Collision of uterine rhabdoid tumor and endometrioid adenocarcinoma: a case report and review of the literature

Uterine collision tumor. Case report and review of the literature

Objectives

To report the case of a patient with a uterine collision tumor and to conduct a review of the literature.

Material and methods

A 76-year-old patient who presented to the national cancer referral center in Bogota (Colombia), where she was diagnosed with a uterine collision tumor consisting of a seroustype endometrial adenocarcinoma and a cervical adenosarcoma. The patient underwent surgical treatment followed by chemotherapy and supplemental radiotherapy, and died 16 months later. A search was conducted in the Medline via PubMed and Embase databases, including reports and case series of women with a diagnosis of uterine collision tumor, with retrieval of information regarding diagnosis, treatment and prognosis. A narrative summary of the findings was made.

Results

The search identified 36 titles, of which 14 studies with 17 patients were included. The most frequent histopathological diagnosis was endometrial adenocarcinoma and high and low grade endometrial sarcoma (47 %). Primary treatment was surgery and adjuvant treatment with chemotherapy and radiotherapy (15 %) was performed in close to 50 % of cases. One-year survival was 75 %.

Conclusions

No cases of uterine collision tumors with the histopathology or in the location of the reported case were found in the literature. If this reported case is taken into account, 2-year mortality is 28 %. Further studies to describe the immunohistochemistry, treatment and prognosis of this condition are needed.

SWI/SNF-deficient malignancies of the female genital tract

Mutations and other molecular events involving subunits of the SWI/SNF chromatin remodelling complex are common in a wide variety of malignancies, including those arising at various sites in the female genital tract. Endometrioid and clear cell carcinomas in the uterine corpus and ovary not uncommonly contain mutations in ARID1A and these also occur in other endometriosis-associated ovarian neoplasms such as seromucinous tumours. In these organs, mutations in SMARCA4, SMARCB1, ARID1A and ARID1B (with subsequent loss of corresponding protein expression as a reliable surrogate) are relatively common in undifferentiated carcinomas, including the undifferentiated component of dedifferentiated carcinoma. SMARCA4 mutations are extremely common (almost ubiquitous) in small cell carcinoma of the ovary of hypercalcaemic type (SCCOHT), occurring in about 98% of these neoplasms, often in association with epigenetic SMARCA2 loss. SMARCB1-deficient vulval neoplasms include epithelioid sarcoma and myoepithelial carcinoma, as well as related malignancies which defy easy classification. Recently the spectrum of SWI/SNF deficient female genital malignancies has been expanded to include SMARCA4-deficient undifferentiated uterine sarcoma and mural nodules of anaplastic carcinoma in ovarian mucinous neoplasms.

A Rare Case of Recurrent Pituitary Collision Tumors

Pituitary collision tumors are sporadically reported and rare. We present a case of pituitary collision tumors with nonfunctioning pituitary adenoma (NFPA) and craniopharyngioma. In order to look for any common activated pathway, we examined WNT/β-CATENIN signaling activation, known to be involved in tumorigenesis in both craniopharyngioma and NFPA. We found nuclear accumulation of β-CATENIN protein and expression of LEF1 protein, markers of active β-CATENIN signaling in the craniopharyngioma but not in the pituitary adenomas. In our case, the NFPA is invasive macroadenoma, which is a frequently identified type of pituitary adenoma in collision tumor cases. Recurrence of this tumor was first observed after 8 years of follow-up. Based on this case, we suggest that pituitary collision tumors require long-term follow-up.

Collision Tumor of Endometrial Large Cell Neuroendocrine Carcinoma and Low-Grade Endometrial Stromal Sarcoma: A Case Report and Review of the Literature

