Seborrhoeic Keratosis of External Auditory Canal & its Management

Seborrhoeic keratosis (SK) is a benign neoplasm of the skin. They are usually found to occur anywhere in the body except palms, soles and mucous membranes. The skin of the external auditory canal is an extremely rare site for the occurrence of this benign neoplasm. Malignant transformation rarely occurs in this benign condition. It should be differentiated from other malignant condition like squamous cell carcinoma, basal cell carcinoma, Bowen's disease, malignant melanoma or keratoacanthoma. Surgery is the mainstay of treatment though recurrence is very common. It can be removed by cryotherapy using liquid nitrogen or curettage, light fulgaration, shave removal or painting with pure TCA if the lesion is small. Diathermy shoul be used as minimal as possible to avoid scar formation.

An elderly female presented to ENT OPD with left ear blood-stained discharge. On inspection there was irregular blackish mass filling the entire left external auditory canal, fine needle aspiration cytology came to be seborrhoeic keratosis. Since on imaging the tumor was confined to the external auditory canal, it was excised completely by transcanal route. Surprisingly histopathology came to be squamous cell carcinoma. Considering the age and limited confinement of the tumor, she was kept on regular follow up.

Seborrhoeic keratosis though a common benign tumor, malignant transformation may occur. Treatment is patient specific and may be modified considering the age and comorbidity of the patient.