Ovarian tumors of low malignant potential

Opinion statement Ovarian tumors of low malignant potential (LMP) differ from epithelial ovarian carcinoma in etiology, molecular biology, and prognosis. LMP tumors are not precursor lesions to ovarian carcinoma. Treatment is primarily surgical. Women found to have an ovarian tumor of LMP should undergo removal of the involved adnexa; surgical staging; and cytoreductive surgery. Women in the reproductive years should be given the option of conservative surgery, preserving the contralateral adnexa and uterus. There is no proven benefit to adjuvant chemotherapy or radiotherapy after primary surgery. In most cases, the diagnosis of an ovarian tumor of LMP conveys good prognosis, with excellent long-term survival.     

Ovarian tumors of low malignant potential (borderline tumors): immune morphology and current status

CA 125, CA 19-9 and CEA were demonstrated in tissue samples of 30 ovarian borderline tumors by immunohistochemistry. Of the 21 serous and 9 mucinous borderline tumors, 23 were in stage I and 7 stage III. None of the patients died of disease. All mucinous borderline tumors were CA 125 negative, 89% CA 19-9 positive and 44% CEA positive. 62% of the serous borderline tumors were CA 125 positive, 52% CA 19-9 and 19% CEA positive. Tumors of low malignant potential responded to CA 19-9 like invasive carcinomas. The incidence of positive responses to CA 125 ands CEA fell between that of benign and malignant tumors. The marker pattern did not correlate with tumor stage and cytological grading. The biological behavior of ovarian borderline tumors ranges between that of benign tumors and invasive carcinomas and cannot be classified as definitely belonging to either group. It is plausible that they are primarily of the borderline type, and not benign tumors that undergo malignant degeneration.     

Ovarian Brenner tumors. I. Metaplastic, proliferating, and of low malignant potential

In several studies, attempts were made to establish criteria for distinguishing malignant Brenner tumors from proliferating and low malignant potential ones. Although these criteria can be applied to the majority of cases, there still exist tumors that present problems in classification. In applying the World Health Organization (WHO) criteria for Brenner tumors, the most important feature for distinguishing the intermediate forms from the malignant ones is the presence of stromal invasion in the latter. This feature has generally been considered difficult to employ because of the fundamental fibroepithelial nature of Brenner tumors, the stroma being derived from the ovarian stroma. A logical and relatively easily applicable classification of Brenner tumors is presented in this report. Although more complex than the WHO classification, it includes newly recognized variants of the Brenner tumor and avoids using the same terminology to describe different types and degrees of epithelial abnormalities. Fourteen unusual Brenner tumors were studied, intermediate between typical benign and frankly malignant ones, and were classified into 3 categories representing progressive epithelial abnormalities. These include metaplastic, proliferating, and tumors of low malignant potential. In none of these does stromal invasion occur. Each of these categories corresponds to a particular urothelial abnormality or neoplasm. Through this classification, a better understanding of the morphology and biologic behavior of unusual types of Brenner tumors can be expected.     

Update on low malignant potential ovarian tumors

Low malignant potential (LMP) ovarian tumors represent a small subset of epithelial ovarian cancers that were first identified 70 years ago but were recognized in a systematic way only within the last 30 years. These lesions afflict women at a much younger age than invasive ovarian cancer, behave in a more indolent manner, and have a much more favorable prognosis. The management of women with LMP tumors is primarily surgical; adjuvant therapy plays little role in early disease and its use in advanced disease is not well defined. Ongoing investigations are attempting to define prognostic factors that may assist clinicians in the appropriate application of postoperative therapy.     

Stage I epithelial ovarian tumors of low malignant potential

Clinical and pathological details of 10 patients with stage I low malignant potential tumors of the ovary, between September, 1969, and February, 1988, have been reviewed. The mean age of the patients was 46.6 years. Six patients had serous and four had mucinous tumors. Of the 10 patients, five had a unilateral salpingo-oophorectomy, one had a bilateral salpingo-oophorectomy and four a total abdominal hysterectomy and bilateral salpingo-oophorectomy. The mean duration of follow-up was 12.8 years. All patients have remained alive and disease-free. A recurrence occurred in one patient who has been managed well by additional surgery. Stage I ovarian tumor of low malignant potential appears to carry a favorable prognosis.     