Large cell neuroendocrine carcinoma (LCNEC) of the endometrium is an exceedingly rare histologic subtype of endometrial cancer (0.8%). These tumors are highly aggressive with a propensity for metastasis and have a poor prognosis. Among the 17 cases reported to date, 9 cases were pure large cell neuroendocrine tumors and 8 were collision tumors of LCNEC with endometrial carcinomas (7 endometrioid and 1 serous). In this article, we report a case of collision tumor composed of an endometrial LCNEC and a low-grade endometrial stromal sarcoma (LGESS). The patient was a 48 year-old woman who presented with a large abdominal mass for about 10 years and underwent total hysterectomy, bilateral salpingo-oophorectomy, and tumor debulking. Microscopic evaluation demonstrated an LGESS with extensive osseous metaplasia that penetrated through the myometrium and invaded into pelvic and abdominal cavity, forming a 40.0-cm mass. Cytogenetic analysis of the LGESS revealed an abnormal female karyotype (45, XX) with multiple structural abnormalities. Incidentally, small foci of LCNEC were identified within the endometrium. The LCNEC focally invaded the myometrium with involvement of the endocervix, extensive lymph-vascular space invasion, and metastases to bilateral ovaries. Subsequently, the patient was treated with cisplatin/etoposide chemotherapy and had been doing well for about a year until presenting with recurrence of LCNEC in the abdomen. She passed away a month later due to medical complications. This report reveals an extremely rare endometrial collision tumor with unusual pathologic features and clinical presentations.

SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus): a clinicopathologic entity distinct from undifferentiated carcinoma

Small cell carcinoma of the ovary, hypercalcemic type is a rare, aggressive malignancy which usually occurs in young women and is characterized by mutations in SMARCA4, with few other alterations. We recently encountered uterine tumors with morphologic, immunohistochemical, and genetic similarities to small cell carcinoma of the ovary, hypercalcemic type. Herein we report the clinicopathologic and molecular features (using a targeted massively parallel sequencing [MPS] assay) of these tumors. The cases were diagnosed on cervical and endometrial biopsies (n = 2, 34, and 29 years) or hysterectomy and bilateral salpingo-oophorectomy (n = 3, 25, 33, and 58 years). The tumors were composed of sheets of large atypical epithelioid cells with prominent rhabdoid morphology, indistinguishable from the "large cell" variant of small cell carcinoma of the ovary, hypercalcemic type. In three cases, the ovaries were pathologically examined to exclude a primary ovarian malignancy. Immunohistochemically, four of four cases showed SMARCA4 loss, and were negative or only focally positive for keratins, EMA, and claudin-4. One of three cases was positive for WT-1. Targeted MPS was successfully performed on 4 of 5 tumors, and showed recurrent mutations in SMARCA4, with few other alterations. Of the cases diagnosed on hysterectomy, all had extensive lymphovascular invasion, extra-uterine spread, and marked infiltrative growth. These tumors were uniformly aggressive; all patients died of disease (median survival 7 months, range 1-43 months). We propose this entity be called "SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus)", a term which describes both the tumor's underlying molecular abnormality and its morphology. Its unique clinicopathologic and molecular features differentiate it from other related malignancies, including undifferentiated endometrial carcinoma, small cell carcinoma of the ovary (hypercalcemic type), and epithelioid sarcoma. We review and discuss previously reported "rhabdoid tumors of the uterus;" while they are a heterogenous group of tumors, some of them are likely examples of this entity. Correctly identifying cases of SMARCA4-deficient uterine sarcoma from histologic mimics is important as it may have prognostic, predictive, and germline implications.

Pancreatic Collision Tumor of Ductal Adenocarcinoma and Neuroendocrine Tumor

A pancreatic collision tumor is a rare entity that can be challenging to diagnose. We present a very rare case of a pancreatic collision tumor composed of both a neuroendocrine tumor and a ductal adenocarcinoma. Preoperative diagnosis was clinically challenging because both the radiology and fine-needle biopsy were consistent with a typical neuroendocrine mass. However, gross examination of the mass postoperatively revealed neuroendocrine cells with rare foci of ductal adenocarcinoma without a transition zone. Awareness of this entity is important so that medical practitioners consider pursuing surgical management of pancreatic lesions that otherwise would be managed exclusively with surveillance.

A Rare Collision Tumour of Uterus- Squamous Cell Carcinoma and Endometrial Stromal Sarcoma

Collision tumours are defined by co-existence of two tumours in the same or adjacent organs which are topographically and histologically distinct with minimal or no histological admixture. Collision tumours have been described in many organs notably thyroid, brain, adrenal gland, stomach and rarely uterus. Most of the collision tumours reported in uterus have two components; an adenocarcinoma and a sarcoma. We report a case of a 60-year-old lady who presented with complaints of post-menopausal bleeding. A cervical biopsy was performed which showed a non-keratinizing squamous cell carcinoma of cervix. Intra-operatively the uterus was bulky with a 6 cm x 5 cm polypoidal mass in the endometrial canal along with a 2 cm friable cervical growth. The fleshy uterine cavity mass was a spindle cell tumour with moderate pleomorphism and frequent mitosis. It was immunopositive for CD10 and negative for smooth muscle actin and cytokeratin 5/6. The other growth showed non-keratinizing squamous cell carcinoma which was positive for cytokeratin 5/6. Based on the distinct topographical location and limited areas of tumour admixture of the two tumours, a diagnosis of collision tumour of uterus comprising of endometrial stromal sarcoma (high grade) uterus and squamous cell carcinoma cervix was made.

