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

ceruminous glands Ceruminous glands are specialized sudoriferous glands (sweat glands) located subcutaneously in the external auditory canal, in the outer 1/3. Ceruminous glands are simple, coiled, tubular glands made up of an inner secretory layer of cells and an ou ...

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 luminal cells. These may be positive for alpha smooth muscle actin ...

s at the periphery, adjacent to the

basement membrane The basement 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 Epithelium, epithelial tissues including mesot ...

. The luminal cells will often have decapitation (

apocrine Apocrine () glands are a type of exocrine gland, which are themselves a type of gland, i.e. a group of cells specialized for the release of secretions. Exocrine glands secrete by one of three means: holocrine, merocrine and apocrine. In apocrine ...

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

lipofuscin Lipofuscin is the name given to fine yellow-brown pigment granules composed of lipid-containing residues of lysosomal digestion. It is considered to be one of the aging or "wear-and-tear" pigments, found in the liver, kidney, heart muscle, retin ...

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

mitoses In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...

, and no

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated dige ...

Immunohistochemistry Immunohistochemistry (IHC) is the most common application of immunostaining. It involves the process of selectively identifying antigens (proteins) in cells of a tissue section by exploiting the principle of antibodies binding specifically to an ...

can be performed to confirm the biphasic nature of the tumor. All cells are positive with pancytokeratin and

epithelial membrane antigen Mucin short variant S1, also called polymorphic epithelial mucin (PEM) or epithelial membrane antigen (EMA), is a mucin encoded by the ''MUC1'' gene in humans. Mucin short variant S1 is a glycoprotein with extensive O-linked glycosylation of its e ...

; only the luminal

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery ...

s are positive with CK7; only the basal cells are positive with

CK5/6 Cytokeratin 5/6 antibodies are antibodies that target both cytokeratin 5 and cytokeratin 6. Topic Completed: 3 June 2019. Revised: 8 December 2019 These are used in immunohistochemistry, often called CK 5/6 staining, including the following applic ...

, 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 diff ...

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

chromogranin Granin (chromogranin and secretogranin) is a protein family of regulated secretory proteins ubiquitously found in the cores of amine and peptide hormone and neurotransmitter dense-core secretory vesicles. Function Granins (chromogranins or sec ...

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

and

CK20 Keratin 20, often abbreviated CK20, is a protein that in humans is encoded by the ''KRT20'' gene. Keratin 20 is a type I cytokeratin. It is a major cellular protein of mature enterocytes and goblet cells and is specifically found in the gastric ...

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.