Molecular pathology of atypical polypoid adenomyoma of the uterus

A Clinicopathological Review of 203 Cases of Atypical Polypoid Adenomyoma of the Uterus

OBJECTIVE

To provide a reference for the diagnosis and treatment of atypical polypoid adenomyoma (APA).

METHODS

This was a retrospective study of 203 APA patients from 2011 to 2021. The clinicopathological characteristics, treatments, and prognosis were analyzed.

RESULTS

The average age at diagnosis of APA patients was 39.30 ± 11.01 years, and premenopausal women accounted for 81.3%. Abnormal uterine bleeding or menorrhagia were the most common clinical manifestations of APA. The uterine fundus (78.3%), followed by the lower segment of the uterus (11.8%), was the most common location of the APA lesions. Abnormal blood vessels were seen on the surface of 28 APA tumors. APA can coexist with atypical endometrial hyperplasia (18.2%) and endometrial cancer (10.8%). Immunohistochemical analysis was performed on 99 samples. In the glandular component, ER (94.8%), PR (94.8%), Ki-67 (51.5%), p53 (45.6%), PTEN (18.8%), and mismatch repair proteins (96.4%) were positively expressed. Stromal immunophenotype expression was exhibited as follows: CD10-(89.5%), p16+(86.9%), h-caldesmon-(66.7%), Desmin+(75%), and Vimentin+(88.9%). Fifty-five APA patients received TCR, and 33 of them received adjuvant therapy after the operation. The postoperative recurrence rate (9.1% vs. 36.4%, p < 0.05) and malignant transformation rate (3.0% vs. 18.2%, p < 0.05) of the treated group were significantly lower than the untreated group.

CONCLUSIONS

APA usually occurs in women of childbearing age, and the diagnosis is based on pathological morphology. APA has a low malignant potential, and those who have fertility requirements can undergo conservative TCR treatment, supplemented by progesterone treatment after surgery and close follow-up. Total hysterectomy is the treatment of choice for APA patients with atypical endometrial hyperplasia around the lesion.

Immunophenotype of Atypical Polypoid Adenomyoma of the Uterus: Diagnostic Value and Insight on Pathogenesis

Atypical polypoid adenomyoma (APA) is a rare uterine lesion constituted by atypical endometrioid glands, squamous morules, and myofibromatous stroma. We aimed to assess the immunophenotype of the 3 components of APA, with regard to its pathogenesis and its differential diagnosis. A systematic review was performed by searching electronic databases from their inception to January 2019 for immunohistochemical studies of APA. Thirteen studies with 145 APA cases were included. APA glands appeared analogous to atypical endometrial hyperplasia (endometrioid cytokeratins pattern, Ki67≤50%, common PTEN loss, and occasional mismatch repair deficiency); the prominent expression of hormone receptors and nuclear β-catenin suggest that APA may be a precursor of "copy number-low," CTNNB1-mutant endometrial cancers. Morules appeared as a peculiar type of hyperdifferentiation (low KI67, nuclear β-catenin+, CD10+, CDX2+, SATB2+, p63-, and p40-), analogous to morular metaplasia in other lesions and distinguishable immunohistochemically from both conventional squamous metaplasia and solid cancer growth. Stroma immunphenotype (low Ki67, α-smooth-muscle-actin+, h-caldesmon-, CD10-, or weak and patchy) suggested a derivation from a metaplasia of normal endometrial stroma. It was similar to that of nonatypical adenomyoma, and different from adenosarcoma (Ki67 increase and CD10+ in periglandular stroma) and myoinvasive endometrioid carcinoma (h-caldesmon+ in myometrium and periglandular fringe-like CD10 pattern).

