Histopathological classification of childhood rhabdomyosarcomas: relationship with clinical parameters and prognosis

Primary rhabdomyosarcoma of the breast in a 17-year-old girl: Case report

RATIONALE

Primary rhabdomyosarcoma of the breast is very rare disease with poor prognosis and no definitive treatment has yet been established.

PATIENT CONCERNS

A 17-year-old girl presented with right breast mass without distant metastasis in image study.

DIAGNOSIS

The result of core needle biopsy was intraductal carcinoma; however, histopathologic finding after mastectomy was primary rhabdomyosarcoma of breast.

INTERVENTIONS

Adjuvant chemotherapy was recommended because resection margin was involved by tumor cells, but she did not visit the clinic anymore. Five months later, tumor recurred with local invasion and chemotherapy of vincristine, doxorubicin, and cyclophosphamide alternating with ifosfamide and etoposide (VAC/IE) was done.

OUTCOMES

In the course of chemotherapy and sequential follow-up, there was no tumor growth until now.

LESSONS

Primary breast rhabdomyosarcoma is an uncommon disease, as a result diagnosis is often delayed. For the same reason, there is little information about treatment. This report may be helpful for managing the disease.

PAX7 Expression in Rhabdomyosarcoma, Related Soft Tissue Tumors, and Small Round Blue Cell Neoplasms

Rhabdomyosarcoma, the most common soft tissue malignancy of childhood, is a morphologically variable tumor defined by its phenotype of skeletal muscle differentiation. The diagnosis of rhabdomyosarcoma often relies in part on the identification of myogenic gene expression using immunohistochemical or molecular techniques. However, these techniques show imperfect sensitivity and specificity, particularly in scant tissue biopsies. Here, we expand the toolkit for rhabdomyosarcoma diagnosis by studying the expression of PAX7, a transcriptional regulator of mammalian muscle progenitor cells implicated in the pathogenesis of rhabdomyosarcoma. Immunohistochemical analysis of tissue microarrays using a monoclonal anti-PAX7 antibody was used to characterize PAX7 expression in 25 non-neoplastic tissues, 109 rhabdomyosarcomas, and 697 small round blue cell or other soft tissue tumors. Among non-neoplastic tissues, PAX7 was specifically expressed in adult muscle progenitor cells (satellite cells). In embryonal rhabdomyosarcoma, PAX7 expression was positive in 52 of 63 cases (83%), negative in 9 of 63 cases (14%), and focal in 2 of 63 cases (3%). PAX7-positive embryonal rhabdomyosarcoma cases included several showing focal or negative myogenin expression. PAX7 expression in alveolar rhabdomyosarcoma was positive in 6 of 31 cases (19%), negative in 14 of 31 cases (45%), and focal in 11 of 31 cases (36%). In addition, PAX7 was expressed in 5 of 7 pleomorphic rhabdomyosarcomas (71%) and 6 of 8 spindle cell rhabdomyosarcomas (75%). Among histologic mimics, only Ewing sarcoma showed PAX7 expression (7/7 cases, 100%). In contrast, expression of PAX7 was not seen in the large majority (688/690, 99.7%) of examined cases of other soft tissue tumors, small round blue cell neoplasms, and leukemias/lymphomas. In summary, immunohistochemical analysis of PAX7 expression may be a useful diagnostic tool in the assessment of skeletal muscle differentiation in human tumors.

Pediatric sclerosing rhabdomyosarcomas: a review

Sclerosing RMS (SRMS) is a recently described subtype of RMS that has not yet been included in any of the classification systems for RMSs. We did pubmed search using keywords “sclerosing, and rhabdomyosarcomas” and included all pediatric cases (age ≤ 18 years) of SRMSs in this review. We also included our case of an eleven-year-old male child with skull base SRMS and discuss the clinical, histopathological, immunohistochemical, and genetic characteristics of these patients. Till now, only 20 pediatric cases of SRMSs have been described in the literature. Pediatric SRMS more commonly affects males at a mean age of 9 years. Extremeties and head/neck regions were most commonly affected. Follow-up details were available for 16 patients with mean follow-up of 25.3 months. Treatment failure rate was 43.75%. Overall amongst these 16 patients, 10 were alive without disease, 4 were alive with disease, and two died. Thus, overall and disease-free survival amongst these 16 patients were 87.5% and 62.5%, respectively. The literature regarding clinical behaviour and outcome of pediatric patients with SRMSs is patchy. Detailed molecular/genetic analysis and clinicopathological characterization with longer follow-ups of more cases may throw some light on this possibly new subtype of RMS.

