Rhabdomyosarcoma. Biology and treatment

Diagnostic journey and multimodal management of a rare urogenital rhabdomyosarcoma with rectovaginal fistula in an adolescent: a case report

Introduction and importance

Rhabdomyosarcoma is a malignant tumour that originates from immature muscle cells and belongs to the category of soft-tissue sarcomas. It is predominantly diagnosed in children under the age of 6. This condition can manifest within the genitourinary tract and may exhibit non-specific symptoms such as changes in bowel habits and fever. Early detection and a comprehensive, multidisciplinary approach are essential to achieving more favourable outcomes. This report highlights an uncommon case of urogenital rhabdomyosarcoma in a 15-year-old girl, in addition to the presence of a rectovaginal fistula.

Case presentation

A 15-year-old girl with presented with fever, altered bowel habits, and a lump in her lower abdomen, abdominal discomfort, and incomplete bowel evacuation. She also had faecal discharge from the vagina. Diagnostic imaging and biopsy confirmed urogenital rhabdomyosarcoma with a rectovaginal fistula. The patient is currently undergoing induction chemotherapy and is scheduled for radiation therapy and surgery.

Clinical discussion

Rhabdomyosarcoma is a rare paediatric oncologic concern due to its aggressive nature and potential metastasis. The presentation varies based on age, tumour location, and metastasis presence. This patient presented with altered bowel habits, a pelvic mass and unusual feculent discharge, suggesting a rectovaginal fistula. Diagnostic imaging confirmed the diagnosis, and induction chemotherapy led to a positive response and reduced tumour size.

Conclusion

Urogenital rhabdomyosarcoma is an aggressive malignancy with non-specific symptoms, making early diagnosis challenging. An accurate diagnosis requires high suspicion, imaging, and a biopsy. Multidisciplinary management, including surgery, chemotherapy, and radiation therapy, improves outcomes and improves paediatric patients' prognosis and quality of life.

Distant metastasis of alveolar rhabdomyosarcoma with pancreatic parameningeal localization in children: clinical case series

Rhabdomyosarcoma is a malignant neoplasm that develops from embryonic mesenchymal cells, with an annual incidence of 4.3 cases per 1,000,000 children. The prevalence of the tumor process is estimated on the basis of data from a comprehensive examination, including magnetic resonance imaging with intravenous contrast, ultrasound examination of the primary focus of regional and distant metastasis zones, computed tomography and radioisotope studies. The overall 5-year survival rate for localized rhabdomyosarcoma reaches 70 %. During the initial diagnosis, distant metastasis to the lungs, bones, and bone marrow is detected, which significantly worsens the prognosis in 20–25 % of patients. The factors of an extremely unfavorable prognosis for the course of alveolar rhabdomyosarcoma are the occurrence of regional and distant metastases before the start of specific treatment, dissemination of the tumor lesion during treatment, and the presence of translocation of the 13q14 sector. Publications contain data on a high (11.2 %) prevalence of metastases of alveolar rhabdomyosarcoma in the pancreas. In the presence of metastatic lesions of the pancreas, surgical treatment is effective only in combination with chemoradiotherapy. Long-term results of treatment of this cohort of children are unsatisfactory due to the high risk of recurrence and dissemination of the tumor.

Aim. To study risk factors, evaluate methods and prospects for the treatment of children with metastatic pancreatic lesions in parameningeal alveolar rhabdomyosarcoma. The article considers three clinical cases of such a lesion. We would like to draw the attention of pediatric oncologists and radiologists to the possible association of metastases in the pancreas in children with localization of rhabdomyosarcoma in the head and neck region, which requires improvement of examination protocols in this group of patients.

Plexin-B2 and Semaphorins Do Not Drive Rhabdomyosarcoma Proliferation or Migration

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma for which subsets of patients have longstanding unmet clinical needs. For example, children with alveolar rhabdomyosarcoma and metastases at diagnosis will experience only 8% disease-free 5-year survival for nonlocalized unresectable recurrent disease. Hence, development of novel therapeutic strategies is urgently needed to improve outcomes. The Plexin-Semaphorin pathway is largely unexplored for sarcoma research. However, emerging interest in the Plexin-Semaphorin signaling axis in pediatric sarcomas has led to phase I cooperative group dose-finding clinical trials, now completed (NCT03320330). In this study, we specifically investigated the protein expression of transmembrane receptor Plexin-B2 and its cognate SEMA4C ligands in clinical RMS tumors and cell models. By RNA interferences, we assessed the role of Plexin-B2 in cell growth and cell migration ability in selected alveolar and embryonal RMS cell model systems. Our results affirmed expression of Plexin-B2 across human samples, while also dissecting expression of the different protein subunits of Plexin-B2 along with the assessment of preferred Semaphorin ligands of Plexin-B2. Plexin-B2 knockdown had positive or negative effects on cell growth, which varied by cell model system. Migration assayed after Plexin-B2 knockdown revealed selective cell line specific migration inhibition, which was independent of Plexin-B2 expression level. Overall, these findings are suggestive of context-specific and possibly patient-specific (stochastic) role of Plexin-B2 and SEMA4 ligands in RMS.