Immunohistochemical results and case report of an incidental finding of uterine polypoid adenomyoma after long-time therapy for metrorrhagia

We present a 25-year-old female woman with a 9-year history of metrorrhagia, in whom a uterine polypoid adenomyoma (UPA) was incidentally detected. Intense nuclear staining in the uterine adenomyoma tissue showed an immunoreaction with BAF250a/ARID1A, Arginase-2 as well as 1LRH-2E1/NR5A2, suggesting a role of these proteins and transcriptional activity of their genes in uterine polypoid adenomyoma development. Neither Nidogen-2 nor SF-1/NR5A1 were expressed in UPA.

Mutations of RAS genes in endometrial polyps

Endometrial polyps are common, yet the molecular mechanisms underlying their formation and progression remain unclear. We examined gene mutations possibly related to the pathogenesis of endometrial polyps, as well as to their clinical features. Four premenopausal patients with endometrial polyps, who were not under drug treatment, were recruited. Whole exomes of endometrial polyps and peripheral blood lymphocytes were analyzed by next‑generation sequencing, and somatic mutations were derived by subtraction. Then, 35 samples of endometrial polyps and 12 samples of atypical polypoid adenomyoma were newly recruited to validate the identified mutations by polymerase chain reaction‑reverse sequence specific oligonucleotide method. The mutations were also analyzed in separate stromal and glandular components of the polyps after laser‑capture microdissection. Whole exome sequencing revealed that KRAS mutations were the only type of mutation detectable in multiple cases (2/4). Targeted mutation analysis revealed that 16 of 35 samples (45.7%) of endometrial polyps harbored RAS mutations. Mutation‑positive cases exhibited a significantly higher number of endometrial polyps (3.25±2.70 vs. 1.74±0.87, P=0.045). Laser‑capture microdissection in NRAS‑mutated endometrial polyps revealed that both stromal and glandular components harbored RAS mutations. There was no RAS mutation in 12 samples of atypical polypoid adenomyoma. This is the first report demonstrating that pathogenic RAS mutations are frequent in non‑treated endometrial polyps. RAS mutations may have an important role in tumorigenesis and in the formation of multiple endometrial polyps.

[Pitfalls in the histopathological diagnostics of endometrial carcinoma and its precursors : Clinically relevant differential diagnoses, avoidance of false positive diagnoses]

Making an incorrect histopathological diagnosis of an endometrial lesion may lead to unwanted loss of fertility and therapy-associated morbidity; therefore, endometrial carcinomas need to be correctly typed and differentiated from hyperplastic precursors, benign lesions and artifacts. Typical diagnostic pitfalls are described in this article. Misdiagnosing endometrial lesions can be avoided by paying thorough attention to gross as well as microscopic features and by taking crucial differential diagnoses into consideration. These are, in particular, well-differentiated endometrioid adenocarcinoma of the endometrium versus atypical endometrial hyperplasia, myoinvasive endometrioid adenocarcinoma versus atypical polypoid adenomyoma and endometrioid carcinoma versus serous carcinoma of the endometrium with a predominantly glandular pattern. It is also important to consider the possibility of a false positive diagnosis of atypical endometrial hyperplasia or carcinoma in cases of biopsy-induced artifacts.

A practical approach to the diagnosis of mixed epithelial and mesenchymal tumours of the uterus

The current 2014 World Health Organization (WHO) Classification of mixed epithelial and mesenchymal tumours of the uterus includes categories of carcinosarcoma, adenosarcoma, adenofibroma, adenomyoma and atypical polypoid adenomyoma, the last two lesions being composed of an admixture of benign epithelial and mesenchymal elements with a prominent smooth muscle component. In this review, each of these categories of uterine neoplasm is covered with an emphasis on practical tips for the surgical pathologist and new developments. In particular, helpful clues in the distinction between carcinosarcoma and dedifferentiated endometrial carcinoma will be discussed. In addition, salient features to help distinguish between adenofibroma, adenosarcoma, embryonal rhabdomyosarcoma and other mesenchymal neoplasms in the differential diagnosis will be outlined. Finally, a discussion of adenomyoma and its main differential diagnostic considerations will be covered.

