• 1.
  

  a) F b) F c) T d) F e) F

A Gynecologic Oncology Group prospective phase III randomised trial compared whole abdominal radiation to ifosfamide plus cisplatin as adjuvant treatment for completely resected uterine carcinosarcoma, stage I, II, III, or IV. This study showed marginally superior disease-free survival and overall survival for women assigned to chemotherapy treatment, compared with women assigned to whole abdominal radiation. The conclusion of the study was that future adjuvant treatment studies should be chemotherapy-based.

• 2.
  

  a) F b) F c) F d) F e) F

A phase III randomised trial of adjuvant whole abdominal radiation compared with observation did not show benefit to whole pelvis radiation therapy among women with stage I or II uterine leiomyosarcoma. A small phase III randomised trial of adjuvant doxorubicin did not show benefit. A prospective phase II study of gemcitabine plus docetaxel followed by doxorubicin showed encouraging 2-year progression-free survival rates; however, these data are limited because of the absence of a no-chemotherapy concurrent control group, and cannot be used as the basis for making this adjuvant treatment approach standard.

• 3.
  

  a) F b) T c) F d) F e) F

Three prospective phase II trials show efficacy for fixed-dose-rate gemcitabine-docetaxel. This regimen is a reasonable first-line choice, particularly for women whose congestive heart failure history precludes the use of doxorubicin. Liposomal doxorubicin, as a single agent, showed a 15% response rate in a phase II Gynecologic Oncology Group trial for women who have not had prior chemotherapy treatment. Liposomal doxorubicin is not routinely substituted for doxorubicin for the treatment of uterine leiomyosarcoma. Phase II trials have shown cisplatin to be inactive in uterine leiomyosarcoma. Aromatase inhibitors are not supported by prospective data demonstrating objective responses. Retrospective data show limited objective response rates (under 10%) among highly selected women with oestrogen receptor and progesterone receptor positive tumours. Tamoxifen use has been associated with increased risk for uterine sarcomas, and is not generally used for the treatment of metastatic disease.

• 4.
  

  a) F b) F c) F d) F e) T

Stage I leiomyosarcomas are subdivided according to tumour size. Lymph-node status and myometrial invasion are not taken into consideration in the staging system. Stage I low-grade endometrial stromal sarcoma are subdivided according to tumour size. Lymph-node status is not taken into consideration in the staging system. In a recent study, Garg et al. assessed the correlation of the new FIGO staging system with survival in women with stage I low-grade endometrial stromal sarcomas extracted from the Surveillance, Epidemiology and End Results (SEER) database. Among the 310 women with low-.grade disease, difference in 5-year overall survival between stages IA (< 5 cm) and IB (> 5 cm) was statistically significant (100% v 93.5%; P = 0.003). Stage I adenosarcomas are subdivided according to myometrial infiltration. Sarcomatous overgrowth (i.e the presence of pure sarcoma without epithelial elements in more than 25% of the tumour) is a risk factor for recurrence, but it is not taken into consideration in the staging system. Carcinosarcomas are staged according to the new FIGO staging system for endometrial carcinomas.

• 5.
  

  a) F b) T c) F d) F e) T

A review of the literature on lymph-node metastases in uterine leiomyosarcoma showed a low incidence of occult retroperitoneal involvement (about 4–11%) at least in women without macroscopic spread of the disease and a limited prognostic relevance for lymph-nodal status. Some recent data on small studies have reported nodal involvement in 33–45% of women undergoing lymph-node dissection during primary or secondary surgery. In the study by Chan et al. data from 831 women with endometrial stromal sarcoma were collected from the SEER database. Lymph-node involvement was detected in 9.9% of 282 women who had lymphadenectomy, and it was found to be a prognostic factor for poorer survival. The survival of women who underwent a lymph-node dissection, however, was not significantly different compared with that of women who did not. No meta-analysis has been carried out on this subject. Retrospective studies have produced controversial data. According to a Gynecologic Oncology Group study on prognostic factors in early stage uterine sarcoma, women with uterine carcinosarcoma who had either para-aortic or pelvic lymph-node metastases had significantly greater failure rates than those without node metastases. The magnitude of this effect was dependent on the cell type. Among homologous tumours, lymph-node involvement increased the risk of failure by 4.38- fold, whereas the risk increased 1.8–fold among heterologous tumours.

