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.²

History 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 history

A 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-therapy. Post-operative follow-up computed tomography showed no evidence of macroscopic residual disease or recurrence.

The patient remained clinically well and was kept under observation until she presented six months later to the fast track breast clinic with a lump in the right breast, identified on self-examination. Clinical examination revealed a 1cm x 1cm untethered lump in the 9 o’clock position of the breast, surrounded by nodularity. There was no associated lymphadenopathy. She underwent triple assessment with core biopsy taken of the breast lump under ultrasonography guidance.

Histological examination of the core biopsy showed fibrofatty tissue replaced extensively by necrotic tumour. The viable edge consisted of irregular, infiltrative islands of highly atypical cells, forming glands and papillary structures. Marked nuclear pleomorphism and hyperchromasia with abnormal mitoses were present (Fig 1).

Figure 1.

Histology from core biopsy of the breast: metastatic tumour with papillary architecture (40x magnification)

The core biopsies were compared with the histology from the previous laparotomy for the peritoneal carcinoma (Fig 2). The biopsy demonstrated a papillary serous carcinoma. While this is most commonly of ovarian origin, in this case the tumour affected the serous level and appeared to be infiltrating down into the tissue, suggestive of a primary peritoneal carcinoma rather than an ovarian carcinoma. The breast histology matched the initial samples and immunohistochemical stains were also compatible.

Figure 2.

Initial peritoneal histology from laparotomy (20x magnification)

Conclusions

Metastases to the breast from an ovarian primary tumour are rare although noted in the literature.⁵ Less well recognised is a metastasis to breast tissue from peritoneal origin, Metastatic papillary carcinoma as in our case. Diagnostic difficulties can arise in the poorly differentiated nature of peritoneal and ovarian carcinomas and this case highlights that close clinicopathological correlation is required when tissue is analysed and patients have undergone treatment for other cancers. These patients can present complex treatment management cases with multiple specialties involved. Close links between multidisciplinary groups are essential to enable good patient care.