Canalicular adenoma.Canalicular adenomas are benign neoplasms with a unique predilection for the upper lip (~80% of cases). They account for 1% of all salivary gland neoplasms. Their incidence peaks during the seventh decade of life; they are distinctly uncommon in patients younger than 50 years of age. The female-to-male predominance is approximately 2:1. These tumors develop as slowly enlarging, moveable, compressible, submucosal submucosal /sub·mu·co·sal/ (-mu-ko´sal) 1. pertaining to the submucosa. 2. beneath a mucous membrane. nodules that are usually asymptomatic. Superficial tumors may exhibit a bluish tint in the overlying mucosa, mimicking a mucocele. Multi focal tumors may be seen clinically. Canalicular adenomas are typically smaller than 2 cm. They are ordinarily well circumscribed and encapsulated. The multifocality of these tumors may be identified only microscopically rather than clinically. Care must be taken to avoid misdiagnosing these microscopic loci as an invasive carcinoma. The histologic appearance of canalicular adenomas is very consistent; they are made up of columnar epithelial cells that form thin, branching, and interconnecting cords in a very loose but highly vascular stroma (figure 1). Double rows of cells alternately oppose and then separate from one another, producing a "beads-on-a-string" or "canaliculi Canaliculi Also known as lacrimal ducts, these tube-like structures carry the tears from the eyes to the lacrimal sac. Mentioned in: Dacryocystitis " appearance. The epithelial cells are cuboidal cuboidal /cu·boi·dal/ (ku-boi´d'l) resembling a cube. cuboidal, adj See cuboid. to tall and columnar in type, with uniform nuclei and inconspicuous nucleoli nucleoli plural form of nucleolus. (figure 2). The loose stroma and the characteristic eosinophilic eosinophilic /eo·sin·o·phil·ic/ (-fil´ik) 1. readily stainable with eosin. 2. pertaining to eosinophils. 3. pertaining to or characterized by eosinophilia. cuffing of capillaries are useful hints to the diagnosis. The cells are reactive with keratin keratin (kĕr`ətĭn), any one of a class of fibrous protein molecules that serve as structural units for various living tissues. The keratins are the major protein components of hair, wool, nails, horn, hoofs, and the quills of feathers. , vimentin, and S-100 protein, but immunohistochemical analysis is seldom needed in view of the characteristic histologic and clinical appearance. Occasionally, the differential diagnosis includes adenoid cystic carcinomas or basal cell adenoma. [FIGURES 1-2 OMITTED] Recurrences develop on occasion, but most cases of "recurrence" are actually new primary growths from a multifocal neoplasm. Complete excision yields excellent outcomes. Suggested reading Ellis GL, Auclair PL. Tumors of the salivary glands. In: Ellis GL, Auclair PL, eds. Atlas of Tumor Pathology. 3rd Series. Fascicle fascicle /fas·ci·cle/ (fas´i-k'l) 1. a small bundle or cluster, especially of nerve, tendon, or muscle fibers. 2. a tract, bundle, or group of nerve fibers that are more or less associated functionally. 17. Washington, D.C.: Armed Forces Institute of Pathology Armed Forces Institute of Pathology A section of the US military which provides consultations, reference atlases and educational programs for pathologists , 1996:95-103. Rousseau A, Mock D, Dover DG, Jordan RC. Multiple canalicular adenomas: A case report and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;87:346-50. From the Department of Pathology, Woodland Hills Medical Center, Southern California Permanente Medical Group, Woodland Hills, Calif. |
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