Squamous carcinoma of the colon: primary or metastatic?

A patient is reported who developed a tumour of the transverse colon, which at presentation appeared histologically and clinically to be a primary squamous cell keratinizing carcinoma, arising from an area of in situ carcinoma in the colonic epithelium. However, she had had a stage 1 cervical carcinoma treated by Wertheim's hysterectomy 7 years previously and although there were no other signs of recurrence, this raised the possibility that the lesion might be metastatic. Thirty-seven previously reported cases of primary squamous carcinoma of the colon and those of squamous carcinoma metastasizing to the colon and mimicking primary lesions are reviewed.