Rabdomiossarcoma embrionário de colo uterino: relato de caso em adolescente / Embryonic rabdomyosarcoma of the cervix: case report in a teenager

O rabdomiossarcoma embrionário, variante botrioide, é uma neoplasia maligna dos tecidos moles que deriva de células musculares mesenquimais embrionárias. Alguns fatores de risco genéticos são conhecidos, mas a doença geralmente se apresenta de forma esporádica. É raro manifestar-se em adolescentes, assim como é raro ser primário do colo uterino. Cursa com a presença de pólipos e até massas que se sobressaem na vagina com casos de sangramento vaginal anormal. O diagnóstico é realizado essencialmente pela história e exame anatomopatológico. Quanto maior o tempo para confirmação do diagnóstico, pior o prognóstico. Há várias modalidades de tratamento ­ que deve ser individualizado e envolver uma equipe multidisciplinar ­, que, basicamente, incluem quimioterapia, radioterapia e cirurgia. Os resultados geralmente são menos favoráveis em adolescentes, quando comparados com os de crianças com a mesma neoplasia.(AU)

Embryonic rhabdomyosarcoma, a botryoid variant, is a malignant neoplasm of soft tissues that derives from embryonic mesenchymal muscle cells. Some genetic risk factors are known, but the disease usually presents itself sporadically. It's rarely manifested in adolescents, just as it is rare to be primary in the cervix. It occurs with the presence of polyps and even masses that protrude in the vagina with cases of abnormal vaginal bleeding. The diagnosis is made essentially by history and anatomopathological examination. The longer the time to confirm the diagnosis, the worse the prognosis. There are several treatment modalities ­ involving a multidisciplinary team ­ that must be individualized and basically include chemotherapy, radiotherapy and surgery. The results are generally less favorable in adolescents, when compared with those of children with the same neoplasia.(AU)

Paternal uniparental disomy with segmental loss of heterozygosity of chromosome 11 are hallmark characteristics of syndromic and sporadic embryonal rhabdomyosarcoma.

Costello syndrome (CS) arises from a typically paternally derived germline mutation in the proto-oncogene HRAS, and is considered a rasopathy. CS results in failure-to-thrive, intellectual disabilities, short stature, coarse facial features, skeletal abnormalities, congenital heart disease, and a predisposition for cancer, most commonly embryonal rhabdomyosarcoma (ERMS). The goal of this study was to characterize CS ERMS at the molecular level and to determine how divergent it is from sporadic ERMS. We characterized eleven ERMS tumors from eight unrelated CS patients, carrying paternally derived HRAS c.34G>A (p.Gly12Ser; 6) or c.35G>C (p.Gly12Ala; 2) mutations. Loss of heterozygosity (LOH) was evaluated in all CS ERMS by microarray and/or short tandem repeat (STR) markers spanning the entire chromosome 11. Eight CS ERMS tumors displayed complete paternal uniparental disomy of chromosome 11 (pUPD11), whereas two displayed UPD only at 11p and a second primary ERMS tumor showed UPD limited to 11p15.5, the classical hallmark for ERMS. Three sporadic ERMS cell lines (RD, Rh36, Rh18) and eight formalin fixed paraffin embedded (FFPE) ERMS tumors were also analyzed for RAS mutations and LOH status. We found a higher than anticipated frequency of RAS mutations (HRAS or NRAS; 50%) in sporadic ERMS cell lines/tumors. Unexpectedly, complete uniparental disomy (UPD11) was observed in five specimens, while the other six showed LOH extending across the p and q arms of chromosome 11. In this study, we are able to clearly demonstrate complete UPD11 in both syndromic and sporadic ERMS. © 2016 Wiley Periodicals, Inc.

Oncogenic NRAS, required for pathogenesis of embryonic rhabdomyosarcoma, relies upon the HMGA2-IGF2BP2 pathway.