Three histologically distinct cancers of the uterine corpus: A case report and review of the literature

Collision tumors, which are characterized by the coexistence of two or more completely distinct and independent tumors in the uterine corpus, are very rare. A collision tumor is mainly composed of two distinct tumor types, epithelial and mesenchymal. To the best of our knowledge, there has only been a single case in which a choriocarcinoma with an endometrial carcinoma were coexistent but histologically distinct. We herein report the first case of a collision tumor in a 52-year-old woman, with a history of two pregnancies and two deliveries. The collision tumor was composed of three histologically distinct neoplasms in the uterine corpus, namely an endometrioid carcinoma, an undifferentiated carcinoma and a choriocarcinoma. The patient underwent hysterectomy, bilateral adnexectomy and pelvic lymph node dissection, followed by six cycles of adjuvant chemotherapy with paclitaxel/carboplatin due to the high risk of endometrial cancer, and an additional five cycles of chemotherapy with methotrexate, as the β-human chorionic gonadotropin level was beyond the normal range. Following adjuvant chemotherapy, the tumor markers were within normal limits and no relapses of the cancer have been observed during 1 year of follow-up. Diagnosing a collision tumor prior to surgery is difficult if the neoplasms are in close proximity, or if one of the tumors predominates. Careful pathological examination is crucial for accurately diagnosing the neoplasms in a collision tumor and ensuring appropriate management and a favorable prognosis.

[Metastatic collision tumour. A case report]

BACKGROUND

Collision tumours are extremely rare. They are defined by the presence of two tumours of different histological origin in the same organ.

CLINICAL CASE

A 71 year old female with history of a carcinoid tumour removed 20 years ago without any recurrence. The patient was admitted with intestinal occlusion symptoms secondary to a right flank abdominal tumour. An exploratory laparotomy was performed, removing the tumor and applying optimal debulking. The histopathological study reported bilateral ovary adenocarcinoma, as well as metastatic collision tumour of two histological types: well differentiated adenocarcinoma and a mixed malignant mesodermic Mullerian tumor. The patient was treated with adjuvant chemotherapy with poor results (death in 24 months).

CONCLUSIONS

The presence of collision tumours is extremely rare. There are no statistics or specific treatment reported. Diagnosis is made with histopathology. At the moment, no similiar cases have been reported.

Pattern of SMARCB1 (INI1) and SMARCA4 (BRG1) in poorly differentiated endometrioid adenocarcinoma of the uterus: analysis of a series with emphasis on a novel SMARCA4-deficient dedifferentiated rhabdoid variant

The role of the switch/sucrose nonfermenting chromatin remodeling complex in the initiation and progression of cancer is emerging. In the female genital tract, only ovarian small cell carcinoma, hypercalcemic type harbors recurrent inactivating SMARCA4 mutations. Otherwise, only rare case reports documented SMARCB1 involvement in endometrial cancer. We analyzed 24 grade 3 uterine endometrioid adenocarcinomas and 2 undifferentiated carcinomas for immunohistochemical expression of SMARCB1 and SMARCA4. All tumors showed high-grade nuclear features with a predominance of solid growth pattern. All cases showed intact nuclear SMARCB1 expression in all tumor cells. However, 1 case of a 78-year-old woman showed complete loss of SMARCA4 in 90% of the tumor with retained expression in 10% of the tumor. The SMARCA4-intact component was a moderate-to-poorly differentiated endometrioid adenocarcinoma. The SMARCA4-deficient dominating component showed solid growth of highly anaplastic undifferentiated large cells with prominent rhabdoid features. None of the 25 SMARCA4-intact cases showed rhabdoid cell morphology. To our knowledge, this is the first systematic study of SMARCB1 and SMARCA4 expression in endometrioid adenocarcinoma of uterus and the first description of a novel SMARCA4-deficient variant of dedifferentiated/undifferentiated endometrial carcinoma. The presence of a differentiated SMARCA4-intact endometrioid component points to a novel pathway of dedifferentiation in endometrioid adenocarcinoma as a consequence of a "second hit." This case further underlines the close link between the "rhabdoid phenotype" and the SWI/SNF pathway.

