Pleomorphic Adenoma of the External Auditory Canal: A Rare Presentation

Pleomorphic Adenoma of the External Auditory Canal From Ceruminous Gland Adenoma: Case Report and Review of the Literature

We describe a right external auditory canal (EAC) recurrent ceruminous pleomorphic adenoma (CPA) accompanied by itching and review the clinical features and histopathology of this disease. A female in her 70s presented with a right EAC mass accompanied by itching. We initially diagnosed the mass as a ceruminous gland adenoma (CGA) following excisional biopsy. Two years and nine months later, the tumor recurred at the same site. A preoperative computed tomography (CT) scan demonstrated no bone destruction, and magnetic resonance imaging (MRI) showed a 1 × 1 cm mass with a clearly defined margin in the right EAC. We completely excised the recurrent tumor using a transmeatal approach under general anesthesia. Histopathology demonstrated haphazard proliferation of tubule-glandular structures lined by two layers of the epithelium in the hypocellular stroma composed of a mucoid matrix. The recurring tumor was diagnosed as a CPA. Here, an EAC tumor-originally diagnosed as a CGA following excisional biopsy-recurred and was subsequently diagnosed as a CPA. CPA can be considered an unusual variant of CGA.

Pleomorphic adenoma of the external auditory canal

Pleomorphic adenoma (PA) of the external auditory canal (EAC) is a rare clinical entity with a few cases reported in the literature. The clinical diagnosis of these lesions can be formidable due to their rarity and unusual location. This tumor occurs at various other anatomical locations apart from the major salivary glands. A 30-year-old female presented with a two-year history of a gradually enlarging and painless mass in the left external auditory canal. The tumor was excised, and histopathological and immunohistochemical evaluation revealed a mixed tumor with both epithelial and stromal components of different proportions, recognized and classified today by the World Health Organization (WHO) as a pleomorphic adenoma. The post-operative course was uneventful, and at the 10-month follow-up, no recurrence of the pleomorphic adenoma was noted. We highlight the histological features and the immunohistochemical profile of the tumor and review the literature on glandular neoplasms of the EAC and their recent classification, emphasizing on the histogenesis, clinical presentations, and microscopic features of the tumor. In addition, we aim to discuss vital features in differentiating these tumors from other tumors of the external auditory canal to enable clinicians and pathologists to recognize this uncommon benign neoplasm.

External Auditory Canal Pleomorphic Adenoma: A Rare Case Presentation

Pleomorphic adenoma originating from the external auditory canal is extremely rare, benign tumor. Ceruminal glands are modified sweat glands of the skin, present in the external auditory canal that may give rise to (a) benign tumors such as ceruminous adenoma, pleomorphic adenoma, and syringocystadenoma papilliferum, or (b) malignant tumors such as ceruminous adenocarcinoma, adenoid cystic carcinoma, and mucoepidermoid carcinoma. We report a case where a 25-year-old woman presented with right aural swelling and otalgia since 1 year. A canal-filling aural mass was noted on clinical examination. Computed tomography imaging showed no intracranial extension or any association with the adjacent parotid gland. Subsequent excision biopsy and histologic examination revealed features suggestive of pleomorphic adenoma. Similar to the pleomorphic adenoma of salivary glands, recurrence or malignant degeneration with cellular atypia and metastasis can occur on rare occasions. Care must be taken to distinguish this from adenoid cystic carcinomas, ceruminous adenocarcinomas, and mucoepidermoid carcinomas.

Pleomorphic Adenoma of External Auditory Canal: Case Report of First Endoscopic Resection and Literature Review

Ceruminous pleomorphic adenoma is a very rare, mostly benign tumor originating from the ceruminal glands in the external auditory canal. Histologically, it is a mixed tumor with epithelial and stromal parts of different proportions, and is recognized today by the World Health Organization (WHO) as a ceruminous adenoma. Similar to the pleomorphic adenoma of salivary glands, recurrence or malignant degeneration with cellular atypia and metastasis can occur on rare occasions. Here, we describe an 87-year old female patient with a growing spherical mass in the right external auditory canal. After exclusive endoscopic tumor resection, a ceruminous pleomorphic adenoma was histologically diagnosed. Due to the absence of nuclear pleomorphism, no increased mitotic rate, no perineural invasion and no fusion transcripts of the MYB or MYBL1 gene loci, an adenoid cystic carcinoma could be excluded. The postoperative course was without any evidence of complications. A literature review identified 44 articles with 49 patients that were considered. Hearing loss and ear sensations were the most commonly reported symptoms. Most cases underwent an excision via an endaural or retroauricular approach. Recurrences were described in four patients, three of which had a malignant transformation.

A Persistent Foramen of Huschke: A Small Road to Misery in Necrotizing External Otitis

BACKGROUND AND PURPOSE

Necrotizing external otitis is a serious complication of external otitis with different spreading patterns. A persistent foramen of Huschke is a dehiscence located antero-inferior in the osseous external ear canal and posterior-medial to the temporomandibular joint. This dehiscence can facilitate extension of infection in an anterior pattern next to classic spread along the fissures of Santorini. The aim of this study was to define the prevalence and size of a persistent foramen of Huschke in patients with necrotizing external otitis.

MATERIALS AND METHODS

We retrospectively examined 78 CT temporal bone studies (39 patients with necrotizing external otitis, 39 control subjects). The side and presence of the foramen were noted, and its prevalence was calculated. The maximal width of the foramen of Huschke was measured in the axial plane and classified as subtle, mild, moderate, or extensive.

RESULTS

A persistent foramen of Huschke was present in 21 patients (26 ears) and 7 control subjects (9 ears). Prevalence was 50% (20/40) and 11.5% (9/78) in affected ears of patients with necrotizing external otitis and control subjects, respectively. Almost all affected ears showed an anterior distribution pattern of necrotizing external otitis. The extensive dehiscence was most common in affected ears.

CONCLUSIONS

An anterior necrotizing external otitis spreading pattern is associated with the presence and increased size of a persistent foramen of Huschke. These findings facilitate the theory that a persistent foramen of Huschke is an additional risk factor the development of necrotizing external otitis.