Colposcopy

Colposcopy (from Greek kolpos — vagina, skopeo — to examine) is a highly informative method of visual instrumental diagnosis of cervical, vaginal, and vulvar pathology performed using a binocular microscope (colposcope) with a light source.

Etiology and pathophysiology

The method is based on examining the reaction of the epithelium and vascular pattern under magnification (from 7 to 30 times) during diagnostic tests (extended colposcopy):

1. Test with 3% acetic acid: The acid causes coagulation of intracellular proteins and transient vascular spasm. Pathological epithelium (dysplasia, HPV lesion) with high nuclear density whitens more intensely and longer than normal (effect of aceto-white epithelium).
2. Schiller’s test (with Lugol’s solution): Mature stratified squamous epithelium rich in glycogen stains dark brown with iodine. Pathologically altered cells (cancerous, dysplastic) are poor in glycogen and remain unstained (iodine-negative).

Clinical significance

Colposcopy is an integral part of cervical cancer screening (triad: cytology + HPV test + colposcopy). It allows differentiation between benign changes (ectopy, transformation zone, Nabothian cysts) and suspicious ones (leukoplakia, punctuation, mosaic, atypical vessels). The main aim of the procedure is navigation for targeted biopsy from the most altered area for accurate histological verification of diagnosis.