Ceruminous glands are specialized, apocrine glands discerned within cartilaginous portion of external auditory canal. Preponderant function of the glands is to secrete cerumen. Besides, primary neoplasms of the external auditory canal are extremely exceptional. Ceruminous adenoma is an exceptional, benign neoplasm arising from cerumen secreting, modified apocrine, ceruminous glands. However, ceruminoma as a terminology is contemplated to be archaic. Notwithstanding, ceruminous gland neoplasia can be considered as potentially malignant or of “uncertain malignant potential” as biological behaviour of the tumefaction remains undefined. The neoplasm can be challenging to discern on account of a variety of emergent clinical representations within the external auditory canal. Cogent tumour categorization is possible on histopathological examination. The neoplasm is associated with favourable prognosis following comprehensive surgical excision.
The neoplasm occurs within external auditory canal, especially incriminating the extraneous segment which demonstrates a preponderance of ceruminous glands. Nevertheless, areas such as parotid gland or middle ear may be implicated . The exceptional, benign ceruminous adenoma usually appears beyond > 50 years although adolescents may exhibit the neoplasm. Ceruminous adenoma commonly emerges in adults between 24 years to 85 years. An equivalent gender predilection is delineated [2,3]. Malignant metamorphosis occurs in an estimated 70% instances of ceruminous adenoma with the emergence of possible intracranial extension and distant metastasis. Malignant metamorphosis is accompanied by pain and facial nerve paresis [2,3]. Concurrent conditions such as chronic otitis media, infection of parotid gland and cervical lymphadenopathy appear as coincidental features [2,3].
The gradually progressive neoplasm represents with otalgia, yellowish ear discharge, pruritus, chronic irritation, impediment of external auditory canal and conductive deafness. Intermittent pyrexia or haemorrhage may occur. Tinnitus, vertigo or cranial nerve palsies are usually absent. Tumefaction can be associated with ruptured tympanic membrane or otorrhea [2,3]. Predominant clinical manifestations are hearing loss, pyrexia, persistent earache, minimal or moderate otalgia and otorrhoea with concomitant chronic otitis media. Bilateral cervical lymphadenopathy may accompany the neoplasm. Concurrence with preceding trauma or surgical intervention is usually absent [3,4]. Comorbid conditions such as atrial fibrillation, diabetes mellitus, arterial hypertension or glaucoma can be discerned [3,4].
Upon gross examination, ceruminous adenoma emerges as a reddish, polypoid, solid, well circumscribed tumefaction with a smooth or ulcerated surface or a partially skin covered, fusiform nodule of magnitude varying from 0.4 centimetres to 2.0 centimetres or as a smooth, spherical, un-encapsulated tumefaction discharging serosanguinous or yellowish fluid upon pressure. Cystic alterations are infrequently discerned. Cut surface depicts a subcutaneous, well circumscribed, solid or cystic lesion [3,4].
Upon cytology, the grey/white, cellular aspirate demonstrated cohesive, mono-layered sheets and papillary fragments of epithelial cells. Tumour cells are imbued with abundant, eosinophilic cytoplasm with spherical to elliptical, bland nuclei and inconspicuous nucleoli. Spindle-shaped, myoepithelial-like cells and few plasmacytoid cells are also observed. Eosinophilic stromal fragments are preponderantly composed of fibroblastic, spindle-shaped cells. Cellular stromal fragments appear commingled with epithelial cell aggregates [3,4]. The neoplasm can uniquely manifest papillae, dense, cohesive cellular clusters of epithelial and myoepithelial cells and disseminated plasmacytoid cells. The cellular elements are admixed within fibromyxoid stromal fragments [3,4].
Microscopic variations of architectural pattern of the un-encapsulated neoplasm are delineated as densely accumulated glands, foci of cystic dilatation, solid areas, and configuration
of papillary structures [3,4]. Upon microscopy, a cystic lesion
layered with epithelium is denominated. The lining epithelium is
comprised of dual cell population wherein the intrinsic, luminal
epithelial layer is composed of tubules of cylindrical, cuboidal
or low columnar epithelial cells of intermediate magnitude
imbued with intensely eosinophilic cytoplasm, spherical nuclei,
and focal decapitation secretion. Occasionally, cylindrical cells
demonstrate cytoplasmic projections extending into tubular
lumina. Extraneous cell layer configures fascicles, miniature solid
cell aggregates or exceptional tubules articulated of elliptical to
spindle- shaped myoepithelial cells with scanty cytoplasm and
elongated, hyperchromatic nuclei. Cellular and nuclear atypia or
mitotic activity is absent [4,5].
Tumour is composed of proliferating cells configuring tubular
glands, solid sheets, papillae and cysts. Tubules and glands are
coated with a dual cell population. Luminal epithelial cells appear
as tall, columnar to cylindrical cells imbued with abundant,
granular, eosinophilic cytoplasm and bland, spherical to elliptical
nuclei. Luminal epithelial cells demonstrate focal decapitation
secretion whereas peripheral epithelial cell layer is basaloid.
