Neoplastic alopecia (NA) is defined as an organized hair loss in single or multiple areas of the scalp caused by a primary tumor that has metastasized to the skin of the scalp. Due to its localization and clinical appearance, NA should be placed in differential diagnosis with alopecia areata or other entities. To date, pathognomonic dermoscopic criteria of NA have not yet been described: the absence of classical criteria of other scalp diseases in addition to a major neovascularization with on-focus arborizing vessels and erosions or ulcerations may help the clinician to suspect a diagnosis of secondary alopecia. Dermatologists should pay more attention to these rare forms of secondarism because in exceptional cases, a simple alopecia of the scalp can hide a new, relapsing or metastatic neoplasia.
