Clear cell carcinoma of the female genital tract (not everything is as clear as it seems)

High-grade Anaplastic Transformation of Ovarian Serous Borderline Tumor: A Distinctive Morphology With Abundant Dense Eosinophilic Cytoplasm and Dismal Prognosis

Ovarian serous borderline tumors (SBTs) have a generally favorable prognosis. Although the risk of progression to low-grade serous carcinoma is well documented, progression to high-grade carcinoma is rare. We report the clinicopathologic features of seven SBTs, each associated with the presence of a morphologically unique high-grade component with an extremely dismal prognosis. All of the SBTs exhibited typical hierarchical branching and scattered eosinophilic cells, whereas the high-grade component consisted of a profuse proliferation of epithelioid cells with abundant dense, eosinophilic cytoplasm, variable nuclear pleomorphism, and evident loss of WT1, estrogen receptor, and p16 positivity. In most cases, the SBT demonstrated an abrupt transition to the high-grade component, but one patient initially presented with the usual SBT and developed a recurrent disease that was composed entirely of the high-grade component. Targeted next-generation sequencing revealed identical driver mutations in both the SBT and high-grade components (BRAF in 3, KRAS in 1), confirming clonality. Three cases, in addition, harbored telomerase reverse transcriptase promoter mutations in both components. One case, despite insufficient material for sequencing, was BRAF V600E-positive by immunohistochemistry. Most patients with available follow-up data died within 9 months of diagnosis. This study confirms prior reports of ovarian SBT transformation to high-grade carcinoma and further characterizes a distinct subset with abundant dense eosinophilic cytoplasm and an extremely dismal prognosis. The presence of BRAF mutations in a major subset of these tumors questions the notion that BRAF is associated with senescent eosinophilic cells and improved outcomes in SBT. The role of the additional telomerase reverse transcriptase promoter mutations merits further investigation.

Diaphragmatic clear cell carcinoma with Lynch syndrome after surgery for atypical endometrial hyperplasia and ovarian endometriosis: A case report

Clear cell carcinoma (CCC) of the diaphragm is rare, with an origin that is reported to be associated with malignant transformation of extraperitoneal endometriosis. Lynch syndrome (LS) is an autosomal dominant hereditary cancer syndrome caused by germline pathogenic variants in one of the DNA mismatch repair (MMR) genes, MLH1, MSH2, MSH6 and PMS2. Women with LS have a significantly increased lifetime risk of endometrial and ovarian cancer. CCC is a common histology of endometriosis- and LS-associated malignancy. The present study describes the case of a 51-year-old woman with an intra-abdominal mass found during a routine physical examination. The patient had undergone total hysterectomy and bilateral adnexectomy for atypical endometrial hyperplasia (AEH) and ovarian endometriosis, respectively, 3 years previously. Enhanced computed tomography showed a mass on the surface of the liver. Laparoscopic examination of the abdominal cavity revealed a tumor on the underside of the right diaphragm, which was then surgically excised. Pathological examination of the excised tumor, along with immunohistochemistry, led to a diagnosis of CCC. Since LS was suspected due to the genetic family history of the patient, microsatellite instability analysis was performed on the diaphragmatic tumor, and the results were positive. Immunohistochemistry was performed for MMR proteins in AEH and CCC cells, both of which revealed loss of MSH2 and MSH6 expression. Following detailed genetic counseling, genetic testing of MMR genes was performed, revealing a germline pathogenic variant in MSH2 (c.1000C>T, p.Gln344*), thus confirming the diagnosis of LS. To the best of our knowledge, this is the first case report of concurrent diaphragmatic CCC and LS. Patients with LS and endometriosis are at risk of developing ovarian cancer or intra-abdominal malignant tumors. In addition, immunohistochemistry screening for MMR proteins should be considered in patients with AEH and a family history of LS-related cancer, to enable early clinical intervention in cases of endometrial cancer.

