Is it possible to have acanthosis nigricans without diabetes?

Yes: Other causes include lymphoma, gastrointestinal or genitourinary cancers, and drugs such as human growth hormone and some oral contraceptives. Reference: national library of medicine.

Yes: Acanthosis nigracans is darkening skin commonly found on cheeks, necks, and underarms. This is from Insulin resistance. Obesity, metabolic syndrome and polycystic ovarian syndrome can cause this as well. Losing weight, eating less, exercising, and possibly using Insulin sensitizers such as metformin can help.