Atypical Polypoid Adenomyoma of the Uterus: An Immunohistochemical and Molecular Study of 21 Cases

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.

Clinicopathological characteristics and fertility preserving treatment of atypical polypoid adenomyoma

Objective

Atypical polypoid adenomyoma (APA) is a rare benign tumor frequently diagnosed in young women that may coexist with or progress to atypical endometrial hyperplasia (EAH) or endometrioid endometrial carcinoma (EEC). This study aimed to investigate which subset of patients with APA are prone to concurrent or subsequent EAH or EEC, evaluate the necessity of progestin treatment in patients with APA only after achieving a complete response (CR) through hysteroscopic lesion resection, and assess the impact of concurrent APA on the fertility-preserving treatment of EAH or EEC.

Methods

This retrospective single-center study analyzed 86 patients with APA treated at the Obstetrics and Gynecology Hospital of Fudan University between January 2010 and October 2021. Patients with EAH or EEC only who underwent fertility-preserving treatment during the same period were matched in a 2:1 ratio with patients with concurrent APA and EAH or EEC. The clinicopathological characteristics, treatments, and prognosis were analyzed.

Results

The median patient age was 31 years (range 21-47 years). Among the 86 included patients, nine underwent total hysterectomy, 62 received conservative treatment, and the remaining 15 were lost to follow-up. A comparison of the 16 patients with APA only versus the 58 patients with APA and concurrent or subsequent EAH or EEC revealed that a homeostasis model assessment of insulin resistance (HOMA-IR) of > 2.2 (P = 0.047) and high-density lipoprotein (HDL) concentration of < 1.2 mmol/L (P = 0.028) were independent risk factors for EAH or EEC in patients with APA. Among the 17 patients with APA only who received conservative treatment and achieved a CR after hysteroscopic lesion resection, 13 received hormone treatment for a median duration of 6.3 months. The median follow-up time for these 17 patients was 49.0 months, during which no recurrence of APA was observed, but six patients developed endometrial hyperplastic diseases. Regarding the impact of concurrent APA on fertility-preserving treatment for EAH or EEC, the median time to achieve a CR was 24.0 weeks (95% confidence interval [CI]: 23.0-40.4) in the APA group and 26.0 weeks (95% CI: 24.3-32.3) in the non-APA group (P = 0.424). There were no significant differences between the two groups in the outcomes of fertility-preserving treatment.

Conclusion

Patients with APA only may still develop endometrial hyperplastic diseases after complete resection of the lesion under hysteroscopy to achieve a CR, particularly those with a HOMA-IR of > 2.2 or HDL concentration of < 1.2 mmol/L. Concurrent APA did not affect the efficacy of fertility-preserving treatment in patients with EAH or EEC.

Prolapsed Atypical Polypoid Adenomyoma-A Case Report and Literature Review

Atypical polypoid adenomyoma (APAM) is a rare polypoid benign tumor of the uterus that causes irregular vaginal bleeding in women of reproductive age. It has the potential for malignant transformation, but it does not metastasize. APAM may coexist with endometrial hyperplasia and adenocarcinoma, usually leading to misdiagnosis. Histopathologically, it is a biphasic tumor, represented by the endometrioid glands with a complex histoarchitecture, with sometimes squamous morular metaplasia or cytologic atypia, interspersed with a fibromyomatous stroma. This tumor has a high incidence of recurrence. We present a very rare case of a 21-year-old patient, a virgin, without a significant medical history, with a bleeding mass occupying the vagina. The mass was excised using forceps, scissors, and a suture of the visible pedicle. After a four-year follow-up and no additional medical treatment, no relapse was observed. Given the risk of recurrence and progression, APAM might be treated via a hysterectomy in patients with no desire for pregnancy. Due to a lower recurrence rate, the conservative treatment of atypical polypoid adenomyoma performed via an operative hysteroscopy represents the best choice. Previously diagnosed in hysterectomy specimens, with the introduction of better-performing indirect imaging techniques, adenomyosis is a clinical entity that has the possibility of being diagnosed in the presurgical stage.