Isolation of NELL 1 Aptamers for Rhabdomyosarcoma Targeting

NELL1 (Neural epidermal growth factor-like (EGFL)-like protein) is an important biomarker associated with tissue and bone development and regeneration. NELL1 upregulation has been linked with metastasis and negative prognosis in rhabdomyosarcoma (RMS). Furthermore, multiple recent studies have also shown the importance of NELL1 in inflammatory bowel disease and membranous nephropathy, amongst other diseases. In this study, several anti-NELL1 DNA aptamers were selected from a randomized ssDNA pool using a fluorescence-guided method and evaluated for their binding affinity and selectivity. Several other methods such as a metabolic assay and confocal microscopy were also applied for the evaluation of the selected aptamers. The top three candidates were evaluated further, and AptNCan3 was shown to have a binding affinity up to 959.2 nM. Selectivity was examined in the RH30 RMS cells that overexpressed NELL1. Both AptNCan2 and AptNCan3 could significantly suppress metabolic activity in RMS cells. AptNCan3 was found to locate on the cell membrane and also on intracellular vesicles, which matched the location of NELL1 shown by antibodies in previous research. These results indicate that the selected anti-NELL1 aptamer showed strong and highly specific binding to NELL1 and therefore has potential to be used for in vitro or in vivo studies and treatments.

Diagnosis and management of primary malignant tumors in the upper extremity

Bone and soft tissue sarcomas of the upper extremity are relatively uncommon. In many cases, they are discovered incidentally during evaluation of traumatic injuries or common ailments such as rotator cuff tendonitis or tennis elbow. Thus, it is important for all orthopedic surgeons to understand the differential diagnosis, workup, and treatment for upper extremity lesions. An appreciation of the clinical and radiographic features of primary malignant lesions aids in identifying patients that need referral to an orthopedic oncologist and a multidisciplinary team.

Erectile function after treatment for rhabdomyosarcoma of prostate and bladder

INTRODUCTION

Rhabdomyosarcoma (RMS) accounts for 5% of all pediatric tumors; 15-20% of these tumors are located in the urogenital tract, mostly originating from the prostate or bladder. In the light of the steadily improving prognosis for patients with RMS through interdisciplinary-multimodal study protocols with 60-70% long-term survivors, non oncological aspects such as erectile function (EF) have become increasingly important. The aim of this study was to evaluate EF in patients having undergone treatment for RMS of the bladder and prostate.

DESIGN

The medical records of 24 male patients having undergone surgical treatment for pelvic RMS between 1975 and 2014 were reviewed, and follow-up was obtained. Erectile function was determined using the Self-Estimation Index of Erectile Function-No Sexual Intercourse (SIEF-NS) and the Erection Hardness Scale (EHS). Potential prognostic factors were evaluated in respect to their impact on EF.

RESULTS

Thirteen patients were included in the study (median age 20 years). Median follow-up period was 12.7 years (1.09-39.85). All patients completed the EHS; nine patients completed the SIEF-NS. All three patients with preserved erectile function (EHS = 4) showed a score indicating no or minimal impairment on sexual function on SIEF-NS (median 33). None of these patients had undergone external radiotherapy, and radical cystoprostatectomy had been performed before the third year of life in two out of three. The remaining patients had erectile dysfunction (EHS = 0). Three patients had an unsatisfying treatment attempt with sildenafil. Seven patients, including all with failures of oral PDE-5-inhibitors, were successfully treated with intracavernous injection of Alprostadil (Summary Table).

DISCUSSION

This was the largest study, to date, evaluating erectile EF in patients treated for RMS of the bladder or prostate. EF was preserved in some patients, despite aggressive treatment modalities. Patients affected by erectile dysfunction after therapy showed limited response to PDE-5 inhibitors, but even after failure of the latter, an intracavernous injection of Alprostadil showed a significant improvement in EHS and SIEF-NS. Limitations of the study included the retrospective nature, small sample size, and heterogeneity of underlying disease, stage, and treatment modalities used.

CONCLUSIONS

The results suggested that in a subset of patients, EF was preserved after radical surgical treatment of RMS, especially in young boys. Intracavernous injection of Alprostadil was effective, even after failure of PDE-5-inhibitors, and should be offered to patients without spontaneous erections, whereas PDE-5-inhibitors appeared to be largely ineffective. External radiation therapy appeared to have a negative impact on EF.

Clinicopathological characteristics and treatment outcomes of Chinese patients with genitourinary embryonal rhabdomyosarcoma

Background

Genitourinary embryonal rhabdomyosarcoma is rarely reported in China. This retrospective analysis aimed to characterize the clinicopathologic features and treatment outcomes of genitourinary embryonal rhabdomyosarcoma in a sample of Chinese patients.

Methods

Basic demographic and clinical data of 29 patients, who were diagnosed with genitourinary embryonal rhabdomyosarcoma between January 2000 and December 2011, were retrieved and analyzed.

Results

In these patients, 25 were males and 4 were females with a median age of 12 years. Paratesticule was the most common lesion site, followed by the prostate, bladder, and vagina. The median tumor size was 5.80 cm. Six patients had clinically positive regional nodes. At the initial diagnosis, patients had a metastatic disease. According to the TNM staging classification for the IRS-IV, phase I lesions were detected in ten cases, phase II lesions in six cases, phase III lesions in four cases, and phase IV lesions in nine cases. The median survival of all patients was 63 (range from 6 to 118) months. The 1-, 3-, and 5-year survival rates for these patients were 93%, 83%, and 52%, respectively. Multivariate analyses demonstrated that staging and anemia were significant predictors of prognosis.

