A rare case of extraovarian primary peritoneal carcinoma in a 72 year-old woman

Background

Extraovarian Primary Peritoneal Carcinoma (EOPPC) was first described by Swerdlow in 1959 [1]. Basically, EOPPC is a malignancy that spreads widely inside the peritoneal cavity involving mostly the omentum with minimal or no ovarian involvement. Most of the EOPPC cases reported have been of serous histology; histopathological, immunohistochemical, and clinical similarities have been observed between EOPPC and Epithelial Ovarian Cancer (EOC).

Materials and methods

In June 2007 a 72 year-old woman was referred to our Unit for recurrent abdominal pain, constipation, loss of weight (BMI 17.5), serious asthenia and fever. Laboratory biochemistry showed hypocromic microcitic anemia, leucocytosis, increased plasma levels of flogistic markers and serious increase of CA 125 marker (373,2 U/ml – normal range 0-35 U/ml). Abdominal US scan confirmed by CT scan (Figure 1), revealed a high vascularised solid mass close to the peritoneum (maximum diameter 10-12cm), ascites among intestinal handles and into Douglas pouch. The colonoscopy did not show any neoplasm. A solid mass not separable from omentum, irregular morphology was found by median laparotomy (Figure 2); no primary tumor was found anywhere else in the abdomen.

Figure 1

Figure 2

Results

The morphological features such as serous papillary carcinoma and the presence of many psammoma bodies and the immunohistochemical highly positive for CA 125 (Figure 3) have determined the diagnosis of EOPPC.

This patient received a first-line chemotherapeutic treatment with paclitaxel (135mg/m²/24 hr) and cisplatin (75 mg/m²) in combination for six cycles. No evidence of recurrence was found at the 2-year follow-up.

Figure 3

Immunoistochemical staining for the CA 125 oncoprotein: the picture shows intense membrane staining in neoplastic cells (magnification x400).

Conclusions

As the EOPPC is mullerian malignancy as the epithelial layer of ovary and the peritoneum share a common embryological origin and it undergoes a chemotherapeutic treatment as ovarian primary carcinoma. Paclitaxel with platinum compounds have been introduced into chemotherapeutic regimens for EOC. In the first report describing the use of the combination of paclitaxel (135mg/m²) and cisplatin (50 to 75 mg/m²), given for six cycles in four EOPPC patients, Menzin et al [2] showed a complete surgical response in one patient and a partial surgical response in the others. Patients with EOPPC should be reported separately from those with ovarian carcinoma but should be treated in a similar fashion.