The squamous cells seen in the normal urine usually does not come from urinary tract. Only the last two third of the male urethra is lined with squamous cells. The urinary tract is lined with transitional, cubic, or cylindrical cells. A large number of squamous cells are mostly seen with woman's specimen and are probably the result of an accidental washing of the external genitalia.

Nevertheless, it is necessary to be vigilant with elderly patient's specimens. Patients in this group could have a squamous metaplasia of the bladder. The frequency of this anomaly is low, but is not negligible in the elderly population.

NB! Proliferative lesions of the lower urinary tract are sometimes of squamous cells type (squamous cell carcinoma).