Primary vs Secondary Alopecia Neoplastica

Alopecia Neoplastica: Patchy Hair Loss Due to Entry of Neoplastic Cells into Hair Follicles

“Alopecia neoplastica” (AN) is a phenomenon whereby neoplastic cells damage hair follicles leading to patchy hair loss that looks like alopecia areata or scarring alopecia.

Primary AN happens when the neoplasm (either benign or malignant) invading hair follicles comes from the skin. Secondary AN occurs when the neoplastic cells invading hair follicles arrive there via metastases.

Causes of primary AN include primary angiosarcomas, hemangioendotheliomas, ectopic extramammary Paget disease, syringomatous carcinoma, amelanotic melanoma, and desmoplastic melanoma. Benign causes include − nerve sheath myxoma, neuroma, nevocellular nevusm, osteomyoma-like tumor, syringomas, trichoepithelioma

Causes of secondary AN include breast cancer, lung cancer, kidney cancer and cancers of the gastrointestinal tract

REFERENCE

Kelly E. Flanagan et al. Primary Alopecia Neoplastica: A Novel Case Report and Literature Review.Skin Appendage Disord. 2021 Nov; 7(6): 499–509.