Introduction
Oral squamous papilloma is a benign tumor, but its potential for malignant transformation has yet to be studied. The authors report an unusual case presentation of an oral squamous cell carcinoma (SCC) arising from a squamous cell papilloma (SCP).

Case presentation
A 61 years old immunocompromised female patient complained of an asymptomatic white mass on the buccal mucosa. The diagnosis of squamous cell papilloma (SCP) was made, and the benign nature of the lesion was confirmed by two biopsies. The lesion suddenly increased in size, and the third biopsy revealed a malignant squamous cell carcinoma (SCC) grade II. At this stage, radical surgical intervention was the treatment of choice, and reconstruction with a combination of the pectoralis major and deltopectoral flaps was performed.

Discussion
Clinical and histopathological diagnosis of oral squamous papilloma is challenging. Reconstruction of composite head and neck defects is another challenge, especially in elderly and immunocompromised patients. The whole process of diagnosis and progress of the presented case might provide useful knowledge regarding the nature of the lesion and its future management.

Conclusion
The authors emphasize the need for establishing a clear understanding of potentially malignant oral lesions. Close observation, multiple biopsies, early detection, precise diagnosis, and a multidisciplinary team approach are all of paramount importance.