Alveolar rhabdomyosarcoma presenting as an acute orbital mass in the medial rectus muscle

Rhabdomyosarcoma is the most common pediatric primary neoplasm in the orbit, often presenting with rapid proptosis and orbital symptoms. We describe a 15-year-old girl who presented with an acute mass in her medial rectus muscle that was subsequently diagnosed as widely disseminated alveolar rhabdomyosarcoma. To our knowledge, this represents the first reported case in which an enlarged extraocular muscle was the initial manifestation of disseminated alveolar rhabdomyosarcoma.

Delayed radiotherapy following dose intensive chemotherapy for parameningeal rhabdomyosarcoma (PM-RMS) of childhood

PURPOSE

To evaluate the local control rates and survival rates of patients with Group III parameningeal rhabdomyosarcoma (PM-RMS) treated with a dose intensive chemotherapy regimen followed by irradiation.

MATERIALS AND METHODS

Twenty-six patients with group III, PM-RMS were enrolled in a prospective pilot trial at the Mayo Clinic, Rochester, MN and Children's Hospital and Regional Medical Center Seattle, WA. The median age at diagnosis was 8.5 years (range 1.5-19 years). The male to female patient ratio was 1.6:1. Twenty-three patients had embryonal histology with the remaining three alveolar. Risk factors indicating high risk disease included intracranial extension (10 patients), base of skull erosion (12 patients), and cranial nerve palsy (10 patients). The median follow-up period for all patients was 82 months (range 17-148 months). Patients were treated with an intensified chemotherapy regimen followed by definitive local irradiation at week 12 following further chemotherapy. The median time from initiation of chemotherapy to irradiation was 16 weeks (range 6-23). The median dose delivered was 50.4Gy (50.4-66.6Gy).

RESULTS

Response was assessed after the fourth course of chemotherapy. Three patients exhibited a complete response, 22 a partial response, and 1 patient had no response after two cycles of chemotherapy and proceeded to irradiation at week 6. The 5-year estimated event free survival was 81% (+/-15%, 95% CI). Two patients died from progressive metastatic disease; 1 patient died from secondary malignancy; and 2 patients died from locally progressive disease. The 5-year local control rate was 92% (+/-10.6%, 95% CI).

CONCLUSIONS

Treatment of group III PM-RMS patients with neo-adjuvant, intensive chemotherapy with a delay in irradiation resulted in excellent local-regional control rates and survival rates and may allow for a response-based radiotherapy approach.

Sphingosine-induced apoptosis in rhabdomyosarcoma cell lines is dependent on pre-mitochondrial Bax activation and post-mitochondrial caspases

Sphingolipids is the collective term ascribed to components of the sphingomyelin cycle. Modulation of the cellular levels of individual sphingolipids can induce a diverse range of cellular responses including apoptosis, proliferation, and cell cycle arrest. We present data showing that rhabdomyosarcoma cell lines, independent of lineage (alveolar rhabdomyosarcoma and embryonal rhabdomyosarcoma), are particularly sensitive to the induction of apoptosis as a result of an elevation in the cellular levels of sphingosine (D-erythro-sphingosine). Sphingosine-mediated apoptosis does not require its metabolism to the related proapoptotic molecule ceramide and is stereospecific because exposure of the rhabdomyosarcoma cell line RD to the L-erythro and DL-threo isoforms of sphingosine did not induce apoptosis. Importantly, for efficient induction of apoptosis, sphingosine required Bax activation and consequential translocation to the mitochondria. This resulted in selective mitochondrial release of cytochrome c and Smac/Diablo but not other mitochondrial related factors (apoptosis-inducing factor, endonuclease G, and HtrA2/Omi). Using small interfering RNA, reduced Bax expression conferred the impaired release of mitochondrial cytochrome c to the cytoplasm following sphingosine exposure, inhibiting the induction of apoptosis. Furthermore, dissipation of the inner mitochondrial membrane potential and enhanced production of reactive oxygen species were not observed. Bax activation and cytochrome c release were independent of caspases; however, caspase-3 and caspase-9 activity distal to the mitochondria was essential for the execution of apoptosis.

