Epidermal cysts have been sparsely reported in oral or perioral locations. To our knowledge, only 4 cases of labial epidermal cysts, two on the upper lip and two on the lower lip, have been reported on PubMed, and there have been no reported case in the Korean dermatologic literature. The mechanism of these cysts on the oral mucosa can be explained in three ways. First, displaced epithelial aggregation can occur secondary to trauma. This is called an ‘implantation phenomenon’, and this implanted cell may then proliferate and develop a cystic formation. Second, as some reports for intraoral hair show, aberrant pilar differentiation of mucosal keratinocytes could be considered a hypothetical avenue of pathogenesis. Finally, as in this case, epithelial proliferation of adjacent hair follicle origin cells can infiltrate the mucosal skin area through subcutaneous tissue. When we dissected for separation of the cyst from adjacent tissue, the cystic wall was connected with the epidermal portion of the mentolabial fold. This finding may be strong evidence that the labial cyst originated from adjacent mentolabial skin.
The excision of any benign subcutaneous cyst takes into account the potential risk of postsurgical scarring. Thus, a mucosal intraoral approach, like in our case, is an alternative to percutaneous excision to remove a cyst. The intraoral approach method may avoid a visible scar on the overlying skin. However, when the cyst is located between the skin and underlying muscles, caution must be taken to avoid damage to surrounding muscles, arteries, and nerves. kamagra soft tablets
Our case is interesting, as the findings of a labial epidermal cyst resembling mucocele or a salivary gland tumor in morphology, and the connection finding of a cystic base with adjacent hairy skin, suggested subcutaneous infiltration of the cyst.