Atypical squamous cell carcinoma of the larynx and hypopharynx: radiologicfeatures and pathologic correlation

The objective of this study was to analyze the radiologic features of atypi cal forms of squamous cell cancer and correlate them with clinical, endosco pic, and histopathologic findings. The CT and MRI images of 31 patients wit h atypical forms of squamous cell carcinoma were reviewed retrospectively a nd the radiologic findings were correlated with clinical, endoscopic, and h istopathologic findings. Histopathologic diagnoses included undifferentiate d carcinoma of nasopharyngeal type (n=8), verrucous carcinoma (n=18), spind le cell carcinoma (n=3), and basaloid cell carcinoma (n=2). Undifferentiate d carcinoma of nasopharyngeal type was located in the supraglottis or pirif orm sinus beneath an intact mucosa at endoscopy and a solid mass with homog enous enhancement at CT or MRI was characteristic for those tumors and warr anted further investigations to obtain the definitive histologic diagnosis. Verrucous carcinoma displayed characteristic clinical, radiologic, and pat hologic features, namely, an exophytic tumor arising from the glottic level displaying a rugged surface with finger-like projections but with only min or submucosal infiltration. Spindle cell carcinoma appeared as a polypoid m ass with a thin stalk arising from the supraglottis. Basaloid cell carcinom a displayed a distinct lobulated enhancement pattern which was observed on contrast-enhanced T1-weighted SE images. Although the MR and CT features of atypical forms of squamous cell carcinoma cannot be considered pathognomon ic they should raise the differential diagnosis even if endoscopic biopsy h as been negative. The radiologist's awareness of the appearance of these un usual tumors on CT and MR images may greatly facilitate the diagnostic work -up and helps to guide the endoscopist to the adequate biopsy site in order to establish the correct diagnosis.