A 52-year-old male visited a dentist`s office for a routine checkup. During the extraoral examination, a lesion was noted on the skin of the neck.
Joen Iannucci Haring, DDS, MS
The patient was unaware of the lesion located on the skin of the back of the neck. When questioned about prolonged sun exposure, the patient stated that he has worked in outdoor construction for more than 20 years. At the time of the dental visit, the patient appeared to be in a good state of health, and no significant findings were noted during the health history.
The extraoral examination revealed one lesion located on the skin of the back of the neck. The lesion measured approximately 7 mm in diameter and exhibited a rolled and indurated (hard) border with a depressed, crusted center. No other lesions were noted on the skin of the patient`s head and neck area, and no palpable lymph nodes were identified.
Based on the clinical information presented, which one of the following is the most likely diagnosis?
* Squamous cell carcinoma
* Basal cell carcinoma
* Sebborheic keratosis
* Actinic keratosis
__ Basal cell carcinoma
Basal cell carcinoma is the most common type of skin cancer, accounting for approximately 65 percent of all primary skin malignancies. Basal cell carcinoma is a slow-growing, locally invasive cancer which rarely spreads to lymph nodes and seldom metastasizes. In most cases, it is a localized lesion that can be surgically removed in its entirety, resulting in an overall high cure rate and very low mortality rate.
The predominant causative factor of basal cell carcinoma is prolonged sun exposure. People with outdoor occupations (sailors, farmers, construction workers, for example) and outdoor sportsmen are especially prone to developing basal cell carcinoma. Caucasians are more susceptible than individuals of darker races. Other causative factors include radiation damage and genetic factors such as those that occur in the autosomal dominant disease, Basal Cell Nevus Bifid Rib Syndrome.
Basal cell carcinoma occurs more frequently in men than in women. Although this form of skin cancer may occur at any age, more than 75 percent of patients with basal cell carcinoma are over the age of 40.
As a rule, sun-exposed areas of the body are more prone to developing basal cell carcinoma than areas not exposed to the sun. In 90 percent of cases, this type of cancer is found on the skin between the eyebrows and upper lip. Other frequent areas of involvement include the scalp, nose, forehead, ears, eyelids, and outer canthus of the eye. Basal cell carcinoma never occurs on the lips or inside the oral cavity.
The six different clinical types of basal cell carcinoma are: nodulo-ulcerative, pigmented, morphea-type, superficial, linear, and fibroepithelial. The most common form is termed nodulo-ulcerative or nodular basal cell carcinoma. All of the other types are not routinely seen. The nodular form usually occurs as a solitary lesion, although two or more lesions are not uncommon.
The early presentation of the nodular basal cell carcinoma is that of a small, firm, waxy nodule with scattered capillaries (telangiectasias) on its surface. Most of these lesions are less than 1 cm in diameter. As this skin cancer enlarges, the center of the lesion becomes depressed and results in a firm, elevated, and rolled border. Without treatment, the nodule will continue to increase in size and exhibit a central ulceration. Hemorrhage is common. Often, there is a history of repeated ulceration and then crusting before the ulcer becomes permanent.
In addition to skin cancers, numerous benign and pre-malignant skin lesions can be seen in the head and neck area. Lesions such as sebaceous hyperplasia, seborrheic keratosis, actinic keratosis, and keratoacanthoma are often mistaken for basal cell carcinoma and should be considered in the differential diagnosis.
* Sebaceous hyperplasia may be easily confused with basal cell carcinoma. This lesion represents hypertropic sebaceous glands and appears as a small, yellow-white, umbilicated nodule covered with tiny telangiectasias. The depressed center contains a sebaceous material (keratin) that can be exuded by lateral pressure. Sebaceous hyperplasia is found on oily areas of skin in persons 30 and older. These lesions are usually less than 5 mm in diameter, seen in clusters, and never crust and bleed. This lesion is not induced by the sun.
* Seborrheic keratosis is a round to ovoid, irregularly raised, and light brown to black lesion that ranges in size from a few millimeters to several centimeters. The surface is irregular and warty, exhibiting a stuck-on appearance with a waxy or greasy feel. Seborrheic keratoses are seen on the face, chest, and back of middle-aged to elderly individuals. This lesion is not induced by the sun.
* Actinic keratosis is a flat, brownish lesion with a dry, scaly appearance and a sandpaper feel. This lesion is found on exposed skin surfaces and is considered to be pre-malignant. Approximately 25 percent of actinic keratoses progress on to become skin cancer, specifically squamous cell carcinoma. Actinic keratoses are seen in the elderly, especially in those with a history of extensive sun exposure.
* A keratoacanthoma appears as a solitary, dome-shaped nodule with a keratotic plug. These lesions appear in older individuals aged 50 to 70 and are fast growing, often reaching the size of 1 cm to 1.5 cm in one to two months. If this lesion is not treated, it will regress spontaneously in six to 12 months.
If a lesion is suspected to represent basal cell carcinoma, the dentist should promptly refer the patient to a physician for further evaluation. A biopsy and histologic examination is necessary to establish a diagnosis.
The aim in the treatment of basal cell carcinoma is for a permanent cure with the best cosmetic results, an important consideration since the majority of the basal cell carcinomas are found on the face. Recurrences result from inadequate treatment and usually appear during the first four to 12 months after treatment. After treatment, patients with basal cell carcinoma should be followed closely for recurrence.
Basal cell carcinoma can be treated effectively with a variety of methods. Those used most often include curettage with electrodesiccation, scalpel excision, cryosurgery, laser surgery, and radiotherapy. Moh?s microscopically controlled excision is another treatment that is particularly useful in the removal of basal cell carcinomas. In this procedure, the cancer is removed with as little normal tissue as possible. During u the surgery, the physician removes the cancer and examines it using a microscope to make certain no cancer cells remain.
The prognosis for basal cell carcinoma is excellent. Although basal cell carcinoma is able to invade and destroy surrounding tissue, it rarely metastasizes. Approximately 100 cases of metastasis have been reported. Most of these cases involved the regional lymph nodes, while other sites of involvement included bone, lung, and liver. In cases of metastasis, the prognsis is poor.
The dental professional?s role
As health professionals, both dentists and hygienists can play an important role in the early detection of skin cancer, particularly since skin cancer lesions are highly visible and easily accessible in the head and neck region. The dental professional who recognizes the signs of skin cancer and recommends that the patient visit a physician for further evaluation is providing a valuable patient service that facilitates early diagnosis, treatment, and cure.
Joen Iannucci Haring, DDS, MS, is an associate professor of clinical dentistry, Section of Primary Care, The Ohio State University College of Dentistry.