Two Unusual Cases of Oral Lichen Planus Arising After Oral Squamous Cell Carcinoma: Can Oral Cancer Trigger Autoimmunity?

Autoimmune diseases occur when the immune system fails to recognize self-antigens expressed on the body's own cells and attacks them. Oral lichen planus (OLP) is a chronic autoimmune mucocutaneous disease of the oral cavity characterized by white/red lesions. Considered a potentially malignant disorder, OLP evolution into oral squamous cell carcinoma (OSCC) is still a matter of debate. While chronic autoimmune inflammation is considered a potential risk factor for malignant transformation in many solid tumors, the opposite idea that cancer may trigger autoimmune responses remains controversial. We describe 2 patients who developed lesions clinically suggestive of OLP with histological evidence of lichenoid infiltration some time after OSCC removal, even in areas far from the neoplastic site. Neither patient had OLP before the diagnosis of OSCC, or reported exposure to OLP-associated etiologic factors, and neither. experienced tumor recurrence during follow-up. Our findings suggest that oral cancer remission may be linked to OLP development, but further studies are necessary to unveil the underlying mechanisms and possible prognostic implications.