Clinicopathological and immunohistochemical aspects of conventional and unicystic canalicular adenoma: a case series

Objective

To describe a well-documented series of 10 new cases of conventional and unicystic canalicular adenoma (CAD).

Study design

This was a retrospective study in which the original hematoxylin and eosin and immunohistochemical slides of all cases of CAD diagnosed between 2014 and 2024 were re-evaluated. Clinical data regarding age, gender, clinical presentation, evolution time, and related symptoms were retrieved from the patients’ medical records.

Results

Ten CADs were identified. Most patients were female (n = 6), with a mean age of 61.2 years. Most tumors presented as a solitary asymptomatic nodule, particularly on the upper lip (n = 7), and two patients reported slight pain or sensitivity. All tumors were well-delimited with a connective tissue capsule. A bosselated or lobulated appearance and cystic formation were observed in all cases. Other features were also observed, such as solid areas, clear cells, beading, morules, and pseudostratification. Eight cases were classified as conventional and two as unicystic. All cases were positive for CK7, S100 protein, and SOX10, while negative for p40 and p63.

Conclusions

This paper described 10 additional cases of CAD, with classic and uncommon microscopic findings, including unicystic. We highlighted the importance of an immunohistochemical panel in differentiating CAD from other salivary gland tumors.