The expanding family of SMARCB1(INI1)-deficient neoplasia: implications of phenotypic, biological, and molecular heterogeneity

Since the description of atypical teratoid/rhabdoid tumors of the central nervous system and renal/extrarenal malignant rhabdoid tumors in children, the clinicopathologic spectrum of neoplasms having in common a highly variable rhabdoid cell component (0% to 100%) and consistent loss of nuclear SMARCB1 (INI1) expression has been steadily expanding to include cribriform neuroepithelial tumor of the ventricle, renal medullary carcinoma and a subset of collecting duct carcinoma, epithelioid sarcoma, subsets of miscellaneous benign and malignant soft tissue tumors, and rare rhabdoid carcinoma variants of gastroenteropancreatic, sinonasal, and genitourinary tract origin. Although a majority of SMARCB1-deficient neoplasms arise de novo, the origin of SMARCB1-deficient neoplasia in the background of a phenotypically or genetically definable differentiated SMARCB1-intact "parent neoplasm" has been convincingly demonstrated, highlighting the rare occurrence of rhabdoid tumors as "double-hit neoplasia." As a group, SMARCB1-deficient neoplasms occur over a wide age range (0 to 80 y), may be devoid of rhabdoid cells or display uniform rhabdoid morphology, and follow a clinical course that varies from benign to highly aggressive causing death within a few months irrespective of aggressive multimodality therapy. Generally applicable criteria that would permit easy recognition of these uncommon neoplasms do not exist. Diagnosis is based on site-specific and entity-specific sets of clinicopathologic, immunophenotypic, and/or molecular criteria. SMARCB1 immunohistochemistry has emerged as a valuable tool in confirming or screening for SMARCB1-deficient neoplasms. This review summarizes the different phenotypic and topographic subgroups of SMARCB1-deficient neoplasms including sporadic and familial, benign and malignant, and rhabdoid and nonrhabdoid variants, highlighting their phenotypic heterogeneity and molecular complexity.

Collision of three histologically distinct endometrial cancers of the uterus

A collision tumor is defined by the presence of two separate masses in one organ, which are pathologically distinct. We described a 70-yr-old patient who complained of abnormal vaginal bleeding with a collision tumor of the uterine corpus. The patient received total hysterectomy, bilateral salphingo-oophorectomy, bilateral pelvic-paraaortic lymphadenectomy, omentectomy, and intraperitoneal chemotherapy. The uterine corpus revealed three separate masses, which were located at the fundus, anterior and posterior wall. Each tumor revealed three pathologically different components, which were malignant mixed müllerian tumor, papillary serous carcinoma, and endometrioid adenocarcinoma. Among these components, only the papillary serous carcinoma component invaded the underlying myometrium and metastasized to the regional lymph node. Adjuvant chemotherapy and radiation therapy were performed. The patient is still alive and has been healthy for the last 8 yr. We have reviewed previously reported cases of collision tumors which have occurred in the uterine corpus.

Heterologous and rare homologous sarcomas of the uterine corpus: a clinicopathologic review

