The CUBED Versus ABCDE Recognition Tools in the Detection of Malignant Melanomas Arising in the Foot: An Analysis of Four Recent Case Studies in a Single NHS Community Trust.

Abstract

Background: Melanoma of the foot and nail unit carries a worse prognosis than cutaneous melanoma elsewhere because lesions are frequently hidden, misdiagnosed, and therefore diagnosed at more advanced stages. Traditional ABCDE criteria are often insufficient for foot and nail presentations; the CUBED recognition tool was developed to improve detection of atypical plantar and subungual lesions.

Aim: To evaluate four consecutive cases of foot melanoma seen in a single NHS community podiatry department, compare case characteristics against ABCDE and CUBED recognition tools, and describe service responses that aimed to improve early detection.

Methods: A retrospective case series of four patients diagnosed with foot melanoma between 2019 and 2022 in one community podiatry service. Clinical features, referral timelines, diagnostic pathways, treatments, and outcomes were extracted and mapped against ABCDE and CUBED criteria. Shared-learning interventions developed by the department following these cases are described.

Results: All four cases were toe-based melanomas (one lentigo maligna, one nail-bed malignant melanoma, two acral melanomas). Presentations commonly included irregular colour, bleeding or ulceration, delayed healing, diagnostic uncertainty, and lesion enlargement. CUBED criteria more consistently identified concerning features across the series than ABCDE criteria, prompting urgent dermatology referral in each case. Outcomes varied: one patient remains disease-free after excision, one developed distant metastasis and died, two underwent toe amputation and received systemic treatment. Departmental responses included case-based teaching and a poster campaign promoting CUBED and ABCDE recognition across local clinical networks.

Conclusion: Podiatrists are pivotal in early detection of foot melanoma. The CUBED tool demonstrated greater sensitivity for atypical foot and nail lesions in this series. Wider education and adoption of CUBED alongside ABCDE may reduce misdiagnosis, shorten diagnostic delay, and improve clinical outcomes.