Testicular fusocellular rhabdomyosarcoma as a metastasis of elbow sclerosing rhabdomyosarcoma: A clinicopathologic, immunohistochemical and molecular study of one case

Sclerosing rhabdomyosarcoma (SRMS) is an infrequent variant of rhabdomyosarcoma characterized by extensive intercellular hyaline fibrosis. We report the case of a 37 year-old male with a 9 x 6 cm SRMS on the right elbow. Histologically, the tumor showed an abundant extracellular hyaline matrix with extratumoral vascular emboli and microscopic foci of fusocellular embryonal rhabdomyosarcoma (FRMS) separated by a fibrotic band from the sclerosing areas. One year later the patient presented with a right intratesticular tumor of 1.2 x 0.8 cm, which was reported as pure FRMS. Immunohistochemically, SRMS was positive only for MyoD1 and Vimentin and negative for Myogenin and Desmin. Both the elbow emboli with the extratumoral foci of FRMS and the intratesticular tumor were positive for Myogenin, MyoD1, Vimentin and Desmin. Using fluorescent in situ hybridization (FISH), the SRMS and the FRMS tumor cells of the elbow and the FRMS tumor cells of the testis were found to be negative for FOXO1A translocation in chromosome 13. PCR chimeric transcriptional products PAX3-FKHR and PAX7-FKHR were not found. Six months following testicular resection, the patient died of multiple metastases in the mediastinum, lung and right thigh.

Insulin-like growth factor-I has different effects on myogenin induction and cell cycle progression in human alveolar and embryonal rhabdomyosarcoma cells

Alveolar rhabdomyosarcoma (RMS) has a much poorer outcome than embryonal RMS. In this study, we found that IGF-I affected the induction of myogenin and cell cycle progression in alveolar RMS cells, but not in embryonal RMS cells. IGF-I enhanced the induction of myogenin protein in alveolar RMS SJ-Rh30 and KP-RMS-MS cells as it did in myoblast C2C12 cells, but not in embryonal RMS RD or KP-RMS-KH cells. IGF-I induction of myogenin protein was blocked by anti-IGF-IR monoclonal antibody alphaIR-3 and the mTOR-specific inhibitor rapamycin. In Rh30mTOR-rr cells, which stably express a rapamycin-resistant mutant mTOR, rapamycin did not inhibit IGF-I induction of myogenin protein. These data suggest that IGF-I induces myogenin in alveolar RMS cells through the IGF-IR/mTOR pathway. In C2C12 cells, IGF-I induces myogenin protein followed by cell cycle arrest leading to myogenic differentiation. IGF-I promoted G1-S cell cycle progression without any signs of terminal differentiation in alveolar RMS cells. On the other hand, IGF-I promoted neither cell cycle arrest nor G1-S cell cycle progression in embryonal RMS cells. In alveolar RMS SJ-Rh30 cells, 4E-BP1, one of two effectors downstream of mTOR, was continuously hyperphosphorylated by IGF-I, whereas in embryonal RMS RD cells, 4E-BP1 was only transiently hyperphosphorylated. These findings suggest that the different effects of IGF-I on myogenin induction and cell cycle progression in alveolar and embryonal RMS cells are due to a difference of phosphorylation status of 4E-BP1. These different responses to IGF-I help to explain immunohistochemical and clinical behavioral differences between alveolar and embryonal RMS.

Immunohistochemical detection of myogenin and p21 in methylcholanthrene-induced mouse rhabdomyosarcomas

3-Methylcholanthrene (MC)-induced 10 embryonal (ERSs) and 24 pleomorphic rhabdomyosarcomas (PRSs) of the dermis in mouse were examined immunohistochemically for myogenin, p21 and proliferating cell nuclear antigen (PCNA) nuclear reactivity and myosin reactivity. ERSs had higher expression of myogenin and p21 compared with that of myosin. PRSs were divided into two groups having high (moderate or marked reactivity; HLM) and low (mild reactivity; LLM) levels of myosin expression. Expression of p21 was higher in HLM-PRSs than in LLM-PRSs. Statistically significant association was observed between myosin and p21 expression in PRSs, but not between myosin and myogenin expression. Myogenin and p21 reactivity were observed in myoblast-like cells, but rarely in multinucleated cells. In ERSs, small undifferentiated myogenic precursor cells were also positive for p21. No difference of PCNA reactivity was observed between HLM-PRSs and LLM-PRSs, although its reactivity was higher in PRSs than in ERSs. The results suggest that myogenin is related to myoblast-like cell differentiation in PRSs and that p21 plays essential roles in myotube formation and myosin expression. In ERSs, p21 may be involved in inhibition of myogenic precursor cell proliferation and differentiation.

