Dermatitis neglecta, a condition that results from inadequate skin cleansing, is still little reported in the literature and underreported. Although benign, it is aesthetically uncomfortable. It is associated with conditions that lead to fear of sanitizing a given region and may be related to psychiatric and neurological disorders. This observational study consisted of the case report of a patient followed up in a University Hospital in northeastern Brazil, with the objective of demonstrating the rare association between dermatitis neglecta and breast fibroadenoma. A young patient with a history of depressive disorder had crusted and hyperpigmented skin lesions covering the left breast and massive tumor in the same breast. The patient was oriented regarding the cleaning and removal of crusts, resulting in good clinical response. She underwent excision of the tumor, and the anatomopathological study was compatible with fibroadenoma. Interdisciplinary follow-up, including treatment for psychiatric disorder, was fundamental for the patient’s recovery, considering the improvement of her mood after establishing the therapy and successful final breast reconstruction. Dermatitis neglecta can resemble other types of dermatitis, in such a way that it is essential to establish a differential diagnosis to avoid unnecessary evaluation procedures, interventions, and therapies. In this exuberant case of dermatitis neglecta, the importance of comprehensive health care is emphasized.