Serous carcinoma of the ovary and peritoneum with metastases to the breast and axillary lymph nodes: a potential pitfall.

Metastasis of ovarian or peritoneal serous carcinoma to the breast and/or axillary lymph nodes is a rare event. Nevertheless, its recognition and distinction from mammary carcinoma are of great clinical importance because the treatment and prognosis differ significantly. Eighteen cases of ovarian or peritoneal serous carcinoma metastatic to the breast and/or axillary LNs from a 14-year period (1990-2003) were retrieved from our files. Clinical information was obtained from the patients' charts. The age of the patients ranged from 21 to 67 years (median, 55 years). The primary tumors included 14 ovarian serous carcinomas (11 high grade and 3 low grade; 2 of the low-grade tumors presented as serous tumors of low malignant potential and recurred as low-grade serous carcinoma) and 4 peritoneal serous carcinomas (3 high grade and 1 low grade). Of the ovarian neoplasms, 1 was stage I and 10 were stage III tumors; the breast and/or axillary lymph node metastases were discovered on average 30 months after presentation (range, 7-135 months). Three of the ovarian serous carcinomas were stage IV tumors; in 1 case, there were axillary lymph node metastases at initial presentation; and in 2 cases, breast and/or axillary lymph node metastases developed at 18 and 102 months. Two of the 4 patients with peritoneal serous carcinoma presented with stage IV disease, having synchronous breast and axillary lymph node metastases; the other 2 patients developed them at 11 and 16 months after presentation. Four patients had multiple breast lesions and 8 patients had a single metastasis. In 4 cases, the breast metastases were initially interpreted as infiltrating ductal carcinoma. The remaining 6 patients had axillary lymph node involvement only. The metastases in 17 of the cases had papillary features, with psammoma bodies present in 4. Immunoperoxidase studies for GCDFP-15 and WT-1 were performed in 4 cases; all 4 were positive for WT-1 and negative for GCDFP-15. Follow-up was available for 17 patients, with 7 patients known to be dead from disease (survival range, 2-31 months) after the development of metastatic disease to the breast or axillary lymph nodes. Ten patients were alive with disease at their last follow-up, which ranged from 1 to 30 months after the breast or axillary LN metastasis developed. Metastases to the breast or axillary lymph nodes from ovarian and/or peritoneal serous carcinomas are uncommon. Most of the patients in whom metastatic disease develops have a known history of advanced stage ovarian or peritoneal carcinoma. Breast and/or axillary LN involvement at initial presentation can occur but is rare. Differentiation between metastatic and primary tumors of the breast is of great importance because treatment and prognosis differ significantly. Clinical history, the presence of papillary architecture, and WT-1 expression are useful in establishing the correct diagnosis.