Case report: Sublingual mucinosis in a dog

Oral focal mucinosis (OFM) is a rare clinic-pathological condition histologically similar to focal skin mucinosis and thus, OFM is considered as the oral counterpart of cutaneous focal mucinosis (1, 2). Cutaneous mucinosis refers to an excessive deposition of mucinous substance in the dermis that clinically manifests as a thickening of the skin or as a vesicular appearance (3, 4). A generalized cutaneous mucinosis, of likely genetic origin, occurs primarily in Shar-pei dogs, giving them its characteristic appearance (5). In other breeds, severe mucinosis is associated with secondary diseases such as intertrigo, bacterial infections and entropion, all of which can lead to severe deterioration in the health of the animal (6). In human, OFM was first described and named by Tomich in 1974 (1). Its pathogenesis is still unclear, but an increased production of hyaluronic acid (HA) by fibroblasts in expense of collagen production and myxoid degeneration is suggested (7, 8). Clinically, oral lesions often present as a small (<1 cm) submucosal, single, pink, and slow-growing asymptomatic nodule containing gelatinous material (8, 9). The gingiva and palate are the most affected sites (9, 10). OFM has already been reported in literature in a dog as a nodular lesion on the buccal mucosa (11). This is the first case described with this type of presentation.