A ceruminous adenoma is a benign glandular neoplasm which arises from the

ceruminous glands Ceruminous glands are specialized sweat glands located subcutaneously in the external auditory canal, in the outer third. Ceruminous glands are simple, coiled, tubular glands made up of an inner secretory layer of cells and an outer myoepithelia ...

located within the external auditory canal. These glands are found within the outer one third to one half of the external auditory canal, more common along the posterior surface; therefore, the tumor develops within a very specific location.

Signs and symptoms

Ceruminous adenoma are rare tumors, accounting for less than 1% of all external ear tumors. The patients will present with a mass, perhaps associated pain, and may have changes in hearing (usually a sensorineural or a conductive hearing loss). Some patients have tinnitus. Nerve paralysis is very uncommon.

Pathology findings

The tumors are usually small, with a mean size of about 1.2 cm. The tumors are separated into three histologic types based on the dominant findings: * Ceruminous adenoma * Ceruminous pleomorphic adenoma * Ceruminous syringocystadenoma papilliferum All of the tumors are unencapsulated, but are usually well defined or circumscribed. The overlying surface epithelium is not involved. The tumor shows a dual or biphasic appearance, with glandular or cystic spaces showing inner luminal secretory cells with abundant granular, eosinophilic cytoplasm subtended by basal,

myoepithelial cell Myoepithelial cells (sometimes referred to as myoepithelium) are cells usually found in glandular epithelium as a thin layer above the basement membrane but generally beneath the lumen (anatomy), luminal cells. These may be positive for ACTA2, alph ...

s at the periphery, adjacent to the

basement membrane The basement membrane, also known as base membrane, is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between epithelial tis ...

. The luminal cells will often have decapitation (

apocrine Apocrine () is a term used to classify the mode of secretion of exocrine glands. In apocrine secretion, secretory cells accumulate material at their apical ends, often forming blebs or "snouts", and this material then buds off from the cells ...

) secretions and will also have yellow-brown, ceroid,

lipofuscin Lipofuscin is the name given to fine yellow-brown pigment Granule (cell biology), granules composed of lipid-containing residues of Lysosome, lysosomal digestion. It is considered to be one of the aging or "wear-and-tear" pigments, found in the l ...

-like (cerumen) pigment granules. There is no pleomorphic, limited

mitoses Mitosis () is a part of the cell cycle in eukaryotic cells in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis is an equational division which gives rise to genetically identical cells in which the ...

, and no

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

Immunohistochemistry Immunohistochemistry is a form of immunostaining. It involves the process of selectively identifying antigens in cells and tissue, by exploiting the principle of Antibody, antibodies binding specifically to antigens in biological tissues. Alber ...

can be performed to confirm the biphasic nature of the tumor. All cells are positive with pancytokeratin and epithelial membrane antigen; only the luminal

cell Cell most often refers to: * Cell (biology), the functional basic unit of life * Cellphone, a phone connected to a cellular network * Clandestine cell, a penetration-resistant form of a secret or outlawed organization * Electrochemical cell, a de ...

s are positive with CK7; only the basal cells are positive with CK5/6, p63, S100 protein.

CD117 Proto-oncogene c-KIT is the gene encoding the receptor tyrosine kinase protein known as tyrosine-protein kinase KIT, CD117 ( cluster of differentiation 117) or mast/stem cell growth factor receptor (SCFR). Multiple transcript variants encoding d ...

can be positive in either population. The cells are negative with chromogranin,

synaptophysin Synaptophysin, also known as the major synaptic vesicle protein p38, is a protein that in humans is encoded by the ''SYP'' gene. Gene The gene is located on the short arm of X chromosome (Xp11.23-p11.22). It is 12,406 bases in length and li ...

and CK20.

Diagnosis

The major diagnosis from which to separate ceruminous adenoma is ceruminous adenocarcinoma, which shows an infiltrative growth, pleomorphism, mitoses, necrosis, and lacks ceroid pigment granules. Other tumors which need to be excluded include a neuroendocrine adenoma of the middle ear (middle ear adenoma), paraganglioma, and endolymphatic sac tumor.

Management

The tumors are usually removed in small pieces due to the anatomic confines of the area.

Prognosis

Patients treated with complete surgical excision can expect an excellent long term outcome without any problems. Recurrences may be seen in tumors which are incompletely excised.

Epidemiology

While there is a wide age range at clinical presentation (12–85 years), most patients come to clinical attention at 55 years (mean). There is no gender difference.