Conclusions

Our findings suggest that metastasis predicts a poor prognosis. Chemotherapy played an important role in comprehensive treatment. Palliative and neo-adjuvant chemotherapy could increase median survival time.

Nab-paclitaxel is an active drug in preclinical model of pediatric solid tumors

PURPOSE

To investigate the antitumor effect of nab-paclitaxel, an albumin-stabilized nanoparticle formulation of paclitaxel, on pediatric solid tumor models.

EXPERIMENTAL DESIGN

A panel of three rhabdomyosarcoma, one osteosarcoma and seven neuroblastoma cell lines were exposed to increasing concentrations of nab-paclitaxel in vitro. Cell viability was evaluated using the Alamar Blue Assay. Antitumor effect was further assessed in vivo in NOD/SCID xenograft and metastatic neuroblastoma mouse models. Tumor sections were analyzed by immunohistochemistry for cleaved caspase-3 and phospho-histone H3. Plasma and intratumoral paclitaxel concentrations were measured by liquid chromatography-mass spectrometry. Ratio of intratumoral and plasma concentration was compared between nab-paclitaxel and paclitaxel treatment groups.

RESULTS

Nab-paclitaxel displayed significant cytotoxicity against most pediatric solid tumor cell lines in vitro in a dose-dependent manner. In vivo, nab-paclitaxel showed antitumor activity in both rhabdomyosarcoma (RH4 and RD) and neuroblastoma [SK-N-BE(2) and CHLA-20] xenograft models. In the SK-N-BE(2) metastatic model, nab-paclitaxel treatment significantly extended animal survival compared with control (P < 0.01). Nab-paclitaxel treatment induced tumor cell-cycle arrest and apoptosis in vivo. In the RH4 model, increased local relapse-free intervals were observed with nab-paclitaxel treatment (37.7 ± 3.2 days) comparing with paclitaxel (13.6 ± 2.07 days). Local relapsed tumors following paclitaxel treatment proved to be paclitaxel-resistant and remained responsive to nab-paclitaxel. Mechanistically, a higher tumor/plasma paclitaxel drug ratio in favor of nab-paclitaxel was observed.

CONCLUSIONS

Nab-paclitaxel showed significant antitumor activity against all pediatric solid tumors associated with an enhanced drug intratumor delivery. Furthermore, testing of nab-paclitaxel in pediatric solid-tumor patient population is under development.

Dynamic and nuclear expression of PDGFRα and IGF-1R in alveolar Rhabdomyosarcoma

Since the advent of tyrosine kinase inhibitors as targeted therapies in cancer, several receptor tyrosine kinases (RTK) have been identified as operationally important for disease progression. Rhabdomyosarcoma (RMS) is a malignancy in need of new treatment options; therefore, better understanding of the heterogeneity of RTKs would advance this goal. Here, alveolar RMS (aRMS) tumor cells derived from a transgenic mouse model expressing two such RTKs, platelet-derived growth factor (PDGFR)α and insulin-like growth factor (IGF)-1R, were investigated by fluorescence-activated cell sorting (FACS). Sorted subpopulations that were positive or negative for PDGFRα and IGF-1R dynamically altered their cell surface RTK expression profiles as early as the first cell division. Interestingly, a difference in total PDGFRα expression and nuclear IGF-1R expression was conserved in populations. Nuclear IGF-1R expression was greater than cytoplasmic IGF-1R in cells with initially high cell surface IGF-1R, and cells with high nuclear IGF-1R established tumors more efficiently in vivo. RNA interference-mediated silencing of IGF-1R in the subpopulation of cells initially harboring higher cell surface and total IGF-1R resulted in significantly reduced anchorage-independent colony formation as compared with cells with initially lower cell surface and total IGF-1R expression. Finally, in accordance with the findings observed in murine aRMS, human aRMS also had robust expression of nuclear IGF-1R.

IMPLICATIONS

RTK expression status and subcellular localization dynamics are important considerations for personalized medicine.

Comparison of dose intensity of vincristine, d-actinomycin, and cyclophosphamide chemotherapy for child and adult rhabdomyosarcoma: a retrospective analysis

PURPOSE

The prognosis of adult rhabdomyosarcoma (RMS) has been considered dismal. The question is raised that vincristine, d-actinomycin, and cyclophosphamide (VAC) chemotherapy may not be administered as per schedule for adult RMS; consequently, low dose intensity (DI) leads to poor prognosis. Herein, we examined whether the administration of VAC chemotherapy for adults and children with RMS is feasible with regard to the DIs of VAC.

METHODS

Chart review was retrospectively performed for all identified patients. The percentage of relative DI (RDI) was calculated according to the Children's Oncology Group D9803 protocol. Further, we examined the RDI in the first 6 cycles of VAC (induction phase) and the DI after the first 6 cycles of VAC (maintenance phase).

