Morules in endometrial carcinoma and benign endometrial lesions differ from squamous differentiation tissue and are not infected with human papillomavirus

BACKGROUND: Squamous differentiation/squamous metaplasia is often associated with endometrial adenocarcinoma and benign lesions, such as endometrial hyperplasia and chronic endometritis. Morules have distinct histological characteristics, and are referred to as squamous metaplasia or squamoid metaplasia. AIM: To focus on the histological characteristics of morules and clarify the difference between morules and squamous differentiation. MATERIALS/METHODS: Twenty endometrioid carcinomas with morules or squamous differentiation, five adenosquamous carcinomas, and eight non-carcinomatous endometrial lesions with morules were investigated. Numerous antibodies for epithelial membrane antigen (EMA), involucrin, cytokeratins, neuropeptides, and oncofetal antigens were used for immunohistochemistry. In situ hybridisation and polymerase chain reaction were used to detect human papillomavirus (HPV). RESULTS: The morules observed were uniform cell clusters, with no squamous differentiation. They were immunonegative for epithelial antigens including involucrin, EMA, and cytokeratins, but were positive for neurone specific enolase. A few morules were immunopositive for acetylcholine esterase, and one case was positive for somatostatin; neither oncofetal nor proliferative cell markers, including blood group A, B, and AB, or other neuropeptides were demonstrated in the morules. HPV DNA was not found in either the morules in the carcinomas or in the benign lesions. However, true squamous differentiation tissue in four endometrioid carcinomas and two adenosquamous carcinomas was HPV positive using in situ hybridisation. CONCLUSION: Morules are histologically distinct from squamous metaplasia/squamous differentiation tissue. Morules are thought to be neuroectodermal-like cell clusters, and are not infected with HPV. In contrast, some of the true squamous differentiation tissue was associated with HPV infection.     

Immunohistochemical analysis of morules in colonic neoplasms: morules are morphologically and qualitatively different from squamous metaplasia.

Morules develop in several neoplasms and have been considered as a type of squamous metaplasia despite the absence of keratinization and intercellular bridges. The objective of this study was to clarify the pathological significance of morules and to distinguish morules from squamous metaplasia in colonic neoplasms. Ten cases of morule-associated colonic neoplasms (4 adenocarcinomas, 1 adenoma with carcinoma in situ, and 5 adenomas), and 3 cases of squamous metaplasia in colonic adenocarcinoma were examined morphologically and immunohistochemically. Morules were well-defined structures composed of small, oval to short-spindled cells with bland nuclei, and frequently associated with intranuclear inclusions that were positive for biotin and biotin-binding enzymes (pyruvic acid carboxylase and propionyl CoA carboxylase). On immunohistochemical examination, morules characteristically showed nuclear overexpression of beta-catenin, cyclin D1 and p63, low Ki-67 labeling index (<1%), cytoplasmic overexpression of CD10, and no expression of cytokeratin 20. These molecules were useful for the differentiation of morules. Furthermore, p63 and 34betaE12 positivities in morules suggested that they have a basal/stem cell phenotype. Thus, morules were morphologically and qualitatively different from squamous metaplasia. We consider that morules in colonic neoplasms are cell clusters with a basal/stem cell phenotype, and have less proliferative and less invasive potential than other cancer cells.     

Pulmonary endodermal tumor resembling fetal lung: a clinicopathologic study of five cases with immunohistochemical and ultrastructural characterization