Endometrioid Adenocarcinoma Resembling Cutaneous Pilomatrix Carcinoma: A Case Report of an Aggressive Neoplasm in a Young Woman With Diffusely Aberrant Beta-catenin Expression and Associated Morular Metaplasia and Atypical Polypoid Adenomyoma-type Change

Endometrioid carcinoma with histopathologic resemblance to cutaneous pilomatrix carcinoma with mutations in the gene encoding beta-catenin, CTNNB1 are rare. There are minimal numbers of reports of high-grade tumors with this divergent differentiation in the literature. We report the case of a 29-yr-old female with an unusual presentation of endometrial cancer with overall histologic appearance indicative of a recently reported aggressive subtype of Federation of Gynecology and Obstetrics (FIGO) IVB grade 3 endometrioid carcinoma with features resembling cutaneous pilomatrix carcinoma. She was treated with a primary chemotherapy regimen with an initial significant response to treatment before developing symptomatic brain metastasis for which she underwent whole-brain radiotherapy. We discuss the unusual histologic and radiologic presentation as well as her individual management throughout this case report. The apparent association with morular metaplasia and atypical polypoid adenomyoma suggests that this rare carcinoma is within a spectrum of lesions associated with aberrant beta-catenin expression/beta-catenin mutation. Its aggressive nature highlights the importance of early recognition of this rare lesion.

Utility of a PAX2, PTEN, and β-catenin Panel in the Diagnosis of Atypical Hyperplasia/Endometrioid Intraepithelial Neoplasia in Endometrial Polyps

The diagnosis of atypical hyperplasia/endometrioid intraepithelial neoplasm (AH/EIN) within endometrial polyps (EMPs) often poses a diagnostic conundrum. Our previous studies demonstrated that a panel of immunohistochemical (IHC) markers consisting of PAX2, PTEN, and β-catenin can be effectively utilized for the identification of AH/EIN. A total of 105 AH/EIN within EMP were analyzed using the 3-marker panel. We also evaluated these cases for the presence of morules. Benign EMP (n=90) and AH/EIN unassociated with polyp (n=111) served as controls. Aberrant expression of PAX2, PTEN, or β-catenin was observed in AH/EIN in EMP in 64.8%, 39.0%, and 61.9% of cases, respectively. At least 1 IHC marker was abnormal in 92.4% of cases. Overall, 60% of AH/EIN in EMP demonstrated abnormal results for≥2 IHC markers. The prevalence of PAX2 aberrancy was significantly lower in AH/EIN in EMP than in nonpolyp AH/EIN (64.8% vs. 81.1%, P =0.007), but higher than in benign EMP (64.8% vs. 14.4%, P <0.00001). The prevalence of β-catenin aberrancy was significantly higher in AH/EIN in EMP than in nonpolyp AH/EIN (61.9% vs. 47.7%, P =0.037). All control benign EMP demonstrated normal expression of PTEN and β-catenin. Morules were present in 38.1% of AH/EIN in EMP versus 24.3% in nonpolyp AH/EIN, and absent in benign EMP. A strong positive association was found between β-catenin and morules (Φ=0.64). Overall, 90% cases of atypical polypoid adenomyoma (n=6) and mucinous papillary proliferation (n=4) showed IHC marker aberrancy. In conclusion, the 3-marker IHC panel (PAX2, PTEN, and β-catenin) is (1) a useful tool in the diagnosis of AH/EIN in EMP; (2) PAX2 loss should be interpreted with caution and in combination with morphology and other markers.

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).

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.

Detection of MED12 mutations in mesenchymal components of uterine adenomyomas

Adenomyoma of the uterus is a biphasic nodular lesion composed of a mesenchymal component with smooth muscle differentiation and a glandular epithelium. The neoplastic nature of uterine adenomyomas has been controversial because some are considered to be nodular adenomyosis. MED12 mutations are involved in the pathogenesis of uterine smooth muscle tumors (leiomyomas and leiomyosarcomas) and biphasic tumors of the breast (fibroadenomas and phyllodes tumor). To investigate the histogenesis of uterine adenomyomas, we performed pathological and genetic analyses, including Sanger sequencing of MED12. In total, 15 cases of uterine adenomyomas were retrieved and assessed for clinicopathological factors. Immunohistochemistry for smooth muscle actin, desmin, and CD10 was performed. Exon 2 of MED12 was Sanger sequenced using DNA obtained by macrodissection of the adenomyomas. For cases that were positive for somatic MED12 mutations, we next performed microdissection of the mesenchymal and epithelial components. The DNA extracted from each component was further analyzed for MED12 mutations. MED12 mutations were detected in two adenomyomas (2/15, 13%), all in a known hot spot (codon 44). In both lesions, MED12 mutations were detected in multiple spots of the mesenchymal component. The epithelial component did not harbor MED12 mutations. The relatively low frequency of MED12 mutations suggests that not all adenomyomas are leiomyomas with entrapped glands. However, the results of our study suggest that a subset of uterine adenomyomas are true mesenchymal neoplasms.