Gynecologic clear cell carcinoma and paraneoplastic cerebellar Degeneration: A literature review and case study

•Paraneoplastic cerebellar degeneration (PCD) is rare condition associated with gynecologic malignancy. •PCD presents with progressive cerebellar dysfunction in the setting of malignancy and confers a poor neurologic prognosis. •PCD associated with ovarian clear cell cancer may have more favorable neurologic outcomes versus other histologies. •The mainstay of PCD treatment is treatment of malignancy; symptom management may improve quality of life.

A complete durable response of vaginal clear cell carcinoma with pembrolizumab: A case report

Primary clear cell adenocarcinoma of the vagina represents a rare form of cancer historically correlated with in-utero diethylstibestrol (DES) exposure. Mainstay treatment modalities include surgery, radiation, and chemotherapy. There has been a growing interest in immunotherapy in the field of oncology. KEYNOTE 826 demonstrated that patients with persistent, recurrent, or metastatic cervical cancer including patients who had adenocarcinoma showed improved progression and overall survival by the addition Pembrolizumab to chemotherapy plus or minus bevacizumab. To date, there are no documented cases using pembrolizumab as adjuvant treatment for active or recurrent vaginal clear cell adenocarcinoma. We present a case of a young patient with recurrent vaginal clear cell carcinoma who showed a complete and durable response to Pembrolizumab.

Clinical perspectives of rare ovarian tumors: clear cell ovarian cancer

Ovarian clear cell carcinoma (OCCC) is a rare and distinct histological type of epithelial ovarian carcinoma in terms of its histopathological, clinical and genetic features. Patients with OCCC are younger and diagnosed at earlier stages than those with the most common histological type-high-grade serous carcinoma. Endometriosis is considered a direct precursor of OCCC. Based on preclinical data, the most frequent gene alternations in OCCC are mutations of AT-rich interaction domain 1A and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha. The prognosis of patients with early-stage OCCC is favorable, whereas patients at an advanced stage or who have the recurrent disease have a dismal prognosis due to OCCC's resistance to standard platinum-based chemotherapy. Despite a lower rate of response due to its resistance to standard platinum-based chemotherapy, the treatment strategy for OCCC resembles that of high-grade serous carcinoma, which includes aggressive cytoreductive surgery and adjuvant platinum-based chemotherapy. Alternative treatment strategies, including biological agents based on molecular characteristics specific to OCCC, are urgently needed. Furthermore, due to its rarity, well-designed collaborative international clinical trials are needed to improve oncologic outcomes and the quality of life in patients with OCCC.

Claudin-18 as a Promising Surrogate Marker for Endocervical Gastric-type Carcinoma

HIK1083 and trefoil factor 2 (TFF2) are known to be expressed in gastric-type carcinoma (GAS), but they do not reliably mark all GASs, and focal expression can be missed in biopsy specimens. We aimed to investigate whether claudin-18 and alpha-methylacyl-CoA racemase (AMACR) could be surrogate markers to separate GAS from other types of endocervical adenocarcinoma (ECA) and to compare their usefulness with that of HIK1083 and TFF2. Claudin-18 and AMACR immunohistochemistry was performed, and the results were compared with that of TFF2 and HIK1083, using whole sections of 75 ECAs (22 GASs and 53 non-GASs) and 179 ECAs with tissue microarrays (TMAs). TMAs were built to simulate the assessment of immunohistochemical stains in small biopsies. Any membranous (claudin-18) or cytoplasmic/membranous (AMACR, TFF2, HIK1083) staining of >5% of tumor cells was considered positive. Of 75 ECAs with whole sections, claudin-18 was significantly more frequently expressed in GASs (21/22) compared with non-GASs (8/53) (P<0.01). In ECAs with TMAs, claudin-18 expression was significantly frequent in GASs (15/23, 65.2%) than in non-GASs (3/152, 2.0%; all usual-type) (P<0.01). All claudin-18-positive GASs showed intense staining except 1 case. Claudin-18 shared the same degree of sensitivity and specificity with HIK1083 and TFF2. Three clear cell carcinomas were positive for claudin-18, but none showed intense staining. AMACR was expressed in a subset of ECAs and showed no impact in distinguishing between GAS and other ECAs. Our results suggest that claudin-18 is a promising surrogate marker to separate GAS from other types of ECA, including clear cell carcinoma.

