Squamous Cell Carcinoma
SQUAMOUS CELL CARCINOMA
SQUAMOUS CELL CARCINOMA DEFINITION
Squamous cell carcinoma of the skin is a common form of skin cancer that develops in the thin, flat squamous cells that make up the outer layer of the skin.
Squamous cell carcinoma of the skin is usually not life-threatening, though it can be aggressive in some cases. Untreated, squamous cell carcinoma of the skin can grow large or spread to other parts of your body, causing serious complications.
Most squamous cell carcinomas of the skin result from prolonged exposure to ultraviolet (UV) radiation, either from sunlight or from tanning beds or lamps. Avoiding UV light helps reduce your risk of squamous cell carcinoma of the skin and other forms of skin cancer.
Squamous cells are found in many places in your body and squamous cell carcinoma can occur in anywhere squamous cells are found. Squamous cell carcinoma of the skin refers to cancer that forms in the squamous cells found in the skin.
SQUAMOUS CELL CARCINOMA CAUSES
Both long-term sun exposure over your lifetime and occasional extended, intense exposure (typically leading to sunburn) combine to cause damage that can lead to BCC. Almost all BCCs occur on parts of the body excessively exposed to the sun — especially the face, ears, neck, scalp, shoulders, and back. On rare occasions, however, tumors develop on unexposed areas. In a few cases, contact with arsenic, exposure to radiation, open sores that resist healing, chronic inflammatory skin conditions, and complications of burns, scars, infections, vaccinations, or even tattoos are contributing factors. It is not possible to pinpoint a precise, single cause for a specific tumor, especially one found on a sun-protected area of the body or in an extremely young individual.
SQUAMOUS CELL CARCINOMA PATHOPHYSIOLOGY
The tissue of origin for renal cell carcinoma (RCC) is the proximal renal tubular epithelium. Renal cancer occurs in a sporadic (nonhereditary) and a hereditary form, and both forms are associated with structural alterations of the short arm of chromosome 3 (3p). Genetic studies of the families at high risk for developing renal cancer led to the cloning of genes whose alteration results in tumor formation. These genes are either tumor suppressors (VHL, TSC) or oncogenes (MET).
At least four hereditary syndromes associated with renal cell carcinoma are recognized, as follows:
- von Hippel-Lindau (VHL) syndrome
- Hereditary papillary renal carcinoma (HPRC)
- Familial renal oncocytoma (FRO) associated with Birt-Hogg-Dube syndrome (BHDS)
- Hereditary renal carcinoma (HRC)
VON HIPPEL-LINDAU SYNDROME
vonHippel-Lindau syndrome, or von Hippel-Lindau disease, is an autosomal dominant syndrome that confers predisposition to a variety of neoplasms, including the following:
- Renal cell carcinoma with clear cell histologic features
- Pancreatic cysts and islet cell tumors
- Retinal angiomas
- Central nervous system (CNS) hemangioblastomas
- Endolymphatic sac tumors
Renal cell carcinoma develops in nearly 40% of patients with von Hippel-Lindau disease and is a major cause of death among these patients. Deletions of 3p occur commonly in renal cell carcinoma associated with von Hippel-Lindau disease. TheVHL gene is mutated in a high percentage of tumors and cell lines from patients with sporadic (nonhereditary) clear cell renal carcinoma. Several kindreds with familial clear cell carcinoma have a constitutional balanced translocation between 3p and either chromosome 6 or chromosome 8.
Mutations of the VHL gene result in the accumulation of hypoxia-inducible factors (HIFs) that stimulate angiogenesis through vascular endothelial growth factor (VEGF) and its receptor (VEGFR). VEGF and VEGFR are important new therapeutic targets.
HEREDITARY PAPILLARY RENAL CARCINOMA
Hereditary papillary renal carcinoma is an inherited disorder with an autosomal dominant inheritance pattern; affected individuals develop bilateral, multifocal papillary renal carcinoma. Germline mutations in the tyrosine kinase domain of theMET gene have been identified.