Myogenin and desmin immunohistochemistry in the assessment of post-chemotherapy genitourinary embryonal rhabdomyosarcoma: prognostic and management implications

PURPOSE

Posttreatment genitourinary embryonal rhabdomyosarcoma often shows well differentiated rhabdomyoblasts, which are detectable on routine histological staining. Definite areas of residual undifferentiated rhabdomyosarcoma indicate residual/recurrent disease. However, the recent use of immunohistochemical staining with desmin and myogenin in resected specimens and surveillance biopsies following adjuvant therapy may demonstrate scant positive staining cells that appear undifferentiated on light microscopy. To our knowledge the clinical significance of this finding is currently unknown. Therefore, we reviewed our retrospective experience with genitourinary embryonal rhabdomyosarcoma to examine the relationship between immunostain positive undifferentiated cells and subsequent clinical outcome.

MATERIALS AND METHODS

A total of 14 children with a median age of 2.75 years (range 8 months to 7 years) with genitourinary embryonal rhabdomyosarcoma were identified in the histopathology database. All had biopsy confirmation of the diagnosis, followed by multi-agent chemotherapy. Two children in whom there was obvious residual active tumor at the resection margins were excluded from further analysis. Histopathological findings in all patients on the resection/posttreatment biopsy were reviewed. All specimens were immunostained with desmin and myogenin to detect residual undifferentiated rhabdomyoblasts. The relation between histopathological findings and outcome was determined.

RESULTS

There were 14 cases of genitourinary embryonal rhabdomyosarcoma. In 2 cases (14%) residual embryonal tumor was pathologically confirmed following initial treatment. In 12 cases no obvious residual tumor was present following initial therapy. Rhabdomyosarcoma affected the bladder in 10 cases and the vagina in 2. There were no distant metastases in any child. Ten patients underwent local resection following chemotherapy and 2 underwent followup biopsies only without resection. A total of 11 cases showed well differentiated, posttreatment rhabdomyoblasts that was identifiable on routine hematoxylin and eosin staining with margins apparently free of tumor and 1 showed no morphological evidence of residual rhabdomyosarcoma. However, all cases demonstrated at least scant abnormal desmin and myogenin positive cells in the specimens. Four patients had no further treatment and none had clinical recurrence. All were well 10 years (range 8 to 13) after treatment. Eight patients received further treatment (chemotherapy and/or radiotherapy) based on clinical and pathological findings, followed by further resection in 3. One patient died of disease but 7 were well a median of 7.2 years (range 8 months to 13 years) after treatment.

CONCLUSIONS

The significance of undifferentiated myogenin/desmin positive cells in genitourinary embryonal rhabdomyosarcoma in the absence of morphological residual/recurrent embryonal rhabdomyosarcoma remains unclear since such cells can be detected in all cases of posttreatment embryonal rhabdomyosarcoma. In some cases findings are associated with clinical disease recurrence, while others with identical histopathological findings following initial treatment have no clinical sequelae even in the absence of further treatment. In genitourinary embryonal rhabdomyosarcoma close and regular clinical surveillance is essential. Desmin/myogenin immunohistochemistry to detect scattered undifferentiated cells does not appear to provide useful prognostic information.

Results of a prospective minimal disseminated disease study in human rhabdomyosarcoma using three different molecular markers

BACKGROUND

Rhabdomyosarcoma (RMS) has 2 major histologic subtypes: alveolar (ARMS) and embryonal (ERMS). ARMS is more aggressive and prone to distant tumor dissemination, whereas ERMS tends to expand and recur locally. Little information is available on bone marrow involvement by RMS.

METHODS

We determined the sensitivity and specificity of MyoD1, myogenin, and PAX-FKHR transcripts as RMS markers and used them to study prospectively by reverse-transcriptase polymerase chain reaction (RT-PCR) a series of consecutive unselected RMS patients enrolled in the Italian Association of Pediatric Hematology and Oncology national trial. Prevalence of minimal disseminated disease (MDD) and its response kinetics to chemotherapy were assessed.

RESULTS

MyoD1 and myogenin were specifically associated with RMS, independently of histologic subtype, whereas PAX3/7-FKHR transcripts were expressed only in ARMS. Sensitivity was higher for MyoD1 compared with myogenin and PAX-FKHR. Out of a cohort of 40 patients, MDD positivity was limited to ARMS, with the sole exception of 1 ERMS. Prevalence of MDD positivity increased when a real-time polymerase chain reaction approach was used on a subgroup of patients. RT-PCR was more sensitive than microscopic examination of bone marrow biopsies. The study of the response kinetics of MDD showed that in approximately half of the cases, bone marrow was cleared of disease after 1 cycle of chemotherapy.

