A fisherman in his early sixties went to see his dermatologist because he has a bleeding lesion on the upper rim of his ear. It has been there for about two years but recently has been getting larger.
Non-healing lesions of the ear should be carefully evaluated for features that suggest malignancy. Ulceration, bleeding, odd pigmentation, asymmetry, nodularity, and rapid growth are all features that should prompt concern. It is often necessary to perform a biopsy of these types of lesions in order to determine if there is evidence of cancer. If the biopsy indicates skin cancer, treatment strategies are based upon the size of the tumor as well as the type.
Basal Cell Carcinoma
Basal cell carcinomas are the most common malignant neoplasm of the ear, representing 45 percent of ear cancers. Chronic long-term sun exposure is the predominant cause of basal cell carcinoma. Specifically, ultraviolet B (UVB) radiation has been identified as a major carcinogen. The incidence of cancer increases with age. Other risk factors include fair skin, outdoor occupations, and a history of previous skin cancer.
People may initially develop a skin lesion that is nodular (lumpy), ulcerated, and/or bleeding. Basal cell carcinomas of the ear typically occur on the back surface of the pinna. Imaging may be used to evaluate advanced disease with tumor extension to the adjacent temporal bone and soft tissue structures of the head and neck. The overall rate of basal cell cancer metastasis is extremely low, at less than 1 percent.
Treatments of ear basal cell carcinoma may be either surgical or non-surgical. Non-surgical options include treatment with chemicals to destroy the tumor such as topical 5-fluorouracil. This may be successful with small superficial lesions, but is far less effective with larger lesions. Radiation therapy is also an option, but is usually reserved for patients who are poor surgical candidates because of other conditions or for people whose lesions are too extensive to be surgically removed.
Surgery is far more commonly used to treat basal cell carcinomas affecting the ear or the ear canal. Cryosurgery, which involves freezing lesions with liquid nitrogen, may be used to treat small basal cell carcinomas (< 1 cm) with well-defined borders. Standard surgical excision (removal) is the mainstay of treatment. Ninety-five percent of basal cell carcinomas < 2 cm in size can be successfully treated with local excision with a proper margin (normal tissue removed around the tumor).
Mohs surgery is a layer-by-layer removal of the tumor. Each layer that is removed is examined under the microscope to verify that no tumor remains. If there is remaining tumor in the removed specimen, further excision is done immediately. When the layers are clear, the surgery is finished. This approach allows more of the structure of the ear to be preserved. This technique is particularly useful for recurrent basal cell carcinomas, those larger than 2 cm, or those with an aggressive microscopic appearance. Five-year cure rates using Mohs technique approach 97.1 percent.
Squamous Cell Carcinoma of the External Ear
Squamous cell carcinomas account for 20 percent of all cancerous skin growths (cutaneous malignant neoplasms) and commonly occur in elderly males. Risk factors for squamous cell carcinoma include a suppressed immune system, advanced age, a non-healing ulcer, and a history of exposure to chemicals such as arsenic, soot, coal, tar, paraffin, and petroleum oil. The most important risk factor is exposure to ultraviolet B rays (UVB exposure).
The appearance of squamous cell tumors is variable and includes plaques, nodules, and ulcerations. They may break up into small pieces when rubbed and are prone to bleeding. Squamous cell tumors frequently occur on the helix or tragus, but may occur on any sun-exposed areas.
Imaging may be used to evaluate advanced disease with tumor spread to the adjacent temporal bone and soft tissue structures of the head and neck. The overall risk of metastasis (spread) for cutaneous squamous cell carcinoma of the external ear is approximately 6 to 18 percent, much higher than for basal cell tumors.
Treatment of squamous cell carcinoma of the external ear is similar to that for basal cell carcinoma; however larger surgical margins (the amount of normal tissue removed around the tumor) are required. Some tumors pose a greater risk of spreading disease through the body’s system of lymph nodes. Consequently, it is sometimes necessary to remove lymph nodes in the neck (elective neck dissection) and/or to remove the parotid salivary gland for advanced lesions.