RESULTS

We identified a total of 27 adults and 18 children with RMS, respectively. The mean RDIs of vincristine in total phase were significantly lower in adults than that in children (P = 0.04). In induction phase, the mean RDIs of vincristine and cyclophosphamide were similar for both groups; however, they were dropped significantly in adults during maintenance phase (P < 0.05). Mean RDIs of vincristine in elderly patients tended to become low. Low RDI was mainly attributable to hematologic toxicity, infection, and peripheral neuropathy. The prognosis of low versus high RDI was similar.

CONCLUSIONS

The RDIs of vincristine and cyclophosphamide in the maintenance phase were significantly lower than that in children. VAC chemotherapy for adults was not feasible; these patients require a different regimen.

Clinical outcomes of adult and childhood rhabdomyosarcoma treated with vincristine, d-actinomycin, and cyclophosphamide chemotherapy

BACKGROUND

Outcomes in adult patients with rhabdomyosarcoma are poor, with a 5-year survival rate of approximately 30 %. The current study aimed to compare the clinical outcomes of adult and childhood rhabdomyosarcoma patients with local and metastatic disease and to examine the impact and timing of local therapy on metastasis.

METHODS

Clinicopathological features and patient outcomes were reviewed retrospectively for rhabdomyosarcoma patients receiving chemotherapy between 1981 and 2010 at our institution. Adults were defined as those aged 21 years or older.

RESULTS

Of the 98 patients identified, 36 were adults (median age, 29; range, 21-72) and 62 were children (median age, 11; range, 0.6-20). Median progression-free survival of localized and metastatic disease for children and adults was as follows: localized disease, 166.9 versus 22.4 months (p = 0.005), and metastatic disease, 13.3 versus 13.3 months (p = 0.949), respectively. Multivariate regression analysis revealed that older age (≥ 21 vs. <21) was a significant poor prognostic factor in localized disease. Conversely, age was not related to survival in metastatic disease. Receiving radiotherapy to the primary site was an independent factor indicating a better prognosis. An analysis of the optimal timing of local therapy was performed for 53 patients; however, its significance on survival could not be determined.

CONCLUSIONS

Age was a negative prognostic factor in rhabdomyosarcoma patients with localized disease, but it did not affect the survival in metastatic disease. For metastatic disease, although local therapies may be effective for survival, the timing of such therapies should be determined individually.

Urogenital tumours in childhood

The commonest urogenital tumours in childhood are Wilms tumour of the kidney and rhabdomyosarcoma in the pelvis. We review these tumours along with other primary renal tumours and less common ovarian and testicular tumours in childhood. Current clinical concepts, relevant staging investigations and imaging features are described.

Evasion mechanisms to Igf1r inhibition in rhabdomyosarcoma

Inhibition of the insulin-like growth factor 1 receptor (Igf1r) is an approach being taken in clinical trials to overcome the dismal outcome for metastatic alveolar rhabdomyosarcoma (ARMS), an aggressive muscle cancer of children and young adults. In our study, we address the potential mechanism(s) of Igf1r inhibitor resistance that might be anticipated for patients. Using a genetically engineered mouse model of ARMS, validated for active Igf1r signaling, we show that the prototypic Igf1r inhibitor NVP-AEW541 can inhibit cell growth and induce apoptosis in vitro in association with decreased Akt and Mapk phosphorylation. However, drug resistance in vivo is more common and is accompanied by Igf1r overexpression, Mapk reactivation, and Her2 overexpression. Her2 is found to form heterodimers with Igf1r in resistant primary tumor cell cultures, and stimulation with Igf2 leads to Her2 phosphorylation. The Her2 inhibitor lapatinib cooperates with NVP-AEW541 to reduce Igf1r phosphorylation and to inhibit cell growth even though lapatinib alone has little effect on growth. These results point to the potential therapeutic importance of simultaneous targeting of Igf1r and Her2 to abrogate resistance.

Factors predicting local recurrence, metastasis, and survival in pediatric soft tissue sarcoma in extremities

BACKGROUND

Pediatric soft tissue sarcomas are rare and differ from those in adults regarding the spectrum of diagnoses and treatment. Sarcomas in extremities may have different prognoses from those located elsewhere.

QUESTIONS/PURPOSES

We sought risk factors predicting local recurrence, metastasis, and overall survival and asked whether radiation and chemotherapy influenced local recurrence, metastasis, and overall survival.

METHODS

We retrospectively reviewed all 98 patients aged 18 years or younger diagnosed with soft tissue sarcomas in extremities from 1990 to 2008. Age, tumor size, depth, location, bone or neurovascular involvement, histologic subtypes, unplanned excision, surgical margins, metastasis at diagnosis, and adjuvant treatments were reviewed for each patient. We determined the effect of each prognostic variable on local recurrence, metastasis, and overall survival.

RESULTS

Ninety-four patients underwent surgical excision and seven patients had local recurrence at a median time of 18.6 months. Radiation therapy reduced the rate of local recurrence. Fourteen patients had metastasis at diagnosis and seven patients later developed metastasis. The median time to metastasis was 20.9 months. Six patients died and the median time to death was 28.0 months. Metastasis at diagnosis was a predictive factor for death.

CONCLUSIONS

When limited to extremities, radiation therapy reduced the rate of local recurrence in pediatric soft tissue sarcomas. Metastases at diagnosis predict death.

