The long spots on the stomach brown considerations and pigmented nevus, seborrheic keratosis, lichen planus and so on. 1. Nevus pigmentosus: the cause is unknown, belongs to benign skin tumor, manifested as local black, brown spots or papules, at the same time and the surrounding skin boundary is clear, not accompanied by itching, pain and other discomforts, generally without special treatment. 2. Seborrheic keratosis: this disease belongs to benign epidermal tumors, its occurrence is mostly related to age, ultraviolet radiation, etc., the patient’s skin will appear darker, clear plaques, the general surface of the lesion is more rough. 3. lichen planus: this disease is due to horse salad bacteria infection caused by skin diseases, mainly manifested as a clear boundary rash, the color can be manifested as brown, light brown, white, etc., the surface of the rash is often accompanied by scales. For patients with brown spots on the stomach, it is recommended to go to the regular hospital dermatology department, clear cause of the disease under the guidance of the doctor active treatment.