Cervical cytology in the detection of uterine clear cell carcinoma: Diagnostic predictors from a case-control study

INTRODUCTION

Uterine clear cell adenocarcinoma (CCC) is a rare, aggressive malignancy with poor prognosis. The present study aimed to identify and describe its characteristic morphological features in cervical cytology.

METHODS

This was a 3-year retrospective case-control study. Cases included cervical samples of histopathologically proven endometrial and cervical CCC. Controls included cervical samples of histopathologically proven endometrial serous carcinoma (n = 15), endometrioid adenocarcinoma (n = 20), and endocervical adenocarcinoma (n = 15). Twenty-eight cytomorphological features were evaluated; the strength of association was determined by odds ratio (OR) and Cramer's V, and the diagnostic accuracy of statistically significant features was assessed.

RESULTS

Cases consisted of histopathologically proven 25 (34.7%) endometrial and 13 (18.0%) cervical CCC. Corresponding cervical samples were available for a total of 14 (36.8%) patients, of which 13 (92.8%) were positive for epithelial cell abnormality. On univariate analysis, three cytomorphological variables were significant predictors of uterine CCC: presence of dense cytoplasm (OR = 88; V = 0.72), deep nuclear membrane irregularities (OR = 17.5; V = 0.55), and coarse chromatin (OR = 21.3; V = 0.46). Dense cytoplasm had the highest positive predictive value (92%) and high specificity (97.8%), whereas coarse chromatin had the highest sensitivity (92.3%) and negative predictive value (96.7%).

CONCLUSIONS

The presence of dense cytoplasm and deep nuclear membrane irregularities in the tumour cells were strong predictors, and coarse chromatin a moderate predictor, of uterine CCC compared to its close cytological mimics.

Trefoil Factor 2 (TFF2) as a Surrogate Marker for Endocervical Gastric-type Carcinoma

Gastric-type carcinoma (GAS) is the most common human papilloma virus-independent endocervical adenocarcinoma (ECA), characterized by an aggressive behavior. Trefoil factor 2 (TFF2) is a mucin-associated peptide expressed in normal gastric but not endocervical glands. This study was carried out to investigate whether TFF2 could be a surrogate marker to separate GAS from other types of ECA. ECAs from 9 international institutions were reviewed for consensus histotype. Of them, expression of TFF2 was immunohistochemically examined compared with that of HIK1083, using whole sections of 50 ECAs (10 GASs and 40 non-GASs) and 179 ECAs (24 GASs and 155 non-GASs) with tissue microarrays (TMAs). TMAs were assessed to simulate assessment of immunohistochemical stains in small biopsies. Both markers were similarly scored, and any cytoplasmic/membranous staining of >5% of tumor cells was considered positive. Of 50 ECAs with whole sections, TFF2 was significantly more frequently expressed in GASs (8/10) compared with non-GASs (5/40) (P<0.01). In 179 ECAs with TMAs, TFF2 was also significantly more frequently expressed in GASs (7/24) compared with non-GASs (4/155) (P<0.01). There was no significant difference in specificity among the 2 markers. Double positivity for TFF2 and HIK1083 in ECAs was highly specific in separating GASs from non-GAS (P<0.01). A significantly smaller percentage of GASs were TFF2 positive in TMAs than in whole sections (P<0.01). Our results suggest that TFF2 is a promising marker, along with HIK1083, to confirm a diagnosis of GAS. This marker may be negative in small biopsies, indicating the necessity of using other exclusionary markers in combination with rigorous morphologic review and extensive sampling in resection specimens.

