Alopecia neoplastica - Hair and Scalp
Metastatic spread to the scalp occurs through lymphatic and/or hematogenous spread. In AN, there is atrophy or complete loss of the hair follicles, which is likely due to invasion of the tumor into the deep dermis with an accompanying desmoplastic reaction. Tumor infiltration of the hair follicle is an occasional occurrence. The epidermis is generally spared. Hair regrowth after treatment of the underlying malignancy is not globally seen.
Of the reported cases, the most common site of the primary cancer is the breast by an overwhelming majority, though metastases from the lung, stomach, colon, cervix, and placenta have also been recognized. Rarely, AN may be the presenting sign of an underlying cancer. The presence of AN (like other forms of cutaneous metastases) is a poor prognostic factor.
The majority of reported patients are women of Northern European descent in their fourth to eighth decade of life. This demographic parallels the epidemiology of the dominant underlying malignancy. In cases where a malignancy was previously diagnosed, the time interval between diagnosis and the appearance of AN ranged from less than 1 year to 20 years, with most cases occurring within 3 years.
C79.2 – Secondary malignant neoplasm of skin
L66.9 – Cicatricial alopecia, unspecified
400088006 – Scarring alopecia
94570001 – Secondary malignant neoplasm of skin of scalp
Differential Diagnosis & Pitfalls
- Discoid lupus erythematosus
- Central centrifugal cicatricial alopecia
- Lichen planopilaris
- Pseudopelade of Brocq