Synchronous bifocal alveolar rhabdomyosarcoma

We report a case of bifocal rhabdomyosarcoma involving the hand and thigh in an 11-year-old female. We highlight the importance of a thorough clinical examination and an aggressive surgical approach in which each lesion is treated as a separate primary.

The challenging role of radiation therapy for very young children with rhabdomyosarcoma

PURPOSE

To evaluate local control and toxicity for very young children treated with multimodality therapy for rhabdomyosarcoma (RMS).

METHODS AND MATERIALS

From 1990 to 2004, 20 patients<or=36 months at diagnosis were treated at our institution. Nineteen underwent chemotherapy (CMT), surgery and/or intraoperative high-dose-rate brachytherapy (IOHDR), and external-beam radiation (EBRT). Median age was 17 months. Sites included extremity (7), trunk (5), parameningeal (4), orbit (1), head/neck (1), bladder/prostate (1). Histologies consisted of 10 embryonal (53%) and 9 alveolar/undifferentiated (47%). Ten had delayed gross total resection (GTR) at median time of 17 weeks after the start of CMT, and 8 of these underwent IOHDR. Median interval between start of CMT and EBRT was 18 weeks. Median EBRT dose was 36 Gy. EBRT technique was either intensity-modulated (11), three-dimensional (3), or two-dimensional (5). Functional outcome was assessed for patients alive>or=1 year after diagnosis (15) in terms of mild, moderate, or severe deficits.

RESULTS

Median follow-up was 33 months for survivors and 23 months for all patients. Two-year actuarial local control, event-free survival, disease-specific survival, and overall survival were 84%, 52%, 74%, and 62%, respectively. All patients who began EBRT<or=18 weeks after the start of CMT had their disease controlled locally. Five have mild deficits and 10 have no deficits.

CONCLUSIONS

A reduced dose of 36-Gy EBRT after delayed GTR may maximize local control while minimizing long-term sequelae for very young children with RMS, but unresectable tumors (e.g., parameningeal) require higher doses. Normal-tissue-sparing techniques such as intensity-modulated radiation therapy and IOHDR are encouraged. Local control may be maximized when EBRT begins <or=18 weeks after initiation of CMT, but further study is warranted. Longer follow-up is required to determine the full extent of late effects.

A case report of rhabdomyosarcoma of the uterus associated with uterine inversion

BACKGROUND

Alveolar rhabdomyosarcoma is an uncommon malignant soft tissue tumor rarely found in the genital tract. This tumor is associated with a poor prognosis, especially in the adult population. Equally as rare are non-puerperal uterine inversions secondary to sarcomas.

CASE

A 21-year-old obese woman was initially evaluated with excessive vaginal bleeding. On exam, a large pedunculated mass protruding from the cervix was seen and biopsy of this mass revealed an alveolar rhabdomyosarcoma. The patient was treated with adjuvant chemotherapy consisting of VAC (Vincristine, Actinomycin, and Cyclophosphamide) for a presumed cervical rhabdomyosarcoma. After five cycles of chemotherapy the patient underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy, at which time a complete uterine inversion was noted with the tumor located at the fundus of the uterus. Final pathology showed alveolar rhabdomyosarcoma of the uterus. The patient then received additional postoperative VAC regimen for a total of 10 treatments and remains in good health with no evidence of disease 20 months from diagnosis.

CONCLUSION

This case report describes the only reported case of uterine inversion secondary to alveolar rhabdomyosarcoma of the uterus and discusses current therapeutic options for adults.

Immune-mediated thrombocytopenia following dactinomycin therapy in a child with alveolar rhabdomyosarcoma: the unresolved issues

The authors report a case of severe dactinomycin-induced thrombocytopenia in a child with alveolar rhabdomyosarcoma. The phenomenon is consistent with an immune process leading to the formation of platelet-specific antibodies. This study shows that this can be induced even with the first dose of actinomycin, and its persistence is unpredictably prolonged and does not correlate linearly in an inverted fashion with the platelet count. It will be important to identify the subsets of patients who can develop this phenomenon by molecular techniques and to define the exact mechanism in vitro leading to formation of these antibodies. This would facilitate profiling the therapy, preventing the need for multiple platelet transfusions with their obvious hazards.