• 6.
  

  a) T b) F c) F d) F e) F

Some investigators have reported that progesterone receptor positivity seems to be associated with a lower risk of recurrence in women with leiomyosarcoma. Both p16 over-expression and p53 over-expression are more frequent in uterine leiomyosarcomas than in leiomyomas . The assessment of p16, in combination with p53 and Ki-67, may be of value as an adjunct to morphological examination in the differential diagnosis of problematic uterine smooth muscle tumours. Some recent data suggest that the expression of Ki-67, p53, p16, Twist and bcl-2 expression may help the clinician to identify a subset of leiomyosarcomas with different clinical behaviours. Further investigation on larger groups, however, is warranted to elucidate this issue. Progesterone receptors are expressed in about 95% of low-grade endometrial stromal sarcomas. Some recent data suggest that an elevated pre-operative serum CA125 is a marker of extra-uterine disease and deep myometrial invasion, and an elevated postoperative serum CA125 is a poor prognostic factor for survival in women with uterine carcinosarcoma. Further investigation on larger groups is warranted to elucidate this issue.

• 7.
  

  a) T b) F c) T d) F e) F

Five- year survival is about 50–55% for women with stage I leiomyosarcoma and 84–100% for those with stage I low-grade endometrial stromal sarcoma. Among women with stage I low-grade endometrial stromal sarcoma,women with tumour size 5 cm or less (stage IA) have a significantly better survival than those with tumour size over 5 cm (stage IB). Oestrogen replacement therapy increases the risk of recurrence and is contraindicated in women who have previously had hysterectomies for endometrial stromal sarcoma. The prognosis of adenosarcoma is usually favourable, and only 25% of women ultimately die of their disease. Deep myometrial invasion and sarcomatous overgrowth (i.e the presence of pure sarcoma without epithelial elements in more than 25% of the tumuor) are associated with an increased risk of recurrence or metastases in women with uterine adenosarcoma.

• 8.
  

  a) T b) F c) F d) T e) F

Most studies have shown that stage is an independent prognostic indicator in multivariate analysis, although overlap in survival has been seen between different stages. Recent studies have shown that none of these systems are ideal in predicting patient outcomes. Only a few studies have shown that tumour size (ranging from 5 cm to 11 cm) is an independent prognostic indicator. Some studies have shown that it is not significant at all. The incidence of lymph-node metastasis is low, and most studies have shown that it is associated with extra-uterine and advanced diseases. Distant metastasis should be regarded as stage IV.

• 9.
  

  a) F b) F c) F d) T e) T

Poorly differentiated or undifferentiated endometrial sarcoma lack endometrial stromal differentiation and exhibit destructive myometrial invasion. ESS is a slow-growing tumour, but 14–60% may have late recurrence. Cervical invasion is not a significant prognostic index in ESS (low grade). Garg et al. however, reported an association with worse outcome in high-grade ESS; 5-year overall survival rates were 24.4% and 49.6% for those with and without cervical invasion (P = 0.02). Shah et al. reported no difference in 5-year survival rate between women with and without lymph-node metastasis in low-grade ESS (85.7% v 95.2%; P = 0.234). Although ESS (low grade) is hormone-sensitive, and some case reports have shown detrimental effects of hormonal replacement therapy, more recent studies have shown that ovarian preservation does not worsen survival or increase the risk of recurrence, especially in early stage disease.

• 10.
  

  a) F b) F c) T d) F e) F

No studies have been published on the prognostic significance of the presence of a heterologous component in adenosarcoma. Adenosarcoma of the endocervix is staged as adenosarcoma of the uterus, and so disease involving ovaries should be staged as stage IIa. Routine lymphadenectomy is not justified as nodal metastasis is found in only 0–6.5% of women, and has no proven therapeutic effect. Adenosarcoma with sarcomatous overgrowth is defined as having a sarcomatous component greater than 25% of the whole tumour volume. At least one study by Krivak et al. has shown that the median survival of ASSO is shorter than that of carcinosarcoma, although the difference is not significant (13 months v 33 months; P = 0.0522).

