Progressive hearing loss in a rare case of ceruminous pleomorphic adenoma of the external auditory canal





Abstract


Ceruminous Pleomorphic Adenoma (CPA) of the External Auditory Canal (EAC) is an uncommon neoplasm arising from the ceruminous glands, representing the cutaneous counterpart of pleomorphic adenoma of salivary glands. Only 49 cases of CPA have been reported in literature. CPA is usually a benign tumour, although cases of malignant transformation with local recurrence and metastasis have been described.


We present the case of a 61-year old male patient with a story of slowly progressive hearing loss, aural fullness and foreign-body sensation in the left ear. Otoscopy revealed a smooth, non-tender lesion covered by normal skin obstructing the external auditory meatus. The lesion was radically removed and a CPA was histologically diagnosed. The patient underwent regular follow-up and there was no evidence of recurrence 40 months after the surgery.


Besides sharing the clinical and management details of our patient, we summarized the main features of clinical cases available in literature in order to clarify the differential diagnosis, the clinical and hystopathological aspects, and the treatment.


CPA is an unusual neoplasm, it should always be considered in the differential diagnosis of a conductive hearing loss due to an obstructive lesion of the EAC.



Introduction


Ceruminous pleomorphic adenoma (CPA) is a rare neoplasm firstly described by Mark and Rothberg in 1951 [ ], that has been included among ceruminous adenoma in the last WHO classification [ ]. CPA arises usually in the context of the ceruminous glands of the external auditory canal (EAC) [ ]. Tumours of the ceruminous glands are rare, accounting for only 2.4% of tumours affecting the EAC [ ]. Specifically, so far only 49 cases of CPA have been described [ ].


We report a case of CPA of the EAC presenting with progressive hearing loss and we summarize the main features of clinical cases available in literature in order to clarify the differential diagnosis, the clinical and hystopathological aspects, and the treatment.



Case-presentation


A man aged 61came to the Department of Otolaryngology of our Hospital complaining slowly progressive hearing loss, aural fullness and foreign-body sensation of the left ear. Otoscopy revealed a stenosis of the left EAC due to a smooth, non-tender lesion covered by normal skin ( Fig. 1 ). At the audiological evaluation, the audiometry exam showed a left moderate conductive hearing loss at 0.25-2KHz frequencies with an air-bone gap (ABG) of 25 dB and a sensorineural drop at high frequencies ( Fig. 2 ). The CT scan revealed the presence of a mass limited to the left EAC without erosion of the nearby bone or extension to the middle ear. The features of the lesion were better defined with a magnetic resonance imaging (MRI) scan: it confirmed the presence of a 1,1× 2 cm mass on the anterior and superior wall of EAC, with high signal intensity on T2 sequences, low signal intensity on T1-sequences and homogeneous gadolinium-enhancement ( Fig. 3 ). The patient underwent complete resection of the tumour with endoaural approach (sleeve resection) [ ]. The histopathologic examination demonstrated a lesion with epithelial and stromal components. Basaloid cells organized in ribbons and nests, representing a ductal differentiation, were highlighted in epithelial component with a stromal myxoid component ( Fig. 4 ). The final diagnosis was “Ceruminous Pleomorphic Adenoma”. Two-months postoperative audiometry demonstrated ABG closure. The patient underwent regular follow-up and there have been no signs of relapse 40 months after the surgical intervention.




Fig. 1


Otoscopic view of the left external auditory canal (EAC) using a 0° rigid 4mm endoscope: a smooth mass of the anterior and superior wall occupies the external auditory canal.



Fig. 2


Pre-operative audiological evaluation with a Pure Tone Audiometry (PTA): a left moderate conductive hearing loss at 0.25-2KHz frequencies (with an air-bone gap of 25 dB) with a sensorineural drop at high frequencies is highlighted.

Jul 5, 2021 | Posted by in OTOLARYNGOLOGY | Comments Off on Progressive hearing loss in a rare case of ceruminous pleomorphic adenoma of the external auditory canal
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