Pulmonary endodermal tumor resembling fetal lung describes an uncommon neoplasm of the lung which also has been referred to as pulmonary blastoma and adenocarcinoma of fetal lung type. We describe five cases which fall within a narrow band on the spectrum of pulmonary neoplasms with both epithelial and mesenchymal features. These five cases all occurred as well-defined masses visible on chest radiograph in middle-aged females, and were treated by surgical excision. Histopathologically, low and high grades of malignancy are found. Well-formed racimose glands with cytoplasmic vacuolization resemble endometrioid carcinoma. Neoplastic columnar cells have abundant glycogen in the cytoplasm. Morules of cells within the glands have optically clear nuclei. Ultrastructurally, the optically clear nuclei are occupied by a filamentous substructure of chromatin. Multiple neuroendocrine hormones are present in low-grade malignancy. Nuclear pleomorphism, lymphatic invasion, multifocal necrosis, lack of mesenchyme at the pulmonary interface, and restricted neuroendocrine expression suggest high-grade malignancy. A mesenchymal stroma surrounding the glands is an intrinsic part of the neoplasm, but the stroma does not appear malignant, and did not form part of the metastasis in the single case where a metastasis occurred. Stromal cells show fibroblastic and myofibroblastic differentiation. Pulmonary endodermal tumor resembling fetal lung typically is a low-grade malignancy, with a better prognosis than the majority of lesions sometimes described as pulmonary blastoma or adenocarcinoma of fetal lung type.     

Morule-like features and tumor-associated lymphoid proliferation in gallbladder carcinoma

A unique case of gallbladder carcinoma with morule-like features and tumor-associated lymphoid proliferation in a 53-year-old man is presented. The surgically resected gallbladder demonstrated a polypoid tumor with a thin stalk, measuring 1.3 x 0.5 cm. Histologically, a well-differentiated tubular adenocarcinoma was accompanied by multiple spindle cell nodules. The stroma of the tumor showed dense lymphocytic infiltrate. Immunohistochemically, the spindled cell nodules were diffusely positive for cytokeratin AE1/AE3 but negative for S-100, NSE, and chromogranin A. The immunohistochemical results considered to be spindle cell nodules were morule-like features. Intranuclear expression of beta-catenin was observed in morule-like features and carcinoma cells. Ki-67 labeling index was 16.7% of carcinoma cells, but Ki-67 immunoreactivity was negative in spindle cell nodules; therefore, morule-like features were considered to represent metaplastic foci of carcinoma cells and not nodular growth of carcinoma cells. Although the exact pathogenesis of marked lymphoid proliferation in the stroma remained unknown, tumor-produced substances may derive from lymphoid proliferation.     

Pulmonary blastoma with germ cell (yolk sac) differentiation: report of two cases.

Pulmonary blastoma is a rare lung neoplasm of disputed histogenesis and variable biologic behavior. Typical cases contain both epithelial and mesenchymal tissues, and a variety of patterns of differentiation have been described. While expression of oncofetal antigens in these tumors has been noted rarely, a coexisting component of germ cell tumor has not been reported previously. We describe the clinical and pathologic features of two cases of pulmonary blastoma having alpha-fetoprotein production and histologic areas of yolk sac tumor. We also report the finding of immunohistochemical staining of fetal lung tissue for alpha-fetoprotein.     

Morules with optically clear nuclei in ovarian borderline endometrioid tumor

Optically clear nuclei (OCN) have been observed in morules of some neoplasms and in some conditions unrelated to the development of the morules. We first report a case of ovarian borderline endometrioid tumor (BET) showing the morules associated with OCN. The patient was a 47-year-old premenopausal woman with a left ovarian cystic tumor, atypical endometrial hyperplasia, and elevated serum levels of FSH, LH, estradiol, and CA 125. The resected ovarian tumor measured 6 cm in diameter, and showed a papillary growth. Histologically, the ovarian tumor was consistent with BET, and the morules with OCN were scattered. Immunohistochemically, OCN were proven to be rich in biotin. An aberrant nuclear expression of beta-catenin was observed in both the tumor cells and the morular cells. Our case may suggest the possibility that the appearance of OCN with or without morules in ovarian tumors is related to endometrioid differentiation of the tumor cells, and should be recognized as a diagnostic clue of ovarian endometrioid tumors. Although female sex hormones have been reported to play a role in the occurrence of OCN, the participation of beta-catenin mutation has also been suggested.     

