Derm Dx: An asymptomatic flesh-colored nodule of unknown duration

A 42-year-old fair-skinned woman requests a full body examination. Her medical history is negative for skin cancer, genodermatoses, and thyroid disease. She underwent lumpectomy for breast cancer 3 years earlier. On examination, scattered nevi and a flesh-colored nodule are noted on her upper back. The lesion is asymptomatic, and the patient is unsure how long it has been present.