Differential diagnosis of rare diseases presenting as palatal ulcers: a case series

Background: Ulcers involving the palate can be the initial manifestation of various diseases, with common etiologies often diagnosed through clinical and routine examinations. However, rare systemic diseases presenting as palatal ulcers are easily misdiagnosed or missed due to their low incidence and nonspecific manifestations. This study aims to enhance recognition of such rare diseases by analyzing their clinical and pathological features.

Case Description: We report five cases of rare diseases with palatal ulcers as the initial symptom. Case 1: a 76-year-old man with a non-healing ulcer on the left maxillary gingiva extending to the hard palate; histopathology and T-SPOT test confirmed oral tuberculosis. Case 2: a 23-year-old woman with recurrent palatal pseudomembranes; fungal culture and gene sequencing diagnosed chronic mucocutaneous candidiasis (CMC) due to STAT1 mutation. Case 3: a 20-year-old woman with 2-year recurrent ulcers, loose teeth, and systemic symptoms (e.g., dwarfism); biopsy confirmed Langerhans cell histiocytosis (LCH). Case 4: a 25-year-old man with a 3-month history of palatal ulcers and characteristic “snail track” lesions; combined with his history of ulcerative colitis and intestinal histopathology, a diagnosis of pyostomatitis vegetans (PSV) was confirmed and controlled with mesalazine and azathioprine. Case 5: a 44-year-old male presented with a palatal ulcer persisting for over 4 months, which gradually enlarged and was accompanied by submandibular lymphadenopathy. Through T cell receptor gene monoclonal rearrangement detection and histopathological examinations, he was diagnosed with peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS).

Conclusions: Ulcers involving the palatal region warrant heightened vigilance for underlying systemic disorders. An integrated approach encompassing clinicopathological correlation, microbiological assays, genetic profiling, and comprehensive systemic evaluation enables definitive diagnosis and prevents diagnostic delays or misdiagnoses.