Serous ovarian tumors of low malignant potential with peritoneal implants

Between 1956 and 1985, 82 patients with metastatic low-grade serous ovarian carcinoma, subsequently reclassified by pathologic review as serous ovarian tumors of low malignant potential with peritoneal implants, were seen at the authors' institution. Median age was 34 years (range, 17-64 years). Original stage distribution was as follows: 32 Stage II, 46 Stage III, and four Stage IV. Peritoneal implants in 72 patients were classified as benign (22 patients), noninvasive (37), or invasive (13). For ten patients, implants were clinically documented but histologic material was unavailable. The most common sites of peritoneal implants included the pelvic peritoneum (42), omentum (33), uterus (33), and fallopian tube (26). All patients underwent primary surgery. Postoperative therapy consisted of radiotherapy in 18 patients, single-agent chemotherapy in 37 patients, combination chemotherapy in 25 patients, and no therapy in two patients. Second-look laparotomy documented response to chemotherapy in 42% of patients with no gross residual disease and in 80% of patients with macroscopic residual disease (40% complete response, 40% partial response). Disease-free survival rates were 95% at 5 years and 91% at 10 years. The International Federation of Gynecologists and Obstetricians (FIGO) stage, extent of residual disease, type of postoperative treatment, and type of peritoneal implants had no effect on survival. Based on a comparison of the present study's findings with those in the literature, the authors propose possible explanations for differences in survival by type of peritoneal implants and outline recommendations for clinical management until further studies elucidate the role of postoperative therapy.     

Aberrant promoter methylation of multiple genes in malignant ovarian tumors and in ovarian tumors with low malignant potential

BACKGROUND: Methylation-mediated suppression of detoxification, DNA repair, and tumor suppressor genes has been implicated in cancer development and progression. Studies also have indicated that concordant methylation of multiple genes (methylator phenotypes), rather than a single gene, may predict cancer prognosis. The current study was designed to determine whether a methylator phenotype exists in ovarian cancer, whether methylation frequencies differ between malignant ovarian tumors and ovarian tumors with low malignant potential (LMP or borderline), and whether methylation of multiple genes affects patient survival. METHODS: The current study included 234 consecutively diagnosed patients with either LMP (n = 19 patients) or malignant (n = 215 patients) ovarian tumors. DNA samples were extracted from fresh frozen tissues and were analyzed for methylation in the promoter region of 6 genes (p16, breast cancer 1 [BRCA1], insulin-like growth factor-binding protein 3 [IGFBP-3], glutathione S-transferase pi 1 [GSTP1], estrogen receptor-alpha [ER-alpha], and human MutL homologue 1 [hMLH1]) by using methylation-specific polymerase chain reaction analysis. RESULTS: The frequencies of methylation in malignant tumors and LMP tumors were 0% and 0% for GSTP1, respectively; 9% and 0% for hMLH1, respectively; 21% and 5% for BRCA1, respectively; 42% and 21% for p16, respectively; 44% and 26% for IGFBP-3, respectively; and 57% and 42% for ER-alpha, respectively. A methylator phenotype was not detected, but a calculated methylation index (MI) that was based on the total number of genes methylated in each tumor was associated with ovarian cancer risk and progression. A higher MI was associated with malignant tumors (odds ratio, 10.11; 95% confidence interval [95% CI], 1.19-85.75) and disease progression (hazards ratio, 6.53; 95% CI, 1.39-30.65). CONCLUSIONS: Although a methylator phenotype was not identified, the current results suggested that methylation of multiple genes may play an important role in ovarian cancer development and progression and may have clinical implications in prognosis.     

Behaviour of ovarian tumors of low malignant potential treated with conservative surgery

Objective

Fertility-sparing surgery has been proposed for the treatment of borderline ovarian tumors. The aim of this study was to evaluate the outcome of patients submitted to cystectomy (CYS) compared with patients treated by unilateral salpingo-oophorectomy (USO) or bilateral salpingo-oophorectomy with/without total hysterectomy (radical surgery, RS).

Methods

We reviewed retrospectively the data of patients treated in 3 institutions for borderline ovarian tumors. One hundred and sixty-eight patients underwent laparoscopic or laparotomic surgical treatment from 1985 to 2006. Tumor recurrence rate, disease-free survival and site of recurrences were evaluated. Specific prognostic factors, such as stage, histology, micropapillary subtype, exophytic tumor growth, intraoperative spillage, endosalpingiosis, staging procedures, and route of surgery were analysed.

Results

Thirty-five patients underwent cystectomy, 50 unilateral salpingo-oopohorectomy, and 83 radical surgery. Twelve patients in the CYS group (34.3%), 10 in the USO group (20.0%), and 5 (6.0%) in RS group relapsed. Five-year progression-free survival (PFS) was 59.6%, 78.4%, and 93.5% in CYS, USO and RS groups, respectively. None of the relapsed patients died of disease.

