Ovarian cystadenocarcinoma and pseudomyxoma peritonei

The cell of cancer origin provides the most reliable roadmap to its diagnosis, prognosis (biology) and therapy

Cancers arise from single transformed cells from virtually every organ of the body, divide in a relatively uncontrolled manner, and metastasize widely. A search for a "magic bullet" to precisely diagnose, characterize, and ultimately treat cancer has largely failed because cancer cells do not differ significantly from their organ-specific cells of origin. Instead of searching for genomic, epigenetic, transcriptional, and translational differences between cancers and their cells of origin, we should paradoxically focus on what cancer cells have in common with their untransformed cells of origin. This redirected search will lead to improved diagnostic and therapeutic strategies where therapeutic index considerations and drug-limiting toxicities can largely be circumvented. We cite three cancer examples that illustrate this paradigm-shifting strategy: pseudomyxoma peritonei (PP), metastasis of unknown origin (cancers of unknown primary) (MUO), and cancers that arise from potentially dispensable organs (CAD). In each of these examples, the cell of cancer origin still provides the most reliable road map to its diagnosis, prognosis (biology), and therapy.

Clinicopathological Characteristics of Pseudomyxoma Peritonei Originated from Ovaries

Objective

This study aims to demonstrate clinicopathological characteristics and immunohistopathological phenotypes of pseudomyxoma peritonei (PMP) originated from ovaries.

Methods

The primary origin of PMP was explored by reviewing H&E sections retrospectively and performing a series of immunohistochemical staining on CK7, CK20, CDX2, CEA, Villin, SATB2, CA125, ER, PR, and MUC.

Results

Among 310 PMP patients, a few originated from extra-appendix, whereas eight cases were of ovarian origin (2.6%), including three teratoma-associated ovarian mucinous tumors and five primary ovarian mucinous tumors with spontaneous or iatrogenic rupture, respectively. Most peritoneal metastases were acellular mucin or low-grade mucinous carcinoma peritonei (6/8, 75%), while the rest were high-grade mucinous carcinoma peritonei (2/8, 25%). Tumors were positive for CK20, CDX2, CEA, and Villin. SATB2 was specifically diffuse positive in teratoma-associated ovarian mucinous tumors, and negative in primary ovarian mucinous tumors. Differential expression of MUC was observed in these tumors.

Conclusion

PMP of ovarian origin is extremely rare. The precise diagnosis requires serial sections of the appendix or suspicious tissue to exclude appendiceal mucinous neoplasms, as well as comprehensive analysis of clinical features, surgical findings, histopathological characteristics, and immunohistochemistry on specific biomarkers.

Female patients with pseudomyxoma peritonei: a single-institution clinicopathologic study of 35 cases

PURPOSE

To explore clinicopathologic/prognostic aspects of pseudomyxoma peritonei (PMP).

METHODS

We reviewed records of 35 female patients with PMP treated at a single institution.

RESULTS

Patients' median age was 57.0 years (range 35.0-71.0 years). Their median pre-surgery level of carbohydrate antigen 19-9 (CA-199) was 80.95 U/ml (range 0.00-1,562.10 U/ml); of carbohydrate antigen 12-5 (CA-125), 44.00 U/ml (range 0.90-231.20 U/ml); and of carcinoembryonic antigen (CEA), 17.20 ng/ml (range 2.04-211.60 ng/ml). Of the 35 patients, 23 (65.7 %) underwent cytoreductive surgery (CRS) by gynecological oncologists and 12 (34.3 %) underwent non-CRS surgeries by general gynecologists or surgeons, including one patient who refused surgical treatment beyond a diagnostic laparoscopy. After surgery, 18 patients (51.4 %) had residual lesions, 11 (31.4 %) had complete lesion removal and 6 (17.1 %)had insufficient information on residual lesion; 21 (60.0 %) had appendiceal-based tumors and 12 (34.3 %) had ovarian-based tumors. Median follow-up time was 37 months (range 1-148 months), during which 28 patients (80.0 %) had relapsed. By the end of the study, 12 patients (34.3 %) died of PMP, 16 (45.7 %) survived with disease, and 7 (20 %) survived without disease. Median progress-free survival (PFS) was 12 months (range 0.5-114.0 months). Median overall survival time was 42 months (range 5-150 months). Ovarian tumor origin, post-surgery residual lesions, preoperative CA199 > 258.9 U/ml and CA125 > 70.6 U/ml were independent predictors of PFS.

CONCLUSIONS

PMP is rare in women, and has a poor long-term survival rate. Multi-center cooperation to gather more cases is needed to explore its behavior and proper treatment.