Understanding malignant transformation of endometriosis: imaging features with pathologic correlation

PURPOSE

Transformation of benign endometriosis to endometriosis-associated ovarian carcinoma (EAOC) is rare; however, women with endometriosis are four times more likely to develop EAOC which can present 20 years earlier than de novo ovarian cancer. Presenting symptoms are often vague and the radiologist's role in recognizing EAOC is critical for early detection and treatment. Histopathologic evaluation remains the mainstay for definitive diagnosis.

METHODS

Using a case-based approach, this article will review the sonographic, CT, and MRI features of EAOC with an emphasis on MRI. Histopathologic correlation of benign and malignant endometriosis will be reviewed.

RESULTS

Multiple factors contribute to the malignant transformation of endometriosis including genetic alterations, hormonal influences, oxidative stress, and inflammation. Malignancy most often occurs in ovarian endometriomas with less common sites involving the rectovaginal septum, rectosigmoid colon, and abdominal wall scars. The most common pathologic subtypes are endometrioid adenocarcinoma and clear cell carcinoma. MRI is the most specific imaging modality for evaluating EAOC. Key MR features include solid enhancing nodules (accentuated by subtraction imaging), nodular septations, loss of T2 shading within the endometrioma, and diffusion restriction.

CONCLUSIONS

EAOC is a distinct disease that affects women with benign endometriosis at younger ages than classic ovarian cancer. Understanding the imaging features of malignant transformation of endometriosis is essential for early diagnosis and timely definitive treatment.

Abdominal Wall Clear Cell Carcinoma: Case Report of a Rare Event with Potential Diagnostic Difficulties

Clear cell carcinoma (CCC) is a well-known aggressive histological type of carcinoma, predominantly seen in ovary and endometrium. However, CCC arising in abdominal wall is a very rare event. We report a case of a 48-year-old woman with an abdominal wall mass at her cesarean section (c-section) scar, which increased in size and became painful in the last months. Radiology revealed a 7 cm mass in the right inferior rectus muscle sheath, suggestive of endometriosis. An irregular, firm mass was resected, densely adherent to the rectus muscle and pubic bone. Frozen section revealed a multicystic lesion with minimal cytologic atypia, and a benign cystic neoplasm was favored. However, permanent sections showed marked nuclear atypia, hobnail morphology, and areas of infiltrative growth within fibrous stroma. No benign endometrial glands were found, although fibrosis and hemorrhage were present. Napsin-A, racemase, and PAX-8 were positive, consistent with CCC, likely arising within a c-section endometriosis focus. Although CCC usually presents with moderate to marked nuclear atypia, it can be mild and, especially in cases with a predominant cystic pattern, create diagnostic difficulties. An endometriosis-associated malignancy should be considered in the differential with any enlarging nodule or increasing pain within an abdominal wall scar.

Germ cell tumour growth patterns originating from clear cell carcinomas of the ovary and endometrium: a comparative immunohistochemical study favouring their origin from somatic stem cells

AIMS

To report a series of 11 ovarian and one endometrial neoplasm in elderly patients with mixed clear cell tumour and germ cell tumour (GCT) components, to compare their immunohistochemical profiles and demonstrate a putative stem cell population.

METHODS AND RESULTS

The clear cell tumours included 11 clear cell carcinomas (CCC) and one borderline clear cell tumour, while the GCT always included glandular yolk sac tumour (YST). In four cases, there were also foci of teratoma with immature neuroepithelial and endodermal tissues and undifferentiated areas showing true embryoids. To distinguish between the clear cell and YST components, the following antibodies were used: HNF1-β, napsin-A, cytokeratin 7 (CK7), PAX8, EMA, AFP, SALL4, villin, glypican-3 (GPC-3), GATA3, HepPar-1, OCT4, CDX2, CD30 and SOX2. HNF1-β, CK7, EMA and GPC-3 were often expressed in both components. Other markers had higher specificity for each cellular lineage; napsin-A and PAX8 were expressed only in CCC, while SALL4, villin, AFP and HepPar-1 were positive in the glandular YST component but negative in the clear cell component. OCT4 expression occurred in six of 10 cases and consistently in teratoma (four of four).

