Jacob, a 33-year-old construction worker, complains of a "lump on his back" over his scapula. It has been there for about a year and is getting larger. He says his wife has been able to squeeze out a cheesy-textured substance on occasion. He worries this may be cancer. When gently pinched from the side, a prominent dimple forms in the middle of the mass. What is most likely?A) An enlarged lymph nodeB) A sebaceous cystC) An actinic keratosisD) A malignant lesion