Unusual association of alveolar rhabdomyosarcoma with pancreatic metastasis: emerging role of PET-CT in tumor staging

BACKGROUND

Pancreatic metastases in childhood cancer have been rarely reported in the radiology literature although ample evidence exists in pathology reports for its occurrence in patients with alveolar rhabdomyosarcomas (RMS).

OBJECTIVE

Assess the occurrence of pancreatic metastases in alveolar rhabdomyosarcomas, increase awareness of this association and reassess current staging protocols.

MATERIALS AND METHODS

Three major oncology centers reviewed their records and imaging examinations. Patients' history and demographics, primary tumor site and histology, presence of tumor recurrence, and presence and location of other metastases were reviewed.

RESULTS

Pancreatic metastases occurred in eight patients with alveolar RMS. Four of these presented at diagnosis and four with disease recurrence. In recurrent disease, the duration between the diagnosis of the primary tumor and pancreatic metastases varied from 8 months to 6 years (mean +/- SD: 2.38 +/- 2.49 years). In all patients who received PET scans, pancreatic metastases showed a marked FDG-uptake, but had variable detectability with CT. Pancreatic metastases were not associated with certain primary tumor locations or presence of other metastases, mandating an evaluation of the pancreas in all cases of alveolar rhabdomyosarcomas.

CONCLUSION

Radiologists should be sensitized and actively evaluate the pancreas in patients with alveolar RMS. Optimizing CT and PET-CT protocols may increase the diagnostic yield.

Vascular reconstruction in lower limb musculoskeletal tumours

BACKGROUND

Individual experience in the investigative, planning and operative aspects of lower limb musculoskeletal tumours is often small, making comparison between results difficult. The aim of the study was to describe the recent experience of a single tertiary referral unit performing limb salvage surgery, to identify areas of concern that are amenable to intervention and to provide clinicians an understanding of the surgical options.

METHODS

Nine patients with peripheral limb musculoskeletal tumours are described. Four patients had a leiomyosarcoma, and one each of osteosarcoma, synovial chondrosarcoma, synovial sarcoma, liposarcoma and recurrent malignant peripheral nerve sheath tumour.

RESULTS

Thirty-day mortality was nil. Two patients (one with a leiomyosarcoma and one with an osteosarcoma) died at 6 months follow-up because of pulmonary metastases. One patient with synovial chondrosarcoma developed a local recurrence and underwent an above-knee amputation. Six patients at 18 months follow-up are alive with no evidence of local recurrence and a functional lower limb.

CONCLUSION

These cases are a challenge to the clinicians, radiologists and pathologists. Review by a multidisciplinary team can produce successful results with low post-operative morbidity and mortality. Longer follow-up is required to determine the long-term implications.

Pancreatitis as an unusual presentation of rhabdomyosarcoma

The most common etiologies of acute pancreatitis in children are trauma, multi-system disease, drugs, infections, idiopathic and congenital anomalies of the pancreaticobiliary system. Acute pancreatitis is rarely associated with underlying childhood malignancies. We report a 12-year-old male with acute pancreatitis as the presenting symptom of an alveolar metastatic rhabdomyosarcoma.

Neck lumps and head and neck tumours in children

This article discusses the presentation, investigation and treatment of both benign and malignant lumps encountered in the head and neck region in children.

The role of radiology in paediatric soft tissue sarcomas

Paediatric soft tissue sarcomas (STS) are a group of malignant tumours that originate from primitive mesenchymal tissue and account for 7% of all childhood tumours. Rhabdomyosarcomas (RMS) and undifferentiated sarcomas account for approximately 50% of soft tissue sarcomas in children and non-rhabdomyomatous soft tissue sarcomas (NRSTS) the remainder. The prognosis and biology of STS tumours vary greatly depending on the age of the patient, the primary site, tumour size, tumour invasiveness, histologic grade, depth of invasion, and extent of disease at diagnosis. Over recent years, there has been a marked improvement in survival rates in children and adolescents with soft tissue sarcoma and ongoing international studies continue to aim to improve these survival rates whilst attempting to reduce the morbidity associated with treatment. Radiology plays a crucial role in the initial diagnosis and staging of STS, in the long term follow-up and in the assessment of many treatment related complications. We review the epidemiology, histology, clinical presentation, staging and prognosis of soft tissue sarcomas and discuss the role of radiology in their management.

Pediatric surgical oncology: management of rhabdomyosarcoma

A malignant tumor of striated muscle origin, Rhabdomyosarcoma (RMS) is a childhood tumor that has benefited from 30 years of multimodality therapeutic trials culminating in a greater than 70% overall current 5-year survival. Prognosis for RMS is dependent on anatomic primary tumor site, age, completeness of resection, presence and number of metastatic sites, histology and biology of the tumor cells. Multimodality treatment is based on risk stratification according to pretreatment stage, postoperative group, histology and site. Therefore, pretreatment staging is vital for assessment and is dependent on primary tumor site, size, regional lymph node status, and presence of metastases. Unique to RMS is the concept of postoperative clinical grouping that assesses the completeness of disease resection and takes into account lymph node evaluation both at the regional and metastatic basins. At all sites, if operative resection of all disease is accomplished, including microscopic disease, survival is improved. Therefore, the surgeon plays a vital role in determining risk stratification for treatment and local control of the primary tumor for RMS.