Frequent β-catenin gene mutations in atypical polypoid adenomyoma of the uterus

Atypical polypoid adenomyoma (APA) is an uncommon polypoid lesion of the uterus. To clarify the mechanism of its histogenesis, we examined the functional role of β-catenin, with reference to expression of p21(waf1), cyclin D1, cyclin E, CD10, and α-smooth muscle actin (SMA), as well as cell proliferation, in 7 lesions. In the epithelial components, expression of nuclear β-catenin, p21(waf1), and cyclin D1 was increased in a stepwise fashion from normal tissue through complex atypical hyperplasia and adenomyoma to APA lesions, particularly in squamous morular areas, whereas cell proliferation, as well as cyclin E expression, was significantly decreased in the latter. Similar findings were evident in the stromal lesions, with the exception of a case of nuclear β-catenin. In addition, coexpression of CD10 and α-SMA markers was observed in the stromal components in 3 APA cases, in line with the results of normal secretory endometrial and adenomyoma samples, suggesting that cells progress to myofibromatous cells in response to differentiation-promoting events. Finally, β-catenin gene (CTNNB1) mutations were detected in all APA cases, the single nucleotide substitutions being in the epithelial but not the stromal components. These findings suggest that activation of β-catenin signaling, probably secondary to the gene abnormalities, plays an important role in the formation of the complex epithelial architecture in APAs, leading to inhibition of cell proliferation through overexpression of p21(waf1). In contrast, changes in the stromal cell phenotype may occur through a shift from CD10 to α-SMA immunopositivity, independent of CTNNB1 status.

A multiple perspectives on atypical polypoid adenomyoma of uterus

Atypical polypoid adenomyoma (APA) is a rare benign uterine tumor, with less than 200 cases have been reported in English literature. Although, it is considered as a benign lesion and treated conservatively previously, more and more cases show that APA has a high rate of recurrence or residual, and is found to precede the development of carcinoma. Given the data from present research on APA, the therapy of APA becomes more complex and must be cautious, especially for the nulliparous and premenopausal patients. In addition, because of the low incidence, studies on this disease are less, and the etiology and pathogenesis of APA is still unclear. In this review, we aim to summarize recent researches concerning APA from multiple perspectives, including clinical presentation, histogenesis, immunohistochemistry and molecular features, diagnosis and differential diagnosis, treatment opinion and prognosis, which may provide theory and clinical basis for the future clinical treatment and research of this rare disease.

Coexisting atypical polypoid adenomyoma and endometrioid endometrial carcinoma in a young woman with Cowden Syndrome: Case report and implications for screening and prevention

► Cowden Syndrome is a rare hereditary cancer syndrome, which confers an increased risk of breast, thyroid, endometrial and colon cancer. ► Atypical polypoid adenomyoma does not generally represent a premalignant lesion, but must be carefully screened for foci of malignancy. ► Cancer screening must be intensified for patients who meet the diagnostic criteria for Cowden Syndrome.

Pathology of mixed Müllerian tumours

The term 'mixed Müllerian tumour' applies to uterine tumours composed of epithelial and mesenchymal elements of Müllerian origin. These neoplasms are classified into adenomyomas, adenofibromas, adenosarcomas, and carcinosarcomas (malignant Müllerian mixed tumours) based on whether the epithelial and stromal elements are benign or malignant. The rare atypical polypoid adenomyoma usually involves the lower uterine segment and, on curettings, may be confused with invasive adenocarcinoma. Adenosarcomas are low-grade neoplasms classified halfway along the spectrum of mixed Müllerian tumours, with adenofibromas at one end and carcinosarcomas (malignant Müllerian mixed tumours) at the other. Some tumours currently classified as 'adenofibromas' on the basis of their low mitotic count and lack of nuclear atypia are, in fact, well differentiated adenosarcomas. Carcinosarcoma is composed of admixed but distinctive carcinomatous and sarcomatous elements. On the basis of the clonal origin of both tumour components, carcinosarcomas are currently thought to be metaplastic carcinomas rather than uterine sarcomas.