Non-endometrioid carcinomas of the uterine corpus: a review of their pathology with emphasis on recent advances and problematic aspects

This review considers the clinical and pathologic features of the various histologic subtypes of endometrial carcinoma excluding those of pure endometrioid type, as the latter tumors were the subject of a previous contribution in the Journal (Vol. 9, No. 2). Non-endometrioid carcinomas, which account for about 10% of endometrial carcinomas, may pose a great array of problems in differential diagnosis, including their distinction not only from benign lesions but also endometrioid carcinoma and various tumors that may secondarily involve the uterine corpus. The most common subtypes are serous, mucinous, and undifferentiated. Rarer tumors are clear cell, squamous, transitional cell carcinomas, and a variety of poorly differentiated carcinomas with unusual forms of differentiation, such as hepatoid carcinoma, carcinomas with trophoblastic elements, and giant cell carcinoma. Mixed carcinomas, which are common, are also discussed, including those with a component of endometrioid carcinoma. The final section deals with endometrial involvement by metastatic tumors, lesions that, albeit rare, are sometimes neglected in the differential diagnosis of endometrial carcinomas. Important aspects emphasized are: (1) The potential for serous carcinoma to be mimicked by various forms of papillary endometrioid carcinoma. (2) The rarity of clear cell carcinoma and the greater frequency of clear cells in endometrioid carcinoma. (3) The frequency of mucinous epithelium in tumors of mixed cell type. (4) The frequency with which neoplastic mucinous epithelium originates from the endometrium. (5) The striking degree of differentiation of some squamous cell carcinomas. (6) The occasional predominance of non-endometrioid carcinomas (especially serous or undifferentiated carcinoma) within malignant mullerian mixed tumors. (7) The spectrum of reactive epithelial changes and other non-neoplastic abnormalities that may mimic serous or clear cell carcinoma.     

β-Catenin Expression Pattern in Stage I and II Ovarian Carcinomas : Relationship with β-Catenin Gene Mutations, Clinicopathological Features, and Clinical Outcome

The immunohistochemical expression pattern of beta-catenin has been correlated with beta-catenin gene mutations, clinicopathological features, and disease outcome in 69 stage I and II ovarian carcinomas. beta-Catenin expression was localized in the nuclei, in addition to the cytoplasm and membrane, in 11 tumors (16%): nine endometrioid carcinomas with widespread nuclear expression and two serous carcinomas with focal nuclear expression. The remaining 58 carcinomas (84%) only had membranous beta-catenin expression. All but one of the endometrioid carcinomas with nuclear beta-catenin expression had considerable squamous metaplasia, and five of these cases had large areas of endometrioid tumor of low malignant potential. In addition, beta-catenin nuclear expression was observed in atypical epithelial cells in endometriotic glands adjacent to an endometrioid carcinoma. Sequencing was performed on 25 tumors and corresponding normal tissue: all 13 endometrioid tumors as well as 12 carcinomas of other histological types (four serous, two clear cell, two mucinous, and two mixed). There were oncogenic mutations in the phosphorylation sequence for GSK-3beta in exon 3 of the beta-catenin gene in seven endometrioid carcinomas with beta-catenin nuclear expression. Three mutations affected codon 32 (D32G, D32Y, and D32Y), one affected codon 33 (S33C), two affected codon 37 (S37C and S37F), and one affected codon 41 (T41A). No mutations were observed in the other 18 carcinomas analyzed, comprising two endometrioid and two serous carcinomas with beta-catenin nuclear expression, and 14 carcinomas of different histological types with only membranous expression. In the univariate and multivariate survival analyses, beta-catenin nuclear expression was selected as an indicator of good prognosis, because no patient whose tumor expressed beta-catenin in the nuclei showed relapses or died, in contrast to the 19 relapses and deaths among patients with tumors that only had beta-catenin membranous expression, including three of the four patients with endometrioid carcinomas. Oncogenic beta-catenin mutation is characteristic of a group of endometrioid carcinomas with a good prognosis, most of which originate from previous benign or borderline lesions. Endometrioid carcinomas with exclusively membranous expression of beta-catenin seem to represent a different subgroup of carcinomas that probably have a worse prognosis. In early-stage ovarian cancer, determination of the beta-catenin expression pattern could prove to be a useful marker for selecting low-risk patients.     

