Canalicular adenoma is a type of growth that occurs in human
salivary glands. It is a benign growth which occurs in the
epithelial cells, and is typically arranged in columns of cells that form interconnecting cords. Canalicular adenoma is a very rare
benign neoplasm; it constitutes about 1% of all
salivary gland tumors and about 4% of all benign salivary gland tumors.[1][2]
A
hematoxylin and
eosin stained slide of canalicular adenoma showing multifocality
Presentation
Canalicular adenoma is most common in patients age 70 to 80, with females affected about four times as often as males. Most growths present in the upper lip; some also occur in the a few present in
palate or
buccal (cheek) tissue as a slowly enlarging mass.[3] The growths will often arise in multiple places at the same time or develop multiple nodes, despite not being clinically invasive or
malignant.[1][4]
Diagnosis
Canalicular adenoma growths are usually small at the time they are noticed, with an average size of about 1.6 cm.[1] Their
histologic appearance is very distinct, with a channel-like pattern between cords and ribbons; the pattern has been described as resembling a "string of pearls."
A hematoxylin and eosin stained slide of canalicular adenoma showing large canaliculiA hematoxylin and eosin stained slide of canalicular adenoma showing beading
The growths often contain are often small bight
squamous balls, or morules. They also tyipcally contain a well-developed supporting tissue - a fibrous
stroma - which is rich in
hyaluronic acid and
chondroitin sulphate.[1] In a few cases, the growths may contain small
calcium deposits or microliths. Although it is seldom necessary, a
pathologist can confirm the existence of canalicular adenoma through
immunohistochemistry studies, with the cells reacting with pancytokeratin, S100 protein and SOX10, with a delicate
GFAP reaction around the periphery.[5][1][6][7] Although it is a benign tumor, a positive diagnosis of canalicular adenoma may be necessary to exclude the existence of other medical conditions such as a
basal cell adenoma,
pleomorphic adenoma,
adenoid cystic carcinoma, and polymorphous adenocarcinoma.
Treatment
Most instances of canalicular adenoma are treated with conservative
surgery.[1]
^Ferreiro JA (Dec 1994). "Immunohistochemical analysis of salivary gland canalicular adenoma". Oral Surg Oral Med Oral Pathol. 78 (6): 761–765.
doi:
10.1016/0030-4220(94)90093-0.
PMID7534898.
^Huebner TA, Almubarak H, Drachenberg CB, Papadimitriou JC (Apr 2014). "Canalicular adenoma--search for the cell of origin: ultrastructural and immunohistochemical analysis of 7 cases and review of the literature". Ultrastruct Pathol. 38 (2): 74–82.
doi:
10.3109/01913123.2013.833564.
PMID24144157.
S2CID40082155.