[Basal cell naevus syndrome as the cause of a chronic foot ulcer]

A 46-year-old man presented to the surgery outpatient clinic with an ulcer on top of his left foot. He had previously been diagnosed with basal cell naevus syndrome but had withdrawn from follow-up. His foot showed a deep ulcerating defect accompanied by profound necrosis extending to the metatarsophalangeal joints. There was a nodular skin defect over the first metatarsophalangeal joint, which was shown by histopathology to be a basal cell carcinoma, and the ulcer was bordered by a raised wall. Further physical examination revealed more than 200 dermal lesions which were identified by the dermatologist who was called in for consultation as basal cell carcinomas; multiple depressions due to abnormal local keratinisation were also seen on the palms of the hands and the soles of the feet. These findings led to a diagnosis of 'basal cell naevus syndrome'. The patient was treated by amputation of the lower leg followed by excision and curettage of the remaining basal cell carcinomas. At the time of the last follow-up, the patient was being checked periodically in the dermatology outpatient clinic. Basal cell naevus syndrome is a rare autosomal dominant hereditary disease. The prevalence is estimated to be between 1 in 57,000 and 1 in 164,000. Basal cell naevus syndrome is generally caused by a mutation in the 'patched homolog' (PTCH)-I gene, located on chromosome 9q22.3. Although the syndrome affects multiple organ systems, the most characteristic of this disorder is the appearance of multiple basal cell carcinomas.