Atypical polypoid adenomyoma of the uterus: an immunohistochemical study on 5 cases

Immunohistochemical studies of atypical polypoid adenomyoma (APA) of the uterus are very rare. Five cases of APA were retrieved from the surgical cases of our laboratory. The ages were 38, 41, 54, 65, and 77 years (mean ± SD, 55 ± 14.6 years). The diameters of APA were 1.2, 1.9, 2.3, 3.2, and 7.0 cm (mean ± SD, 3.12 ± 2.00 cm). Histologically, APA consisted of complex glandular element and mesenchymal fibromuscular element. No endometrial stroma was present. Mucins were found in the glands but not in the mesenchyma. The glands were consistently positive for pancytokeratin (AE1/3, CAM5.2), cytokeratin (CK) 7, CK8, CK18, CK19, vimentin, CA125, estrogen receptor, progesterone receptor, MUC1, and MUC6. The glands were consistently negative for CK14, CK20, CEA, epithelial membrane antigen, S100 protein, p53, CD10, MUC2, and MUC5AC. Some cases were positive for CK34βE12 (4/5), CK5/6 (4/5), and CA19-9 (4/5). The Ki-67 labeling ranged from 3% to 10%. The mesenchymal element was consistently positive for vimentin, α-smooth muscle actin, estrogen receptor, progesterone receptor, and CD10, while consistently negative for pancytokeratin (AE1/3, CAM5.2), CK34βE12, CK5/6, CK7, CK8, CK14, CK18, CK19, CK20, CEA, epithelial membrane antigen, S100 protein, CA125, CA19-9, p53, MUC1, MUC2, MUC5AC, and MUC6. Some cases were positive for desmin (2/5). Ki-67 labeling ranged from 1% to 8%. In conclusion, the immunoprofile of APA was reported. The findings provide basic knowledge of APA of the uterus.

Immunohistochemical markers in endometrial hyperplasia: is there a panel with promise? A review

OBJECTIVE

Despite advances in defining the biology of endometrial carcinomas, there has been little progress in determining markers that distinguish preinvasive endometrial proliferations. The goal of this literature review was to identify studies on endometrial hyperplasia (EH) that describe markers with potential to predict response to progestin therapy or potential for progression to invasive disease.

METHODS

Articles published between January 2000 and October 2006 were identified using the key words endometrial hyperplasia and progesterone receptor or estrogen receptor or biologic marker or immunohistochemistry/immunohistochemical. Articles that reported immunohistochemical studies on specimens of human EH +/-endometrioid endometrial carcinoma with a normal comparison group were included. Only those who reported hyperplasia with atypia separately from nonatypical hyperplasia and with a sample size greater than 10 specimens for the sum of complex and atypical samples were included.

RESULTS

A total of 289 abstracts were reviewed and 150 articles potentially met inclusion criteria. Of these, 123 described immunohistochemical studies on human EH specimens. Only 46 met all criteria for analysis of 61 different markers.

CONCLUSIONS

PTEN seems to have the greatest potential for diagnostic utility in EH, perhaps in combination with Bcl-2 and Bax. However, more uniform and rigorous studies are required to confirm these and additional markers' utility diagnostically in a diagnostic panel. As a major clinical priority is to determine which lesions can be treated medically and which require surgical intervention, focusing future studies on markers that distinguish response to hormone therapy or are involved in hormone regulation, will be important future considerations.

