[Squamous carcinoma of the anal canal and its variations. Personal experience and review of the literature].

Six cases of anal canal squamous carcinoma are presented. The authors precise the present view about pathological, epidemiological, clinical and therapeutical aspects of these lesions. They stress, also, the primary role of embryology and anatomy in the oncogenesis of such tumours; the importance to single out specific population at risk, absolutely different from the typical one for rectal adenocarcinoma and the role of chemoradiation therapy as treatment of choice of these neoplasms. Particular importance is given to modern histologic and histogenetic classification of these tumours, stressing the difficulties to distinguish the various histologic types.