However, characteristic oral mucosal locations of the RAS are the buccal and labial mucosa
as well as tongue (41).
The literature shows that a decrease of saliva, mainly from the posterior palatal and the labial mucosa
regions, may exacerbate the discomfort of dry mouth sensation even in the presence of normal major salivary gland function [23, 34].
The most common oral locations for the CA are the tongue, labial mucosa
, floor of the mouth and gingiva.
The percentage of occurrence of ulcers in different sites of mouth as labial mucosa
, buccal mucosa, tongue, soft palate, and floor of mouth was 25.9%, 44.4%, 33.3%, 0%, 3.7% respectively.
Caption: Figure 4: (a and b) Intraoral examination showing red pigmentation in the upper and lower labial mucosa
(5) Another cohort study of 142 children allowed suspect foods to contact only the labial mucosa
in order to reduce the risk of systemic reactions (1 case of anaphylaxis occurred nevertheless).
With respect to the primary anatomical site, oral squamous cell carcinoma (OSCC) lesions mostly occur at the tongue, followed by floor of the mouth, alveolar ridge/ gingiva, buccal mucosa, labial mucosa
and hard palate (Scully & Porter and Neville & Day).
The labial mucosa
exhibits dilation of the orifices of the minor salivary glands through which thick saliva (mucin-rich) flows more intensely due to the inflammatory process inside the glandular parenchyma.
Malignant peripheral nerve sheath tumor (MPNST) is a sarcoma originating from peripheral nerves occurring rarely in oral cavity with only 11 cases reported in lower labial mucosa
to date in English literature.12
They have also been reported on the labial mucosa
in men.8 Rarely multiple satellite lesions may develop - especially in adolescents and young adults after prior attempts to remove the original lesion.
 Typically, cGVHD oral mucosal lesions are characterized as erythema, lichenoid and ulcerative lesions involving any site including labial mucosa
, buccal mucosa, tongue, hard and soft palate, floor of mouth and gingiva.