Pure sarcomas of the uterine corpus are uncommon, constituting less than 3% of all malignancies at this site, and most of them are leiomyosarcomas and endometrial stromal sarcomas. Rare histotypes of homologous sarcomas and heterologous sarcomas are occasionally encountered, and the absence of significant accumulated experience with these histotypes at this location may potentially raise diagnostic and patient management difficulties. In this article, the clinicopathologic attributes of all earlier reported sarcomas of the uterine corpus other than leiomyosarcomas and endometrial stromal sarcomas are summarized. Included are embryonal rhabdomyosarcoma, pleomorphic rhabdomyosarcoma, angiosarcoma, alveolar soft part sarcoma, malignant perivascular epithelioid cell tumors (PEComas), osteosarcoma, chondrosarcoma, liposarcomatous tumors, malignant extrarenal rhabdoid tumors, Ewing sarcoma/primitive neuroectodermal tumor, and other rare histotypes. Embryonal rhabdomyosarcoma (20%), Ewing sarcoma/primitive neuroectodermal tumor (17%), angiosarcoma (14%), and pleomorphic rhabdomyosarcoma (13%) appeared to be more common than the others, although there was no single overwhelmingly prevalent histotype in the group. A subset, including embryonal rhabdomyosarcoma, alveolar soft part sarcoma, and PEComas, peak in the premenopausal years, but most of the others were observed in postmenopausal women. Favorable outcomes have been reported for the patients diagnosed with alveolar soft part sarcoma, and the prognosis for their counterparts with PEComa remains a matter of debate. Multimodal therapeutic approaches to contemporary patients with embryonal rhabdomyosarcomas have resulted in significantly improved outcomes. Unfortunately, most of the other sarcomas have been associated with rapid tumor progression and unfavorable patient outcomes. The differential diagnosis for these sarcomas is often extensive and varies by histotype, but their accurate diagnosis fundamentally requires the careful exclusion of biphasic malignancies.

Endometrial and ovarian carcinomas with undifferentiated components: clinically aggressive and frequently underrecognized neoplasms

Carcinomas of the endometrium and ovary with undifferentiated components are uncommon neoplasms that are likely underdiagnosed. They are important to recognize as they have been shown to be clinically aggressive. We identified 32 carcinomas with undifferentiated components as defined by Silva and co-workers, 26 endometrial and 6 of ovarian origin. The patient age ranged from 21 to 76 years (median 55); 40% of patients were <or=50 years of age. Most patients (58% of endometrial and 83% of ovarian carcinomas with undifferentiated components) presented at advanced stages (FIGO III-IV). Pelvic and para-aortic lymph nodes were the most frequent sites of metastases. Twenty tumors, entirely undifferentiated, consisted of sheets of dyshesive, ovoid cells with uniform, large vesicular nuclei, whereas 12 tumors contained combinations of differentiated endometrioid adenocarcinoma with undifferentiated components. Although most undifferentiated tumors had a monotonous cytologic appearance without prominent stroma, six showed focal nuclear pleomorphism and eight cases had variably sized zones of rhabdoid cells in a background of myxoid stroma. The tumors were frequently misdiagnosed; they received a wide range of diagnoses, including FIGO grade 2 or 3 endometrioid carcinoma, carcinosarcoma, high-grade sarcoma including endometrial stromal sarcoma, neuroendocrine carcinoma, lymphoma, granulosa cell tumor and epithelioid sarcoma. Up to 86% of the cases showed focal, but strong keratin and/or epithelial membrane antigen staining, with CK18 being the most frequently positive keratin stain. They were predominantly negative for neuroendocrine markers, smooth muscle markers and estrogen receptor/progesterone receptor. Mismatch repair protein expression by immunohistochemistry was evaluated in 17 cases, and 8 (47%) were abnormal (7 with loss of MLH1/PMS2 and 1 with MSH6 loss). Follow-up was available for 27 patients, although it was very short in many cases, ranging from 0.5 to 89 months (median 9 months). Eleven patients (41%) died of the disease in 0.5-20 months, four are alive with disease and twelve patients have no evidence of disease. Endometrial and ovarian carcinomas with undifferentiated components have a broad histologic differential diagnosis, but they show specific histologic features that should enable accurate diagnosis. These tumors can occur in young women, may be associated with microsatellite instability and behave in a clinically aggressive manner.

Smooth muscle tumors of the uterus: a practical approach

Smooth muscle tumors (SMTs) are the most frequent mesenchymal tumors of the uterus. The majority of the uterine SMTs are readily classificable as benign or malignant based on their gross and microscopic appearances. However, when unusual features are seen in some leiomyoma variants, the differential diagnosis with a leiomyosarcoma may become challenging. Moreover, diagnostic criteria for the different subtypes of leiomyosarcoma are not uniform. Finally, non-smooth muscle tumors that originate in the uterus may show overlapping histologic and even immunohistochemical features with uterine SMTs, more commonly with the spindle and epithelioid variants, complicating their correct classification. The diagnosis of malignant uterine SMTs has important prognostic and therapeutic implications. This review provides a practical approach to the diagnosis of uterine leiomyosarcoma based on a systematic assessment of histologic parameters as well as a systematic approach to its differential diagnosis based on histologic and immunohistochemical features.

