Which lesion is typically not associated with skin thickening or dimpling?

The lesion typically not associated with skin thickening or dimpling is postoperative scarring. Postoperative scarring, which can occur after surgical procedures like a lumpectomy or mastectomy, often results in changes to the skin's appearance, but it does not generally cause the changes linked to underlying pathology such as tumors or inflammatory processes.

In contrast, other lesions like hamartomas, fat necrosis, and fibroadenomas can lead to various forms of skin changes. Hamartomas, which are benign tumors made up of an abnormal mixture of cells and tissues, can cause skin irregularities due to their growth and relation to surrounding structures. Fat necrosis can occur as a result of trauma or surgery and often leads to localized inflammation, which may manifest as skin changes, including thickening or dimpling. As for fibroadenomas, although they are also benign, they can be palpable and sometimes produce alterations to the skin appearance if they grow large enough or if there is associated compression of surrounding tissues.

Therefore, postoperative scarring is directly related to surgical intervention and its effects on the skin, rather than to a pathological condition that would cause skin thickening or dimpling.