Dark mark under breast area

I just noticed a dark mark under my breast/above my rib cage area. Does anyone know what this might be or what would cause it? I know my ribs were hurting a…

Acanthosis Nigricans: Treatment, Pictures, and Causes

Acanthosis Nigricans (AN) Nationwide Children's Hospital

Acanthosis Nigricans: Treatment, Pictures, and Causes

Acanthosis Nigricans: Treatment, Pictures, and Causes

Acanthosis Nigricans (AN) Nationwide Children's Hospital

Acanthosis Nigricans: Treatment, Pictures, and Causes

Acanthosis Nigricans: Treatment, Pictures, and Causes

Dark mark under breast area

Acanthosis Nigricans: Treatment, Pictures, and Causes

Acanthosis Nigricans: Treatment, Pictures, and Causes