FAMILIAL RENAL ONCOCYTOMA AND BIRT-HOGG-DUBE SYNDROME
Individuals affected with familial renal oncocytoma can develop bilateral, multifocal oncocytoma or oncocytic neoplasms in the kidney. Birt-Hogg-Dube syndrome is a hereditary cutaneous syndrome. Patients with Birt-Hogg-Dube syndrome have a dominantly inherited predisposition to develop benign tumors of the hair follicle (ie, fibrofolliculomas), predominantly on the face, neck, and upper trunk, and these individuals are at risk of developing renal tumors, colonic polyps or tumors, and pulmonary cysts.
HEREDITARY RENAL CARCINOMA
Affected individuals with this inherited medical condition have an increased tendency to develop oncocytomas, benign kidney tumors that have a low malignant potential.
SQUAMOUS CELL CARCINOMA SYMPTOMS
Squamous cell carcinoma of the skin most often occurs on sun-exposed skin, such as your scalp, the backs of your hands or your ears. But squamous cell carcinoma of the skin can occur anywhere on your body, including inside your mouth, on your anus and on your genitals.
Signs and symptoms of squamous cell carcinoma of the skin include:
- A firm, red nodule
- A flat sore with a scaly crust
- A new sore or raised area on an old scar or ulcer
- A rough, scaly patch on your lip that may evolve to an open sore
- A red sore or rough patch inside your mouth
- A red, raised patch or wart-like sore on or in the anus or on your genitals
SQUAMOUS CELL CARCINOMA DIAGNOSIS
f you have an abnormal area that might be skin cancer, your doctor will do exams and tests to find out if it is cancer or some other skin condition. If there is a chance the skin cancer may have spread to other areas of the body, other tests might be done as well.
MEDICAL HISTORY AND PHYSICAL EXAM
Usually the first step is for your doctor to take your medical history. The doctor will ask when the mark on the skin first appeared, if it has changed in size or appearance, and if it is causing any symptoms (pain, itching, bleeding, etc.). You may also be asked about past exposures to causes of skin cancer (including sunburns and tanning practices) and if you or anyone in your family has had skin cancer.
During the physical exam, the doctor will note the size, shape, color, and texture of the area(s) in question, and whether they are bleeding, oozing, or crusting. The rest of your body may be checked for moles and other spots that could be related to skin cancer.
The doctor may also feel the nearby lymph nodes, which are bean-sized collections of immune system cells under the skin in certain areas. Some skin cancers can spread to lymph nodes. When this happens, the lymph nodes can become larger and might be felt as lumps under the skin.
If you are being seen by your primary doctor and skin cancer is suspected, you may be referred to a dermatologist (a doctor who specializes in skin diseases), who will look at the area more closely.
Along with a standard physical exam, some dermatologists use a technique called dermatoscopy (also known asdermoscopy, epiluminescence microscopy [ELM] or surface microscopy) to see spots on the skin more clearly. The doctor uses a dermatoscope, which is a special magnifying lens and light source held near the skin. Sometimes a thin layer of alcohol or oil is used with this instrument. The doctor may take a digital photo of the spot.
When used by an experienced dermatologist, this test can improve the accuracy of finding skin cancers early. It can also often help reassure you if a spot on the skin is probably benign (non-cancerous) without the need for a biopsy.
If the doctor thinks that a suspicious area might be skin cancer, the area (or part of it) will be removed and sent to a lab to be looked at under a microscope. This is called a skin biopsy. If the biopsy removes the entire tumor, it’s often enough to cure basal and squamous cell skin cancers without further treatment.
There are different types of skin biopsies. The doctor will choose one based on the suspected type of skin cancer, where it is on your body, its size, and other factors. Any biopsy will probably leave at least a small scar. Different methods can result in different scars, so if this is a concern, ask your doctor about possible scarring before the biopsy is done. No matter which type of biopsy is done, it should remove as much of the suspected area as possible so that an accurate diagnosis can be made.
Skin biopsies are done using a local anesthetic (numbing medicine), which is injected into the area with a very small needle. You will probably feel a small prick and a little stinging as the medicine is injected, but you should not feel any pain during the biopsy.
SHAVE (TANGENTIAL) BIOPSY
For a shave biopsy, the doctor shaves off the top layers of the skin with a small surgical blade. Usually the epidermis and the outer part of the dermis are removed, although deeper layers can be taken as well if needed. Bleeding from the biopsy site is then stopped by applying an ointment or a chemical that stops bleeding, or by using a small electrical current to cauterize the wound.