CONCLUSIONS

MyoD1 and myogenin transcripts can be used as tumor markers for MDD assessment in virtually all RMS cases, whereas PAX-FKHR is specific for ARMS. Sensitivity of RT-PCR methods was superior compared with standard morphologic assays. Our study suggests that bone marrow involvement is more common in ARMS compared with ERMS, and that MDD can be often cleared by the initial chemotherapy cycles.

Rhabdomyosarcoma: molecular diagnostics of patients classified by morphology and immunohistochemistry with emphasis on bone marrow and purged peripheral blood progenitor cells involvement

Two histologically distinct subtypes of rhabdomyosarcomas (RMS), embryonal and alveolar, are different in many aspects, such as age distribution, primary site, and clinical outcome. We analyzed a group of 30 patients with RMS. The aim was to broaden the spectrum of diagnostic tools in evaluating the primary tumors, their recurrences and/or metastases, and to extend the diagnostic boundary to bone marrow and purged peripheral progenitor blood cell samples. We have performed the RT-PCR assay to analyze RMS for the presence of expression of MyoD1 gene and for the presence of chimeric transcripts PAX3/FKHR or PAX7/FKHR. MyoD1 gene expression was found in all 30 patients in samples from primary tumors. The chimeric transcripts PAX/FKHR were identified in 13 of 15 patients with alveolar RMS. Furthermore, the fusion transcript PAX7/FKHR was identified in 2 of 15 patients with RMS classified as embryonal by histology. Bone marrow samples (12) and peripheral blood progenitor cell specimens (13) in ten patients were examined by RT-PCR. We were able to identify 7 patients with bone marrow involvement and/or with contamination of peripheral blood progenitor cells by the tumor cells. We demonstrate that employing molecular diagnostics has an impact on staging, therapy monitoring and recognition of malignant cells at the tumor resection margins.

Spindle cell rhabdomyosarcoma in adults

The spindle cell variant of rhabdomyosarcoma (RMS) is uncommon and is most often encountered in the paratesticular region of children in whom it has a good prognosis. Only isolated cases in adulthood have been described. Sixteen cases of spindle cell RMS occurring in adults were retrieved from our files. Eleven patients were male and 5 were female. Patient age ranged from 18 to 79 years (median, 32 years). Tumor size varied from 1.5 to 35 cm (median, 6 cm). The head and neck region, including the oral cavity, parotid gland, nasopharynx, and nasal cavity, was the commonest affected area, accounting for >50% of the cases, followed by retroperitoneum, thigh, leg, subscapular area, hand, vulva, and paratesticular region (1 case each). Follow-up was available in 12 cases, ranging from 1 to 102 months (median, 16.5 months). Treatment modalities included surgery, chemotherapy, and radiation. Two patients died of uncontrolled local disease 13 and 27 months after diagnosis; 4 were alive without disease at 12, 17, 24, and 102 months, including 1 patient with metastasis to 10 of 50 pelvic lymph nodes at presentation; 3 are alive with localized disease at 16, 17, and 19 months; and 1 was followed for 6 months and showed persistent local disease. One patient is alive at 10 months after diagnosis with evidence of metastatic disease to bone, lungs, and breast. All the tumors showed long fascicles of spindle cells with elongated, vesicular nuclei and pale indistinct cytoplasm. Scattered spindled or polygonal rhabdomyoblasts with abundant brightly eosinophilic cytoplasm were present in all cases. In 3 cases, focal areas showed pseudovascular, sclerosing features. There were no round cell or pleomorphic areas. Positive immunohistochemical results were as follows: desmin (15 of 15 cases), myf-4 (12 of 12), fast myosin (7 of 9), myoglobin (2 of 3), HHF-35 (9 of 9), and SMA (11 of 14). One tumor was focally positive for keratins and EMA. All tumors were negative for caldesmon, S-100 protein, and GFAP. Spindle cell RMS is a rare neoplasm in adults and appears to have distinct clinicopathologic features when compared with cases occurring in the pediatric population. Specifically, it appears to be most common in the head and neck region, and although only limited follow-up is available so far, these lesions appear to have a more aggressive clinical course in adults.