• 11.
  

  a) F b) F c) F d) T e) F

Lymph-node metastasis are frequent in uterine carcinosarcoma. About 14–38% of women with uterine carcinosarcoma confined to the uterus are upstaged to stage IIIc because of occult lymph-node metastasis after lymph-node dissection. The frequency and pattern of lymph-node metastasis of uterine carcinosarcoma is similar to that of high-risk endometrial adenocarcinoma. About 12–23% of women with carcinosarcoma apparently confined to the uterus were found to have adnexal involvement, and 23% had occult metastases, suggesting that bilateral salpingo-oophorectomy should be part of surgical management for carcinosarcoma, even in women with apparently early disease. Uterine carcinosarcoma rapidly spreads to peritoneal surfaces, with 32–61% of women having extrauterine disease during staging. Although lymph-node dissection improves surgical staging and provides prognostic information on women with apparently early stage carcinosarcoma, it is still unclear whether lymph-node dissection improves patient survival.

• 12.
  

  a) F b) F c) T d) F e) F

As uterine leiomyosarcoma usually spreads haematogenously, rather than via a retroperitoneal or transperitoneal route, these surgical staging procedures seem to be less important in women with early stage disease. The incidence of occult ovarian metastasis in women with early stage leiomyosarcoma has been found to range from 3.4–3.9%, and most macroscopic ovarian metastases are associated with either macroscopic lymph-node metastasis or other macroscopic extra-uterine disease. In addition, the preservation of ovarian tissues does not seem to increase the risk of recurrence, indicating that ovarian tissues can be preserved in premenopausal women unless these tissues show macroscopic involvement. Complete surgical excision is the only curative treatment modality currently known. Occult lymph-node metastasis was found in only 0–3.7% of women with early stage leiomyosarcoma, although one study reported that this frequency was 75%. In other studies, lymph-node metastasis was observed only in women with peritoneal spread or was almost always associated with other extra-uterine disease. Therefore, lymph-node dissection is not recommended for women with early stage leimyosarcoma. Isolated or limited lung recurrences are good candidates for surgical treatment because resection of isolated lung metastases has been found to prolong survival.

• 13.
  

  a) F b) F c) F d) F e) T

Recent larger studies have suggested that ovarian preservation does not affect the outcomes of premenopausal women with early stage disease. In addition, the rate of adnexal metastasis seems to be negligible in the absence of gross adnexal involvement and extra-uterine disease. Therefore, ovarian tissues can be preserved on the basis of individualised counselling in premenopausal women with early stage disease if the tumour is completely excised. Complete surgical excision is the only curative treatment modality currently known. The incidence of lymph-node metastasis in women with early stage disease ranges from 0–5%. Most lymph-node metastases are detected in women with extra-uterine disease or gross lymph-node involvement. Therefore, lymph-node dissection is not recommended for women with apparently early stage disease without extra-uterine disease or gross lymph-node involvement. Although lymph-node dissection has been recommended in women with advanced-stage disease or gross lymph-node metastasis, the therapeutic role of lymph-node dissection is unclear.

• 14.
  

  a) T b) F c) T d) T e) T

Invasion into adjacent myometrium distinguishes an endometrial stromal nodule and low-grade stromal sarcoma. Tumour cells of low-grade endometrial stromal sarcoma resemble endometrial stroma in proliferative phase and do not show serious cytological atypia. Lymphovascular permeation is common in low-grade stromal sarcoma and may produce worm-like plugs of tumour that is discernable macroscopically. CD10 is a sensitive marker for endometrial stromal cells. Low-grade stromal sarcoma is often positive for progestogen receptors and may be responsive to progestin treatment. In contrast, undifferentiated uterine sarcoma is usually negative for progestogen receptors.

• 15.
  

  a) T b) T c) F d) T e) T

Adenosarcoma usually exists in the form of a polypoid lesion composed of glandular epithelium surrounding curved cleft spaces with peri-glandular stromal condensation. It is a low-grade malignancy. Both the epithelial and stromal components in a carcinosarcoma are malignant. It displays an aggressive clinical course. Uterine tumour resembling ovarian sex-cord stromal tumour is a tumour with prominent sex cord-like differentiation with inconspicuous endometrial stromal background. It is benign. Atypical polypoid adenomyoma often co-exists with atypical hyperplasia of the endometrium. It is composed of endometrial glands of architectural complexity and squamous metaplasia as well as abundant smooth-muscle fibres. Both the epithelial and stromal components in an adenofibroma are benign.