Clinicopathologic features and genetic alterations in endometrioid carcinoma of the uterus with villoglandular differentiation

Serious and endometrioid carcinomas differ dramatically in their clinical behavior; however, the specific significance of villoglandular (papillary) differentiation in endometrioid carcinoma has been studied rarely. We compared the clinicopathologic features and genetic alterations in 28 villoglandular endometrioid carcinomas compared with 60 nonvilloglandular endometrioid carcinomas and 60 healthy women. The study revealed a slight increase in the frequency of early-stage disease in villoglandular tumors compared with nonvilloglandular tumors. No differences were observed in the age at onset or cellular grade. The oncogene and susceptibility gene analyses revealed a positive association of K-ras oncogene mutation and germline variants of the cytochrome P-450 1A1 (CYP1A1) gene and an inverse association of the p53PIN3 variant with villoglandular carcinomas, whereas no differences were observed in the c-erbB2/neu oncogene amplification or the methylenetetrahydrofolate reductase germline variant. Finally, a positive association was found between CYP1A1 and methylenetetrahydrofolate reductase variants and the presence of papillary differentiation in the myometrial component. The results suggest that the villoglandular differentiation pattern arises without aggressive clinicopathologic features in a genetic background of transforming and carcinogen-metabolism genes, characteristic of estrogen-related endometrial tumors (type 1) not exhibiting an unfavorable prognosis.     

Beta-catenin mutations in pulmonary blastomas: association with morule formation

To elucidate the contribution of beta-catenin gene mutation to the development of pulmonary blastomas, we analysed mutations in three well-differentiated fetal adenocarcinomas (WDFAs) and six biphasic pulmonary blastomas (BPBs). For comparison, eight clear-cell adenocarcinomas with fetal lung features were also examined. beta-Catenin gene mutations were found in all three WDFAs, two BPBs, and none of the clear-cell adenocarcinomas with fetal lung features. All tumours with mutations had a common histological feature, namely morule formation, and showed a characteristic heterogeneous beta-catenin expression pattern that was revealed by immunohistochemistry. Strong nuclear/cytoplasmic expression of beta-catenin was seen in clustered cells in the morular areas and in single cells in glands, and was associated with neuroendocrine differentiation. As beta-catenin mutations are rare among lung tumours, this distinctive genetic feature, which is also immunohistochemically detectable as overexpression with a heterogeneous pattern, has diagnostic significance. The presence of this common genetic alteration found in both WDFA and BPB implies a histogenetic linkage between these tumours.     

Frequent nuclear beta-catenin accumulation and associated mutations in endometrioid-type endometrial and ovarian carcinomas with squamous differentiation