Mutation of the INI1 gene in composite rhabdoid tumor of the endometrium

Composite rhabdoid tumors are typically adult tumors that contain a component of rhabdoid cells, which are characteristic of the aggressive childhood malignant rhabdoid tumor. Pediatric rhabdoid tumors are characterized by the inactivation of the hSNF5/INI1/SMARCB1 gene, with subsequent loss of expression of the protein. In contrast, only a single composite rhabdoid tumor has demonstrated involvement of the INI1 gene. In our study, INI1 protein expression was studied in 2 uterine carcinosarcomas with rhabdoid components (composite rhabdoid tumors). The rhabdoid component of 1 tumor showed lack of immunoreactivity for the INI1 protein and strong positivity for cyclin D1, whereas the adenocarcinomatous component of the tumor and both components of the second tumor were immunoreactive for the INI1 protein and negative for cyclin D1. Loss of one INI1 allele and a mutation in exon 7 of the remaining allele were detected in the first tumor, consistent with the immunohistochemistry results. Our results demonstrate that deletions and mutations of the INI1 gene can occur also in rare composite rhabdoid tumors of adulthood. Further studies are necessary, however, to determine the prognostic significance of this finding.

Uterine leiomyomas with inclusion bodies: An immunohistochemical and ultrastructural analysis of 12 cases

We describe 12 cases of leiomyoma with intracytoplasmic inclusion bodies, which were detected in a group of 447 leiomyomas examined at our institution between December 2005 and March 2006. Ten of these tumors were typical leiomyomas, and two cases represented atypical (bizarre) leiomyoma. In some cases, the presence of intracytoplasmic inclusion bodies resulted in a rhabdoid or skeletal muscle-like appearance of the tumor cells. Ultrastructurally, there were two types of inclusions. One of them consisted of an abnormal aggregation of intermediate and actin filaments. Another type of inclusions was composed of dense granular material without an apparent fibrillar structure. The ultrastructure of the inclusions correlates with immunohistochemical and histochemical stainings. The inclusions with apparent fibrillar arrangements were PAS negative, stained red by trichrome, and were, at least at the periphery, actin-, desmin-, and h-caldesmon-positive. The dense granular inclusions were at least focally PAS-positive, stained red by trichrome, and were negative immunohistochemically. The intracytoplasmic inclusions were found in atypical (bizarre) leiomyomas of the uterus and occasionally in epithelioid leiomyomas and leiomyosarcomas. However, to the best of our knowledge, these inclusions have not been found in typical uterine leiomyomas to date.

Lung adenocarcinoma metastasizing to cerebellopontine angle schwannoma (collision tumor)

Collision tumors are composed of two histologically distinct neoplasms which present at one location. Collision of a malignant tumor originating outside the central nervous system with a primary intracranial neoplasm is a rare event. Here we report on a CPA schwannoma containing a metastasis of adenocarcinoma in a 57-years old woman. Searching for the primary tumor resulted in the detection of a carcinoma in the superior lobe of the left lung.

Triple simultaneous primary gynecological malignancies in a 56-year-old patient

The occurrence of double simultaneous primary cancers is common. However, the occurrence of synchronous primary triple gynecological malignancies is an extremely rare event. In this report, the clinical and pathologic findings of a 56-year-old female patient with synchronous triple primary gynecological cancers including well-differentiated ovarian mucinous cystadenocarcinoma, well-differentiated endometrial endometrioid adenocarcinoma, and uterine leiomyosarcoma were presented. Synchronous primary, well-differentiated endometrial endometrioid adenocarcinoma and leiomyosarcoma of uterus without any ovarian neoplasm has only been once described in the English literature. To our knowledge, the presented patient is the first case in aspect of accompanying ovarian mucinous adenocarcinoma to endometrial endometrioid adenocarcinoma and leiomyosarcoma of uterus.