Spindle cell rhabdomyosarcoma of the tongue in an infant: a case report with emphasis on differential diagnosis of childhood spindle cell lesions

Malignant tumors are extremely uncommon in infants, specifically in the head and neck region. We present a three-day-old infant with a large, polypoid, soft tissue mass arising from the floor of the mouth. Histologically, this neoplasm consisted of hypercellular and myxoid areas. A mixture of poorly oriented, small, undifferentiated, hyperchromatic, and round to elongate spindle cells was seen. A high degree of striated muscle differentiation was present, along with areas marked by a herringbone pattern, as well as hemangiopericytic vessels and rare mitosis. Immunohistochemical examinations revealed strong nuclear staining for myogenin and diffuse cytoplasmic staining for desmin and muscle-specific actin (HHF-35). The tumor did not stain for S-100. Based on histologic results and immunostains, this lesion was diagnosed as spindle cell rhabdomyosarcoma. This type of lesion involving the tongue is rarely seen in females, neither in association with a herringbone pattern nor with hemangiopericytic vessels. Furthermore, rare benign and malignant spindle lesions, such as cellular fibromatosis, fetal rhabdomyoma, infantile hemangiopericytoma, infantile rhabdomyofibrosarcoma, and infantile fibrosarcoma, should be in the differential diagnosis and excluded.

Embryonal rhabdomyosarcoma presenting in an adult: a case report and discussion of immunohistochemical staining

Embryonal rhabdomyosarcoma is the most common soft tissue sarcoma of childhood but is rarely seen in adults. We report an embryonal rhabdomyosarcoma of the cheek in a 21-year-old Filipino man presenting as a rapidly enlarging mass. An incisional biopsy was consistent with embryonal rhabdomyosarcoma. The patient failed to respond to one cycle of chemotherapy after initial diagnosis and workup for metastatic disease. Wide local excision of the tumor was then completed with the use of the Mohs technique to clear the glabrous cutaneous margins during surgery. A Mohs surgeon and dermatopathologist were involved in interpretation of the Mohs sections. Subsequent immunohistochemical staining revealed a poorly differentiated spindled and epithelioid cell tumor, which stained diffusely positive for vimentin, S-100, and MyoD1. Rare rhabdomyoblasts were present and stained positively for desmin, muscle-specific actin, and phosphotungstic acid hematoxylin. The patient subsequently underwent radiation therapy for a total of 6,000 cGy, followed by two cycles of chemotherapy. The patient continues to be disease-free at 22 months after his wide local excision.

Intraosseous rhabdomyosarcoma of the mandible: a case report

Rhabdomyosarcoma is the most common soft-tissue sarcoma of the head and neck region in children and adolescents. Oral cavity involvement is relatively uncommon, with tongue, soft palate, hard palate, and buccal mucosa being the sites of predilection. This report presents a rare case of intraosseous oral rhabdomyosarcoma arising in the mandibular bone of a 6-year-old child. Clinical, radiologic, and histopathologic features and possible pathogenesis are discussed.

Expression of cyclin-dependent kinase inhibitor p27/Kip1 and AP-1 coactivator p38/Jab1 correlates with differentiation of embryonal rhabdomyosarcoma

Cyclin-dependent kinase (CDK) inhibitor p27/Kip1 (p27) is a diagnostic and prognostic marker of various malignancies. Low expression of p27 reflects poor differentiation and poor prognosis, and an inverse correlation between the expression of p27 and degree of tumor malignancy has been reported. Because p27 mutation is extremely rare in human tumors, it is important to study the expression of p27 and its inactivator, p38/Jab1 (JAB1). Here we analyzed the expression of p27 and JAB1 by immunohistochemistry in embryonal rhabdomyosarcoma (E-RMS). We first confirmed the expression of p27 and JAB1 in normal human tonsillar epithelium, and observed a coordinated expression pattern depending on cell differentiation. Subsequently, specimens of eight poorly- and three well-differentiated E-RMS were examined for the expression of p27 and JAB1. The analyses revealed that four out of eight poorly-differentiated E-RMS were negative for p27, with positivity for nuclear JAB (NJAB) (- / + for p27/NJAB) in three and negativity for any JAB-1 expression ( - / -) in one. The remaining four poorly-differentiated E-RMS expressed p27 in the nuclei, together with predominant NJAB (+ / +). In three well-differentiated E-RMS, only one expressed nuclear p27 and all of these three expressed no NJAB (+ / - for p27/NJAB), but expressed predominant cytoplasmic JAB1 (CJAB). These findings suggest that JAB1 may play an important role in determining the differentiation stage of rhabdomyosarcoma cells by modulating the activity of CDK inhibitor p27.

[Embryonal botryoid rhabdomyosarcoma of the bladder]

A 10-year-old black child presented with bloody urine and urine retention due to a bladder tumor. Cystoprostetatectomy led to the diagnosis of embryonal botryoid rhabdomyosarcoma. At gross examination, tumor presented a grape-shaped form. Microscopically, the specimen presented undifferentiated cells in a myxoid stroma and subepithelial cambium. The tumor was desmin and MyoD positive. The child died before chemotherapy could be completed.

