Ceruminous gland carcinoma

From Felipedia

Ceruminous gland carcinoma are a simple malignant apocrine tumor of the feline ear showing differentiation to ceruminous epithelium.

Benign or malignant neoplasms that develop from the modified apocrine or cerumen glands in the external ear canal are most common in cats. Because many tumors completely obstruct the ear canal, they are often associated with secondary otitis externa or media with purulent to hemorrhagic discharge. Vestibular signs may be present if there is middle ear involvement. Ceruminous gland adenocarcinomas are locally invasive and may metastasize to regional lymph nodes and to the parotid salivary gland. Distant metastasis to the lungs is rare. The most common include squamous cell carcinoma, ceruminous gland adenoma or adenocarcinoma, sebaceous gland tumour and basal cell tumour. There appears to be no breed predisposition and is more common in cats over 5 years of age. Causes of ear tumours include UV light exposure and chronic local irritation/infection.

The most common ear tumour is the adenocarcinoma, which is fast growing, cystic and in advanced stages, locally invasive to surrounding cartilage and bone. The majority are treated surgically and with radical resection, the prognosis is good.

Diagnosis of ceruminous gland tumors is by deep otoscopic examination under sedation or general anaesthesia, with flushing and suction removal of purulent discharge as needed to visualize the deep vertical and horizontal canals. Use of a videographic otoscope greatly facilitates this procedure. Computed tomography or MRI may be very useful in assessing the tympanic bulla more completely and in determining the extent of tumour invasion, especially in malignant tumors. Definitive diagnosis is made by histopathology after surgical removal of the mass.

Surgical removal of benign ear canal tumors may be accomplished via lateral ear canal resection in most cases, unless there is involvement of the tympanic bulla. Laser surgery has also been used. Total ear canal ablation with bulla osteotomy is the only recommended surgery for removal of malignant ear canal tumors. Lateral ear canal resection is associated with a 75% recurrence rate. Median survival time of animals with malignant ear canal tumors has been reported to be >11.7 mo in cats.

Cats with invasive tumors, squamous cell carcinoma, or neurologic signs at the time of diagnosis had a poorer prognosis. Radiation therapy can be used to treat incompletely excised ceruminous gland adenocarcinomas, with a 56% 1-yr survival rate reported^[1].

References

1. ↑ Wilson, HM (2010) Tumours of the ear. In August, JR (Ed): Consultations in feline internal medicine. Elsevier Saunders, Philadelphia. pp: 707