Mucinous tumours of the ovary

Investigating age and ethnicity as novel high-risk phenotypes in mucinous ovarian cancer: retrospective study in a multi-ethnic population

OBJECTIVES

Primary mucinous ovarian carcinoma represents 3% of ovarian cancers and is typically diagnosed early, yielding favorable outcomes. This study aims to identify risk factors, focussing on the impact of age and ethnicity on survival from primary mucinous ovarian cancer.

METHODS

A retrospective observational study of patients treated at Sandwell and West Birmingham Hospitals NHS Trust and University Hospital Coventry and Warwickshire. Patients included were women aged ≥16 years, with primary mucinous ovarian cancer confirmed by specialist gynecological histopathologist and tumor immunohistochemistry, including cytokeratin-7, cytokeratin-20, and CDX2. Statistical analyses were performed using R integrated development environment, with survival assessed by Cox proportional hazards models and Kaplan-Meier plots.

RESULTS

A total of 163 patients were analyzed; median age at diagnosis was 58 years (range 16-92), 145 (89%) were International Federation of Gynecology and Obstetrics stage I and 43 (26%) patients had infiltrative invasion. Women aged ≤45 years were more likely to have infiltrative invasion (RR=1.38, 95% CI 0.78 to 2.46), with increased risk of death associated with infiltrative invasion (HR=2.29, 95% CI 1.37 to 5.83). Compared with White counterparts, South Asian women were more likely to undergo fertility-sparing surgery (RR=3.52, 95% CI 1.48 to 8.32), and have infiltrative invasion (RR=1.25, 95% CI 0.60 to 2.58). South Asian women undergoing fertility-sparing surgery had worse prognosis than those undergoing traditional staging surgery (HR=2.20, 95% CI 0.39 to 13.14). In FIGO stage I disease, 59% South Asian and 37% White women received adjuvant chemotherapy (p=0.06). South Asian women exhibited a worse overall prognosis than White women (HR=2.07, 95% CI 0.86 to 4.36), particularly pronounced in those aged ≤45 years (HR=8.75, 95% CI 1.22 to 76.38).

CONCLUSION

This study identified young age as a risk factor for diagnosis of infiltrative invasion. Fertility-sparing surgery in South Asian women is a risk factor for poorer prognosis. South Asian women exhibit poorer overall survival than their White counterparts.

Ovarian mucinous and seromucinous neoplasms: problematic aspects and modern diagnostic approach

The morphological spectrum of primary ovarian mucinous and seromucinous tumours is broad and presents an array of diagnostic challenges, many unique to these tumour types. This reflects the heterogeneous nature of these lesions, their varied histogenesis and evolving classification systems over recent decades, with further modification to the seromucinous category incorporated in the recently published 5^th edition of the WHO Classification of Female Genital Tumours. In this review we provide an update on the classification of these neoplasms and discuss their histogenesis and diverse morphology, focusing on areas which are diagnostically problematic. We also cover tumour grading, differential diagnosis, immunohistochemistry, the recent elucidation of the molecular underpinnings of ovarian mucinous neoplasia and discuss the gross and intraoperative handling of these tumours. A number of diagnostic issues remain unresolved highlighting the importance of further research on this front, as well as a multidisciplinary approach in the care of patients with ovarian mucinous and seromucinous neoplasia.

Stromal Endocrine Cell Micronests Associated With an Ovarian Mucinous Cystadenoma: Endocrine Cell Preservation (Pseudohyperplasia) Potentially Mimicking Stromal Sex Cord Proliferation or Tumor Microinvasion

Endocrine cell micronests (ECMs) have been described only twice previously in the ovary, both in association with mucinous neoplasms exhibiting intraepithelial endocrine cell hyperplasia. We report a 31-yr-old patient with a mucinous cystadenoma in which ECMs were distributed in the stroma surrounding degenerate glandular elements. Immunohistochemistry demonstrated only sparse endocrine cells within the neoplastic glands. We postulate that the ECMs in this case reflected relative preservation of endocrine elements in the context of epithelial atrophy, a process more commonly encountered in gastrointestinal pathology. Ovarian ECMs should also be distinguished from stromal sex cord proliferations and tumor microinvasion.

