An unusual case of bilateral verrucous carcinoma of the foot (epithelioma cuniculatum)
A 44-year-old male with a diagnosis of intellectual disability presents with a many year history of enlarging cauliflower-like tumours of both feet (Fig. ).\nEight years prior to presentation, he had similar warty lesions resected from between the clefts of three toes on the left, with an amputation of one toe on the right. The histopathological report showed warty Bowen's disease with well-differentiated SCC.\nThe growths involved the interdigital folds of the toes of both feet. A CT scan showed tumour bony cortical disruption of the left second toe, with features suspicious for bone marrow invasion. The patient was further investigated with MRI, which showed tumour appearing to be closely related to bone and interphalangeal joints.\nThe extent of the lesions and possibility of bony involvement resulted in the decision to perform bilateral forefoot amputations.\nThe patient was followed up for 1 year and no further recurrences or metastasis were detected. He was able to ambulate with the assistance of orthotics.\nHistologically, the specimen displayed both endophytic and exophytic morphology, comprising of warty papillomatous projections lined by variably atypical stratified squamous epithelium and overlying hyperkeratosis and parakeratin. The endophytic component showed deep acanthotic growths with a periphery of mitotically active basaloid cells and variable atypical squamous cells with frequent atypical mitoses. The endophytic downgrowths of tumour formed burrows filled with keratinous material, in keeping with verrucous carcinoma. No lymphovascular or perineural invasion was identified. Immunohistochemical staining for p16 showed strong nuclear and cytoplasmic reactivity, suggesting an human papillomavirus (HPV) related tumour.