Skeletal Muscle-like and Rhabdoid Cells in Uterine Leiomyomas

We describe eight unusual uterine leiomyomas characterized by a component of cells that suggested skeletal muscle differentiation or resembled the rhabdoid cells of extrarenal rhabdoid tumors. All of the tumors were referred because of problems in differential diagnosis, particularly distinction from an epithelioid smooth muscle tumor, a smooth muscle tumor of uncertain malignant potential, or a tumor with skeletal muscle differentiation. The patients were aged 27 to 50 (mean, 38) years, and the presenting clinical features and gross appearance of the tumors were similar to those of typical uterine leiomyomas. On microscopic examination, seven of the tumors were well circumscribed, whereas one showed slight irregularity of its margin. The characteristic feature of the tumors was a variable number of rounded, polygonal, or strap-shaped cells with abundant deeply eosinophilic cytoplasm and fibrillar, or occasionally hyaline, intracytoplasmic globules. Cytoplasmic cross-striations were not identified. The cells usually had eccentric, round-to-oval nuclei with conspicuous nucleoli. A variable number of the rhabdoid/skeletal muscle-like cells, as well as cells without these features, contained multiple or multilobed, pleomorphic, hyperchromatic nuclei, thus qualifying the tumors as leiomyomas with bizarre nuclei. Foci of hydropic change were present in all of the tumors. The mitotic index was low (<1 mitotic figure/10 high-power fields) and necrosis was absent in all the tumors. The rhabdoid/skeletal muscle-like cells were immunoreactive for desmin and h-caldesmon, but not for cytokeratin (AE1/AE3) or skeletal muscle markers (myoglobin, Myo-D1, or myogenin). Intracytoplasmic whorls of intermediate filaments were observed in the cells of one case examined by electron microscopy; there was no ultrastructural evidence of skeletal muscle differentiation. The histologic, immunohistochemical, and ultrastructural features indicated that the peculiar cells in these leiomyomas likely represented smooth muscle cells with an unusual phenotype rather than the cells of uterine tumors with skeletal muscle differentiation, extrarenal rhabdoid tumors, or epithelioid smooth muscle tumors. An association with leiomyomas with bizarre nuclei also was suggested.

Double immunolabeling of central nervous system atypical teratoid/rhabdoid tumors

The central nervous system atypical teratoid/rhabdoid tumor (ATRT) is a highly malignant tumor with a heterogeneous immunohistochemical profile and with some morphologic similarity to central nervous system primitive neuroectodermal tumors (PNET). Although several studies have investigated double immunolabeling in PNET, we are aware of no studies of double labeling of ATRT. A total of 10 ATRT from surgical and consultation materials at the Children's Hospital of Philadelphia were selected and stained for a variety of antigens using indirect immunofluorescence to detect single and double labeling. Most tumor cells showed only single labeling; rare cells showed double labeling as follows: 70% of tumors coexpressed (VIM) and glial fibrillary acidic protein (GFAP), 30% smooth muscle actin and GFAP, 20% epithelial membrane antigen (EMA) and VIM, 20% EMA/GFAP, and 20% EMA/SMA. These results are discussed in view of current debates over the histogenesis of CNS PNET and ATRT, and in reference to the classification of rhabdoid tumors as an entity or phenotype.

Malignant biphasic uterine tumours: carcinosarcomas or metaplastic carcinomas?

Uterine carcinosarcomas (malignant mixed Mullerian tumours) are highly aggressive and have traditionally been regarded as a subtype of uterine sarcoma. However, in recent years convincing evidence has suggested that most, but not all, are monoclonal in origin rather than true collision tumours. Data confirm that the carcinomatous element is the "driving force" and that the sarcomatous component is derived from the carcinoma or from a stem cell that undergoes divergent differentiation. Thus, uterine carcinosarcomas are best regarded as metaplastic carcinomas, although the designation carcinosarcoma is likely to remain. Adjuvant treatment for uterine carcinosarcoma should probably be similar to that directed against aggressive high grade endometrial carcinomas rather than being sarcoma based. Importantly, a small proportion of uterine carcinosarcomas are true collision tumours and should be recognised as such because, in some instances, the prognosis may be better than for a similar stage carcinosarcoma.

Cervical carcinoma with rhabdoid phenotype: Report of two cases

This report documents two cases of cervical carcinomas having a prominent rhabdoid cell component. In one instance, rhabdoid cells were present as a component of endocervical adenocarcinoma, whereas in the other case, an undifferentiated cervical carcinoma developed a prominent rhabdoid phenotype on recurrence. Like tumors containing rhabdoid elements which have been described at other sites, these neoplasms behaved in an aggressive manner.