EXTERNAL EAR CANAL TUMORS
Mark J. Levenson, MD, FACS
Tumors of the ear can be benign or malignant. They can occur on the external ear, or in the ear canal, the middle ear or inner ear. Tumors in different areas of the ear behave differently. Thus, it is necessary to describe tumors based on their site of occurrence, as well as their behavior and treatment.
Tumors of the External Ear Canal
The external ear canal begins at the opening of the cup-shaped portion (concha) of the ear and extends downward to the ear drum. Tumors that occur in the ear canal can be benign or malignant. Malignant tumors of the external ear canal are very serious. Immediate biopsy of any suspicious lesion in the external ear canal should be performed immediately.
The most common malignant tumors in this location are basal cell or squamous cell cancers.
In addition, there are glandular tumors of the ear canal which can arise from those glands which produce ear wax. In some of these cases, malignant tumors of the parotid gland (the gland in the front of the ear) can push through the skin and bone of the ear canal as malignant tumors in the ear canal cystic cancer.
A biopsy will confirm the nature of the growth in the ear canal. Appropriate treatment will then be scheduled, depending on the depth and extent of the tumor. The use of CT and MRI scanning has made this evaluation process more accurate.
The ear drum serves as a partial barrier for the growth of tumors which occur in the external ear canal. If the tumor is not deeply seated and is only on the skin of the ear canal, all the skin of the ear canal is removed surgically. The bone underlying it is drilled away, and a skin graft is placed in the ear canal. If the tumor is near the ear drum, the ear drum is also removed with the skin of the ear canal as well as the surrounding bone of the original ear canal. A skin graft is placed against the bare bone, similar to the correction of an atretic ear (see Atresia Skin Grafting).
If the tumors are malignant, radiation therapy should be considered after surgery, particularly in squamous cell cancers. Surgical resection of the ear canal without radiation therapy is adequate for basal cell cancers and low grade glandular malignancies. Squamous cell cancer of the external ear canal, however, is an especially aggressive disease.
It requires more radical surgery, except in the very earliest of cases.
If the tumor is near the edge of the ear drum, complete removal of the skin and bone of the external ear canal as well as the ear drum and the hammer and anvil bones (malleus and incus), is necessary.
In order to obtain a complete removal of all skin and bone of the ear canal, it is necessary to define the facial nerve in its course through the ear and out into the face. The incision in the ear extends to the front of the ear and the parotid gland, (the large salivary gland in the cheek). The gland is identified, and portions of it are removed, in addition to the front (anterior) portion of the ear canal.
The procedure used is a total "enbloc" of the entire ear canal and skin surrounding it, including bone, ear drum, and bones of hearing. Even in cases where the margins of the removed tumor have been confirmed as "clear of disease," radiation therapy must be seriously considered, if squamous cell cancers were present. Squamous cell cancers are known to metastasize locally into the skin and lymph glands. Radiation therapy is given as an adjunct to the surgical treatment, as soon as the ear is healed. Skin grafting of the ear is performed to rebuild the ear canal. A fascial type graft is used to rebuild the ear drum. (See perforations.)
Radical surgery is indicated in cases where the tumor has advanced beyond the confines of the ear drum into the middle ear, or in cases where the tumor seems to have arisen within the middle ear itself. The ear drum, or tympanic membrane, forms a partial barrier against tumors in the external ear canal entering the middle ear. However, tumors can arise in the middle ear itself or be involved as an extension of tumors from the external ear which pass through and around the ear drum.
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