Primary rhabdomyosarcoma of the diaphragm: case report and review of the literature

BACKGROUND

Diaphragmatic sarcomas are extremely rare and mostly described in children. We present the case of an adult with rhabdomyosarcoma of the diaphragm.

METHODS

We performed a literature review, highlighted possible diagnostic pitfalls, and discussed multidisciplinary treatment options.

Tumors of the infratemporal fossa

Neoplastic processes involving the infratemporal fossa may originate from the tissues in the region, but more often are the result of extension from neighboring structures. Metastatic lesions located in the region are rarely encountered. Because of its concealed localization, tumors may remain unnoticed for some time. Clinical signs and symptoms often arise late, are insidious, and may be mistakenly attributed to other structures. The close proximity of the area to the intracranial structures, the orbit, the paranasal sinuses, the nasopharynx, and the facial area demands careful planning of surgical excision and combined procedures may be called for. Modern imaging techniques have made three-dimensional visualization of the extent of the pathology possible. Treatment depends on the histopathology and staging of the tumor. Several surgical approaches have been developed over the years. Radical tumor excision with preservation of the quality of life remain the ultimate goal for those tumors where surgery is indicated. Experience over a decade with various pathologies is presented.

Tumors of the diaphragm

Primary tumors of the diaphragm are rare. The most common benign cystic lesions of the diaphragm are bronchogenic or mesothelial cysts, while the most common benign solid lesion is a lipoma. Benign tumors of the diaphragm are resected if they are symptomatic or if there is a doubt about the diagnosis. The most common primary malignant lesion is rhabdomyosarcoma. Malignant tumors are treated based on histology and often with chemotherapy and/or radiation along with surgical resection if feasible. Endometriosis, a benign process that metastasizes to the diaphragm, is typically treated medically; surgical ablation or resection is considered only after failed conservative treatment. Surgical resection of metastatic malignant tumors, such as ovarian cancer and thymoma, as well as malignancies affecting the diaphragm by direct extension, such as mesothelioma, lung, and esophageal cancer, may provide some survival advantage.

Heparanase activity in alveolar and embryonal rhabdomyosarcoma: implications for tumor invasion

Background

Rhabdomyosarcoma (RMS) is a malignant soft tissue sarcoma of childhood including two major histological subtypes, alveolar (ARMS) and embryonal (ERMS) RMS. Like other human malignancies RMS possesses high metastatic potential, more pronounced in ARMS than in ERMS. This feature is influenced by several biological molecules, including soluble factors secreted by tumor cells, such as heparanase (HPSE). HPSE is an endo-β-D-glucuronidase that cleaves heparan sulphate proteoglycans.

Methods

We determined HPSE expression by Western blot analysis in ARMS and ERMS cells lines and activity in supernatants by an ELISA assay. Stable HPSE silencing has been performed by shRNA technique in RH30 and RD cell lines and their invasiveness has been evaluated by Matrigel-invasion assay. HPSE activity and mRNA expression have also been quantified in plasma and biopsies from RMS patients.

Results

HPSE expression and activity have been detected in all RMS cell lines. Stable HPSE silencing by shRNA technique determined a significant knockdown of gene expression equal to 76% and 58% in RH30 and RD cell lines respectively and induced a less invasive behaviour compared to untreated cells. Finally, we observed that HPSE mRNA expression in biopsies was higher than in foetal skeletal muscle and that plasma from RMS patients displayed significantly more elevated HPSE levels than healthy subjects with a trend to higher levels in ARMS.

Conclusion

In conclusion, our data demonstrate for the first time HPSE expression and activity in RMS and highlight its involvement in tumor cell invasion as revealed by shRNA silencing. Moreover, HPSE expression in RMS patients is significantly higher with respect to healthy subjects. Further studies are warranted to assess possible relationships between HPSE and clinical behaviour in RMS.

Massive bone marrow involvement by clear cell variant of rhabdomyosarcoma

A 16-year-old boy with generalized myalgia and petechial hemorrhage was found to have a diffuse infiltrative disease in his bone marrow (BM). The BM aspirate contained a dense population of vacuolated blast-like cells. The BM biopsy displayed compact sheets of small round cells with clear cytoplasm, reminiscent of Ewing sarcoma. Immunostains were not diagnostically conclusive while transmission electron microscopy on the BM cells demonstrated a clear skeletal muscle differentiation. The morphologic findings led to a tentative designation of metastatic embryonal rhabdomyosarcoma (RMS). It was not until cytogenetic analysis revealed the specific translocation t(2;13)(q35;q14) did the alveolar RMS finally get confirmed. Despite an exhaustive search by imaging studies, a primary tumor was not detected. This case illustrates that the massive BM involvement by atypical alveolar RMS of unknown origin may pose serious diagnostic challenges. Multidisciplinary studies are required to reach a definitive diagnosis.