CONCLUSIONS

There is considerable immunophenotypical overlap between the two components in these mixed neoplasms, and a panel of markers should be used to facilitate the distinction. We propose that OCT4-expressing somatic cancer cells differentiate into GCT and represent spontaneously induced pluripotent stem cells, possibly conditioned by age-related epigenetic factors. These neoplasms have features of prepubertal type GCT showing lack of 12p gain, preponderance of YST and coexistence with immature neuroectoderm. However, there may also be undifferentiated stem cell areas with embryoid bodies, of the type seen in postpubertal testicular GCT, but lacking a complete embryonal carcinoma immunophenotype.

Endometriosis-associated ovarian neoplasia

This article reviews the most relevant pathological and molecular features of ovarian tumours that are associated with endometriosis. Endometriosis is a common condition, affecting 5-15% of all women, and it has been estimated that 0.5-1% of cases are complicated by neoplasia. The most common malignant tumours in this setting are endometrioid adenocarcinoma and clear cell adenocarcinoma, each accounting for approximately 10% of ovarian carcinomas in Western countries. A minority of cases are associated with Lynch syndrome. These carcinomas are often confined to the ovaries at presentation in which case they have relatively favourable outcomes. However, high-stage tumours, particularly clear cell carcinomas, generally have a poor prognosis and this partly reflects relative resistance to current treatment. Histological diagnosis is straightforward in the majority of cases but some variants, for example endometrioid carcinomas with sex cord-like appearances or oxyphil cells, may create diagnostic difficulty. Similarly, clear cell carcinomas can show a range of architectural and cytological patterns that overlap with other tumours, both primary and metastatic, involving the ovaries. Endometriosis-associated borderline tumours are less common, and they often show mixed patterns of differentiation (seromucinous tumours). Atypical endometriosis may represent an intermediate step in neoplastic progression and some of these lesions demonstrate immunohistological and molecular alterations similar to those observed in endometriosis-related tumours. ARID1A mutations are relatively common in all of these tumours, but each has additional characteristic molecular alterations which are likely to be of increasing clinical relevance as targeted therapies are developed. Less is known of the pathogenesis of rarer endometriosis-associated ovarian tumours including endometrioid stromal sarcoma, mesodermal (Müllerian) adenosarcoma, and carcinosarcoma. This article also briefly reviews the issue of synchronous endometrioid carcinomas of the endometrium and the ovary, including the most recent developments on pathogenesis.

Magnetic resonance imaging for distinguishing ovarian clear cell carcinoma from high-grade serous carcinoma

BACKGROUND

To compare the magnetic resonance imaging (MRI) features of ovarian clear cell carcinoma (CCC) and high-grade serous carcinoma (HGSC), to distinguish CCC from HGSC.

METHODS

MRI features (laterality, shape, size, configuration, papillary projection, signal intensity, enhancement, peritoneal implant, lymphadenopathy, ascites) of 40 tumors in 37 patients with CCC, confirmed by surgery and pathology, were compared with those of 62 tumors in 40 patients with HGSC. Statistical analysis was performed using Mann-Whitney and Fisher's exact tests.

