Hello, Brown spot on the heel may be indicative of heel fissures, thickened skin of the heel, corn, dead skin or foot melanoma. Dry skin on the sole of the foot can trigger heel fissures. It can be harmful if you are diabetic, it will take a lot of time to heal. Control your blood sugar levels at all cost. You are suggested to keep the area affected moisturized with body lotions made from almond or coconut oil. Applying ointments containing alpha hydroxy acids or salicylic acid on the affected area will be helpful. However you are suggested to get clinically examined by a dermatologist, get biopsy of the affected area done to detect /confirm foot melanoma, cancer. The dermatologist may refer an oncologist to consult. They may need genetic testing, imaging tests, like a CT scan or an MRI scan to assess how far the cancer has metastasized. In the early stages, a surgeon can remove the melanoma but if the cancer has spread then immunotherapy, radiation therapy or chemotherapy may be required to be done. Get clinically evaluated and treated. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician