Sister Mary Joseph’s nodule secondary to invasive breast cancer

Skin is a metastatic site in 1%–10% of cases of all cancers which metastasize to the skin. Among these, breast cancer cases account for about one-third of cases. Breast cancer presenting as cutaneous metastasis without a palpable breast mass is very rare. We report a case of a female who, in her late fifties presented to us with ascites, cutaneous and umbilical nodules. On investigations, the ascitic fluid showed adenocarcinoma. The initial diagnosis of carcinoma of unknown primary (CUP) was made. Immunohistochemistry on the skin biopsy confirmed the origin from the breast. The patient was managed with chemotherapy followed by trastuzumab plus letrozole. Cutaneous metastasis may be the first and only manifestation of internal malignancies, particularly breast cancer. Healthcare professionals need to be aware of this rare presentation. Breast cancer must be considered as a differential diagnosis in a patient with a diagnosis of CUP especially in women as these subsets of patients will respond favorably to the treatment and may have a survival advantage.