Tumour cell articulations are circumscribed by a fibromyxoid
stroma [4,5]. The un-encapsulated, well circumscribed neoplasm
demonstrates glandular proliferation with distinctive cribriform,
solid, cystic or papillary configuration. Tumour glands are layered
with an inner layer of cuboidal to columnar cells incorporated
with eosinophilic cytoplasm and apical snouts constituted of
decapitation secretion. The peripheral myoepithelial layer is
composed of spindle-shaped cells with hyperchromatic nuclei.
Intrinsic luminal epithelial cells demonstrate yellow-brown,
granular, cerumen pigment. The circumscribing stroma is
hyalinised. Cellular or nuclear pleomorphism, mitotic activity,
tumour infiltration or tumour necrosis is absent [4,5].
Tumefaction is embedded within a fibrous, focally
hyalinised stroma. An attenuated fibrous capsule may partially
circumscribe the neoplasm and appears non-contiguous with
superimposed stratified squamous epidermal layer [4,5]. Upon
immunohistochemistry, dual cell population can be confirmed.
Luminal epithelial cells are immune reactive to cytokeratin 7
along with membranous reactivity to CD117 and p53. Peripheral
or basal epithelial cells are immune reactive to cytokeratin 5/6,
S100 protein and p63. Cerumen can be stained with periodic acid
Schiff’s (PAS) stain or mucicarmine [5,6]. Ki-67 proliferation index
appears at around 60% in luminal nuclei and nearly 5% in basal
nuclei. Apocrine gland-related antigen or gross cystic disease fluid
protein 15 (GCDFP-15) is focally expressed by the neoplastic cells.
Immunohistochemistry is identical to immune staining pattern
discovered in normal ceruminous glands [5,6] (Figures 1-7).
Ceruminous adenoma requires a segregation from •ceruminous adenocarcinoma which is an infiltrative neoplasm configured of irregular glands and frequently accompanied by
perineural invasion. Tumour cell nuclei are imbued with prominent
nucleoli. Ceruminous granules are usually absent. Cellular and
nuclear pleomorphism, foci of tumour necrosis, enhanced mitotic
activity and atypical mitotic figures are delineated [6,7].
neuroendocrine adenoma of the middle ear demonstrates
variable neoplastic configurations such as cellular sheets, solid
areas, trabeculae, cystic articulations, cribriform pattern, or
glandular structures. Generally, papillary architecture is absent.
Tumour glands or tubules are layered with uniform, singular layer
of cuboidal or columnar epithelial cells incorporated with variable
quantities of eosinophilic cytoplasm and spherical to elliptical,
hyperchromatic nuclei with eccentric nucleoli. Neoplastic cells
may appear plasmacytoid and demonstrate significant cellular
and nuclear pleomorphism. The circumscribing stroma is sparse,
fibrotic or myxoid. Mitotic activity is minimal to absent. Necrosis
is absent [6,7].
Paraganglioma demonstrates a classic, organoid pattern with
the configuration of a “zellballen” or nesting of tumour cells.
Tumefaction is constituted of centric, spherical, or elliptical chief
cells imbued with abundant, eosinophilic, granular, or vacuolated
cytoplasm and uniform nuclei with dispersed chromatin. Spindleshaped,
basophilic, peripheral sustentacular cells circumscribe
tumour cell nests and are immune reactive to S100 protein.
Tumour cells may depict cellular and nuclear pleomorphism.
Tumour cell aggregates are subdivided by prominent fibrovascular
stroma. Occasionally, dense fibrous stroma may encircle
clusters of tumour cells. An infiltrative pattern of tumour evolution
is encountered [6,7].
Additionally, various neoplasms arising within external
auditory canal such as exostosis, osteoma, eosinophilic
granuloma, cholesteatoma, cartilaginous choristoma, extraadrenal
paraganglioma, congenital cysts of branchial arch origin,
pleomorphic adenoma or associated tumours of the parotid gland
and meningioma require a segregation. Precise distinction is
possible upon competent histological evaluation and pertinent
Upon physical examination, a spherical, reddish, tender, soft
tissue mass can be observed within the cartilaginous segment
of external auditory canal associated with mucopurulent
discharge. The neoplasm may exude a yellowish fluid upon
pressure. Ear discharge can be subjected to culture and sensitivity
for appropriate bacteriological evaluation [8,9]. Audiometry
delineates conductive deafness of the incriminated ear. Cogent
cytological assessment with fine needle aspiration circumvents
irrelevant, extensive surgical intervention and ameliorates
prognostic outcomes [8,9]. Computerized tomography (CT)
demonstrates a cystic lesion arising within the external auditory
canal. Bone lysis of adjoining osseous fragments is absent. Middle
ear may depict accumulation of fluid [8,9].
Intravenous antibiotics can be administered. Oral antibiotics
or anti-inflammatory medications are usually inefficacious.
Neoplasm confined to external auditory canal can be subjected
to comprehensive surgical excision with a trans-meatal approach
[8,9]. Complete surgical extermination with a broad, tumourfree
perimeter is recommended, thereby ensuring an extended
tumour-free survival. Postoperative tumour alleviation is
accompanied by reduction of ear discharge, disappearance of
otalgia and amelioration of hearing [9,10]. Ruptured tympanic
membrane may heal . Ceruminous adenoma is usually devoid
of tumour reoccurrence as estimated by a mean follow-up of
15 years. Nevertheless, tumour reoccurrence may ensue with incomplete surgical excision or appearance of residual tumour following surgical resection [9,10].