Conclusions

Cystectomy is an effective surgical strategy for patients with borderline ovarian tumor. The higher risk of local relapses is not associated with a reduction in the overall survival. The procedure should be offered to young patients with bilateral tumors and to very young ones, considering the higher risk of local relapse.     

Invasive and noninvasive implants in ovarian serous tumors of low malignant potential

Ovarian serous tumors of low malignant potential ("borderline" serous tumors) are classified according to the histologic features of the primary ovarian tumor, without regard to any coexisting extraovarian disease. The peritoneal implants display a range of histologic appearances, ranging from benign glands (endosalpingiosis), to noninvasive papillary glandular proliferations resembling the ovarian neoplasms, to irregular glands associated with a desmoplastic stroma and having features of invasive disease. This review of 16 patients with histologically documented extraovarian tumor implants seen at Indiana University Medical Center, Indianapolis, and 13 patients whose tumor implants have been previously described in the literature indicates that the clinical stage of disease has much greater prognostic significance than does the implant histologic features. There is a tendency for patients with more advanced disease to have invasive implants. However, within a given clinical stage, disease progression or recurrence was not influenced by the presence or absence of invasive histologic characteristics in the tumor implants.     

Common epithelial tumors of borderline malignancy (carcinomas of low malignant potential)

The creation of the category of ovarian borderline tumors has been a step forward in classification because it has segregated from the general group of common epithelial cancers a subgroup with an unusually good prognosis. Of all borderline tumors, the serous variety is the least difficult for the pathologist to diagnose. The mucinous borderline tumor is not as easy to recognize when an absence of invasion is used as the sole diagnostic criterion, but evaluation of other architectural as well as cytological features is helpful in making the diagnosis. Although the treatment of the majority of serous and mucinous borderline tumors is well standardized, therapy of residual serous borderline tumor is highly controversial and the treatment for pseudomyxoma peritonei, unsatisfactory. Borderline tumors exist in the endometrioid, clear cell, Brenner, and mixed common epithelial categories, but these tumors have been too rare to date in order to clearly characterize their clinical and pathological features. It is hoped that more can be learned about this general group of tumors by a more widespread recognition of their distinctive clinico-pathologic features and by their acceptance as a special subgroup of ovarian cancer. Their behavior differs strikingly from that of other types of malignant ovarian tumors and it is clear that their management should differ accordingly.     

Discrimination between serous low malignant potential and invasive epithelial ovarian tumors using molecular profiling

Tumors of low malignant potential (LMP) represent 20% of epithelial ovarian cancers (EOCs) and are associated with a better prognosis than the invasive tumors (TOV). Defining the relationship between LMPs and TOVs remains an important goal towards understanding the molecular pathways that contribute to prognosis, as well as providing molecular markers, for these EOCs. To this end, DNA microarray analyses were performed either in a primary culture or a tumor tissue model system and selected candidate genes showing a distinctive expression profile between LMPs and TOVs were identified using a class prediction approach based on three statistical methods of analysis. Both model systems appear relevant as candidate genes identified by either model allowed the proper reclassification of samples as either LMPs or TOVs. Selected candidate genes (CAS, CCNE1, LGALS8, ITGbeta3, ATP1B1, FLIP, KRT7 and KRT19) were validated by real-time quantitative PCR analysis and show differential expression between LMPs and TOVs. Immunohistochemistry analyses showed that the two tumor classes were distinguishable by their expression of CAS, TNFR1A, FLIP, CKS1 and CCNE1. These results define signature patterns for gene expression of LMPs and TOVs and identify gene candidates that warrant further study to deepen our understanding of the biology of EOC.     

Molecular evidence for the independent origin of extra-ovarian papillary serous tumors of low malignant potential

BACKGROUND: Molecular data suggest that peritoneal tumors in women with advanced-stage ovarian papillary serous adenocarcinoma are monoclonal in origin. Whether the same is true for ovarian tumors of low malignant potential is not known. We compared peritoneal and ovarian tumors from women with advanced-stage ovarian papillary serous tumors of low malignant potential to determine whether the peritoneal tumors arose from the same clone as the ovarian tumors. METHODS: We studied the clonality of 73 peritoneal and ovarian tumors from 18 women with advanced-stage ovarian papillary serous tumors of low malignant potential. Formalin-fixed, paraffin-embedded tumors and representative normal tissues were sectioned and stained with hematoxylin-eosin, representative sections from separate tumors were manually microdissected, genomic DNA was extracted from the microdissected tumors, and the polymerase chain reaction was used to amplify a CAG polymorphic site in the human androgen receptor locus on the X chromosome to determine the inactivation pattern of the X chromosome and the clonality of the tumors. RESULTS: The pattern of X-chromosome inactivation could be determined from the tumors of 13 of 18 patients. Of the 13 patients, seven (54%) had nonrandom inactivation of the X chromosome, and six of the seven had different inactivation patterns in the peritoneal and ovarian tumors. Three of these patients also had different patterns of nonrandom X-chromosome inactivation in tumors from each ovary. The remaining six patients had random patterns of X-chromosome inactivation in the peritoneal and ovarian tumors. CONCLUSIONS: Our data suggest that peritoneal and ovarian tumors of low malignant potential arise independently.     