RESULTS

There was a statistically significant difference in the mean maximum diameter, laterality, and FIGO stage (P = 0.002, P < 0.001, P < 0.001, respectively) between CCC and HGSC. Compared to HGSCs, CCCs were more frequently oval (30/40, 75 % vs 12/62, 19 %; P < 0.001), more often cystic (21/40, 53 % vs 8/62, 13 %; P < 0.001) and unilocular (23/29, 79 % vs 7/31, 23 %; P < 0.001), had T1-hyperintense cystic components more often (18/29, 62 % vs 5/29, 17 %; P < 0.001), had larger papillary projections (5.13 ± 0.4 cm vs 2.91 ± 0.3 cm; P < 0.001), were peritoneally implanted less frequently (P = 0.001) and had fewer ascites (P < 0.001).

CONCLUSIONS

CCC typically showed an oval, unilocular cystic mass with large papillary projection and T1-hyperintense cystic components. MRI could be helpful for distinguishing CCC from HGSC.

An Isolated Metastasis From Clear Cell Renal Cell Carcinoma to the Uterus: A Case Report and Review of Literature

Ovaries are a favored site for metastatic tumors arising in the female genital tract. Other organs of the mullerian system, that is, the uterine corpus as well as the fallopian tubes, cervix, and the vagina are less commonly involved by metastases. If there is no clinical history of a known extramullerian primary tumor, suspicion that a uterine mass represents metastatic disease is low. We report the case of a renal clear cell carcinoma presenting as an isolated uterine mass and morphologically mimicking a primary endometrial clear cell adenocarcinoma. A review of the English literature yielded only a recent abstract describing 3 cases of renal clear cell carcinoma metastasizing to the endometrium.

Coexistent ARID1A-PIK3CA mutations promote ovarian clear-cell tumorigenesis through pro-tumorigenic inflammatory cytokine signalling

Ovarian clear-cell carcinoma (OCCC) is an aggressive form of ovarian cancer with high ARID1A mutation rates. Here we present a mutant mouse model of OCCC. We find that ARID1A inactivation is not sufficient for tumour formation, but requires concurrent activation of the phosphoinositide 3-kinase catalytic subunit, PIK3CA. Remarkably, the mice develop highly penetrant tumours with OCCC-like histopathology, culminating in haemorrhagic ascites and a median survival period of 7.5 weeks. Therapeutic treatment with the pan-PI3K inhibitor, BKM120, prolongs mouse survival by inhibiting the tumour cell growth. Cross-species gene expression comparisons support a role for IL-6 inflammatory cytokine signalling in OCCC pathogenesis. We further show that ARID1A and PIK3CA mutations cooperate to promote tumour growth through sustained IL-6 overproduction. Our findings establish an epistatic relationship between SWI/SNF chromatin remodelling and PI3K pathway mutations in OCCC and demonstrate that these pathways converge on pro-tumorigenic cytokine signalling. We propose that ARID1A protects against inflammation-driven tumorigenesis.

Pathogenesis and the role of ARID1A mutation in endometriosis-related ovarian neoplasms

Endometriosis-related ovarian neoplasms (ERONs) are a unique group of tumors as they are associated with endometriosis, especially endometriosis presenting as an ovarian endometriotic cyst (endometrioma). ERONs include clear cell carcinoma, endometrioid carcinoma, and seromucinous borderline tumor. A growing body of evidence from both clinicopathologic and molecular studies suggests that most, if not all, ERONs develop from endometriotic cyst epithelium through different stages of tumor progression. The endometriotic cyst contains abundant iron-induced reactive oxygen species that are thought to be mutagenic, and chronic exposure of cystic epithelium to this microenvironment facilitates the accumulation of somatic mutations that ultimately result in tumor development. Molecular analyses of ERONs, including genome-wide screens, have identified several molecular genetic alterations that lead to aberrant activation or inactivation of pathways involving ARID1A, PI3K, Wnt, and PP2A. Among all molecular genetic changes identified to date, inactivating mutations of the ARID1A tumor suppressor gene are the most common in ERON. Understanding the molecular changes and pathogenesis involved in the development of ERON is fundamental for future translational studies aimed at designing new diagnostic tests for early detection and identifying critical molecular features for targeted therapeutics.