Focal squamous differentiation is a common feature of endometrioid endometrial and ovarian carcinomas (E-Em and E-Ova Cas). A close association between mutated beta-catenin accumulation and alteration in cellular morphology has recently been demonstrated in murine L cell lines. To clarify the possible role of beta-catenin abnormalities and changes in tumour morphology, 60 grade (G) 1 or G2 E-Em Cas with areas of squamous differentiation (SqD), including morules and squamous metaplastic (SqM) foci, as well as 32 G1 or G2 tumours without such lesions, were investigated and the results compared with findings for c-jun and wnt-1 expression. Twenty-three E-Ova Cas, with and without SqD lesions, were also examined. In E-Em Cas, frequent nuclear beta-catenin accumulation was observed in 22 (84.6%) of 26 tumours with morules and 15 (45.5%) of 33 with SqM foci, in contrast to 4 (12.5%) of 32 without such lesions. Similar findings were also noted for mutations in exon 3 of the beta-catenin gene, involving codons 32, 33, 34, 37, 41, and 45, the single nucleotide substitutions being identical between SqD and the surrounding carcinoma tissue in most informative cases. The mutations were positively related to nuclear immunopositivity, but inversely to membrane expression, while there was no association with the status of c-jun or wnt-1. These E-Ova Cas, nuclear beta-catenin accumulation and mutations were limited to tumours with SqD features, independent of c-jun and wnt-1 status. These data indicate that beta-catenin abnormalities are relatively common in E-Em and E-Ova Cas with SqD features, implying a role in the squamous differentiation of tumour cells, not necessarily related to c-jun and/or wnt-1 status.     

Fine needle aspiration cytology of invasive micropapillary carcinoma of the breast

AIM: To determine the pathognomonic diagnostic cytological features of invasive micropapillary carcinoma of the breast which is a poor prognostic subtype of infiltrating ductal carcinoma. METHODS: A series of 20 histologically proven tumours were reviewed retrospectively to evaluate the various cytological features, including tumour morules, isolated malignant cells, staghorn epithelial structures, mucinous background and apocrine metaplasia. RESULTS: Tumour morules formation and isolated malignant cells were the two most reliable and constant cytological features, being present in 75% (15/20 cases) of cases. Staghorn epithelial structures were present in 35% (7 cases). Mucinous background (2 cases, 10%) and apocrine metaplasia (4 cases, 20%) of the tumour cells were seen in a few cases only and did not appear very helpful. CONCLUSION: Tumour morules formation, isolated malignant cells and staghorn epithelial structures are the most reliable cytological features, and the presence of these should raise suspicion of invasive micropapillary carcinoma.     

Morules in cribriform-morular variant of papillary thyroid carcinoma: Immunohistochemical characteristics and distinction from squamous metaplasia

Morules are a diagnostic clue to the cribriform-morular variant (C-MV) of papillary thyroid carcinoma, and are superficially similar to squamous metaplasia. In order to clarify the histogenesis of morules and differentiate them from squamous metaplasia, we immunohistochemically compared the morules in five cases of C-MV with squamous metaplasia in six cases of diffuse sclerosing variant (DSV) of papillary thyroid carcinoma. The squamous metaplastic cells were immunopositive for low- and high-molecular-weight cytokeratin, whereas the morular cells were negative or focally positive. Vimentin-positive cells were observed focally in the morules and squamous metaplasia, except for one case of CMV that showed intense positivity. The morular cells showed weak cytoplasmic positivity for beta-catenin, and the cell membrane was not highlighted. Some nuclei of the morular cells were also positive for this antibody. Beta-catenin was intensively positive along the cell membrane of the metaplastic cells, and did not react against the nuclei or cytoplasm. Bcl-2 was positive in the morular cells, but negative in the metaplastic cells. S-100 protein-positive dendritic cells were observed in the metaplastic nests, but not in the morules. We argue that morules appear in connection with nuclear and cytoplasmic aberrant localization of beta-catenin, and are not an early form of squamous metaplasia.     

A case of breast carcinosarcoma with associated myoepitheliosis-like change and morule-like squamous metaplasia. Discussion of possible pathogenetic links

Metaplastic breast carcinomas are histologically heterogeneous and rare tumours constituting <1% of breast malignancies. We present here a case of carcinosarcoma consisting of a predominant sarcomatous component and a minor component of squamous cell carcinoma, a combination seen in <5% of metaplastic breast carcinomas. The presence of myoepitheliosis-like change and morule-like foci of early squamous differentiation within partially uninvolved residual breast tissue provided an opportunity for a detailed immunohistochemical analysis, with intention to look into possible pathogenetic links with the invasive elements. In situ evidence implicating the myoepithelial cell as cell of origin is presented and discussed in view of recent in vitro studies using immortalized human mammary stem/progenitor cell lines.     

