CD10 Immunostaining distinguishes atypical polypoid adenomyofibroma (atypical polypoid adenomyoma) from endometrial carcinoma invading the myometrium

Stromal p16 and SATB2 Expression Does Not Distinguish Atypical Polypoid Adenomyoma (APA) From its Benign Mimics

Atypical polypoid adenomyoma (APA) is a polypoid biphasic lesion of low malignant potential that arises in the lower uterine segment and uterine corpus. The diagnosis of APA is often challenging on biopsy and curettage specimens, and both benign and malignant processes need to be considered in the differential. Stromal expression of p16 and SATB2 have recently been shown to distinguish APA from myoinvasive endometrioid carcinoma. The authors hypothesized that p16 and SATB2 immunohistochemistry could also aid in the distinction of APA from benign adenomyomatous polyp and endometrioid adenomyoma. The study comprised 10 APAs, 7 adenomyomatous polyps, 11 endometrioid adenomyomas, and 10 myoinvasive endometrioid carcinomas. The majority of APAs showed moderate to strong, diffuse p16 and stromal expression. However, most adenomyomatous polyps and endometrioid adenomyomas also exhibited moderate to strong, focal to diffuse p16 stromal expression. SATB2 showed weak to moderate, focal to diffuse expression in the majority of APAs, adenomyomatous polyps and endometrioid adenomyomas. In contrast, p16 and SATB2 were negative to weak and focal in 90% of myoinvasive endometrioid carcinomas. Our findings demonstrate that p16 and SATB2 may be helpful in the differential diagnosis of myoinvasive endometrioid carcinoma and APA while not useful in separating APA from adenomyomatous polyp and endometrioid adenomyoma.

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).

Patterns of SATB2 and p16 reactivity aid in the distinction of atypical polypoid adenomyoma from myoinvasive endometrioid carcinoma and benign adenomyomatous polyp on endometrial sampling

AIMS

Atypical polypoid adenomyoma (APAM) is an uncommon uterine lesion composed of complex endometrioid glands with frequent squamous morular metaplasia and fibromuscular stroma. On endometrial curettage, biopsy or polypectomy specimens, the admixture of endometrioid glands and smooth muscle raises the differential diagnosis of myoinvasive endometrioid carcinoma. Reproductive-age APAM patients may opt for fertility preservation, whereas myoinvasive carcinoma is treated surgically. One previous study reported an incidental finding that the stroma of APAM, in contrast to that of other polypoid lesions, was SATB2-positive. APAM has also been reported to show increased stromal p16 staining. We aimed to assess whether SATB2 and p16 are useful stains for the distinction of APAM from myoinvasive carcinoma and benign adenomyomatous polyps.

METHODS AND RESULTS

Cases of 'atypical polypoid adenomyoma' (n = 32), 'adenomyomatous polyp' (n = 39) and 'myoinvasive endometrioid carcinoma' (n = 30) were identified. Morphological features were assessed, along with the intensity and extent of SATB2 and p16 staining in the stromal component of each lesion. SATB2 expression was seen in the stromal components of 30 of 32 (94%) APAMs, versus none of 39 (0%) benign adenomyomatous polyps and five of 30 (17%) myoinvasive endometrioid carcinomas. Stromal p16 expression was seen in 31 of 31 (100%) APAMs, versus 20 of 39 (51%) benign adenomyomatous polyps and 12 of 30 (40%) myoinvasive endometrioid carcinomas.

CONCLUSIONS

Patchy to diffuse SATB2 and block-type p16 staining of fibromuscular stroma separating atypical endometrioid glands is more consistent with APAM than with myoinvasive endometrioid carcinoma. These stains are potentially useful adjuncts to careful morphological evaluation of endometrial biopsies/curettings.

Atypical polypoid adenomyoma of the endometrium: diagnosis and treatment. A case report

Atypical polypoid adenomyoma (APA) is a rare uterine lesion that commonly recurs after local excision and is occasionally associated with or anticipates the development of atypical hyperplasia or endometrioid adenocarcinoma. We report a case of a 45-year-old woman affected by APA treated with local resection.

Significance of stromal markers in atypical polypoid adenomyoma

Atypical polypoid adenomyoma (APA) may progress to endometrioid carcinoma and may mimic myoinvasive carcinoma on biopsy specimens. Here, we present a case of an APA of the uterine cervix hysteroscopically treated, which recurred two years after and progressed to endometrioid carcinoma. In all biopsy specimens and in the hysterectomy specimen, the benign APA component showed an unusual immunohistochemical stromal pattern (periglandular fringe-like CD10 pattern, diffuse h-caldesmon positivity, p16 negativity), which is typical of myoinvasive carcinoma. Interestingly, the other three cases of cancerized APA assessed for h-caldesmon in the literature showed diffuse stromal positivity also in the benign APA component. Our case shows that the stromal markers used for differentiating between APA and myoinvasive carcinoma may be misleading even when their pattern seems unequivocal. Furthermore, our case suggests that h-caldesmon positivity might be a prognostic marker for progression of APA to carcinoma. Further studies are encouraged in this regard.

