BACKGROUND: Langerhans cell histiocytosis is a rare disorder characterized by abnormal proliferation of Langerhans cells, primarily affecting children and occasionally adults. Etiology remains enigmatic, with genetic and environmental factors implicated. Diagnosis relies on histopathology and clinical manifestations, often necessitating a multidisciplinary approach. CASE PRESENTATION: We report a unique case of Langerhans cell histiocytosis with perianal lesions as initial manifestations in a 41-year-old Chinese deaf male patient with a history of perianal abscess. Examination revealed erosion and plaque-like changes in the mucosa around the anus. Histopathology and immunohistochemistry confirmed Langerhans cell histiocytosis, and a whole-body positron emission tomography-computed tomography scan revealed no other organ involvement, indicating monosystemic disease. Then, 3 months post-treatment, the patient declined a repeated magnetic resonance imaging scan during outpatient follow-up owing to no significant discomfort reported, which resulted in loss to follow-up and discontinuation of treatment. CONCLUSION: This case suggests that perianal lesions may be a manifestation of Langerhans cell histiocytosis, and underscores the importance of whole-body positron emission tomography-computed tomography scanning for follow-up in instances of pure skin involvement.