The patient proceeded to panendoscopy and biopsy of the left piriform sinus mass.
Histopathology:
Sections of the squamous mucosa show features of moderately differentiated squamous cell carcinoma. The tumour forms infiltrative nests and trabeculae, surrounded by desmoplasia. There are foci of keratinisation. It invades into the stroma for 1mm. The tumour cells have enlarged hyperchromatic nuclei, prominent nucleoli and small amounts of dense cytoplasm. No evidence of lymphovascular or perineural invasion is seen. p16 immunostain is negative in the tumour cells.
DIAGNOSIS:
Left piriform fossa: Moderately differentiated squamous cell carcinoma. p16 negative.