Morphological subtypes of ovarian carcinoma: a review with emphasis on new developments and pathogenesis

Ovarian carcinomas comprise a heterogeneous group of neoplasms, the four most common subtypes being serous, endometrioid, clear cell and mucinous. In recent years, our understanding of the underlying pathogenesis and initiating molecular events in the different tumour subtypes has greatly increased, and although ovarian carcinoma is often considered clinically as one disease, there is now a much greater realisation that the various subtypes have a different natural behaviour and prognosis. At present, adjuvant therapy is mainly dependent upon tumour stage and grade rather than type; however, this is likely to change in the future with the development of new chemotherapeutic agents and targeted therapies and clinical trials are necessary to evaluate the efficacy of different agents in clear cell, mucinous and low grade serous carcinomas, neoplasms which are considered relatively resistant to traditional chemotherapeutic regimes. In this review, the major subtypes of ovarian carcinoma are discussed. It is now firmly established that there are two distinct types of ovarian serous carcinoma, low grade and high grade, the former being much less common and arising in many cases from a serous borderline tumour. Low grade and high grade serous carcinoma represent two distinct tumour types with a different underlying pathogenesis rather than low grade and high grade variants of the same neoplasm. Both are usually advanced stage (stage III or IV) at diagnosis. B-raf and k-ras mutations are important molecular events in low grade serous carcinomas while high grade serous carcinomas are almost always associated with TP53 mutation. There is now emerging and compelling evidence that many high grade serous carcinomas (by far the most common subtype of ovarian carcinoma) actually arise from the epithelium of the distal fallopian tube. Future studies regarding the initiating molecular events in the development of this aggressive neoplasm should concentrate on this site. Primary ovarian mucinous carcinomas are uncommon, almost always unilateral and stage I, and largely of so-called intestinal or enteric type. Most arise in a stepwise manner from a pre-existing mucinous cystadenoma and mucinous borderline tumour. Endometrioid and clear cell carcinomas typically present as low stage neoplasms and in many, or most, cases arise from endometriosis; the former are usually well differentiated and there is now evidence that the majority of neoplasms reported in the past as high grade endometrioid carcinoma are of serous type. WT1 is useful in this regard since it is a relatively specific marker of a serous phenotype. It is recommended that different subtypes of ovarian carcinoma are graded using different systems rather than employing a universal grading system.

Immunohistochemistry in the distinction between primary and metastatic ovarian mucinous neoplasms: Table 1

The distinction between a primary and metastatic mucinous carcinoma within the ovary may be problematic. In most cases, the distinction can be made by careful pathological examination encompassing both the gross and microscopic findings and taking into account the distribution of the disease. However, immunohistochemistry may be of value in certain scenarios. In this review, I discuss the value of markers in the distinction between primary ovarian mucinous neoplasms and metastatic mucinous carcinomas from the colorectum, appendix, pancreas, biliary tract, stomach and cervix, the most common primary sites which give rise to metastatic mucinous carcinoma within the ovary. There is a significant degree of immunophenotypic overlap between primary ovarian mucinous neoplasms and metastatic mucinous carcinomas from the gastrointestinal tract, especially the upper gastrointestinal type; this is because most primary ovarian mucinous carcinomas and borderline tumours are of so-called intestinal or enteric type and exhibit some degree of positivity with enteric markers. Mullerian type primary ovarian mucinous neoplasms also exist and exhibit distinct immunohistochemical differences to the more common intestinal type.

Endocervical-like (Müllerian) mucinous borderline tumours of the ovary are frequently associated with the KRAS mutation

AIMS

  Clinicopathological aspects of the endocervical-like mucinous borderline tumour of the ovary (EMBT), including higher frequencies of bilaterality, endometriosis and hormone receptor reactivity, and often admixtures of various Müllerian-type epithelia, closely resembles endometrioid tumour more than mucinous borderline tumour of the intestinal type (IMBT). Thus, the aims of this study were to determine whether EMBT is really a subtype of mucinous borderline tumours, as shown in the current classification system, and to determine the best classification for EMBT.

METHODS AND RESULTS

  The clinicopathological and immunohistochemical features of 17 EMBTs were analysed, including oestrogen receptor (ER), progesterone receptor (PR), PTEN, cytokeratins (CK) 7 and 20, and β-catenin. Additionally, mutational analyses of the KRAS (exon 1) and PTEN genes (all nine exons) were performed in all cases, and the results were compared with literature findings for IMBT and endometrioid tumours. Twelve patients (71%) were confirmed histologically to have endometriosis in one or both ovaries. In seven cases, gradual transitions from endometriotic foci to the EMBT were identified. Immunohistochemically, all cases were reactive for ER and PR, with no nuclear expression of β-catenin. CK7 positivity was strong in all patients, whereas there was no reactivity for CK20. PTEN reactivity was diffuse in the nuclei of epithelial and underlying stromal cells. Sixty-nine per cent showed KRAS mutations in exon 1 and codon 12, but no PTEN mutation was identified in any of the nine exons.

CONCLUSION

  Our study suggests that EMBT has features of both mucinous and endometrioid tumours and is an additional tumour type arising in endometriosis. While clinicopathological features of EMBTs are closer to endometrioid tumours, they still have molecular characteristics closer to IMBTs.