Diffuse myogenin expression by immunohistochemistry is an independent marker of poor survival in pediatric rhabdomyosarcoma: a tissue microarray study of 71 primary tumors including correlation with molecular phenotype

The pathologic classification of rhabdomyosarcoma (RMS) into embryonal or alveolar subtype is an important prognostic factor guiding the therapeutic protocol chosen for an individual patient. Unfortunately, this classification is not always straightforward, and the diagnostic criteria are controversial in a subset of cases. Ancillary studies are used to aid in the classification, but their potential use as independent prognostic factors is rarely studied. The aim of this study is to identify immunohistochemical markers of potential prognostic significance in pediatric RMS and to correlate their expression with PAX-3/FKHR and PAX-7/FKHR fusion status. A single tissue microarray containing 71 paraffin-embedded pediatric RMSs was immunostained with antibodies against p53, bcl-2, Ki-67, CD44, myogenin, and MyoD1. The tissue microarray and whole paraffin blocks were studied for PAX-3/FKHR and PAX-7/FKHR gene fusions by fluorescence in situ hybridization and reverse transcription-polymerase chain reaction. Clinical follow-up data were available for each patient. Immunohistochemical staining results and translocation status were correlated with recurrence-free interval (RFI) and overall survival (OS) using the Kaplan-Meier method, the log-rank test, and Cox proportional hazard regression. The minimum clinical follow-up interval was 24 months (median follow-up=57 mo). On univariable analysis, immunohistochemical expression of myogenin, bcl-2, and identification of a gene fusion were associated with decreased 5-year RFI and 10-year OS (myogenin RFI P=0.0028, OS P=0.0021; bcl-2 RFI P=0.037, OS P=0.032; gene fusion RFI P=0.0001, OS P=0.0058). After adjustment for Intergroup Rhabdomyosarcoma Study-TNM stage, tumor site, age, tumor histology, and translocation status by multivariable analysis, only myogenin retained an independent association with RFI (P=0.034) and OS (P=0.0069). In this retrospective analysis, diffuse immunohistochemical reactivity for myogenin in RMS correlates with decreased RFI and OS, independent of histologic subtype, translocation status, tumor site, or stage.

Primary rhabdomyosarcoma of the breast in a 13-year-old girl: report of a case

We report a case of primary alveolar rhabdomyosarcoma of the breast in a 13-year-old Japanese girl. The patient initially presented with a 13 x 8-cm mass in her left breast, which was diagnosed as alveolar rhabdomyosarcoma after an excisional biopsy. Genetic expression of the tumor revealed t(2;13)(q35-37;q14). She underwent modified radical mastectomy (Bt + Ax) and nine lymph nodes were found to be involved. Systemic examinations showed multiple bone and lung metastases 2 weeks after her operation. Despite chemotherapy with doxorubicin, ifosfamide, and actinomycin D, which resulted in remission for 6 months, she died of the disease 8 months after surgery.

MYCN expression in human rhabdomyosarcoma cell lines and tumour samples

The MYCN oncogene encodes a phosphoprotein that acts as a transcription factor and is involved in the regulation of cell proliferation and differentiation in normal as well as in cancer cells.MYCN amplification and expression have been reported in various tumours, including neuroblastoma and lung cancer, but little is known about its expression in human rhabdomyosarcoma. MYCN expression and amplification were studied in five alveolar and five embryonal rhabdomyosarcoma cell lines and in 19 tumour biopsies. All the cell lines studied expressed MYCN RNA, as demonstrated by northern blot analysis and RT-PCR, but the oncogene was amplified in only one. Similarly, MYCN protein was detected in all cell lines by western blot analysis, with higher levels of expression in alveolar than in embryonal rhabdomyosarcoma cells. RT-PCR analysis of tumour samples demonstrated 18/19 cases positive for MYCN RNA. Although MYCN expression was higher in alveolar than in embryonal rhabdomyosarcoma cell lines, no clear relationship between histology and level of MYCN expression could be established in this tumour series. These data suggest that MYCN expression is a common feature of rhabdomyosarcoma, independent of gene amplification and without a clear relationship with specific histological and clinical features.

