Having a coffee spot satellite foci does not necessarily confirm the diagnosis. Satellite foci refer to moles surrounded by a number of smaller moles of the same color, whereas coffee spots are a type of brown patch. Coffee spots need to be diagnosed through physical examination, dermoscopy and histopathologic examination. 1. Physical examination: The doctor will ask the patient about the time and place of onset of the disease, and then observe and palpate the area to find out the size, number, shape, color, and border of the plaque. 2. Dermoscopic examination: Since coffee spots may grow in different parts of the body, and the performance of coffee spots in different parts of the body is different, dermoscopic examination can be done if necessary. For example, cafe-au-lait spots on the neck may have a grid-like shape, and cafe-au-lait spots on the face may be brown patches, and so on. 3. Histopathological examination: through histopathological examination, it can be observed that the number of melanocytes in the basal layer increases, and the total amount of melanin in the epidermis increases. If there are abnormal plaques on the body, you should consult a doctor in time and do a systematic examination to confirm the diagnosis.