Aberrant Cdx2 expression in endometrial lesions with squamous differentiation: important role of Cdx2 in squamous morula formation

Only a few reports have described Cdx2 expression in endometrial lesions of the uterus. Our aim was to determine whether Cdx2 expression is related to squamous differentiation in endometrial lesions. Furthermore, we examined whether there is any correlation between Cdx2 and beta-catenin, a well-known marker of aberrant nuclear accumulation in endometrial squamous foci secondary to mutation. We performed immunohistochemical analysis of 225 cases (29 normal endometrium, 28 nonproliferative conditions, 21 polyps, 46 hyperplasias, and 101 endometrioid carcinomas) that included 72 cases (4 polyps, 16 hyperplasias, and 52 carcinomas) showing morular or keratinizing squamous differentiation (SD(+)). Normal endometrium and nonproliferative conditions showed no staining for Cdx2. Whereas there was a low rate of Cdx2 positivity in SD(-) polyps (5.9%) and hyperplasias (10%), all SD(+) lesions expressed Cdx2 (P < .001). Thirty-eight (73%) of the SD(+) carcinomas were positive for Cdx2, whereas only 6 SD(-) cases (14.0%) were positive (P < .001). Furthermore, the larger the number of squamous foci, the greater the number of Cdx2-positive cells that was found. The labeling indices of Cdx2 were significantly higher in morular components than in keratinizing or glandular ones (P < .001). There was a strong correlation of the labeling indices of Cdx2 and beta-catenin in squamous foci of hyperplasias and carcinomas. Using immunofluorescence, we confirmed the coexpression of the 2 markers. The Cdx2 protein is expressed frequently in endometrial lesions with squamous differentiation, especially morular-type differentiation, and correlates strongly with nuclear beta-catenin expression. These facts suggest that Cdx2 plays an important role in squamous morula formation.

Hysteroscopic treatment of atypical polypoid adenomyoma diagnosed incidentally in a young infertile woman

OBJECTIVE

To describe the conservative treatment of an atypical polypoid adenomyoma (APA) in a young infertile patient using a modification of the technique previously reported for the conservative treatment of stage IA endometrial cancer.

DESIGN

Case report.

SETTING

Department of Gynaecology and Obstetrics and Pathophysiology of Human Reproduction of the University of Naples "Federico II."

PATIENT(S)

A 35-year-old woman diagnosed incidentally with an APA during routine investigation for primary infertility.

INTERVENTION(S)

Conservative resectoscopic treatment using a four-step technique in which each step is characterized by a pathological analysis: the removal of the APA (step 1), the removal of endometrium adjacent to the APA (step 2), the removal of the myometrium underlying the APA (step 3), and multiple random endometrial biopsies (step 4).

MAIN OUTCOME MEASURE(S)

Complete resection of the APA and ruling out of any malignancy.

RESULT(S)

The conservative surgery was effective as histological examination of all specimens confirmed an APA confined to the endometrium without any other premalignant or malignant lesion. Transvaginal ultrasound and office hysteroscopy with target biopsies at 1 and 6 months after surgery were negative for atypia and malignancy.

CONCLUSION(S)

Our technique under a close, intermittent postoperative surveillance might represent a good therapeutic option for those women with APA who wish to preserve their fertility as well as for those at high medical risk for hysterectomy.

Polypoid endocervical adenomyoma: A case report with clinicopathologic analyses

A case of polypoid endocervical adenomyoma (PEA) in the uterine cervix was encountered in the uterine cervix of a 56-year-old woman. Grossly, a well-circumscribed polypoid tumor was observed protruding from the uterine cervix. Based on the findings of imaging studies, it was assumed to be an adenoma malignum in the uterine cervix. The tumor was composed of a mixture of proliferating glands of endocervical type and fascicles of smooth muscle. No distinct nuclear anaplasia, architectural abnormality or any evidence of destructive stromal invasion was observed. Adenoma malignum, which shows a gastric phenotype with immunoreactivity for HIK-1083, was a serious diagnostic possibility. In the present case, the tumor was a well-circumscribed polypoid lesion, with no cytologic or architectural abnormality; however, focal immunoreactivity was shown for HIK-1083, which thus suggested it to be PEA. Therefore, the results of these ancillary diagnostic modalities should be interpreted with caution and combined with the gross and light microscopy findings.