Expression profiling of serous low malignant potential, low-grade, and high-grade tumors of the ovary

Papillary serous low malignant potential (LMP) tumors are characterized by malignant features and metastatic potential yet display a benign clinical course. The role of LMP tumors in the development of invasive epithelial cancer of the ovary is not clearly defined. The aim of this study is to determine the relationships among LMP tumors and invasive ovarian cancers and identify genes contributing to their phenotypes. Affymetrix U133 Plus 2.0 microarrays (Santa Clara, CA) were used to interrogate 80 microdissected serous LMP tumors and invasive ovarian malignancies along with 10 ovarian surface epithelium (OSE) brushings. Gene expression profiles for each tumor class were used to complete unsupervised hierarchical clustering analyses and identify differentially expressed genes contributing to these associations. Unsupervised hierarchical clustering analysis revealed a distinct separation between clusters containing borderline and high-grade lesions. The majority of low-grade tumors clustered with LMP tumors. Comparing OSE with high-grade and LMP expression profiles revealed enhanced expression of genes linked to cell proliferation, chromosomal instability, and epigenetic silencing in high-grade cancers, whereas LMP tumors displayed activated p53 signaling. The expression profiles of LMP, low-grade, and high-grade papillary serous ovarian carcinomas suggest that LMP tumors are distinct from high-grade cancers; however, they are remarkably similar to low-grade cancers. Prominent expression of p53 pathway members may play an important role in the LMP tumor phenotype.     

Quantitative nuclear morphology in the diagnosis of ovarian tumors of low malignant potential (borderline)

Ovarian tumors of low malignant potential or of borderline malignancy are characterized histologically by the association of malignant type of epithelial proliferation with a noninvasive pattern of growth. Because epithelial proliferation relates to features of nuclear morphology and chromatin structure and because of the difficulties to distinguish nuclear atypism seen in borderline malignancy from that in frankly invasive tumors by usual microscopic study, the authors concentrated their studies exclusively on computerized analysis of cell nuclei images. Using specially developed methods of analysis the authors described geometrical, optical, and structural differences among the epithelial and stromal cell nuclei of benign, borderline, and malignant ovarian tumors. The structural differences concern the pattern of chromatin condensation and suggest that the cytokinetic properties of the borderline tumors are intermediate to those of benign and malignant. The results demonstrate that the quantitative evaluations provide objective and reproducible data useful in the differential diagnostic of the borderline malignancy.     

Comprehensive allelotype study of ovarian tumors of low malignant potential: potential differences in pathways between tumors with and without genetic predisposition to invasive carcinoma.

Ovarian tumors of low malignant potential (LMP) are intermediate between adenomas and ovarian carcinomas (OC); however, the relevance of LMP to ovarian carcinogenesis is not clear. We performed a comparative analysis of allelotypes in 50 cases of LMP (42 mucinous and 8 serous) and 23 cases of OC (15 mucinous and 8 serous) to investigate any differences in genetic changes. Analysis of loss of heterozygosity (LOH) using 25 microsatellite markers reportedly associated with OC revealed that the total LOH frequency at each marker was significantly lower in LMP than in OC (p < 0.01). However, 9 (36%) loci showed higher LOH frequency in mucinous LMP than in mucinous OC. A genome-wide scan for LOH using 91 microsatellite markers and fine mapping revealed that LOH at D7S1805 (7q35) is characteristic of mucinous LMP (19.4% in mucinous LMP, 8.3% in mucinous OC). We further studied LOH in 3 cases of mucinous OC that were accompanied by mucinous LMP lesions. In 2 cases, LOH frequency was higher in the carcinoma portion than in the morphologically LMP portion. The other case showed microsatellite instability in the morphologically LMP portion and LOH in the carcinoma portion. Our results suggest the presence of an LMP-to-OC developmental sequence and the existence of a subset of LMP that does not develop into OC in the mucinous subtype of ovarian tumors.     

