Clinical and Dermoscopic Characterization of Scalp Cutaneous Metastases From Breast Carcinoma: A Multicenter Study of the EADV Task Force on Hair Diseases.

Introduction: Cutaneous scalp metastases from breast carcinoma (CMBC) represent an uncommon manifestation of metastatic disease, with heterogeneous clinical presentations, including nodular or infiltrative lesions and scarring alopecia (alopecia neoplastica). The absence of standardized diagnostic criteria, particularly for alopecic phenotypes, poses challenges to early recognition of CMBC, which may represent either the first indication of neoplastic progression or a late recurrence.

Materials and methods: We retrospectively analyzed a multicenter cohort of 15 patients with histologically confirmed CMBC. Demographic, clinical, molecular, and trichoscopic data were collected and correlated with the main clinical phenotypes: patchy alopecia (alopecia neoplastica) versus nodules/plaques. The statistical analyses we performed were the Mann-Whitney test for group comparisons and Fisher's exact test for categorical variables.

Results: The median age at CMBC diagnosis was 64 years. Alopecia neoplastica was the most frequent phenotype (53.3%). Patients with alopecia neoplastica showed a longer median interval between primary tumor diagnosis and metastasis onset compared to those with nodules/plaques (73.5 months vs. 59.5 months; p = 0.11). Trichoscopic analysis revealed significant differences in the distribution of features between the alopecia neoplastica group and the nodular/plaque group. Statistically significant differences were found among the two groups, including linear-irregular vessels (87.5% vs. 28.6%, p = 0.041), polymorphic vessels (87.5% vs. 28.6%, p = 0.041), pili torti (75% vs. 14.3%, p = 0.041), follicular hyperkeratosis and follicular plugging (87.5% vs. 14.3%, p = 0.01). Overall, the trichoscopic pattern in alopecia neoplastica appeared more variable and heterogeneous compared to that observed in the nodular/plaque phenotype.

Conclusion: Alopecia neoplastica, often underestimated in clinical practice, emerges as the predominant CMBC phenotype in our cohort and is associated with a distinct trichoscopic profile. The complexity of the alopecic phenotype may reflect intrinsic biological differences compared to nodular lesions. Larger prospective studies are needed to validate these findings and incorporate trichoscopic profiles into standard diagnostic pathways.