ORIGINAL ARTICLE Primary Peritoneal Serous Carcinoma Presenting as Inflammatory Breast Cancer Ibrahim Khalifeh, MD,* Michael T. Deavers, MD,* Massimo Cristofanilli, MD,  Robert L. Coleman, MD, à Anais Malpica, MD,* and Michael Z. Gilcrease, MD, PhD* *Departments of Pathology;   Breast Medical Oncology; and à Gynecologic Oncology, MD Anderson Cancer Center, Houston, Texas n Abstract: Metastasis to the breast from extramammary malignancies is rare. Nevertheless, its recognition is important because the prognosis and treatment differ from that of primary breast cancer. We report a unique case of primary perito- neal serous carcinoma that initially presented as inflammatory breast cancer. The patient received neoadjuvant chemother- apy for breast cancer and subsequently underwent bilateral total mastectomy and bilateral sentinel lymph node biopsy. She was found to have extensive intralymphatic carcinoma in both breasts, with only focal minimal breast parenchymal involve- ment, and residual metastatic carcinoma in bilateral sentinel lymph nodes. Further work-up revealed pelvic ascites and omental nodularities. The patient underwent laparoscopic bilateral salpingo-oophorectomy, which revealed high-grade ser- ous carcinoma involving both ovaries and fallopian tubes. Molecular testing of tumor from the ovary and axillary lymph node showed an identical pattern of allelic loss, confirming a common origin for both tumors. To our knowledge, this is the first reported case of an extramammary primary malignancy that not only presented as inflammatory breast cancer but also was diagnosed and initially treated as such. n Key Words: breast cancer, inflammatory carcinoma, primary peritoneal, serous carcinoma O varian or peritoneal serous carcinoma metastasiz- ing to the breast and ⁄ or axillary lymph nodes is uncommon. Fewer than 50 cases have been reported previously, of which fewer than five were primary peritoneal carcinomas (1–12). Most of these have occurred in patients with a known history of primary ovarian or peritoneal carcinoma. It is rare for primary ovarian or peritoneal carcinoma to present clinically as a primary breast tumor, and it is rare for metastatic carcinoma from any extramammary site to present with signs of inflammatory breast cancer (6,7,9, 11,13–16). Although several cases of metastatic carci- noma from various sites have produced clinical signs mimicking inflammatory breast cancer, to our knowl- edge there is no previous report of metastatic carci- noma that not only presented as inflammatory breast carcinoma but also was diagnosed and initially treated as such. We report a unique case of primary peritoneal ser- ous carcinoma that presented clinically as inflamma- tory breast cancer. The patient was treated with neoadjuvant chemotherapy for breast cancer, and the primary peritoneal tumor was not detected until 16 months after the initial breast manifestation. CASE REPORT A 56-year-old Caucasian woman with no family history of breast cancer and negative annual mammo- grams for seven consecutive years presented with slight redness around the periareolar area of the right breast. She was prescribed antibiotics, but the redness did not improve. A few weeks later, redness involved the left breast as well. Bilateral mammograms and MRIs were obtained, and these were negative. She had punch biopsies performed on both breasts, and each of these showed carcinoma in the dermal lym- phatics. In a survey for metastatic disease, an MRI of the brain was negative. PET and CT scans from the base of the brain to the proximal thighs showed the Address correspondence and reprint requests to: Michael Z. Gilcrease, MD, PhD, Unit 85, Department of Pathology, 1515 Holcombe Blvd, Houston, TX 77030, USA, or e-mail: mgilcrease@mdanderson.org. Ó 2009 Wiley Periodicals, Inc., 1075-122X/09 The Breast Journal, Volume 15 Number 2, 2009 176–181