Peritoneal washing cytologic analysis of ovarian serous tumors of low malignant potential to detect peritoneal implants and predict clinical outcome

BACKGROUND:

Patients with ovarian serous tumors of low malignant potential (OSLMP) who have peritoneal implants, especially invasive implants, are at an increased risk of developing tumor recurrence. To the best of the authors' knowledge, the ability of peritoneal washing (PW) cytology to detect the presence and type of peritoneal implants has not been adequately investigated, and its prognostic significance is unknown.

METHODS:

Records and PW specimens of 101 patients diagnosed with and treated for OSLMP between 1996 and 2010 at The University of Texas MD Anderson Cancer Center were retrospectively reviewed. Patients' staging biopsy findings were compared with the results of the authors' review of the PWs. Follow‐up data were also analyzed.

RESULTS:

Of the 96 patients for whom staging biopsy results were available, 26 (27%) had peritoneal implants (17 noninvasive and 9 invasive), 19 (20%) had endosalpingiosis, and 51 (53%) had negative findings. The PW specimens of 18 of the 26 patients (69%) with peritoneal implants were positive for serous neoplasm, and a correlation was found between cytologic and histologic findings (P < .0001). The sensitivity, specificity, positive predictive value, and negative predictive value were 69%, 84%, 62%, and 88%, respectively. Four of 101 patients had disease recurrence; 3 of these patients had invasive implants and 1 patient had noninvasive implants. None of the patients who had negative staging biopsy findings or endosalpingiosis but did have PW specimens that were positive for serous neoplasm developed disease recurrence.

CONCLUSIONS:

PW cytology detects the presence of peritoneal implants with moderate accuracy. However, long‐term studies are needed to determine whether positive PW cytologic findings are an independent predictor of tumor recurrence. Cancer (Cancer Cytopathol) 2012;. © 2012 American Cancer Society.     

A review of p53 expression and mutation in human benign,low malignant potential,and invasive epithelial ovarian tumors

BACKGROUND: In the current study, the authors present pooled data from studies that investigated p53 protein expression and/or mutation in human epithelial ovarian tumors. METHODS: The English literature in the MEDLINE, PubMed, and Ingenta databases was searched to the end of the year 2000 to identify relevant studies. Data were pooled across eligible studies, and the prevalence of p53 expression and mutation among benign, low malignant potential (LMP), and invasive tumors was determined. Prevalence estimates by tumor histology, International Federation of Gynecology and Obstetrics (FIGO) stage, and grade also were calculated. RESULTS: The pooled prevalence estimate for p53 overexpression among epithelial ovarian carcinomas was 51% (95% confidence intervals [95% CI], 50-53%) compared with 17% (95% CI, 15-20%) among LMP tumors and 7% (95% CI, 5-10%) among benign tumors. p53 mutation prevalence estimates were 45% (95% CI, 42-47%), 5% (95% CI, 2-9%), and 1% (95% CI, 0-5%), respectively, for invasive, LMP, and benign tumors. The prevalence of these p53 abnormalities was found to be associated positively with increasing tumor grade and stage. Differences based on histologic subtype also were found. CONCLUSIONS: Although these pooled estimates might appear to offer support for various hypotheses regarding the role of p53 in ovarian carcinoma, the limitations inherent in these data hamper the interpretation of the significance of any of the findings. Future studies will require innovative methods to address the limitations of many previous investigations and more comprehensive investigation into defective tumor suppression mechanisms.     

Uterine smooth muscle tumors of uncertain malignant potential: a case presentation

A 42-year-old virgin woman was admitted to our clinic with increasing menorrhagia and dysmenorrhea for several months. A pelvic ultrasound scan showed a 9 × 7 cm heterogeneous mass in the uterine cavity. Pelvic magnetic resonance imaging showed a large non-homogeneous tumor mass measuring 97 × 56 mm in the uterine cavity. After intravenous contrast material, cystic necrotic areas with marked contrast enhancement were observed in the solid lesion. Tumor markers were all within normal ranges. The patient underwent laparotomy, and total hysterectomy and bilateral salpingo-oophorectomy were performed. Our case was diagnosed as uterine smooth muscle tumor of uncertain malignant potential (STUMP). The patient was put on a close clinical follow-up schedule, and is doing well without recurrence in 2 years later. Patients with STUMP should be counseled regarding the potential for recurrence as leiomyosarcoma, and may require closer surveillance than a yearly examination and may need a consultation with a gynecologic oncologist.