Penile Biopsy

Background

Penile biopsy is used to diagnose benign and malignant lesions of the penis. The technique used varies with the size and location of the lesion and may include punch biopsy or incisional/excisional biopsy.

Indications

Penile biopsy is often performed for the diagnosis of suspected penile caner (see image below). A biopsy is performed to provide histologic confirmation of penile cancer and to assess the depth of microscopic invasion. In the setting of benign lesions, penile biopsy may be performed to identify the etiology of the lesion to guide treatment.

Squamous cell carcinoma (Image courtesy of Hon Pak, MD).

Contraindications

Penile biopsy should not be performed in a patient who is taking anticoagulants or other blood thinners, such as aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs).

Relevant Anatomy

The penile shaft is composed of 3 erectile columns, the 2 corpora cavernosa and the corpus spongiosum, as well as the columns' enveloping fascial layers, nerves, lymphatics, and blood vessels, all covered by skin. The 2 suspensory ligaments, composed of primarily elastic fibers, support the penis at its base. For more information about the relevant anatomy, see Penis Anatomy.

Technical considerations

The type of biopsy performed varies with the size and location of the lesion and the suspicion of malignant disease. For lesions suspicious for cancer, various biopsy techniques may be used, including wet preparation cytology or punch biopsy for suspected carcinoma-in-situ, incisional biopsy for lesions on the shaft of the penis, and excisional biopsy for those involving the prepuce. Incisional biopsy provides the best information regarding the depth of tumor penetration and helps avoid clinical understaging.[1] For those lesions that are thought to be benign in nature, treatment is best accomplished with local excision and thorough histologic evaluation to rule out malignancy. If malignancy is highly suspected, an intraoperative frozen section may be performed for confirmation of malignancy followed by partial or total penectomy, depending on the size, location, and depth of penetration of the cancer.

Procedure planning

The type of biopsy performed should be predetermined to ensure that the appropriate equipment is available. Similarly, if partial/total penectomy is being considered at the time of the biopsy, the consent needs to include such procedures, and the pathology department should be notified of the need for frozen section results. Patients who are taking anticoagulants and/or other blood thinners should stop therapy in advance of surgery to minimize the risk of bleeding.

Anesthesia

Penile biopsy may be performed under local anesthesia (penile block) depending on the size of the lesion and whether or not partial/total penectomy will be performed if the frozen section biopsy is positive.

Complication prevention

To avoid significant bleeding, anticoagulant therapy and other agents that affect hemostasis (ie, NSAIDs) should be stopped prior to the procedure. If infection is present at the site of biopsy, appropriate antibiotic therapy should be instituted prior to biopsy. The biopsy site should be prepped and draped in a sterile fashion. Except for small punch biopsies, suture closure is recommended for cosmesis and hemostasis. The specimen should be large enough to ensure sufficient evaluation. Confirmation of the adequacy of the specimen with pathology should be obtained prior to termination of the procedure. A penile block placed at the beginning of the procedure helps decrease periprocedural pain.

Patient education/informed consent

Patients should be aware of the indications for the biopsy and the implications for subsequent care. Risks of bleeding, infection, pain, poor cosmesis, residual tumor, and insufficient specimen requiring rebiopsy should be reviewed with the patient. For those patients in whom a high risk for penile cancer exists, if simultaneous partial/total penectomy is going to be performed (if the frozen section is positive), this should be included on the consent and discussed with the patient including the risks of partial/total penectomy.

Equipment

The equipment needed for penile biopsy varies with the technique used. For incisional/excisional biopsy, a No. 15 blade scalpel, scissors, hemostat, retractor, forceps, needle holder, and absorbable suture are needed. If a punch biopsy is to be performed, various different size punches need to be available to allow for selection of the appropriate punch intraoperative. See images below.

Biopsy punches come in a variety of sizes and in both reusable and disposable forms. Disposable biopsy punches are lighter and more easily manipulated than their metal counterparts.

A No. 15 Bard-Parker blade, atraumatic forceps, and suture material are used for many soft tissue biopsies. Take care to avoid the use of nonresorbable suture material for closure.

Patient preparation

In most cases, a penile biopsy can be performed under local anesthesia (penile block) unless a simultaneous partial/total penectomy is to be performed if the frozen section is positive. Epinephrine should not be administered with the local anesthesia. The patient is positioned in a supine position and the genitalia are prepped and draped in a sterile fashion.

Punch biopsy

After prepping and draping the patient and administering a penile block, a punch is selected that is large enough to obtain adequate tissue, typically a 3-4 mm punch. A punch that is slightly larger than the lesion can remove the entire lesion. The skin around the lesion is stretched perpendicular to the lines of least tension to create an oval or elliptical defect. The punch is then applied over the lesion and is rotated with a downward force. The blade is twisted back and forth around its center axis until the blade penetrates the skin and one feels a "give." The specimen is then removed. If a small punch is used, the defect can be left open to heal by second intention. If a larger size punch is used, then the defect is closed with an interrupted absorbable suture.[2]

Incisional/excisional biopsy

After prepping and draping the patient and administration of a penile block, the incision is marked out. An ellipse is marked around the lesion with long axis of the ellipse parallel to lines of least tension. The length of the incision should be approximately 3 times the width of the incision, to provide satisfactory closure. Once marked out, the area is incised with a 15-blade scalpel. The corner segment is grasped with a forceps and elevated, and the ellipse of skin with the lesion is then excised with a scalpel or scissors. Care should be taken to ensure that the lesion has been adequately removed. Electrocautery can be used for hemostasis. The edges are closed with interrupted sutures. The specimen is either sent for frozen section or placed in fixative for permanent section.[2]