Cytodifferentiation and clinical outcome after chemotherapy and radiation therapy for rhabdomyosarcoma (RMS)

BACKGROUND

Second-look surgery after therapy for rhabdomyosarcoma (RMS) may yield prognostic information regarding tumor responsiveness to treatment. Favorable outcome is suggested by tumor cells which have undergone maturation (cytodifferentiation).

PROCEDURE

Specimens from patients treated on Intergroup RMS Study-IV (IRSG-IV) were studied before and after treatment. All patients received chemotherapy and most received radiation therapy. Post-treatment specimens were graded according to the quantity of tumor showing cytodifferentiation (0 = absent, 1 = mild, 2 = moderate, 3 = extensive). Proliferative activity by MIB-1, topoisomerase II-alpha, and p53 protein expression were measured.

RESULTS

19/31 cases from IRSG-IV were adequate for analysis. Six out of nineteen patients failed therapy within 1.3 years of treatment. Grade 3 cytodifferentiation was present in 10 cases (2 BRMS, 8 ERMS); none failed therapy. Grade 2 cytodifferentiation was present in 5 cases (1 ERMS, 2BRMS, 2ARMS); 2 patients with ARMS failed therapy. Grade 0-1 cytodifferentiation was present in 4 cases (1 ERMS and 3 ARMS); all failed therapy. Proliferative activity by MIB-1 and topoisomerase II-alpha immunohistochemistry decreased or was unchanged after treatment for all ERMS/BRMS, and 4/5 cases of ARMS. p53 immunohistochemistry showed no consistent pattern of reactivity. Sparse persistent tumor cells were present in 9/10 ERMS, 3/4 BRMS, 5/5 ARMS.

CONCLUSIONS

Extensive cytodifferentiation is more commonly seen in ERMS/BRMS compared with less evidence for cytodifferentiation in ARMS suggesting fundamentally different mechanisms of cellular response to therapy in RMS. Sparse persistent tumor cells in post treatment ERMS/BRMS specimens does not appear to affect outcome.

Juvenile parameningeal rhabdomyosarcoma in a dog causing unilateral denervation atrophy of masticatory muscles

A 23-month-old, male, Labrador retriever dog with a history of slowly progressive right-sided atrophy of the masticatory muscles was submitted for necropsy. A highly invasive neoplasm which destroyed adjacent soft tissues including the right trigeminal nerve was found in the right side of the cranial cavity. Metastases to the liver were also present. Microscopical features of the neoplasm were compatible with those of rhabdomyosarcoma, embryonal type. This diagnosis was confirmed by immunohistochemical demonstration of desmin and muscle actin within tumour cells. In human patients, rhabdomyosarcoma is the most common soft tissue sarcoma of childhood and adolescence. Parameningeal rhabdomyosarcomas are well-known topographic variants that are often non-amenable to complete surgical resection and therefore carry a more guarded prognosis. Juvenile parameningeal rhabdomyosarcoma resulting in denervation atrophy of the muscles of mastication has not been reported previously in dogs. Rhabdomyosarcoma should be included in the differential diagnosis of neoplastic conditions in the head and neck region of juvenile dogs presented with cranial nerve palsies or other neurological deficits suggestive of meningeal or central nervous system invasion.

Thymic carcinosarcoma consisting of squamous cell carcinomatous and embryonal rhabdomyosarcomatous components. Report of a case and review of the literature

A case of thymic carcinosarcoma in an 83-year-old Japanese man is presented. He died of superior vena cava syndrome caused by a rapidly enlarged anterior mediastinum tumor eight months after initial symptoms. Autopsy revealed a 16 x 12 x 25 cm-sized, tan yellow, whitish tumor with a multinodular and microcystic appearance located in the left anterior mediastinum, which involved the residual thymus. The tumor had directly invaded the left pleura, and had metastasized to the right lung and spleen. Histologic examinations of the primary tumor showed a sarcomatous component consisting of racquet- or spindle-shaped cells with cross striations, and small nests of atypical squamous cells scattered throughout the tumor; neither transition between the two components nor intermediate cells with both epithelial and mesenchymal features was seen. Electron microscopic and immunohistochemical examinations confirmed the rhabdomyomatous differentiation of the sarcomatoid component. To our knowledge, there have been only two reported cases showing histologic features similar to the present tumor. For the histogenesis of thymic carcinosarcoma, we propose two hypotheses. The first is that sarcomatous cells are derived from carcinomatous cells by tumoral metaplasia. Secondly, that this type of tumor originates from thymic primitive cells with multidirectional differentiation potential. In accordance with the latter, we consider that the present tumor originated from thymic primitive cells. Thymic carcinosarcoma is a highly malignant tumor, and most patients die within a year. Appropriate therapies must be developed.