• 16.
  

  a) F b) F c) T d) T e) T

Adenofibromas are benign, and no tumour-related deaths have been reported. The existence of this tumour, however, has been recently questioned, as some investigators consider the adenofibroma an exceedingly well-differentiated adenosarcoma that yet may behave aggressively. As adenosarcoma is much more common than adenofibroma, a practical approach is to classify as adenosarcoma any biphasic tumour with atypical hypercellular stroma, peri-glandular stromal cuffing, and one mitosis or more per 10 high power fields (HPFs). Using these criteria, the diagnosis of adenofibroma is made only rarely, comprising only about 5% of one large study of adenofibromas and adenosarcomas. Microscopically, the adenosarcoma shows an intimate mixture of apparently benign glandular epithelium that often resembles inactive or proliferative endometrium and low-grade sarcoma, usually of endometrial stromal type. In one-third of cases, the glandular epithelium is atypical but, in contrast to carcinosarcoma, carcinomatous epithelium is absent. Typically, the glands of adenosarcoma are cystic and the stroma concentrates around them forming peri-glandular cuffs. The stromal component is usually a low-grade homologous sarcoma, such as endometrial stromal sarcoma, leiomyosarcoma, fibroblastic or myofibloblastic sarcoma. The sarcomatous component is typically more cellular around the glands, often forming intraluminal polypoid projections and resembling a phyllodes tumour of the breast. Elsewhere, the stroma is usually less cellular and fibrotic, giving a deceptively benign appearance. The mean mitotic rate is generally two to four mitotic figures per 10 HPF or more; however, in practice, a biphasic tumour with hypercellular and atypical stroma that appears condensed around the glands is diagnosed as an adenosarcoma in the absence of mitotic figures. Some clinically malignant mixed tumours with focal peri-glandular cuffs may show only moderate stromal cellularity, low mitotic count (less than two mitotic figures per 10 HPF) and only mild nuclear atypia. The finding of such cases raises the question of whether or not adenofibroma exists as a tumour entity. A confident diagnosis of adenofibroma cannot be made on a biopsy or curetted tissue, as adenosarcoma cannot be ruled out unless the entire tumour is available for microscopic examination. Therefore, a hysterectomy is required to ensure adequate sampling. Pathologic features of adenosarcoma that are associated with a higher risk of recurrence or metastasis are deep myometrial invasion, lymphovascular space invasion, and sarcomatous overgrowth, especially when it contains rhabdomyosarcoma.

• 17.
  

  a) F b) T c) F d) T e) T

Carcinosarcoma, also referred to as malignant Müllerian mixed tumour (MMMT) is a biphasic neoplasm composed of distinctive and separate, but mixed, carcinomatous and sarcomatous elements. The two elements, however, should not merge with one another. This definition essentially excludes from consideration monophasic tumours, such as sarcomatoid carcinomas or undifferentiated sarcomas. Occasionally, however, carcinosarcomas show either sarcoma or carcinoma almost exclusively. In carcinosarcomas, the malignant epithelial cells trans-differentiate to malignant mesenchymal cells by progressive loss of E-cadherin expression coupled with the expression of non-epithelial cadherins (N-cadherin and cadherin-11) and acquisition of mesenchymal markers (vimentin, fibronectin and others). This epithelial–mesenchymal transition promotes the interaction of tumour cells with the stroma, thus facilitating invasion and metastasis. The carcinomatous component is usually serous (two-thirds of cases) or endometrioid (one-third) but, rarely, it may be clear cell, mucinous, or squamous cell carcinoma. In a recent study, 10% of the carcinomatous components were FIGO grade 1, 10% grade 2, and 80% grade 3. The sarcomatous components are heterogeneous and may be either homologous or heterologous (50% of cases). They usually contain hypercellular sheets of small, hyperchromatic, round to spindle-shaped cells with a high mitotic rate and lacking apparent differentiation. In the homologous type, the sarcoma-like component resembles fibrosarcoma, malignant fibrous histiocytoma, high-grade endometrial stromal sarcoma, leiomyosarcoma, undifferentiated sarcoma or a combination thereof. The heterologous tumour most often contains malignant skeletal muscle or cartilage, resembling either pleomorphic rhabdomyosarcoma or embryonal rhabdomyosarcoma. Rarely, osteosarcoma or liposarcoma are present. Glial, neuronal, melanocytic, yolk sac, angiomatoid, and trophoblastic differentiation may be encountered. Carcinosarcomas are highly aggressive tumours, far more aggressive than usual endometrial carcinomas. The overall 5-year survival is around 30% and for stage I tumours about 50%. This is in contrast to high-grade endometrial cancers for which the 5-year survival in stage I disease is about 80% or better. The overall recurrence rate is 55%, and the most common metastatic sites include ovaries, fallopian tubes, and omentum. Pulmonary metastases can occur late in the course of the disease. In common with previously published research, a recent study has found that the presence of heterologous elements is a statistically significant poor prognostic factor in individuals diagnosed with stage I carcinosarcoma. Rhabdomyosarcomatous component has the worse prognosis of all, and chondrosarcoma is thought to confer a more favourable outcome.