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.

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.

[Mesenchymal and mixed uterine tumors : Current overview and practical aspects]

Benign leiomyomas are the most frequent mesenchymal tumors of the uterus. In contrast, uterine sarcomas are very rare. Leiomyosarcomas are the most frequent sarcomas followed by endometrial stromal sarcomas (ESS). Leiomyosarcomas are characterized by marked nuclear atypia and high mitotic count and may also show tumor cell necrosis and myometrial and vascular invasion. For cases of diagnostic uncertainty, the category of smooth muscle tumor of uncertain malignant potential (STUMP) may be considered but should be rarely used. Besides low-grade ESS and stromal nodules, a category of high-grade ESS was reconsidered by the WHO in 2014. High-grade ESS are characterized by fibromyxoid and round cell histology, myoinvasive growth, and immunoreactivity for cyclin D1 and BCOR and distinct gene fusions involving YWHAE and BCOR, respectively. The very rare undifferentiated uterine sarcomas need to be redefined due to overlap with high-grade ESS. Uterine tumors resembling ovarian sex cord tumors (UTROSCT) rarely behave malignant, but need to be distinguished from endometrial carcinomas. Mixed epithelial and mesenchymal tumors of the uterus are rare with carcinosarcomas occurring more frequently than adenosarcomas. For prognosis of adenosarcomas the recognition of sarcomatous overgrowth is crucial. Carcinosarcomas are histologically heterogeneous although genetically clonal; biologically they are considered as undifferentiated carcinomas. There will be an increasing importance of molecular pathology for the classification of rare and unusual mesenchymal uterine tumors.

Endometrial Endometrioid Carcinoma With Ovarian Metastasis Showing Morula-like Features in a Patient With Cowden Syndrome: A Case Report

Cowden syndrome (CS) is a multiple hamartoma syndrome associated with the development of various tumors, including endometrial cancer. However, the histology of CS-associated endometrial cancer remains to be fully described. To our knowledge, this is the first report of a patient with CS having endometrial endometrioid carcinoma with ovarian metastasis demonstrating morula-like features. A 31-yr-old, nulliparous, Japanese woman presented with abnormal genital bleeding. Endometrial biopsy revealed endometrioid carcinoma with an extensive morular formation, partially resembling atypical polypoid adenomyoma (APAM). Moreover, she had a past history of bilateral breast cancer and a family history of juvenile breast cancer in her mother. Genetic testing revealed they shared the same pathogenic germline PTEN mutation. She underwent an abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node biopsy. Pathologic examination revealed endometrial endometrioid carcinoma with APAM-like histology. Furthermore, the solid components with morula-like morphology and immunophenotypes showed myometrial invasion and ovarian metastasis (FIGO stage IIIA/pT3aN0M0). The present case highlights the need for careful assessment of myometrial invasion and extrauterine spread for appropriate gynecologic treatment even if endometrial biopsy shows APAM-like histology. Moreover, characterization of CS-associated endometrial cancers is required.

Symptoms and classification of uterine adenomyosis, including the place of hysteroscopy in diagnosis

Where histology used the presence of glands and/or stroma in the myometrium as pathognomonic for adenomyosis, imaging uses the appearance of the myometrium, the presence of striations, related to the presence of endometrial tissue within the myometrium, the presence of intramyometrial cystic structures and the size and asymmetry of the uterus to identify adenomyosis. Preliminary reports show a good correlation between the features detected by imaging and the histological findings. Symptoms associated with adenomyosis are abnormal uterine bleeding, pelvic pain (dysmenorrhea, chronic pelvic pain, dyspareunia), and impaired reproduction. However a high incidence of existing comorbidity like fibroids and endometriosis makes it difficult to attribute a specific pathognomonic symptom to adenomyosis. Heterogeneity in the reported pregnancy rates after assisted reproduction is due to the use of different ovarian stimulation protocols and absence of a correct description of the adenomyotic pathology. Current efforts to classify the disease contributed a lot in elucidated the potential characteristics that a classification system should be relied on. The need for a comprehensive, user friendly, and clear categorization of adenomyosis including the pattern, location, histological variants, and the myometrial zone seems to be an urgent need. With the uterus as a possible unifying link between adenomyosis and endometriosis, exploration of the uterus should not only be restricted to the hysteroscopic exploration of the uterine cavity but in a fusion with ultrasound.

