Epidermal Procedures

Sebaceous Cyst

A sebaceous cyst (a form of trichilemmal cyst) is a closed sac or cyst below the surface of the skin that has a lining that resembles the uppermost part (infundibulum) of a hair follicle and fills with a fatty white, semi-solid material called sebum. Sebum is produced by sebaceous glands of the epidermis.

Presentation

The scalp, ears, back, face, and upper arm, are common sites for sebaceous cysts, though they may occur anywhere on the body except the palms of the hands and soles of the feet. In males a common place for them to develop is the scrotum and chest .They are more common in hairier areas, where in cases of long duration they could result in hair loss on the skin surface immediately above the cyst. They are smooth to the touch, vary in size, and are generally round in shape.

They are generally mobile masses that can consist of:
  • Fibrous tissues and fluids
  • A fatty, (keratinous), substance that resembles cottage cheese, in which case the cyst may be called "keratin cyst" This material has a characteristic "cheesy" or "foot odor" smell.
  • A somewhat viscous, serosanguineous fluid (containing purulent and bloody material)

Removal

Surgical excision of a sebaceous cyst is a simple procedure to completely remove the sac and its contents.
There are three general approaches used: traditional wide excision, minimal excision, and punch biopsy excision.
The typical outpatient surgical procedure for cyst removal is to numb the area around the cyst with a local anaesthetic, then to use a scalpel to open the lesion with either a single cut down the center of the swelling, or an oval cut on both sides of the centerpoint. If the cyst is small, it may be lanced instead. The person performing the surgery will squeeze out the keratin (the semi-solid material consisting principally of sebum and dead skin cells) surrounding the cyst, then use blunt-headed scissors or another instrument to hold the incision wide open while using fingers or forceps to try to remove the cyst intact. If the cyst can be removed in one piece, the "cure rate" is 100%. If, however, it is fragmented and cannot be entirely recovered, the operator may use curettage (scraping) to remove the remaining exposed fragments, then burn them with an electro-cauterization tool, in an effort to destroy them in place. In such cases the cyst may or may not recur. In either case, the incision is then disinfected and, if necessary, the skin is stitched back together over it. A scar will most likely result. In some cases where "cure rate" is not 100% the resulting hole is filled with an antiseptic ribbon after washing it with an iodine based solution. This is then covered with a field dressing. The ribbon and the dressing are to be changed once or twice daily for 7-10 days after which the incision is sewed up.
An infected cyst may require oral antibiotics or other treatment before and/or after excision.
An approach involving incision, rather than excision, has also been proposed.

Skin Cancer

Skin cancer is a malignant growth on the skin which can have many causes. The most common skin cancers are basal cell cancer, squamous cell cancer, and melanoma. Skin cancer generally develops in the epidermis (the outermost layer of skin), so a tumor is usually clearly visible. This makes most skin cancers detectable in the early stages. There are three common and likely types of skin cancer, each of which is named after the type of skin cell from which it arises. Unlike many other cancers, including those originating in the lung, pancreas, and stomach, only a small minority of those afflicted will actually die of the disease. Skin cancer represents the most commonly diagnosed cancer, surpassing lung, breasts, colorectal and prostate cancer. Melanoma is less common than basal cell carcinoma and squamous cell carcinoma, but it is the most serious—for example, in the UK there are 9,500 new cases of melanoma each year, and 2,300 deaths. It is the most common cancer in the young population (20 – 39 age group). It is estimated that approximately 85% of cases are caused by too much sun. Non-melanoma skin cancers are the most common skin cancers. The majority of these are called basal cell carcinomas. These are usually localized growths caused by excessive cumulative exposure to the sun and tend not to spread.

Treatment

Currently, surgical excision is the most common form of treatment for skin cancers. The goal of reconstructive surgery is restoration of normal appearance and function. The choice of technique in reconstruction is dictated by the size and location of the defect. Excision and reconstruction of facial skin cancers is generally more challenging due to presence of highly visible and functional anatomic structures in the face.

When skin defects are small in size, most can be repaired with simple repair where skin edges are approximated and closed with sutures. This will result in a linear scar. If the repair is made along a natural skin fold or wrinkle line, the scar will be hardly visible. Larger defects may require repair with a skin graft, local skin flap, pedicled skin flap, or a microvascular free flap. Skin grafts and local skin flaps are by far more common than the other listed choices.

Skin grafting is patching of a defect with skin that is removed from another site in the body. The skin graft is sutured to the edges of the defect, and a bolster is placed atop the graft for seven to ten days, to immobilize the graft as it heals in place. There are two forms of skin grafting: split thickness and full thickness. In a split thickness skin graft, a shaver is used to shave a layer of skin from the abdomen or thigh. The donor site, regenerates skin and heals over a period of two weeks. In a full thickness skin graft, a segment of skin is totally removed and the donor site needs to be sutured closed. [19] Split thickness grafts can be used to repair larger defects, but the grafts are inferior in their cosmetic appearance. Full thickness skin grafts are more acceptable cosmetically. However, full thickness grafts can only be used for small or moderate sized defects.

Local skin flaps are a method of closing defects with tissue that closely matches the defect in color and quality. Skin from the periphery of the defect site is mobilized and repositioned to fill the deficit. Various forms of local flaps can be designed to minimize disruption to surrounding tissues and maximize cosmetic outcome of the reconstruction. Pedicled skin flaps are a method of transferring skin with an intact blood supply from a nearby region of the body. An example of such reconstruction is a pedicled forehead flap for repair of a large nasal skin defect. Once the flap develops a source of blood supply form its new bed, the vascular pedicle can be detached.

Skin Grafting

Skin grafting is a type of medical grafting involving the transplantation of skin. The transplanted tissue is called a skin graft.
Skin grafting is often used to treat:

  • Extensive wounding or trauma
  • Burns
  • Areas of prior infection with extensive skin loss
  • Specific surgeries that may require skin grafts for healing to occur

Procedure

In order to remove the thin and well preserved skin slices and stripes from the donor, surgeons use a special surgical instrument called a dermatome. This usually produces a split-thickness skin graft, which contains the epidermis with only a portion of the dermis. The dermis left behind at the donor site contains hair follicles and sebaceous glands, both of which contain epidermal cells which gradually proliferate out to form a new layer of epidermis. The donor site may be extremely painful and vulnerable to infection.

The graft is carefully spread on the bare area to be covered. It is held in place by a few small stitches or surgical staples. The graft is initially nourished by a process called plasmatic imbibition in which the graft literally "drinks plasma". New blood vessels begin growing from the recipient area into the transplanted skin within 36 hours in a process called capillary inosculation. To prevent the accumulation of fluid under the graft which can prevent its attachment and revascularization, the graft is frequently meshed by making lengthwise rows of short, interrupted cuts, each a few millimeters long, with each row offset by half a cut length like bricks in a wall. In addition to allowing for drainage, this allows the graft to both stretch and cover a larger area as well as to more closely approximate the contours of the recipient area.

An increasingly common aid to both pre-operative wound maintenance and post-operative graft healing is the use of negative pressure wound therapy (NPWT). This system works by placing a section of foam cut to size over the wound, then laying a perforated tube onto the foam. The arrangement is then secured with bandages. A vacuum unit then creates negative pressure, sealing the edges of the wound to the foam, and drawing out excess blood and fluids. This process typically helps to maintain cleanliness in the graft site, promotes the development of new blood vessels, and increases the chances of the graft successfully taking. NPWT can also be used between debridement and graft operations to assist an infected wound in remaining clean for a period of time before new skin is applied.