumours.

METHODS: Pre-treatment CT of 40 patients who had undergone total laryngectomy was retrospectively evaluated and compared with histology. Focal erosions of thyroid cartilage were accounted for neoplastic invasion of the inner cortex. Full-thickness thyroid cartilage invasion was defined as a tumour-like tissue replacing thyroid cartilage or extended in extra-laryngeal soft tissues. Sclerosis and erosion of arytenoid and cricoid cartilages were assessed as signs of neoplastic invasion.

RESULTS: CT erosion showed perfect agreement for thyroid inner cortex and cricoid cartilage invasion and almost perfect agreement (87%) for arytenoid cartilage invasion. For tumours in contact with thyroid cartilages, the absence of CT erosion underestimated inner cortex infiltration. CT showed perfect agreement in predicting full-thickness thyroid cartilage invasion only in the case of extra-laryngeal neoplastic extension. Arytenoid sclerosis showed poor correlation with neoplastic invasion. For primary tumours, CT demonstrated good (inner cortex 75%; full-thickness 85%), substantial (67.5%), and perfect (100%) accuracy in thyroid, arytenoid, and cricoid cartilage invasion, respectively. No CT differences were observed between primary and recurrent laryngeal tumours.

CONCLUSION: Tumour-like tissue extension in the extra-laryngeal soft tissues was accurate in predicting thyroid cartilage full-thickness invasion. Erosions of arytenoid, cricoid, and thyroid cartilages' inner cortex on CT were highly indicative of neoplastic infiltration. No CT difference in cartilage infiltration between primary and recurrent tumours was observed.