What is the diagnosis for a compressible, rubbery, smooth mass found on the chest?

The presence of a compressible, rubbery, smooth mass found on the chest is characteristic of a lipoma. Lipomas are benign tumors made up of adipose (fat) tissue and often feel soft and movable under the skin. They generally do not cause pain and can vary in size. The rubbery texture and smooth surface are typical of lipomas, making them very distinct in terms of physical examination.

In contrast, nevi are pigmented lesions or moles on the skin, which typically do not have the compressible or rubbery characteristics associated with lipomas. Skin tags are small, benign growths that hang off the skin and do not present as smooth, rubbery masses. They are often more fibrous in nature rather than compressible. A possibility of an adenoma generally refers to a glandular tumor, which may not be visible as a smooth mass on the skin and usually pertains to internal tissues rather than subcutaneous findings. Thus, the specific attributes of the mass point directly to a lipoma as the most accurate diagnosis in this scenario.