Embryonic rhabdomyosarcoma (ERMS) is the most common soft-tissue tumor in children. Here, we report the identification of the minor groove DNA-binding factor high mobility group AT-hook 2 (HMGA2) as a driver of ERMS development. HMGA2 was highly expressed in normal myoblasts and ERMS cells, where its expression was essential to maintain cell proliferation, survival in vitro, and tumor outgrowth in vivo. Mechanistic investigations revealed that upregulation of the insulin-like growth factor (IGF) mRNA-binding protein IGF2BP2 was critical for HMGA2 action. In particular, IGF2BP2 was essential for mRNA and protein stability of NRAS, a frequently mutated gene in ERMS. shRNA-mediated attenuation of NRAS or pharmacologic inhibition of the MAP-ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) effector pathway showed that NRAS and NRAS-mediated signaling was required for tumor maintenance. Taken together, these findings implicate the HMGA2-IGFBP2-NRAS signaling pathway as a critical oncogenic driver in ERMS.

A mouse model of rhabdomyosarcoma originating from the adipocyte lineage.

Rhabdomyosarcoma (RMS) is an aggressive skeletal muscle-lineage tumor composed of malignant myoblasts that fail to exit the cell cycle and are blocked from fusing into syncytial muscle. Rhabdomyosarcoma includes two histolopathologic subtypes: alveolar rhabdomyosarcoma, driven by the fusion protein PAX3-FOXO1 or PAX7-FOXO1, and embryonal rhabdomyosarcoma (ERMS), which is genetically heterogeneous. Here, we show that adipocyte-restricted activation of Sonic hedgehog signaling through expression of a constitutively active Smoothened allele in mice gives rise to aggressive skeletal muscle tumors that display the histologic and molecular characteristics of human ERMS with high penetrance. Our findings suggest that adipocyte progenitors can be a cell of origin for Sonic hedgehog-driven ERMS, showing that RMS can originate from nonskeletal muscle precursors.

Late relapse of embryonal rhabdomyosarcoma, botryoid variant, of the vagina.

We report on two very similar cases of vaginal embryonal RMS, botryoid variant, that relapsed 9 and 10 years after initial diagnosis, a few months after the menarche in both cases. A possible causal association with estrogen hormones is hypothesized, particularly for the second case described, in which estrogen receptors were negative in the primary tumor specimen and positive in the relapsing tumor specimen.

Embryonal rhabdomyosarcoma secondary to an open fracture of the tibia: a case report and review of literature.

Embryonal rhabdomyosarcoma (ERMS) is a highly malignant tumor in children and adolescents. It rarely occurs in adults. A 47-year-old patient presented with ERMS of the muscle flap transplant 20 years after an open type III-comminuted fracture of the lower leg. The affected leg was amputated. The patient refused adjuvant chemotherapy and one year after surgery remains disease-free and in good general condition.

Radiation-induced mandibular adult spindle cell rhabdomyosarcoma.

Spindle cell rhabdomyosarcoma (RMS), a variant of embryonal RMS, is a rare tumour, especially in adults. Imaging techniques are used to evaluate the extent of the tumour whereas a biopsy is required to make the final diagnosis. In this article we describe a case of mandibular Spindle cell RMS in a previously irradiated field in a 56-year-old male, and discuss the clinicopathologic and imaging findings. Although the aetiology is still unclear, this case suggests that previous radiation therapy can be a causal factor.

Effects of RAS on the genesis of embryonal rhabdomyosarcoma.