For a punch biopsy, the doctor uses a tool that looks like a tiny round cookie cutter to remove a deeper sample of skin. The doctor rotates the punch biopsy tool on the skin until it cuts through all the layers of the skin, including the dermis, epidermis, and the upper parts of the subcutis. The sample is removed and the edges of the biopsy site are often stitched together.
INCISIONAL AND EXCISIONAL BIOPSIES
To examine a tumor that may have grown into deeper layers of the skin, the doctor may use an incisional or excisional biopsy. An incisional biopsy removes only a portion of the tumor. An excisional biopsy removes the entire tumor.
For these types of biopsies, a surgical knife is used to cut through the full thickness of skin. A wedge or sliver of skin is removed for examination, and the edges of the wound are usually stitched together.
EXAMINING THE BIOPSY SAMPLES
All skin biopsy samples are sent to a lab, where they are looked at under a microscope by a doctor called apathologist. Often, the samples are sent to a dermatopathologist, a doctor who has special training in looking at skin samples.
LYMPH NODE BIOPSY
It’s rare for basal or squamous cell cancer to spread beyond the skin, but if it does it usually goes first to nearby lymph nodes, which are bean-sized collections of immune cells. If your doctor feels lymph nodes near the tumor that are too large and/or too firm, a lymph node biopsy may be done to determine whether cancer has spread to them.
FINE NEEDLE ASPIRATION BIOPSY
For a fine needle aspiration (FNA) biopsy, the doctor uses a syringe with a thin, hollow needle to remove very small fragments of the lymph node. The needle is smaller than the needle used for a blood test. A local anesthetic is sometimes used to numb the area first. This test rarely causes much discomfort and does not leave a scar.
An FNA biopsy is not used to diagnose a suspicious skin tumor, but it may be used to biopsy large lymph nodes near a skin cancer to find out if the cancer has spread to them. FNA biopsies are not as invasive as some other types of biopsies, but they may not always provide a large enough sample to find cancer cells.
SURGICAL (EXCISIONAL) LYMPH NODE BIOPSY
If an FNA does not find cancer in a lymph node but the doctor still suspects the cancer has spread there, the lymph node may be removed by surgery and examined. If the lymph node is just under the skin, this can often be done in a doctor’s office or outpatient surgical center using local anesthesia. It will leave a small scar.
SQUAMOUS CELL CARCINOMA TREATMENT
Most squamous cell carcinomas of the skin can be completely removed with relatively minor surgery or occasionally with a topical medication. Which squamous cell carcinoma of the skin treatments are best for you depends on the size, location and aggressiveness of the tumor, as well as your own preferences.
Treatments may include:
- Electrodesiccation and curettage (ED and C). ED and C treatment involves removing the surface of the skin cancer with a scraping instrument (curet) and then searing the base of the cancer with an electric needle. This treatment is often used for very small squamous cell cancers of the skin.
- Laser therapy. An intense beam of light vaporizes growths, usually with little damage to surrounding tissue and with a reduced risk of bleeding, swelling and scarring. Laser treatment may be an option for very superficial skin lesions.
- Freezing. This treatment involves freezing cancer cells with liquid nitrogen (cryosurgery). It may be an option for treating superficial skin lesions.
- Photodynamic therapy. Photodynamic therapy combines photosensitizing drugs and light to treat superficial skin cancers. During photodynamic therapy, a liquid drug that makes the cancer cells sensitive to light is applied to the skin. Later, a light that destroys the skin cancer cells is shined on the area.
- Medicated creams or lotions. For very superficial cancers, you may apply creams or lotions containing anti-cancer medications directly to your skin.
- Simple excision. In this procedure, your doctor cuts out the cancerous tissue and a surrounding margin of healthy skin. Your doctor may recommend removing additional normal skin around the tumor in some cases (wide excision). To minimize scarring, especially on your face, consult a doctor skilled in skin reconstruction.
- Mohs surgery. During Mohs surgery, your doctor removes the cancer layer by layer, examining each layer under the microscope until no abnormal cells remain. This allows the surgeon to be certain the entire growth is removed and avoid taking an excessive amount of surrounding healthy skin.
- Radiation therapy. Radiation therapy uses high-energy beams, such as X-rays, to kill cancer cells. This may be an option for treating deeper tumors, those that have a risk of returning after surgery and tumors in people who can’t undergo surgery.