Correlation Between Histology and PAX/FKHR Fusion Status in Alveolar Rhabdomyosarcoma

At the molecular level, alveolar rhabdomyosarcomas (ARMS) are characterized by 3 mutually exclusive PAX/FKHR conditions: PAX3/FKHR fusion (present in 60% of cases), PAX7/FKHR fusion (present in 20%), and PAX/FKHR fusion-negativity (present in 20%). The possibility of morphologic variation among these molecular subtypes has not been investigated. We undertook a blinded retrospective study of 65 cases of ARMS (16 PAX/FKHR fusion-negative, 36 PAX3/FKHR-positive, and 13 PAX7/FKHR-positive by routine reverse transcription-polymerase chain reaction). We evaluated cytohistologic parameters such as microcyst formation, solid foci, differentiation, giant cell formation, anaplasia, nuclear grade, mitosis/karyorrhexis index, rosette formation, geographic necrosis, presence and amount of rhabdomyoblastic differentiation, and the presence of foci resembling embryonal rhabdomyosarcoma. We analyzed the results using a simple chi formula. Of these features, only totally solid alveolar architecture reached significance (P=0.00014), with 7 of 16 PAX/FKHR-negative cases lacking this feature, compared with 0 of 36 PAX3/FKHR cases and 2/13 PAX7/FKHR cases. These preliminary results indicate that in general, only totally solid alveolar architecture in ARMS may predict the absence of a PAX/FKHR fusion. No features seemed to predict the presence of a particular fusion type. Our results suggest that histologic assessment of ARMS has limited correlation with PAX/FKHR fusion status.

Clinicopathologic features of rhabdomyosarcoma of gynecologic origin in adults

Rhabdomyosarcoma (RMS) is the most common soft tissue tumor found in children. Up to 20% of RMS tumors in children originate in the genital tract making this the second most common site. RMS of gynecologic origin in adults is much less common. The purpose of this study was to describe the clinical and pathologic features of RMS of the adult female genital tract. We reviewed the histologic slides of women 16 years of age and older and included them in our study if they contained the classic histologic features of RMS as described by the 2002 World Health Organization classification of tumors. Rhabdomyoblastic components present in other established malignancies were not studied. We identified 15 patients, with a median age of 48 years (range, 16 to 69). Eleven (73%) of the tumors were of embryonal histology (cervix, 8; uterus, 2; and ovary, 1). Of the remaining 4 tumors, 2 were of alveolar (vulva) and 2 of pleomorphic (uterus, 1; fallopian tube, 1) histologic subtype. The majority (79%) of these patients presented with locoregional disease and had surgery as their primary intervention (73%). The median progression-free survival (PFS) and disease-specific survival was 9 months [95% confidence interval (CI), 1-24] and 21 months (95% CI, 14-28), respectively. The 5-year disease-specific survival was only 29%. There was a significant difference in PFS between cases of embryonal compared to cases with nonembryonal histology (19 vs. 3 mo, respectively) (P=0.04). Adult RMS of gynecologic origin presents with locoregional disease and most are morphologically similar to pediatric RMS; however, adult RMS behaves more aggressively, with worse overall survival. It is unclear whether these divergent outcomes are the result of differences in clinical management or because these tumors are biologically distinct.

Role of hypoxia inducible factor-1 alpha in modulation of apoptosis resistance

Hypoxia inducible factor-1 (HIF-1) is the major transcription factor and key regulator of adoptive responses to hypoxia. Although it usually promotes tumor cell survival under hypoxia, it has also been implied to trigger apoptosis. Although the impact of hypoxia has been extensively studied in many adult solid tumors, its role in most childhood tumors, for example, in rhabdomyosarcoma (RMS) or Ewing sarcoma (ES), has not yet been addressed. Here, we report that hypoxia protects A204 RMS and A673 ES cells against anticancer drug- or tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis and that Hif-1alpha plays a key role in conferring apoptosis resistance under hypoxia. Although a functional HIF-1 pathway and proapoptotic proteins such as p53 and Bcl-2/E1B 19 kDa interacting protein 3 were activated under hypoxia in both A204 RMS and A673 ES cells, these cells remained refractory to apoptosis. Concomitant analysis of antiapoptotic proteins revealed that hypoxia induced expression of Bcl-2 and inhibitor of apoptosis proteins (IAP)-2 as well as proteins associated with anaerobic metabolism such as the glucose transporter protein GLUT-1 and the glycolytic enzyme Aldolase A. Specific downregulation of Hif-1alpha by RNA interference significantly enhanced apoptosis under hypoxia by preventing the hypoxia-mediated increase in GLUT-1 expression without altering expression levels of the antiapoptotic proteins Bcl-2 or cIAP-2. Moreover, glucose deprivation-induced apoptosis of A204 RMS and A673 ES cells was inhibited under hypoxic conditions in a Hif-1alpha-dependent manner. As GLUT-1 was induced via Hif-1alpha under hypoxia in A204 RMS and A673 ES, these findings suggest that the Hif-1alpha-mediated increase in glucose uptake plays an important role in conferring apoptosis resistance. Thus, hypoxia-inducible genes may represent novel targets for therapeutic intervention in some pediatric tumors, which warrants further investigation.

