EC Dental Science

Canalicular adenoma of salivary gland emerges as a benign epithelial neoplasm constituted of branching, interconnected cords of cuboidal to columnar epithelial cells circumscribed by a pauci-cellular and vascularized stroma. Initially scripted by McFarland in 1942, the neoplasm was contemplated as a variant of monomorphic or basal cell adenoma. Notwithstanding, World Health Organization categorized the neoplasm as a distinct entity in 1991. The nomenclature of canalicular tumour, canalicular mixed tumour, monomorphic adenoma, canalicular subtype, cystic adenoma or adenomatosis of accessory salivary glands appears obsolete.
The benign epithelial neoplasm is pre-eminently composed of monomorphic epithelial cells and is devoid of a distinct basal or myoepithelial cell layer. Tumefaction is frequently confined to minor salivary glands wherein multifocal lesions may be exemplified. Canalicular adenoma commonly emerges within the adult population >50 years with peak age of disease occurrence at seventh decade. A female predominance is observed. Non Asian ethnic groups are frequently implicated [1,2].
Canalicular adenoma configures up to 3% of salivary gland tumours and 4% to 6% of minor salivary gland tumours [1,2]. Canalicular adenoma of salivary gland occurs within the upper lip (80%) followed by buccal mucosa, lower lip and hard and soft palate. Tumour emergence within major salivary glands as the parotid is extremely exceptional wherein a pleomorphic adenoma demonstrating HMGA2-WIF1 genetic fusion may require distinction [1,2]. Of obscure aetiology, canalicular adenoma is posited to arise from terminal ducts of salivary glands wherein intra-lobular ducts appear to simulate intercalated ducts [1,2].
Cytogenetic analysis depicts doubling of normal complement. Genetic fusions appear absent. Clinically, tumefaction represents as a gradually progressive, painful or painless swelling or lesion. Singular or bilateral, multifocal neoplasms may be observed. Clinical symptoms as localized pressure or discomfort along with or devoid of prosthesis may ensue [2,3]. Ulceration of superimposed mucosa may be encountered. Neoplastic occurrence may be delayed to months or years. Occasionally, canalicular adenoma may configure as collision tumour or hybrid tumour. Canalicular adenoma of salivary gland may be appropriately

1. Azar A., et al. “Canalicular adenoma in the parotid gland: a rare case study”. Ear, Nose and Throat Journal (2024): 1455613241262652.
2. Brown AE., et al. “Canalicular-like pleomorphic adenoma of the parotid gland: a recently classified tumor highlighting the use of frozen section analysis and surrogate IHC for gene rearrangement defined subtypes”. International Journal of Surgical Pathology 32.8 (2024): 1547-1551.
3. Katabi N., et al. “Expanding the histological spectrum of salivary gland neoplasms with HMGA2:: WIF1 fusion emphasising their malignant potential: a report of eight cases”. Histopathology 84.2 (2024): 387-398.
4. Aquino SN., et al. “Clinicopathological and immunohistochemical aspects of conventional and unicystic canalicular adenoma: a case series”. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontics 139.3 (2025): e59-e67.
5. Su V., et al. “A rare case of canalicular adenoma in the parotid gland: Highlighting diagnostic limitations of fine-needle aspiration”. American Journal of Otolaryngology 44.2 (2023): 103792.
6. Agaimy A., et al. “HMGA2-WIF1 rearrangements characterize a distinctive subset of salivary pleomorphic adenomas with prominent trabecular (Canalicular adenoma-like) morphology”. American Journal of Surgical Pathology 46.2 (2022): 190-199.
7. Image 1 Courtesy: Wikimedia commons.
8. Image 2 Courtesy: Libre Pathology.