Primary peritoneal serous carcinoma (PPSC) is a rare entity, although it is the most frequent histological subtype of primary peritoneal neoplasms. It was described in 1959 by Swerdlow, who described it as a multifocal systemic disease derived from peritoneal mesothelium and ovarian epithelium. During embryonic development the ovarian epithelium originates from the cell mesothelium as well as the peritoneal mesothelium, this is the reason why they have similar histological characteristics [1-4].
CSPP is histologically indistinguishable from serous adenocarcinomas of the ovary or tubes. To diagnose it, the criteria used by the Gynecology Oncology Group is usually followed [1,4,5]:
- Histologically compatible with serous cell carcinoma.
- Ovaries of normal size, with diameter < 5cm or enlarged because of a benign mass.
- Extra-ovarian involvement greater than ovarian
- Superficial ovarian involvement or stromal invasion smaller than 5 x 5 mm.
It usually appears in postmenopausal women with non-specific symptoms such as abdominal pain and distention or ascites. Mutations in the BRCA gene are risk factors for its development. In CT, ascites, peritoneal thickening and omental infiltration can be evidenced, and analytically it is frequent to associate elevation of the CA 125 tumor marker. Diagnostic laparoscopy/laparotomy plays a very important role in this type of tumor. The differential diagnosis must be made with high-grade tumors of the tubes or ovaries and carcinomas of the colon and stomach. It should also be differentiated from other primary peritoneal tumors such as mesothelioma [1-5].
Therefore, PPSC should be suspected in those patients who present diffuse peritoneal involvement on CT, ascites, CA 125 elevation and normal ovarian size [3,5].
As for treatment, it follows the same guidelines as peritoneal carcinomatosis: it is a combination of chemotherapy with platinum regimens (carboplatin and paclitaxel as first line, as in ovarian carcinoma) and cytoreductive surgery accompanied by hypertermic intraperitoneal chemotherapy (HIPEC) [1-5].
We present a clinical case of a 55-year-old woman with symptoms of months of evolution with predominantly postprandial abdominal pain and progressive abdominal distension. Within her clinical record, we highlight the follow-up in the Cancer Genetic Risk Unit (family history of mother with endometrial and breast cancer, sister with ovarian cancer and maternal aunt with breast cancer) with negative BCRA1/2 genetic study. Among the preoperative studies, abdominal ultrasound was performed with abundant ascites of serous fluid and negative cytology, abdominal-pelvic CT showing peritoneal thickening mainly in the pelvis, gynecological ultrasound and abdominopelvic MRI without presenting other alterations. In the preoperative analysis she presented elevation of CA 125 (554 U/mL) in the determination of tumor markers.
The Multidisciplinary Committee on Abdominal Tumors decided to perform a diagnostic exploratory laparoscopy with multiple biopsies. Intraoperatively, the presence of abundant free liquid (approximately one litre), lesions in the right hypochondrium peritoneum compatible with peritoneal carcinomatosis, yellowish plates with a fibrin-like appearance in Douglas [Figure 1] and hyperemic major omentum with a nodular appearance were observed. Liver, stomach, small bowel, colon, uterus, tubes and ovaries were normal in appearance. In the anatomopathological study of peritoneal and omentum biopsies were reported as primary peritoneal serous carcinoma (high histological grade) with negativity for BRCA1 and BRCA2 in the genomic study of mutations [Figure 2]. Ascitic fluid cytology was negative.
Neoadjuvant with carboplatin + paclitaxel was finally proposed by administering three cycles.
Subsequently, during the study of response to treatment, by means of thoraco-abdominal-pelvic CT, the practical disappearance of peritoneal implants and a thickening of the gastric wall (absent in pre-surgical studies) was evidenced. An endoscopic study was then performed without evidence of neoplasia.
Due to the excellent response to chemotherapy treatment, it was decided to perform surgical rescue (pelvic peritonectomy, bilateral parietal and bilateral diaphragmatic, hysterectomy, double adnexectomy, appendectomy, cholecystectomy and omentectomy) and HIPEC.
Currently awaiting final anatomopathological study.