Soft tissue sarcoma of the upper extremity

Soft tissue sarcomas of the upper extremities are rare and hand surgeons typically encounter only one or two undiagnosed soft tissue sarcomas during their careers. It is incumbent on the physician to review repeatedly the characteristics of these tumors and remain suspicious, because these lesions typically are misdiagnosed and treatment is delayed. The most common soft tissue sarcomas of the upper extremity are the epithelioid sarcoma, synovial cell sarcoma, and malignant fibrous histiocytoma. Limb salvage surgery is the treatment of choice for soft tissue sarcomas to preserve upper extremity function. Following wide tumor resection, adjuvant therapies such as chemotherapy, external beam radiation therapy, and brachytherapy may lessen local recurrence rates, but their effect on overall survival remains unclear.

The truth about alveolar rhabdomyosarcoma

The alveolar variant of rhabdomyosarcoma continues to be underdiagnosed by pathologists. Yet, the correct recognition of this subtype can be of significant import to the oncologist for specifics of patient treatment. This review discusses the important aspects of alveolar rhabdomyosarcoma and hopefully can be of some help in the proper diagnosis of this tumor.

High incidence of medulloblastoma following X-ray-irradiation of newborn Ptc1 heterozygous mice

Individuals affected with the Gorlin syndrome inherit a germ-line mutation of the patched (Ptc1) developmental gene and, analogously to Ptc1 heterozygous mice, show an increased susceptibility to spontaneous tumor development. Human and mouse Ptc1 heterozygotes (Ptc1(+/-)) are also hypersensitive to ionizing radiation (IR)-induced tumorigenesis in terms of basal cell carcinoma (BCC) induction. We have analysed the involvement of Ptc1 in the tumorigenic response to a single dose of 3 Gy X-rays in neonatal and adult Ptc1 heterozygous and wild type mice. We report that irradiation dramatically increased the incidence of medulloblastoma development (51%) over the spontaneous rate (7%) in neonatal but not adult Ptc1 heterozygotes, indicating that medulloblastoma induction by IR is subjected to temporal restriction. Analysis of Ptc1 allele status in the tumors revealed loss of the wild type allele in 17 of 18 medulloblastomas from irradiated mice and in two of three spontaneous medulloblastomas. To our knowledge, irradiated newborn Ptc1(+/-) heterozygous mice constitute the first mouse model of IR-induced medulloblastoma tumorigenesis, providing a useful tool to elucidate the molecular basis of medulloblastoma development.

Rhabdomyosarcoma of the head and neck in children

OBJECTIVE

The purpose of this study was to determine the rhabdomyosarcoma types involving the head and neck (H&N) region in children and their immunophenotype.

DESIGN

Anatomic pathology archives at Texas Children's Hospital were searched for all rhabdomyosarcoma cases over a 20-year period. One-hundred and thirty-seven cases were identified, with 50 being H&N cases. The cases were typed according to the Intergroup Rhabdomyosarcoma Study (IRS) criteria. Immunocytochemistry for myogenic and non-myogenic markers was performed on all H&N cases. Electron micrographs from cases (n=32) where ultrastructural examination had been performed at the time of original diagnosis were reviewed.

RESULTS

Children with H&N rhabdomyosarcomas had a mean age of 5.3 years (median 4 years). There was a male predilection (1.7M:1.0F). Primary tumor sites were: face NOS (18%), orbit/periorbital (16%), nasal cavity/nose (14%), lymph nodes (12%), paranasal sinuses (10%), parameningeal (10%), parotid gland (6%), neck (6%), infratemporal fossa/zygoma (2%), buccal mucosa (2%), palate (2%), and larynx (2%). Metastatic disease at diagnosis (33% of all cases) occurred in the bone marrow (11%), cerebrospinal fluid (6%), peritoneal fluid (6%), lung (4%), parietal pleura (2%), pleural fluid (2%) and pericardial fluid (2%). Rhabdomyosarcoma types (IRS criteria) were: embryonal (60%), alveolar (classic and solid subtypes, 28%), botryoid (4%), undifferentiated (4%), spindle cell (2%) and anaplastic (2%). Immunocytochemical findings were: polyclonal desmin (96%); myogenin (96%); muscle-specific actin (74%), smooth muscle actin (12%). Nonmyogenic markers included: vimentin (100%), CD99 (16%), p53 (16%), pancytokeratin (10%), NSE (8%), LCA (6%), CD20 (6%), EMA (2%), and NB-84 (0%, neuroblastoma). Undifferentiated sarcoma expressed only vimentin. By ultrastructural examination, 44% had readily identified z-bands and myofilaments, 37% had infrequent to rare myofilaments and z-bands, and 19% had myotubular intermediate filaments.

CONCLUSIONS

Distribution of H&N rhabdomyosarcoma IRS types is similar to that for all primary sites, with the exception that embryonal types are modestly increased while alveolar type is mildly decreased. There are many non-myogenic immunocytochemical markers that cross-react with rhabdomyosarcoma. Differentiation between favorable and unfavorable rhabdomyosarcoma types is important for appropriate therapy, and predicting prognosis and survival.