Myogenin is a specific marker for rhabdomyosarcoma: an immunohistochemical study in paraffin-embedded tissues

Myogenin belongs to a group of myogenic regulatory proteins whose expression determines commitment and differentiation of primitive mesenchymal cells into skeletal muscle. The expression of myogenin has been demonstrated to be extremely specific for rhabdomyoblastic differentiation, which makes it a useful marker in the differential diagnosis of rhabdomyosarcomas (RMS) from other malignant small round cell tumors of childhood. Commercially available antibodies capable of detecting myogenin in routinely processed formalin-fixed paraffin-embedded (FFPE) tissue are now available. In this study, we evaluated myogenin expression using the monoclonal myf-4 antibody (Novocastra Labs) on FFPE in a large number of pediatric tumors in order to define the clinical utility of this marker. A total of 119 tumors were studied. These included 48 alveolar RMS (ARMS), 20 embryonal RMS (ERMS), one spindle cell RMS, 16 Ewing's sarcomas (ES), six nephroblastomas, two ectomesenchymomas, seven precursor hematopoietic neoplasms, five olfactory neuroblastomas, three neuroblastomas, six desmoplastic small round cell tumors, and five rhabdoid tumors. Distinct nuclear staining for myogenin was noted in all 69 RMS. Notably, the number of positive tumor cells differed between the ARMS and ERMS. In ARMS, the majority of tumor cells (75 to 100%) were positive, in contrast to ERMS, in which the positivity ranged from rare + to 25% in all but three tumors. Additionally, myogenin positivity was seen in two of two ectomesenchymomas and in two nephroblastomas with myogenous differentiation. All other tumors were clearly negative. Our results indicate that staining for myogenin is an extremely reliable and specific marker for rhabdomyoblastic differentiation. It gives consistent and easily interpretable results in routinely fixed tissues.

p53 protein detection by the western blotting technique in normal and neoplastic specimens of human endometrium

The aim of the study was to investigate p53 protein expression by the Western blotting technique (estimated by integrated optical density - IOD) in normal (n = 13) and neoplastic (n = 40) human endometrial tissues as well as in a case of uterine carcinosarcoma and in a specimen of the botryoid sarcoma of the uterine cervix. p53 protein levels were correlated with patients' age as well as with conventionally used clinicopathological features of the endometrial neoplasm. A statistically significant difference was noted in p53 levels in the nuclear, but not in the cytoplasmatic, fraction between the normal endometria and endometrial cancer tissues (P < 0.0001). In the neoplastic endometria, nuclear p53 protein expression was higher than in cytoplasmatic fraction, and the difference was significant (P < 0.05). Higher nuclear p53 protein levels correlated with advanced histological grading of endometrioid endometrial carcinomas, but no relationship was noted between p53 protein expression and patients' age, clinical stage, histological type or depth of myometrial invasion. A case of uterine carcinosarcoma and a specimen of a botryoid sarcoma of the uterine cervix expressed nuclear p53 oncoprotein (57 IOD and 89 IOD, respectively). In conclusion, we found a statistically higher nuclear p53 levels in malignant as compared to normal human endometrial specimens by the Western blotting technique. Although there were no significant differences between p53 expression and clinicopathological features of the neoplasm (except poor histological grading), further studies are necessary to evaluate the influence of p53 nuclear/cytoplasmatic levels on the clinical outcome of Polish patients suffering from endometrial cancer.

Characterization of a new human embryonal rhabdomyosarcoma cell line, RMS-GR

A human tumor cell line designated RMS-GR was established from an embryonal rhabdomyosarcoma. The monolayer cells were polygonal, round or spindle-shaped. The RMS-GR cell line became stable with a doubling time of 42 h. Tumorigenicity of the cells was confirmed by heterotransplantion into nude mice. Electron microscopic images showed typical cytoplasmic inclusion of aggregated intermediate filaments and myofibril-like thin filaments. The expression of desmin, vimentin, actin and human myoglobin was recognized by cytofluorometric analyses, and a large fraction of CK-MM and small fractions of CK-BB and MCK-1 isoenzymes were found. Chromosomal analysis showed that the modal chromosome number was consistently near triploid with structural abnormalities mostly involving chromosomes 1, 3 and 8, and additional unidentified markers. No alteration of chromosome 2 was observed. The RMS-GR cell line may provide a system to identify genes which are involved in the pathogenic mechanism of rhabdomyosarcomas, and to investigate the modulation of myogenic differentiation.

