Malignant melanoma is a deadly form of skin cancer, and prompt diagnosis is a key factor in providing adequate, life-saving therapy. A 75-year-old man, with long-standing type 2 diabetes mellitus, presented with a 2- to 3-year history of right heel ulcer. He had received various therapies for a diagnosis of diabetic foot ulcer, to no avail. Physical examination showed a black, fungating ulcerated lesion on his right heel, with minimal bleeding. No inguinal lymphadenopathy was palpated. A biopsy was done, which revealed BRAF-negative malignant melanoma, with a vertical growth phase, Breslow 3.1 mm, ulceration, 11 mitoses/mm2, Clark level IV, no lymphatic or vascular invasion observed. Right inguinal lymph node sampling suggested no involvement, but PET-CT suggested pulmonary, right inguinal lymph node and bone involvement. The patient was referred to the oncologists. Written informed consent for publication was given by the patient. Diabetic foot ulcers are a frequently encountered, but serious complication of diabetes mellitus. Delayed healing is often seen, despite adequate therapy. The differential diagnosis of diabetic foot ulcers is vast and includes neoplasia. When a foot ulcer fails to heal, other differential diagnoses must be considered, in order for the patient to receive adequate therapy. Here specialist consultations, including dermatology consultations, could improve chances of delivering the right therapy promptly. This is a factor underlying the emphasis on a multidisciplinary approach to foot ulcer therapy. Our presentation - reported according to the CARE guidelines - also illustrates the fact that failure to reach a timely diagnosis may deny the patient the opportunity to receive adequate treatment. In such cases, "delayed therapy becomes denied (or failed) therapy", paraphrasing the old adage "Justice delayed is justice denied".