• 18.
  

  a) T b) F c) T d) T e) F

In carcinosarcomas, the malignant epithelial cells trans-differentiate to malignant mesenchymal cells by progressive loss of E-cadherin expression coupled with the expression of non-epithelial cadherins (N-cadherin and cadherin-11) and acquisition of mesenchymal markers (vimentin, fibronectin and others).

• 19.
  

  a) F b) T c) F d) T e) T

The carcinomatous component is usually serous (two-thirds of cases) or endometrioid (one-third) but, rarely, it may be clear cell, mucinous, or squamous cell carcinoma. In a recent study, 10% of the carcinomatous components were FIGO grade 1 and grade 2 10% each and 80% grade 3. The sarcomatous components are heterogeneous and may be either homologous or heterologous (50% of cases).

• 20.
  

  a) T b) F c) T d) T e) T

The atypical polypoid adenomyoma typically occurs in premenopausal or perimenopausal women with a mean age of about 39 years who are often nulliparous. A few cases have been associated with Turner syndrome and appear to be a complication of long-term oestrogen therapy. In some cases, the diagnosis is made during investigations for infertility. Women typically present with abnormal vaginal bleeding. Often these lesions arise in the lower uterine segment and a polypoid mass protrudes from the external os. On curettings, the atypical polypoid adenomyoma may be confused with invasive endometrial adenocarcinoma. Irregular endometrial glands showing marked nuclear atypia (high grade) favour a myo-invasive adenocarcinoma, as in atypical polypoid adenomyoma, there is usually no more than mild to moderate cytological atypia. The glands of the latter are set in an abundant stroma, which varies from obviously smooth muscle in nature to fibromyomatous. The smooth muscle component lacks cytologic atypia. In contrast to the elongated fibres of the normal myometrium, the stromal component of atypical polypoid adenomyoma grows in short interlacing fascicles. In curettings or biopsy from an atypical polypoid adenomyoma, there are usually also fragments of normal background endometrium; on the other hand, on a biopsy of an endometrioid adenocarcinoma, it would be most unusual to obtain only fragments of myo-invasive neoplasm without free tumour fragments. The margin between the lesion and the underlying myometrium is usually rounded and well circumscribed, but occasionally merging occurs with underlying adenomyosis. A characteristic though not specific feature, seen in 90% of cases, is the presence of squamous morules (metaplasia) obliterating the glandular lumens. Central necrosis may occur in the squamous nests.

• 21.
  

  a) F b) T c) F d) F e) F

Tumours with diffuse atypia, and no other worrisome features, are known as leiomyomas with bizarre nuclei. Infarct-type necrosis is the ‘good’ type of necrosis and not indicative of malignancy. The presence of any two of these three features in b) is diagnostic of leiomyosarcoma. Although hypercellularity and an infiltrative border may be seen in a leiomyosarcoma, they may also be found in a benign leiomyoma variant called cellular leiomyoma. Vascular invasion may be seen in leiomyoma variants, known as intravenous leiomyomatosis. Presence of epithelioid cells in intravenous leiomyomatosis in itself is not malignant. Myxoid differentiation, without any other features does not automatically signify malignancy.

• 22.
  

  a) T b) T c) F d) T e) F

Difficulty in determining whether the necrosis is tumour-cell necrosis or very early infarct-type necrosis is known as ‘necrosis of an uncertain type’. Some investigators regard this as STUMP. As the threshold for diagnosis of epithelioid leiomyosarcoma is lower than for those of the usual spindle cell type, tumours with uncertainty of cellular differentiation may be labelled as STUMP. Cellularity by itself is not diagnostic of benign or malignant tumours. Assessment of what constitutes a true mitotic figure is particularly difficult in tumours containing bizarre tumour cells that are also degenerating, as the nuclear pyknosis and karyorrhexis can mimic a mitotic figure. The final answer is the differential diagnosis between leiomyosarcoma and endometrial stromal tumour, and not STUMP.

