Biopsy of the skin is the most important diagnostic test for the evaluation of inflammatory dermatoses of the vulva such as lichen sclerosus and lichen simplex chronicus. Punch biopsy is the primary technique to obtain full thickness specimens that can sent for histologic evaluation by a dermatopathologist. It is key to distinguish normal from abnormal.
Inflammatory dermatoses may be the underlying cause of dyspareunia. Lichen simplex chronicus, for example, is associated with red or erythematous lichenified scar or plaque with reduced pigmentation and overlying excoriation. Lichen sclerosus is associated with the texture changes of the skin described as “cigarette paper” or “wrinkled” with reduced pigmentation, scarring of the vulva, including resorption of the labia minora, and narrowing of the vaginal opening or introitus.
A vulvoscope should be used to select the area in the vulva to be biopsied. The physician chooses the most abnormal appearing tissue. The biopsy should be taken next to an erosion or ulceration of the vulvar tissue. The vulvar tissue to be biopsied is first cleansed with an iodine solution. The physician administers 1 cc of 1% lidocaine with 1:200,000 epinephrine subcutaneously with a 30-guage needle. A 4 mm Keyes punch biopsy tool is then pressed vertically into the skin and rotated downward using a twirling motion until the instrument has reached the subcutaneous fat. The cylindrical specimen is gently elevated with a forceps at the edge of the specimen to ensure that it is not crushed. The base of the specimen is cut with an Iris scissor to free the specimen.
The incision should be closed with one interrupted suture of 4-0 Vicryl to reduce healing time and scarring. The specimen is placed in Formulin and sent to a dermatopathologist. The physician should add a differential diagnosis to help the dermatopathologist make a definitive diagnosis.