Atypical localized neutrophilic dermatosis. Localized neutrophilic dermatosis in post-mastectomy lymphedema.

Abstract

Localized neutrophilic dermatosis arising in areas of post-mastectomy lymphedema represents a rare variant of Sweet syndrome, characterized by inflammatory lesions confined to regions with impaired lymphatic drainage and regional immune dysfunction. We present the case of a 76-year-old woman with a history of right ductal breast carcinoma treated with mastectomy, lymphadenectomy, chemotherapy, radiotherapy, and hormonal therapy, who subsequently developed chronic ipsilateral lymphedema. She presented with erythematous maculopapular lesions on the right arm associated with episodes of fever, tenderness, and localized warmth. Laboratory studies revealed leukocytosis, neutrophilia, hyperfibrinogenemia, and elevated C-reactive protein levels.

Skin biopsy demonstrated superficial and deep perivascular inflammatory infiltrates with scattered neutrophils, swollen endothelial cells, and focal erythrocyte extravasation. A diagnosis of localized neutrophilic dermatosis arising in post-mastectomy lymphedema was established, likely favored by the presence of an immunologically vulnerable district related to the patient’s previous oncological treatments.