• 23.
  

  a) F b) F c) F d) F e) T

Histologic differentiation in leiomyosarcomas has not been shown to be associated with a more aggressive clinical behaviour. Issues with these are primarily related to the diagnostic difficulties for pathologists. Myxoid smooth-muscle tumours are usually hypocellular and may result in difficulty in assessing the degree of atypia and mitotic count, which are crucial in deciding whether a tumour is malignant or not. Tumours with epithelioid or sex-cord differentiation may be mistaken for carcinomas or tumours that resemble sex-cord stromal tumours of the ovary (uterine tumours resembling ovarian sex-cord stromal tumours). The presence of lipoblasts may represent a liposarcoma, rather than leiomyosarcoma. Reported cases of uterine liposarcomas may have developed from a pre-existing lipoleiomyoma. As these lesions are so rare, currently, there is no evidence to suggest liposarcoma behaves any more aggressively compared with leiomyosarcomas. Size is a prognostic factor for uterine leiomyosarcomas. This parameter has been incorporated into the current FIGO staging system for uterine sarcomas.

• 24.
  

  a) F b) T c) T d) T e) F

Tumour size of greater than 5 cm and tumour limited to the uterus is stage IA for LMS or endometrial stromal sarcoma. For carcinosarcoma, the staging for endometrial carcinoma should be used; that is, tumour confined to the uterus and myometrial invasion one-half or less. Extrauterine involvement of pelvic tissue for stromal sarcoma or LMS is stage IIB. Extrauterine involvement of pelvic tissue for carcinosarcoma is IIIB with parametrial extension.

• 25.
  

  a) T b) F c) T d) T e) F

Uterine LMS almost always have absence of ERBB1 and ERBB2 expression. The Incidence of uterine sarcoma in the USA has been increasing and is not stable

• 26.
  

  a) T b) F c) T d) F e) T

Malignant tumors are usually associated with increased flow, decreased vascular impedance and decreased apparent diffusion values. It has not been shown that using positron emission tomography leads to improvement of overall survival compared with historical controls.

• 27.
  

  a) F b) F c) F d) F e) F

The Gynecologic Oncology Group has conducted several phase II trials in uterine leiomyosarcoma to identify active chemotherapeutic agents. Inactive agents include thalidomide, cisplatin, piperazinedione, paclitaxel, etoposide, oral etoposide, trimetrexate, topotecan and mitoxantrone.

• 28.
  

  a) F b) F c) F d) T e) T

Some investigators have shown that DNA ploidy and S-phase fraction (SPF) influences clinical outcome Blom et al. found that diploidy and a SPF lower than 10% were independent good prognostic variables for survival ( P = 0.045 and P = 0.041, respectively). Conversely in the study of Wu et al, DNA-ploidy correlated with neither the risk of recurrence nor the risk of death on univariate analysis. The prognostic relevance of vascular endothelial-growth factor (VEGF) and its kinase receptors VEGF R-1 (flt-1) and VEGF R- (flk-2) in uterine sarcoma has not yet defined. Oestrogen receptor and progesterone receptor positivity ranged from 26–87% and from 17– 80%, respectively, in uterine leiomyosarcomas. In particular, the assessment of progesterone receptor status seems to have diagnostic and prognostic relevance. Most investigators reported that p53 expression had a prognostic relevance.

• 29.
  

  a) F b) F c) F d) F e) F

Blom et al. found that p53 expression, mdm-2 expression, DNA ploidy, and S-phase fraction were not related to survival in a study of 44 women. Similarly, the immunohistochemical expression of p53, bcl-2, Ki-67, or proliferating cell nuclear antigen had no prognostic relevance in the study by Iwasa et al, which included 23 women.

• 30.
  

  a) T b) T c) T d) T e) T

The immunophenotype parallels that of the individual elements. For example, the serous components should express cytokeratins, epithelial membrane antigen and p53, whereas the rhabdomyoblastic elements should express desmin, myoglobin, myogenin, MyoD1 and CD34. Sarcomatous components, however, can express cytokeratins (as in leiomyosarcomas) and epithelial component are immunoreactive for vimentin (as in endometrial carcinomas). Such findings reflect the common mesodermal origin of these tumours. Nevertheless, differential immunoreactivity with cytokeratin and vimentin is a helpful method for enhancing the biphasic pattern of carcinosarcomas and distinguishing sarcomatoid or spindle cell carcinoma from the sarcomatous component of carcinosarcoma. The sarcomatous homologous component can also express CD10 (a marker used initially for the diagnosis of endometrial stromal tumours) and CD34.