Breast Metastasis of a Completely Regressed Cutaneous Melanoma – Case Report and Review of Literature

Spontaneous regression of cutaneous melanoma represents a more frequent circumstance in tumors with intense MelanA immunoprofile. Melanoma-derived breast metastases are uncommon and have been predominantly reported in premenopause, as an indicator for widespread disease. We report the case of a 60-year-old female patient, who presented to the surgical department after auto-palpation of a left mammary mass. Digital mammography indicated malignant characteristics, also objectified in the ipsilateral axillary lymph nodes. The microscopical examination and immunohistochemical profile revealed left nodal and upper-outer mammary quadrant metastases of a BRAF-positive achromic melanoma. The clinical and dermoscopic evaluation confirmed the complete regression of the malignant melanocytic lesion, localised at the level of the right inframammary fold. The upper-outer breast quadrant designates the main site of primary tumors (66%), as well as metastases of other malignancies (50%), due to its well-represented vascularisation and glandular tissue. Dermoscopic characteristics of regressed melanoma comprise scar-like depigmentation and polymorphous vessels (irregular linear and globular). The particularities of this case include the age > 40 years old, survival under therapy with Vemurafenib superior to that cited in the literature (24 months to this date), the involvement of the contralateral lymph nodes in relation to the skin lesion and the inverse diagnostic approach – from pathologist to dermatologist. Completely regressed achromic melanoma, identified through diagnostic techniques performed on clinically apparent loco-regional and distant metastases, represents a rare dermato-oncological entity, with controversial implications regarding the prognosis and survival, that requires future histopathological and dermoscopic homogenization.