MED12 mutations and fumarate hydratase inactivation in uterine adenomyomas

STUDY QUESTION

Do the uterine leiomyoma driver events – mediator complex subunit 12 (MED12) mutations, high mobility group AT-hook (HMGA2) overexpression, and fumarate hydratase (FH) inactivation – also contribute to the development of uterine adenomyomas?

SUMMARY ANSWER

MED12 mutations and FH deficiency occur in a subset of uterine adenomyomas, but at lower frequencies than in leiomyomas.

WHAT IS KNOWN ALREADY

Uterine adenomyomas are benign tumours with clinical features very similar to uterine leiomyomas. Mutations affecting MED12, HMGA2 and FH account for up to 80–90% of leiomyomas, but their contribution to adenomyomas is not known.

STUDY DESIGN, SIZE, DURATION

Formalin-fixed paraffin-embedded adenomyoma samples from 21 patients operated on during 2012–2014 were collected at the pathology department’s archives and analysed for uterine leiomyoma driver events.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Adenomyoma diagnoses were verified by a specialized pathologist and representative areas were marked on haematoxylin-eosin slides. DNA was extracted from the tissue samples and sequenced to detect mutations in MED12. Expression levels of HMGA2 and 2SC, a robust indirect method to detect FH inactivation, were analysed by immunohistochemistry (IHC). The coding region of FH was sequenced in one adenomyoma sample showing strong 2SC staining as well as in the same patient’s normal tissue sample. All patients’ medical histories were collected and reviewed.

MAIN RESULTS AND THE ROLE OF CHANCE

MED12 mutation c.131G > A, p.G44D, the most common mutation in uterine leiomyomas, was identified in two samples (2/21; 9.5%). One adenomyoma displayed strong 2SC positivity and subsequent sequencing revealed a frameshift FH mutation c.911delC, p.P304fs in the tumour. The mutation was also present in the patient’s normal tissue sample, indicating that she has a hereditary leiomyomatosis and renal cell cancer (HLRCC) syndrome. HMGA2 protein expression was normal in all adenomyomas.

LIMITATIONS, REASONS FOR CAUTION

Restricted sample size limits the determination of exact mutation frequencies of the studied aberrations in adenomyomas.

WIDER IMPLICATIONS OF THE FINDINGS

Uterine leiomyoma driver mutations do contribute to the development of some adenomyomas. We also report an adenomyoma in the context of hereditary HLRCC syndrome. Despite clinical similarities, the pathogenic mechanisms of adenomyomas and leiomyomas are likely different. Large-scale genomic analyses are warranted to elucidate the complete molecular background of adenomyomas.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by The Academy of Finland, the Sigrid Jusélius Foundation, and the Cancer Society of Finland. The authors declare no conflict of interest.

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.

Expression, Epigenetic and Genetic Changes of HNF1B in Endometrial Lesions

Hepatocyte nuclear factor 1-beta (HNF-1-beta) is a transcription factor involved in cancerogenesis of various tumors, including endometrioid carcinoma. We performed comprehensive analysis of HNF-1-beta in lesions of the endometrium, including protein expression and genetic and epigenetic changes. Expression of HNF-1-beta was analyzed immunohistochemically in 320 cases including both tumor and non-tumor endometrial lesions. Promoter methylation and genetic variants were evaluated, using bisulphite and direct sequencing, in 30 (18 fresh frozen, 12 FFPE tumors) endometrioid carcinomas (ECs) and 15 ovarian clear cell carcinomas (OCCCs) as a control group. We detected expression of HNF-1-beta in 28 % of ECs (51/180 cases), 26 % of serous carcinoma (7/27 cases), 83 % of endometrial clear cell carcinoma (15/18 cases), 93 % of hyperplastic polyps with atypias (13/14 cases), 100 % of hyperplastic polyps without atypias (16/16 cases), 88 % of hyperplasias with atypias (14/16 cases), 91 % of hyperplasias without atypias (10/11 cases), and in ≥80 % of different normal endometrium samples. The control group of OCCCs showed HNF-1-beta expression in 95 % (18/19 cases). Methylation in promoter region was detected in 13.3 % (4/30) of ECs, but not in corresponding normal tissue where available, nor in OCCCs (0/15 cases). Mutation analysis revealed truncating variant c.454C > T (p.Gln152X) in one EC and missense variant c.848C > T (p.Ala283Val) was detected in one OCCC. In conclusion, expression of HNF-1-beta was detected in various extents in all types of lesions analyzed, nevertheless its strong expression was mostly limited to clear cell carcinomas. Biological significance of genetic and epigenetic changes needs further investigation.