Isolated metastatic primary peritoneal carcinoma to the breast: a rare site of disease recurrence

Abstract

Primary breast carcinoma is a common pathology in the UK. It can present with metastatic deposits but it is rare that lesions in the breast are the sole primary or secondary presentation for metastatic cancer from other sources. We present a case of a primary peritoneal cancer recurring after optimal treatment with a new breast lesion and the diagnostic difficulties that this can cause.Primary breast cancer is a common condition: 1.38 million patients were diagnosed worldwide in 2008.1 Metastatic disease to the breast from extramammary sources (excluding metastasis from contralateral breast cancer) is rare. While uncommon, a number of sites have been previously implicated as the primary tumour site metastasising to the breast, including ovarian and gastric cancers, cutaneous malignancies and lung cancers.2,3 It has also been noted that secondary breast cancer can present with microcalcification and can therefore appear as incidental lesions detected on screening mammography. 2History taking can elicit this potential diagnostic pitfall in ascertaining whether patients have suffered with other cancers. However, it should be noted that the metastasis can be present before the primary tumour has been identified and therefore close clinicopathological correlation is needed at multidisciplinary discussions. 4 Case historyA 78-year-old woman who was treated for a primary peritoneal carcinoma presented to our fast track breast clinic a year later with a lump. She had initially presented to a regional gynae-oncology centre with abdominal pain, weight gain and ascites. She underwent a diagnostic laparoscopy with biopsy that demonstrated a poorly differentiated high grade serous carcinoma, most likely of primary peritoneal origin.She received four cycles of neoadjuvant chemotherapy with carboplatin and paclitaxel followed by optimal cytoreductive surgery (laparotomy, total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy with optimal debulking) and two cycles of post-operative chemo-