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.

Very intensive, short-term chemotherapy for children and adolescents with metastatic sarcomas

BACKGROUND

To improve the prognosis for pediatric patients with metastatic sarcomas, including the Ewing sarcoma family of tumors (ESFT), rhabdomyosarcoma (RMS), and undifferentiated sarcoma (UDS), we tested the feasibility of a brief, intensive regimen of chemotherapy that maximizes dose intensity.

PROCEDURE

Twenty-four children and adolescents with metastatic sarcomas received VACIME chemotherapy, consisting of eight courses of vincristine 2 mg/m(2) on day 0; doxorubicin 20 mg/m(2)/day on days 0-3; cyclophosphamide 360 mg/m(2)/day on days 0-4; ifosfamide 1,800 mg/m(2)/day on days 0-4; mesna 2,400 mg/m(2)/day; and etoposide 100 mg/m(2)/day on days 0-4. Doxorubicin was omitted in courses 7 and 8. Granulocyte colony-stimulating factor (G-CSF) was used routinely following each course of therapy. Courses of therapy were repeated every 21 days or as soon as hematopoietic recovery and resolution of nonhematopoietic toxicities permitted. Surgical resection followed course 6, and radiotherapy followed the completion of all therapy.

RESULTS

Thirteen patients achieved a complete response (CR) with chemotherapy alone, and seven more achieved a CR following surgical resection after course 6 (overall CR rate 83%). There was one toxic death. Thirteen patients developed progressive disease, with 2- and 4-year event-free survivals (95% confidence interval) of 50% (30-70%) and 45% (25-65%), respectively. Myelosuppression was severe and cumulative, leading to dose reductions and chemotherapy interval delays. Mucositis was the most common nonhematopoietic toxicity.

CONCLUSIONS

VACIME chemotherapy was a feasible dose-intensive regimen for pediatric patients with metastatic sarcomas. Cumulative hematopoietic toxicity and severe mucositis limited the delivery of chemotherapy as prescribed. The CR and 2-year event-free survival rates were superior to those of most previously reported regimens.

Myc oncogene expression and nude mouse tumorigenicity and metastasis formation are higher in alveolar than embryonal rhabdomyosarcoma cell lines

Accumulated clinical evidence suggests that alveolar rhabdomyosarcoma (ARMS) is more aggressive than embryonal rhabdomyosarcoma (ERMS). Here, we study six childhood rhabdomyosarcoma cell lines, three ERMS and three ARMS. We have assayed the ability of the tumor cells to grow in culture and in nude mice as well as their propensity for pulmonary metastasis formation by tail vein injection. We also compared levels of c- and N-myc oncogene expression and DNA copy number. We find no correlation of histologic tumor type (i.e. ERMS versus ARMS) with growth rate in culture, but we do find suggestive correlations of histologic type with tumorigenicity (mean tumor diameter in millimeters at 6 wk: ARMS 30, ERMS 10; p1 = 0.1) and metastasis formation (ARMS 12, ERMS 0; p1 = 0.1). These properties also correlate with uniform greater overexpression of c-myc in ARMS (mean 39.3-fold, range 16-83) compared with ERMS (mean 5.3, range 4-8) (p1 = 0.05, control fibroblasts = 1). Although c-myc was often amplified in vitro (four of six lines), there was no correlation with histologic type (2/3 ARMS, 2/3 ERMS). These data on rhabdomyosarcoma cell lines derived from verified ERMS and ARMS tumors support the impression from previous clinicopathologic observations that ARMS is a more malignant form of rhabdomyosarcoma than ERMS.

Soft tissue sarcomas in children

In childhood, soft tissue sarcomas comprise a complex group of malignancies of varied histologic subtypes, the prognoses of which depend on the histology, age, site, extent of involvement and a variety of other factors. This paper discusses the varieties of tumors classified as soft tissue sarcomas in childhood and the multimodal approach taken to cure these tumors, with particular attention to the details of difficult surgical problems.

Rhabdomyosarcomas and radiation hypersensitivity in a mouse model of Gorlin syndrome

Gorlin (or nevoid basal cell carcinoma) syndrome is characterized by a variety of clinical problems including generalized overgrowth of the body, cysts, developmental abnormalities of the skeleton and a predisposition to benign and malignant tumors. The syndrome results from germline mutations of the human homolog of the drosophila segment polarity gene patched (ptc). Here we report that mice heterozygous for ptc develop many of the features characteristic of Gorlin syndrome and that they exhibit a high incidence of rhabdomyosarcomas (RMS), the most common soft-tissue sarcoma in children. The downstream signalling partner of ptc, gli1, was overexpressed in all RMSs analyzed, indicating that abnormal signalling of the ptc-gli1 pathway may be common for the various tumors associated with the syndrome. igf2, implicated in the formation of RMSs, was also overexpressed, suggesting cross-talk between the ptc and igf2 pathways in tumorigenesis. Developmental defects in Gorlin syndrome resemble those induced by ionizing radiation. We show that ptc heterozygous mice exhibit increased incidence of radiation-induced teratogenesis. This suggests a role for ptc in the response to ionizing radiation and provides a model for both the systemic (developmental) and stochastic (cancer) abnormalities observed in Gorlin syndrome.