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canalicular adenoma

Friday 9 February 2018


Definition : Canalicular adenoma is a benign neoplasm of a salivary glands which originally was considered to be a variant of basal cell adenoma.

It is most common in the 7th decade of life but can occur from 4th to 9th decades of life. It has a greater tendency to involve the minor salivary glands.

Approximately 70%-90% of the tumors occur in the oral cavity and is particularly common in the upper lip. Infrequently palate, buccal mucosa and parotid gland may be involved. Patients usually present with painless, slowly enlarging nodule.


- Canalicular adenoma


- well-circumscribed nodule
- basaloid tumor / basaloid appearance
- trabecular architecture

  • basaloid bi-layered epithelium arranged in cords, rows

- tubular architecture

  • interconnecting tubules reminiscent of canals

Grossly, canalicular adenomas form a well-circumscribed, pink-tan nodule ranging in size from 0.5 cm to 3.0 cm. Cut surface may show cystic spaces and mucoid material. Multifocal nodules are common.

Microscopically, the tumor shows bilayered basaloid epithelial cells forming interconnecting cords, rows, and tubular structures.

Cystic dilation of canalicular structures may be present and they are well demarcated from surrounding edematous paucicellular stroma.

Differential diagnosis

Differential diagnosis of canalicular adenoma includes :
- basal cell adenoma
- adenoid cystic carcinoma
- pleomorphic adenoma
- ameloblastoma
- cutaneous basal cell carcinoma

This high power micrograph of canalicular adenoma illustrates the bi-layered basaloid epithelium forming cords and tubules surrounded by paucicellular stroma.

The cells are cuboidal to columnar and have hyperchromatic round to oval nucleus with moderate amount of eosinophilic cytoplasm.

Histochemistry: The epithelial component of canalicular adenomas is PAS-positive, diastase sensitive.

Immunohistochemistry: The epithelial cells are pankeratin, vimentin and S100 positive. GFAP shows a linear immunoreactivity. p63, calponin, SMA are negative, suggesting absence of myoepithelial differentiation.

Recent studies have demonstrated ultrastructural findings which suggest possible origin from intercalated duct cells and striated duct luminal cells.

Complete surgical excision is curative.

See also

- salivary gland tumors / salivary tumors