Spindle cell rhabdomyosarcoma (so-called) in adults: report of two cases with emphasis on differential diagnosis

Spindle cell rhabdomyosarcoma (RMS) is a recently described variant of embryonal RMS that carries a relatively favorable prognosis when compared with other forms of RMS. To date, spindle cell RMS has been described only in children. The authors have identified two unusual cases occurring in adults using the following criteria: tumors composed mainly of fascicular, relatively monomorphic spindle-shaped cells that show unequivocal immunohistochemical and ultrastructural evidence of myogenic differentiation. The tumors were identified in a 38-year-old woman and a 56-year-old man, arising in the cheek and left hemidiaphragm, respectively. Both were treated with surgical resection and chemotherapy. The first patient died of uncontrolled local recurrence of her tumor at 27 months after diagnosis, and the second died of metastatic disease at 13 months follow-up. The tumors were composed mainly of fascicles of spindle cells with palely eosinophilic cytoplasm admixed diffusely with sparse polygonal, rounded, or strap-shaped rhabdomyoblasts with brightly eosinophilic cytoplasm and with cross-striations in the first case only. Immunostaining for muscle-related antigens showed staining for smooth-muscle actin (focal), pan-actin HHF-35, desmin, fast myosin, myoglobin, and MyoD1. Both cases were negative for S-100 protein. On electron microscopy, both cases showed neoplastic rhabdomyoblasts with clear-cut sarcomeric differentiation in many of the tumor cells. Spindle cell RMS poses special problems in differential diagnosis when arising in adults and should be distinguished from leiomyosarcoma, malignant peripheral nerve sheath tumor with heterologous rhabdomyoblastic differentiation (malignant Triton tumor), and fibrosarcoma. In view of the good prognosis afforded children with spindle cell RMS and in light of the chemoresponsive behavior of RMS in general, we feel that it is important to identify tumors that meet the criteria for spindle cell RMS occurring in the adult population. However, based on these two cases, it is possible that spindle cell RMS occurring in adults may not be associated with such a favorable outcome.

Botryoid-type embryonal rhabdomyosarcoma of liver in a young cat

An unusual malignant mesenchymal tumor arising in the liver of a 2-year-old cat is described. Histologically, the tumor showed considerable variation in growth pattern, cellularity, and cell types. Phenotypical diversity was confirmed by immunohistochemistry, showing expression of desmin, vimentin, S-100, and neuron-specific enolase in various areas of the tumor. On the basis of histopathology, immunohistochemistry, electron microscopy, and gross morphology, the tumor was classified as botryoid-type embryonal rhabdomyosarcoma. Differential diagnosis included so-called undifferentiated (embryonal) sarcoma of the liver, a rare tumor of the pediatric age group in humans. Problems of tumor heterogeneity and differentiation in mesenchymal tumors are discussed.

Adult embryonal rhabdomyosarcoma metastatic to the breast and diagnosed by fine needle aspiration. A case report

BACKGROUND

Metastasis to the breast from extra-mammary malignancies is rare, but its recognition is important. A solitary metastasis must be distinguished from the primary breast cancer because the treatment and prognosis are quite different.

CASE

A 30-year-old female presented with a 4.0-cm, solitary, nontender mass in the upper outer quadrant of the right breast 11 months after primary surgery for maxillary sinus embryonal rhabdomyosarcoma. The cytomorphology revealed features of small round cell tumor. Immunocytochemical staining disclosed a positive reaction to vimentin and desmin and negative reaction to cytokeratin, confirming the diagnosis of rhabdomyosarcoma.

CONCLUSION

Fine needle aspiration with ancillary studies is essential in the diagnosis of metastatic malignancy of the breast in order to avoid unnecessary mastectomy and to implement appropriate systemic therapy.

A comparative study on morphology and immunohistochemistry of rhabdomyosarcoma and embryonal skeletal muscles

OBJECTIVE

To investigate the histologic and histogenetic relationship between various types of rhabdomyosarcomas (RMS) and embryonal skeletal muscle (ESM) for further understanding of the histogenesis, classification and pattern of differentiation of RMS.

METHODS

Fifty cases of variant types of RMS and 20 cases of ESM at different gestational ages were available. All specimens were stained with HE, PAS, Van Gieson, Masson, phosphotungstic acid hematoxilin and with antibodies for the demonstration of vimentin, desmin, HHF-35 and myoglobin by ABC method.

RESULTS

The results showed that the order of positive expression and the intensity of positive reaction of the different immunohistochemical staining were consistent with the degree of differentiation of the tumor and the development of the ESM. It is obvious that each type of RMS is composed of tumor cells in different degree of differentiation and is derived from primitive mesodermal cells which are capable of potential differentiation towards mature skeletal muscles.

