Source of mucus in normal urine:
(1) glands of the lower genitourinary tract
(2) vaginal secretions in females
(3) after bladder reconstruction (enterocystoplasty)
Features of mucus:
(1) tends to form slender, wavy threads or filaments in urine
(2) better seen in phase or interference contrast microscopy
(3) may be confused with hyaline casts
(4) has a low refractile index
(5) can be stained with a mucin stain
The presence of gross mucusuria suggests a mucinous adenocarcinoma releasing mucus into the urine. Most patients with malignant tumors will also have other findings such as abdominal pain, weight loss and hematuria.
Tumors that may be associated with gross mucusuria:
(1) mucinous adenocarcinoma of the urachus
(2) mucinous adenocarcinoma of the urinary bladder
(3) metastatic mucinous adenocarcinoma to the bladder