Embryonal rhabdomyosarcoma (ERMS) is a devastating cancer with specific features of muscle differentiation that can result from mutational activation of RAS family members. However, to date, RAS pathway activation has not been reported in a majority of ERMS patients. Here, we have created a zebrafish model of RAS-induced ERMS, in which animals develop externally visible tumors by 10 d of life. Microarray analysis and cross-species comparisons identified two conserved gene signatures found in both zebrafish and human ERMS, one associated with tumor-specific and tissue-restricted gene expression in rhabdomyosarcoma and a second comprising a novel RAS-induced gene signature. Remarkably, our analysis uncovered that RAS pathway activation is exceedingly common in human RMS. We also created a new transgenic coinjection methodology to fluorescently label distinct subpopulations of tumor cells based on muscle differentiation status. In conjunction with fluorescent activated cell sorting, cell transplantation, and limiting dilution analysis, we were able to identify the cancer stem cell in zebrafish ERMS. When coupled with gene expression studies of this cell population, we propose that the zebrafish RMS cancer stem cell shares similar self-renewal programs as those found in activated satellite cells.

Tumor de origen desconocido como presentación de rabdomiosarcoma embrionario / Embryonal rhabdomyosarcoma presenting as tumor of unknown origen

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Radiotherapy-induced secondary cranial neoplasms in children.

BACKGROUND: Secondary malignant neoplasms (SMN) in CNS tumor survivors has become problem of increasing concern over the last 20 years. These tumors usually occur in a different site from the primary brain tumor several years after treatment. CASE REPORT: We report secondary cranial malignant neoplasms in three patients who were treated with irradiation and chemotherapy for their primary brain tumors. The first case is a male survivor of an orbital rhabdomyosarcoma who developed a meningioma 8 years later. The other two cases are female survivors of ependymomas who were irradiated at the age of 3 and developed secondary gliomas 8 and 17 years after therapy respectively. CONCLUSION: Patients carry a risk of developing SMNs many years later since irradiation is still an important part of the treatment. An SMN may have a benign course, as in meningioma, or be a dilemma for the patient, as in glioblastoma.

Spinal rhabdomyosarcoma in a child with lipomyelomeningocele.

Malignant tumors arising within dysrhaphic malformations are very rare and are mostly teratomas; so far, only one rhabdomyosarcoma has been reported in this context. We report another case of a girl with lipomyelomeningocele who developed a lumbar rhabdomyosarcoma 2 years after birth and primary closure of the neural tube defect. We present clinical, radiological and pathological findings, discuss possible mechanisms of malignant transformation and review the literature.

PAX7 expression in embryonal rhabdomyosarcoma suggests an origin in muscle satellite cells.

Rhabdomyosarcoma (RMS) is a common paediatric soft tissue sarcoma that resembles developing foetal skeletal muscle. Tumours of the alveolar subtype frequently harbour one of two characteristic translocations that juxtapose PAX3 or PAX7, and the forkhead-related gene FKHR (FOXO1A). The embryonal subtype of RMS is not generally associated with these fusion genes. Here, we have quantified the relative levels of chimaeric and wild-type PAX transcripts in various subtypes of RMS (n=34) in order to assess the relevance of wild-type PAX3 and PAX7 gene expression in these tumours. We found that upregulation of wild-type PAX3 is independent of the presence of either fusion gene and is unlikely to contribute to tumorigenesis. Most strikingly, upregulated PAX7 expression is almost entirely restricted to cases without PAX3-FKHR or PAX7-FKHR fusion genes and may contribute to tumorigenesis in the absence of chimaeric PAX transcription factors. Furthermore, as myogenic satellite cells are known to express PAX7, this pattern of PAX7 expression suggests this cell type as the origin of these tumours. This is corroborated by the detection of MET (c-met) expression, a marker for the myogenic satellite cell lineage, in all RMS samples expressing wild-type PAX7.

Embryonal rhabdomyosarcoma of the orbit in a liver transplant recipient.

Although an increased incidence of de novo malignancies is reported in transplant recipients, rhabdomyosarcoma, an aggressive mesenchymal tumor typical of childhood, is not considered a neoplasm commonly related to immunosuppression. A 21-year-old woman presented with unilateral diplopia and proptosis 16 months after liver transplantation for fulminant hepatic failure. A tumoral mass originating from the medial rectus muscle was partially removed and diagnosed as being an embryonal rhabdomyosarcoma. Since the patient refused complete orbital excision, one course of radiotherapy and six courses of chemotherapy were administered, while immunosuppression was re-modulated, without interruption of the administration of cyclosporine. Complete control of tumor growth was achieved, while no alterations of graft function were observed throughout the treatment period.

