BACKGROUND: Scalp melanomas are usually thicker and show worse prognosis than other sites and other head and neck melanomas. One hypothesis to explain this aggressive behavior could be diagnosis delay attributed to hair concealment of lesions.
METHODS: Primary melanomas of the scalp diagnosed over two decades at four reference centers in Australia and Italy were included. Hair coverage and visibility of the lesions were assessed on preoperative photographic documentation by two investigators and correlated with some prognostic factors (Breslow thickness, mitotic rate, and ulceration). Patients records and pathology reports provided clinical and histological data.
RESULTS: The majority of 113 melanomas included were located on easily visible areas of the scalp - hairless scalp (49%) or hairline (15%). The remaining ones (36%), considered to be hair-covered, showed more frequently thinning of hair (63%) than a dense hair coverage (37%). Melanomas of "hairy scalps" were more frequently invasive (81%) and had higher median Breslow (0.8 ± 1.3 mm) than those arising on bald scalps or areas with thinning of hair (43%; 0 ± 0.6 mm), P = 0.004. However, when considering only the invasive cases (n = 55), Breslow thickness and mitotic rate were not statistically different between concealed and easily visible areas. Melanomas detected by a doctor were thinner than those first noticed by the patient, relatives, or a hairdresser (P < 0.001).
CONCLUSIONS: Most scalp melanomas arose on easily visible areas, which are more prone to ultraviolet damage. Hair-covered ones, despite rare, could be overlooked during examination. Proactive screening of the scalp area should be encouraged.