Isolated Lichen Planus of the Lower Lip: Report of a Rare Case with an Updated Literature Review.

Lichen planus (LP) is a chronic inflammatory, autoimmune entity typically affecting the skin, oral and genital mucosa, and skin appendages, with an underlying malignant potential. Oral lichen planus (OLP) represents the mucosal counterpart of the cutaneous LP and exhibits episodes of exacerbation and remissions. OLP typically manifests as bilateral symmetrical lesions on the buccal mucosa, followed by tongue, and gingiva. However, the occurrence of LP lesions solely on the lip is rarely reported in the literature. The altered clinical appearance of the lip lesions poses a diagnostic threat and raises the possibility of a misdiagnosis. Our aim was to report an unusual case of isolated lower lip LP, and also to carry out a literature review about isolated lip LP lesions, thus, emphasizing the demographic, clinicopathologic attributes, and therapeutic regimen. We report an uncommon occurrence of an isolated lichen planus on the lower lip in a 53-year-old male patient. Clinical evaluation revealed a diffuse erosive crusted lesion bordered by peripheral lacy radiating streaks on the lower lip. After a confirmed OLP histopathology, the patient was treated with low potency topical steroids and Vaseline therapy, with almost completely resolved lesions after 2 months of therapy. We report a rare case of isolated lip LP, and our detailed review revealed 44 reported cases of lip LP till date. The majority of the cases were seen on the lower lip and exhibited an age and gender affinity (mostly in middle-aged males). Significant healing was observed after topical steroid therapy.