Ovarian atypical endometriosis: its close association with malignant epithelial tumours

The incidence of ovarian atypical endometriosis and its association with malignant epithelial tumours in a consecutive series of cases during the period 1987 to 1995 were studied. Atypical glandular changes were observed in four (1.7%) of 255 ovarian endometriosis cases and one patient with ovarian atypical endometriosis developed subsequent endometrioid carcinoma in the abdominal wall. Fifty-four (24.1%) of the 224 ovarian cancers were associated with ovarian endometriosis; 21 with typical and 33 with atypical endometriosis. Clear cell carcinomas and endometrioid carcinomas were most frequently associated with endometriosis, with 54% (27 of 50 cases) and 41.9% (13 of 31), respectively. Atypical endometriosis was found in 18 clear cell carcinomas, in seven endometrioid carcinomas, in four serous carcinomas, in three mucinous borderline tumours, and in one serous borderline tumour. In 13 cases, the atypical endometriosis was in contiguity with malignant epithelial tumours. We consider that atypical endometriosis possesses a precancerous potential or is most frequently associated with clear cell and endometrioid carcinomas. Close screening of cellular atypia or hyperplasia in ovarian endometriosis and careful long-term follow-up of patients with atypical endometriosis is required.     

女性腹膜原发癌的诊断及鉴别诊断

目的 讨论女性腹膜原发癌的组织发生、形态学特点以及诊断要点和鉴别诊断。方法 用普通形态学方法结合组织化学ＰＡＳ法及免疫组织化学染色观察６例女性腹膜原发癌的形态特点。结果 诊断腹膜原发浆液性乳头状癌４例,腹膜原发的宫内膜样癌及移行细胞癌各１例。结论 腹膜原发癌的组织相发于卵巢的分化程度相同的同类型肿瘤一致,诊断腹膜原发癌必须证实双侧卵巢、子宫、泌尿道无同类型肿瘤。此类肿瘤被认为是来源于第二苗勒系统,     

Association of cortactin, fascin-1 and epidermal growth factor receptor (EGFR) expression in ovarian carcinomas: correlation with clinicopathological parameters

Cortactin, fascin-1 and EGFR are recognized as important factors in tumor progression. We tested the hypothesis that cortactin, fascin-1 and EGFR expression correlates with clinicopathological parameters of the four most common ovarian surface epithelial carcinomas--serous cystadenocarcinoma, mucinous cystadenocarcinoma, endometrioid adenocarcinoma, and clear cell carcinoma. Immunohistochemical analysis of cortactin, fascin-1 and EGFR was performed using tissue microarrays of 172 specimens comprising 69 serous cystadenocarcinomas, 44 mucinous cystadenocarcinomas, 45 endometrioid adenocarcinomas and 14 clear cell carcinomas. All ovarian carcinomas showed significant expression of cortactin, fascin-1 and EGFR in staining intensity, tumor percentages and immunostaining scores. In addition, higher immunostaining scores of fascin-1 correlated with more advanced cancer stages (TNM), poorer histological differentiation and poorer survival rate of mucinous cystadenocarcinoma. Similarly, higher immunostaining scores of cortactin correlated with T stages and histological differentiation of serous cystadenocarcinoma. The immunostaining scores of EGFR did not correlate with TNM stages, tumor differentiation or prognosis in the four ovarian surface epithelial carcinomas. Our findings suggest that cortactin and fascin-1 may serve as good biomarkers in evaluating aggressiveness of ovarian serous and mucinous cystadenocarcinoma. And the pharmacological inhibitors of fascin-1 activity may slow down tumor progression and prolong survival time in patients with mucinous cystadenocarcinoma.