Rhabdomyosarcoma arising in mediastinal teratoma in an adult man: a case report.

We report a case of rhabdomyosarcoma which occurred in a mediastinal teratoma in a 44-year-old man. Presentation symptoms were chest pain, hoarseness and a cough. Diagnosis was fortuitous, performed by the histological and immunohistochemical study of a mediastinal tumour biopsy specimen that showed embryonal carcinoma and yolk sac tumour components associated with the rhabdomyosarcoma. After cisplatin-based chemotherapy (bleomycin-etoposide-cisplatin), surgical resection of the residual mediastinal tumour was performed. Histological and immunohistochemical study of this tumour confirmed the presence of mature teratoma and embryonal rhabdomyosarcoma. Evolution was marked by a local extension of the mediastinal tumour, occurrence of multiple metastases and bone marrow involvement. The patient died 8 months after diagnosis despite chemotherapy and radiotherapy. A review of the literature reveals that the development of rhabdomyosarcoma in primary mediastinal teratomas is unusual in adults. The diagnostic, therapeutic and prognostic implications of such an association are reviewed.

Neurofibromatosis 1 associated with embryonal rhabdomyosarcoma of the urinary bladder.

A 10-month-old boy presented with a 6-week history of abdominal pain. The pain was due to a large, stage IV embryonal rhabdomyosarcoma of the urinary bladder. The rhabdomyosarcoma was found in association with neurofibromatosis 1 (NF1) manifesting multiple café au lait spots and bowing of the right calf. The diagnosis of NF1 had not been made before presentation. This case report is intended to heighten the awareness of the manifestations of NF1 and the possibility of developing a nonneuroectodermal tumor as a concomitant of NF1, and to emphasize the importance of timely diagnosis and treatment of such an NF1-associated malignancy. Reports of the epidemiologic evidence for rhabdomyosarcoma in children with NF1 are reviewed.

Embryonal rhabdomyosarcoma of the lung arising in cystic adenomatoid malformation: case report and review of the literature.

Rhabdomyosarcoma (RMS) of the lung is a very rare lesion, but the association with cystic adenomatoid malformation (CCAM) is unlikely to be a coincidence. Although the etiologic factors predisposing infants and children to pulmonary neoplasms are unknown, pulmonary developmental abnormalities may play a pathogenetic role. A case of embryonal pulmonary RMS is described, which was discovered within a congenital CCAM in a 22-month-old child. The hypothesis regarding histogenesis of this neoplasm are also briefly discussed. Because of the risk of malignant change, early removal of the congenital cystic lesions of the lung is advisable.

Microsatellite instability in childhood rhabdomyosarcoma is locus specific and correlates with fractional allelic loss.

Replication errors (RERs) were initially identified in hereditary nonpolyposis colon cancer and other tumors of Lynch syndrome II. Mutations in genes involved in mismatch repair give rise to a mutator phenotype, resulting in RERs. The mutator phenotype is thought to predispose to malignant transformation. Here we show that in the embryonal form of childhood rhabdomyosarcoma, RERs also occur, but in contrast to hereditary nonpolyposis colon cancer, only a subset of the microsatellite loci analyzed show RERs. The occurrence of RERs is strongly correlated with increased fractional allelic loss (P < 0.001), suggesting that the occurrence of RERs is a secondary phenomenon in rhabdomyosarcoma. Coincidental loss of genes involved in mismatch repair, possibly due to their proximity to tumor suppressor genes involved in tumor progression of embryonal form of childhood rhabdomyosarcoma, could explain the observed phenomenon.