CONCLUSIONS

Based on the results of this study, an ideal histologic classification of RMS should reflect not only the cell morphology and histologic structures but also the degree of differentiation of the tumor cells.

Rhabdomyosarcoma. Morphologic, immunohistochemical, and DNA study

In this study 80 cases of predominantly adult rhabdomyosarcoma are presented as follows: 20 cases of the embryonal type, 32 cases of the alveolar and 8 cases of the pleomorphic type. Additional histologic classification was performed in each type. In myotube stage the histologic picture of fetal muscles cannot be compared to the alveolar type of rhabdomyosarcoma. Desmin and sarcomeric actin are observed in 47.7% of all cases, and myoglobin and myosin in only 23.1%. The reactions were diffuse, disperse, or focal. Electron microscopic study subdivides desmin positive tumors into three groups of differentiation. DNA analysis shows that most desmin positive cells are diploid in comparison to all the tumor cells that are hyperdiploid and tetraploid.

Primary embryonal rhabdomyosarcoma of long bone. Case report and review of the literature

We report a case of primary embryonal rhabdomyosarcoma of long bone, presenting as a lytic destructive bone tumor in the right femoral diaphysis of a 7-year-old girl. To our knowledge, this is only the third report of this entity. The neoplasm was a pure embryonal rhabdomyosarcoma with numerous rhabdomyoblasts. Immunohistochemistry confirmed the diagnosis: The cells were reactive with antibodies directed against desmin, muscle-specific actin, and myoglobin. No other neoplastic mesenchymal component was present within the tumor. Although rare, primary rhabdomyosarcoma, along with Ewing's tumor and osteosarcoma, should be considered in the differential diagnosis of malignant bone tumors in childhood.

DNA content and expression of tumour markers in germ cells adjacent to germ cell tumours in childhood: probably a different origin for infantile and adolescent germ cell tumours

The origin of testicular germ cell tumours occurring during childhood is poorly understood. In adults, the classical seminomas and non-seminomas originate from carcinoma in situ of the testis, which can usually also be detected in seminiferous tubules adjacent to the tumours. In order to contribute with information regarding a possible association between carcinoma in situ and the childhood group of germ cell tumours, we investigated seminiferous tubules adjacent to 13 infantile yolk sac tumours, five infantile teratomas, and six adolescent germ cell tumours of various types, using morphological evaluation, immunohistochemical staining with markers for carcinoma in situ cells, and densitometric DNA measurement of the germ cells. We detected clear differences between the germ cell populations adjacent to adolescent and infantile germ cell tumours. The former were associated with both normal germ cells and carcinoma in situ cells, like germ cell tumours occurring in adult men. Although we were in doubt in two cases, the infantile cell germ cell tumours were in general not associated with carcinoma in situ cells. The aetiology of infantile yolk sac tumours and teratomas may therefore be fundamentally different from that of adolescent and adult germ cell tumours. The origin of yolk sac tumours and teratomas remains to be elucidated.

[Establishment and characterization of a childhood embryonal rhabdomyosarcoma cell line with nonrandom chromosome alterations]

A childhood embryonal rhabdomyosarcoma cell line, designated as TS-RM-1, was established from transplanted tumor in nude mouse. TS-RM-1 cells were small, spindle to polygonal shaped and cytoplasm was rich in glycogen. Estimated population doubling time was 31 hours and the distribution of chromosome number was in the range of 88 to 98. The karyotype of TS-RM-1 cells revealed nonrandom structural chromosome alterations, including der(3)t(1;3)(q12;p12-14),16q-,17q+ and 21q+. In immuno-cytohistochemical study, both TS-RM-1 cells and the primary tumor were positive for desmin and vimentin. TS-RM-1 cell line may be useful for studying the association between embryonal rhabdomyosarcoma and a specific alteration in chromosome 3.

Embryonal rhabdomyosarcoma arising in the buccal mucosa: a case report with immunohistochemical and electronmicroscopic findings

Rhabdomyosarcoma is one of the most common soft-tissue neoplasms in children. We report a case of a 9-year-old female with embryonal rhabdomyosarcoma arising in the buccal region with immunohistochemical and electronmicroscopic findings. Under a light microscope, it was observed that the tumor was composed of small round or spindle-shaped cells with pleomorphic and hyperchromatic nuclei. They were immunoreactive for actin, myoglobin and desmin. With an electron microscope, it was found that most tumor cells contained filamentous structures and free ribosomes. Some of them showed typical myofilaments, M-bands and Z-lines. These findings were specific evidence of rhabdomyosarcoma. Twenty courses of VAC (vincristine, D-actinomycin and cyclophosphamide) chemotherapy were administered, followed by surgical resection of the tumor.