The prognosis for squamous cell carcinoma depends not only on the patient’s age and overall immune status, but also on the microscopic appearance, size, and location of the tumor. A better prognosis is associated with a well-differentiated tumor (that is, one that is more like a normal structure). The five-year cure rate for squamous cell carcinomas of the external ear range from 75 to 92 percent.
Squamous Cell Carcinoma of the Temporal Bone
The temporal bone is the part of the skull that surrounds the ear. Squamous cell carcinoma of the temporal bone is a rare condition in which the tumor usually spreads into the bone from the skin of the ear canal. The first symptoms may be bloody ear drainage. Some patients may have had chronic ear infections in the past and the diagnosis may be delayed by confusing the appearance of canal tumors with external otitis.
A biopsy of the lesion in the ear canal is necessary to make the diagnosis. Because of the complex three-dimensional anatomy of the temporal bone, its proximity to vital structures, and low survival rates, tumors developing in this region require aggressive management.
Treatment of squamous cell carcinoma of the ear canal is surgical except in those patients not healthy enough to undergo a major operation. Cancer confined to the skin of the ear canal may be treated with excision of the skin of the ear canal with preservation of the eardrum. If cancer invades the bone of the ear canal and/or involves the eardrum, lateral temporal bone surgery is necessary. In this procedure, the eardrum and ear canal are removed. If the cancer has penetrated the eardrum, removal of the middle ear structures is also necessary. Facial nerve weakness or twitching may require removing the involved segment of the nerve and replacing it with a nerve graft from the neck or leg.
Radiation therapy is used as an additional treatment for patients with more advanced lesions or whose disease has spread into the parotid gland or neck. It may also be indicated for inoperable lesions to alleviate patient discomfort.
Squamous cell carcinoma of the ear canal carries a poor prognosis with recent studies suggesting a five-year survival rate of 83 percent for small tumors down to 25 percent for larger tumors. Facial nerve involvement and spread to lymph nodes are likely indications of a poor prognosis.
Melanoma
The incidence of malignant melanoma in the United States is 11.1 patients for every 100,000 individuals each year and continues to increase. Ear melanoma accounts for less than 1 percent of all melanomas and has a 10-year survival rate of 70 percent.
Melanomas involving the ear typically present on the helix (rim of the ear) and are colored, usually black. Initially painless, these lesions may change in size, ulcerate, and bleed. A thorough head and neck examination requires attention to lymph nodes in the neck or parotid gland that may occur with regional spread of disease.
The diagnosis of melanoma is dependent on the microscopic evaluation of a biopsy. Evaluation should include a chest X-ray and liver function tests to rule out metastases, since this type of cancer has a tendency to spread through the bloodstream into the liver and lungs. CT scanning and MRI are also helpful in detecting metastatic disease.
The extent of surgical treatment and the prognosis depends on the size, depth of invasion, and microscopic appearance of the tumor. Spread to adjacent lymph nodes or to distant organs such as the lungs and liver predict a poor prognosis.
Removal of surrounding lymph nodes is controversial and may include elective regional lymph node removal and parotidectomy. Recently, sentinel lymph node biopsy has become a well-accepted approach in the management of surrounding lymph nodes with no clinical evidence of spread. One or two lymph nodes in the drainage area of the lesion are biopsied for micro-metastases. If tumor cells are present, the rest of the nodes of the drainage area are removed.
Glandular Tumors
Glandular tumors of the ear canal are rare.
Patients with glandular tumors of the ear canal may complain of ear drainage, ear pressure, pain, and conductive hearing loss. Sensorineural hearing loss may signify tumor extension into the inner ear. Imaging by MRI and/or CT scan is helpful in determining the amount of bony erosion and the size of the tumor.
Benign glandular tumors are treated with excision of the tumor and appropriate margins. Malignant tumors are treated with temporal bone resection (see above for details of surgery), and consideration should also be given to radiation after surgery. Removal of the parotid gland may also be necessary in some cases.