Malignant Melanoma of the External Auditory Canal: A Rare Entity

Abstract

Introduction: Although malignant melanomas (MM) are common in the head and neck region; primary malignant melanoma of the external auditory canal (EAC) is rare.

Case report: We present the case of a 50-year-old symptomatic man with a malignant melanoma of the external auditory canal, which clinically masqueraded as a haemangioma. The patient subsequently developed extensive loco-regional metastasis, requiring extensive surgery. We describe the clinical presentation, differential diagnosis, both clinical and pathological in terms of other pigmented lesions in the external auditory canal, detailed histopathology, and literature review.

Conclusion: We want to emphasize the importance of immediate and adequate biopsy of any pigmented lesion in the head and neck region to rule out MM. Also, we emphasize the importance of deep biopsy for proper histopathological assessment in addition to distinguishing it from benign melanocytic nevi, in order to initiate treatment.

Keywords: External auditory canal; HMB-45; Malignant; Melanoma.

Fig 1

Punch biopsy from external auditory canal. (A) Strips of stratified squamous epithelium with underlying melanocytes in the external auditory canal (H&E, 40x); (B) higher magnification showing the melanocytes. (H&E, 200x)

Fig 2

Fine needle aspiration of the parotid gland showing cells with prominent nucleoli and brown coloured melanin pigment (Pap stain, 400x)

Fig 3

Excision specimen showing malignant melanocytes (A) within the lymph node; (B) intermixed with the parotid gland acini. (H&E, 200x)

Fig 4

Immunohistochemistry with tumour cell showing positivity for HMB-45. (IHC, 100x)