Verrucous Carcinoma in External Auditory Canal – A Rare Case

Verrucous carcinoma is a variant of squamous cell carcinoma. It is of low grade malignancy and rarely present with distant metastasis. Oral cavity is the commonest site of this tumour, other sites are larynx, oesophagus and genitalia. Verrucous carcinoma in external auditory canal is extremely rare. This is the presentation of a 45 years old woman who came to the ENT & Head Neck Surgery department of Delta medical college, Dhaka, Bangladesh with discharging left ear and impairment of hearing on the same side for 7 years. Otoscopic examination showed a mass occupying almost whole of the external auditory canal and the overlying skin was thickened, papillary and blackish. Cytology from external auditory canal scrap showed hyperkeratosis and parakeratosis. External auditory canal bone was found eroded at some parts. Excision of the mass was done under microscope. Split thickness skin grafting was done in external auditory canal. The mass was diagnosed as verrucous carcinoma on histopathological examination. Afterwards she was given radiotherapy. Six months follow up showed no recurrence and healthy epithelialization of external auditory canal.


Introduction
Verrucous carcinoma is a variant of well-differentiated squamous cell carcinoma.It has specific clinical and histological features.Various names are used to describe this condition including 'Ackerman's tumour', 'epithelioma cuniculatum' and 'carcinoma cuniculatum'. 1The tumour grows slowly and locally.
It is invasive in nature but unlikely to metastasize.It appears as a painless, thick white plaque resembling a oracauliflower.The most common sites of oral mucosal involvement include the buccal mucosa, followed by the mandibular alveolar crest, gingiva and tongue. 2 Other sites are larynx, oesophagus and genitalia.1.

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Verrucous carcinoma in external auditory canal is extremely rare.The ages range from 50 to 80 years with a male predominance. 3It may grow very large and can destroy adjacent tissue such as bone and cartilage.
The diagnosis is confirmed by histopathology.Surgeon has to provide adequate specimen including the full thickness of the tumour and adjacent uninvolved mucosa for the correct diagnosis.

Case Report
This is the presentation of a 45 years old woman who came to the ENT and Head Neck Surgery department of Delta Medical College, Dhaka, Bangladesh with a mass in left ear with discharge and impairment of hearing on the same side for 7 years.She was treated by some topical and systemic antibiotics on several occasions previously.Otoscopic examination showed a mass occupying almost whole of the external auditory canal and the overlying skin was thickened, papillary and blackish.Cytology from external auditory canal scrap showed hyperkeratosis and parakeratosis.External auditory canal bone was found eroded at some parts during surgery.Excision of the external auditory canal mass was done under general anaesthesia.Whole skin from external auditory canal was excised under microscope.The eroded bony part was made smooth using microdrill.Split thickness skin was taken from anterior aspect of left thigh and grafting was done in external auditory canal.The whole of the specimen was sent for histopathological examination which revealed it as verrucous carcinoma.

Discussion
The etiology of verrucous carcinoma is not well defined.Human papilloma virus (HPV) has been considered one of the causative factors.Smoking seems to be highly associated with the development of mucosal verrucous carcinoma of the head and neck.Poor hygiene, presence of lichenoid and leucoplakic lesions may act as predisposing factors. 4In this report the patient has given no history of such causative factors.
Verrucous carcinoma and verrucous hyperplasia are indistinguishable clinically. 5The clinical association with leucoplakia is significant, and the evidence indicates that untreated leucoplakia may develop into a verrucous carcinoma in time.Verrucous hyperplasia is a forerunner of verrucous carcinoma. 6The transition is so consistent that the hyperplasia, once diagnosed should be treated as verrucous carcinoma.In verrucous carcinoma, regional lymph nodes are often enlarged and tender because of inflammatory involvement which simulate metastatic tumour.Lymph nodes were not involved in this case. 7

Discussion
The etiology of verrucous carcinoma is not well defined.Human papilloma virus (HPV) has been considered one of the causative factors.Smoking seems to be highly associated with the development of mucosal verrucous carcinoma of the head and neck.Poor hygiene, presence of lichenoid and leucoplakic lesions may act as predisposing factors. 4In this report the patient has given no history of such causative factors.
Verrucous carcinoma and verrucous hyperplasia are indistinguishable clinically. 5The clinical association with leucoplakia is significant, and the evidence indicates that untreated leucoplakia may develop into a verrucous carcinoma in time.Verrucous hyperplasia is a forerunner of verrucous carcinoma. 6The transition is so consistent that the hyperplasia, once diagnosed should be treated as verrucous carcinoma.In verrucous carcinoma, regional lymph nodes are often enlarged and tender because of inflammatory involvement which simulate metastatic tumour.Lymph nodes were not involved in this case. 7rgery is considered the choice of treatment for these lesions. 8Radiotherapy alone is controversial.Surgery followed by radiotherapy is the next most preferable treatment and may have benefits, particularly in cases of extensive lesions. 9Recurrence rate is high in cases in which either irradiation or surgery alone is performed.The patient was referred to the department of Oncology for post surgical management where she was treated by radiotherapy.On follow up she was free of any complaints.After six months of completion of radiotherapy, there was no recurrence.
Verrucous carcinoma of external auditory canal is very rare.Clinical presentation of any black, papillary mass in external auditory canal must be excluded for it.1.
Fig 1: Preoperative photograph of external auditory canal (under microscope)