Palatal Erythema with Histological Psoriasiform Pattern: An Enigmatic Oral Finding Shared by a Range of Conditions.

Long standing, asymptomatic, well-demarcated erythema of the hard palate with a histopathological psoriasiform pattern comprises a challenging diagnosis. We present a series of patients with such clinical and histological findings and discuss the possible diagnoses. We collected all patients with palatal erythematous lesions that had well-documented clinical examination. Excluded were patients with definitive diagnosis of oral infections (e.g. candidiasis), neoplastic/pre-neoplastic lesions, auto-immune diseases, reactive lesions, blood disorders and vascular malformations. Thirteen patients (six females, seven males, age range 11-56 years) were included. Histopathologically, a psoriasiform pattern was observed in all biopsied lesions. One patient was diagnosed with hereditary mucoepithelial dysplasia (HMD) and four with cutaneous psoriasis. The remaining eight patients were otherwise healthy. A combination of persistent, asymptomatic palatal erythematous lesion with psoriasis-like histopathology may represent an oral manifestation of HMD or psoriasis, concomitant to extra-oral features. In lack of any known medical background, the term "oral psoriasiform mucositis" is suggested.