Primary rhabdomyosarcoma of the diaphragm: case report and literature review

The authors report a case of primary rhabdomyosarcoma of the diaphragm, an extremely rare presentation with only 14 cases reported in the literature. An 18-year-old male presented 2 spontaneous occurrences of pneumothorax. Computed tomography and magnetic resonance showed a tumoral mass on the right diaphragmatic surface, and after biopsy, the diagnosis was compatible with spindle cell rhabdomyosarcoma. Because the visceral pleura was invaded by the tumoral mass, a right pleuropneumonectomy was performed. The patient received adjuvant chemotherapy, and there was no evidence of disease 15 months after the operation. Based on the Intergroup Rhabdomyosarcoma Study Group (IRSG) criteria, which consider the extent of the disease and its surgical resectability, rhabdomyosarcomas can be classified into 4 groups. In clinical group I, which was the classification of our patient, the tumor is localized and completely resectable, which implies a good prognosis. Rhabdomyosarcoma is a rare tumor, and a good outcome may result if it is completely resected.

Pathologic classification of rhabdomyosarcomas and correlations with molecular studies

Rhabdomyosarcoma, the most common soft-tissue malignancy of childhood and adolescence, comprises a group of differing pathobiologic entities linked by their common propensity for formation of neoplastic skeletal muscle, a feature that results from biological forces related to aberrant transcription signals and the resultant production of myogenic proteins. At a molecular level, however, rhabdomyosarcomas form a heterogeneous group that can be subdivided into distinct clinicopathologic entities based on morphologic appearance and genetic makeup. These differing morphologic features were recognized in the mid-1900s by Horn and Enterline with their division of rhabdomyosarcomas into embryonal, alveolar, botryoid, and pleomorphic subtypes. More recent histologic and biologic studies have resulted in description of additional entities, such as spindle cell and anaplastic rhabdomyosarcoma, and refinements in recognition of the original entities, such as solid-alveolar rhabdomyosarcoma. Familiarity with newer classifications and their relationship to molecular aberrations is key to stratifying patients on current therapeutic protocols and proposed innovative genetic therapies.

Childhood cancer in New Zealand 1990 to 1993

An epidemiological study of childhood cancer in New Zealand identified 409 children aged 0 to 14 years with malignant neoplasms newly diagnosed between 1990 and 1993 inclusive. The original microscopic material on which the diagnoses were based was reviewed in 398 cases and the neoplasms were allocated into the 12 major groupings and 48 further subcategories of the International Classification of Childhood Cancer (ICCC). The pathology reviewers agreed with group and subcategory classification of the confirmed cancers in all but one case of acute leukemia and three cancers of the central nervous system. Changes were also made in the FAB classification of three cases of acute non-lymphocytic leukemia and in the further subcategorisation of three Hodgkin's lymphomas and ten astrocytomas. The results show a high level of diagnostic accuracy for confirmed childhood neoplasms in that time period. Nine of 15 cases of malignant melanoma notified to the study were not confirmed for various reasons, which included a change in the pathological diagnosis in four cases. Compared with Victoria (Australia), New Zealand has a high incidence rate of lymphomas in boys and an unusual female preponderance of Wilms' tumor cases.

Clear cell rhabdomyosarcoma

A clear cell rhabdomyosarcoma was studied by light microscopy, histochemistry, immunohistochemistry, and electron microscopy. It was a large, painful left parapharyngeal mass in a 10-year-old boy with intracranial extension and cervical metastatic enlarged lymph nodes. Tumor tissue was macroscopically grayish. At microscopic examination, the architecture was diffuse and focally alveolar. Tumor cells were of three types. Most cells were large, round or polygonal, with abundant clear vacuolated cytoplasm. Fibrils were sometimes found to be present around the nucleus. Nuclei often had irregular outlines and multiple nucleoli. Mitotic activity was high. Some round or elongated cells had eosinophilic fibrillar cytoplasm and were found to have a few double striations. A few cells were round and medium sized with a high nucleocytoplasmic ratio. Periodic acid-Schiff stain demonstrated huge amounts of intracytoplasmic glycogen in clear cells. Tumor cells showed positive immunostaining for muscle markers (desmin, muscle actins, dystrophin). Electron microscopy showed large lakes of glycogen, lipid droplets, and striated muscle features.

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.