Atypical polypoid adenomyoma follow-up and management: Systematic review of case reports and series and meta-analysis

BACKGROUND

Atypical polypoid adenomyoma (APA) is a rare uterine tumor typically found in fertile age and associated with infertility. Among young nullipara women, conservative treatment is proposed despite the high recurrence rate and the association with endometrial cancer.Our aim was to assess the risk of recurrence with different conservative treatments in fertile ages and the prevalence of malignant or pre-malignant associated lesions to better address an adequate patient counselling when treatment modalities are discussed.

METHODS

This study is a systematic review and meta-analysis of case reports and case series about APA management and follow-up. A literature search was carried from Medline and Scopus for studies published from January 1, 1980 to December 31, 2018.

RESULTS

We included 46 observational studies and 296 cases in fertile women. The prevalence of APA relapse was 44% (CI.95 33-57%) and was lower in cases treated with operative hysteroscopy (22%; CI.95 11-39%) than in cases treated with blind curettage and polypectomy (38%; CI.95 15-67%). The prevalence of the concomitant or during the follow-up diagnosis of endometrial carcinoma was 16% (CI.95 9-29%). The risk of cancer development during follow-up was significantly less in cases treated with histeroscopy (10.56% new cumulative diagnosis at 5 years follow up; CI.95 0-23.7%) than blind curettage and polypectomy (35.5% new cumulative diagnosis at 5 years; CI.95 11.65-52.92%; P < .05). Medical treatment with medroxyprogesterone acetate after surgery does not reduce APA recurrence. Pregnancy was observed in 79% cases in which the desire was expressed.

CONCLUSION

This review suggests that conservative treatment performed by operative hysteroscopy is the optimal choice because it lowers the risk of recurrence, improves the accuracy of concomitant carcinoma or hyperplasia diagnosis, and leaves the possibility of future pregnancies.

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.

[Atypical polypoid adenomyoma: retrospective study about 8 cases from Jeanne-de-Flandre Hospital between 1996 and 2008]

OBJECTIVES

To propose a therapeutic approach and follow-up of patients with atypical polypoid adenomyoma (APA) wishing to remain fertile.

PATIENTS AND METHOD

We are presenting a retrospective study of eight APA cases.

RESULTS

Two patients immediately received radical treatment, and one patient had an endometrial thermocoagulation. The remaining five patients received a conservative treatment with ultrasound and hysteroscopic monitoring. Among them, two had full-term pregnancies, one is being treated for infertility, in one case, the APA disappeared after three hysteroscopy-curettages and macroprogestative treatment. Lastly, one of our patients died from an aggressive endometrioid ovarian bilateral tumour associated with an endometrial adenocarcinoma.

DISCUSSION AND CONCLUSION

Radical treatment is necessary for cases of APA in women no longer wishing to remain fertile. For those wishing to remain fertile, we can offer a conservative treatment once they have been informed regarding the associated risk of relapse, degeneration, and ovarian lesions which necessitate stricter follow-up.

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 characteristics of atypical polypoid adenomyoma with special reference to h-caldesmon

Atypical polypoid adenomyoma (APA) is a relatively rare benign uterine tumor, histologically characterized by proliferation of irregular endometrioid glands accompanied by stromal cells of smooth muscle origin. As the epithelial components of APA usually show cytological atypia, a differential diagnosis between this tumor and endometrioid carcinoma invading myometrium is often difficult, especially in curettage material. This distinction is clinically very important to avoid unnecessary hysterectomy. However, only a few immunohistochemical studies of APA that differentiate it from malignancy have been published. Therefore, we have investigated the expression of several antigens in APA and compared them with those present in myoinvasive carcinoma. Six specimens of APA were studied, along with controls of endometrioid carcinoma invading myometrium. Antibodies to p53, Ki-67, CD10, and h-caldesmon reacted positively using immunohistochemistry. Variable positive expressions of p53 and Ki-67 were observed in both epithelial and stromal components of APA, and in myoinvasive endometrioid carcinoma. CD10 was negative or partially and weakly positive whereas h-caldesmon was completely negative in the stromal cells of all 6 specimens of APA. However, in the myometrium in which endometrioid carcinoma invaded, a fringe-like positive staining pattern was occasionally observed for CD10, whereas a diffuse positive signal was obtained for h-caldesmon. The results of this study indicate that immunohistochemically, p53, and Ki-67 are not reliable markers but that h-caldesmon is useful in distinguishing APA from myoinvasive endometrioid carcinoma. Further, our data suggest that the stromal cells of APA are mainly immature smooth muscle cells, and thus APA may be a mixed tumor.