[Alveolar rhabdomyosarcoma originating in spermatic cord: a case report]

A 19-year-old man visited our hospital complaining of swelling of the left inguinal region. A thumb head-sized tumor was palpated through the skin on the left spermatic cord. Tumor resection was performed because it was dissected easily apart from the left spermatic cord. Pathological examination revealed alveolar rhabdomyosarcoma with positive surgical margin. Computed tomographic scanning revealed no retroperitoneal lymph node swelling, and there were no clinical findings of distant metastasis (clinical stage I). Radical inguinal orchiectomy with combined chemotherapy using vincristine, dactinomycin, and ifosfamide (VAI) was performed. He has been alive without any recurrence for 8 years and 8 months after the surgery.

Continent urinary reconstruction in rhabdomyosarcoma: a new approach

PURPOSE

The authors present here 5 cases of continent urinary diversion in rhabdomyosarcoma applying a recently described technique for the Mitrofanoff Principle devised by the authors.

METHODS

Two previously irradiated rhabdomyosarcoma patients presenting with residual bladder disease and massive sensitive urinary urgency underwent a transverse colonic reservoir with catheterizable stoma. Two other patients presenting with a Bricker conduit underwent conversion into an ileal reservoir. One patient underwent reconstruction after a cystectomy.

RESULTS

All patients were continent and able to perform continent intermittent catheterization.

CONCLUSIONS

The technique proved to be feasible for this group of patients. The authors believe that because of its simplicity, it should be an option of continent urinary diversion when the Mitrofanoff Principle is considered.

mTOR as a Target for Cancer Therapy

The target of rapamycin, mTOR, acts as a sensor for mitogenic stimuli, such as insulin-like growth factors and cellular nutritional status, regulating cellular growth and division. As many tumors are driven by autocrine or paracrine growth through the type-I insulin-like growth factor receptor, mTOR is potentially an attractive target for molecular-targeted treatment. Further, a rationale for anticipating tumor-selective activity based on transforming events frequently identified in malignant disease is becoming established.

Sentinel lymph node mapping and biopsy: a potentially valuable tool in the management of childhood extremity rhabdomyosarcoma

Multimodal therapy, involving surgery, chemotherapy and radiation, now dominates the management of rhabdomyosarcoma (RMS) in childhood. Yet, despite improvements in these practices, extremity tumors continue to fare relatively poorly. Several investigators have identified prognostic factors that can be used to direct therapy and predict outcome. These factors include histology and metastatic disease, the latter requiring accurate staging to identify. The presence of lymph node metastases has been shown to be of prognostic significance and is incorporated into pre-treatment staging schemes. Up to 50% of all surgically evaluated nodes and 17% of clinically negative nodes in extremity RMS may harbor tumor, underscoring the increased risk of understaging the disease if accurate lymph node dissection is not undertaken. Despite its importance, there appears to be no standard format by which regional nodal status is evaluated in extremity RMS. Sentinel lymph node mapping and biopsy are a minimally invasive technique, currently used in the staging of adult breast cancer and melanoma. In adults, the technique is associated with optimum nodal yield and low morbidity. We describe a case in which sentinel node mapping and dissection were used to easily and accurately stage a distal upper extremity alveolar RMS in a child with clinically and radiologically negative regional lymph nodes. The procedure yielded no positive nodes, was associated with no morbidity and spared the child more extensive radiotherapy. We propose the further evaluation of this simple and innovative technique in the overall management of this childhood malignancy.

Volumetric considerations in radiotherapy for pediatric parameningeal rhabdomyosarcomas

PURPOSE

To assess the influence of radiation volume on outcome in pediatric parameningeal rhabdomyosarcomas (PM-RMSs).

METHODS AND MATERIALS

Thirty patients ranging in age from 2 to 18 years (median 6) with PM-RMS were treated at the Hospital of the University of Pennsylvania and the Children's Hospital of Philadelphia between August 1988 and December 1999. The histologic subtypes included embryonal (n = 26), alveolar (n = 3), and undifferentiated (n = 1). Twenty-seven patients had Group III and three had Group IV disease. Twenty-seven patients underwent biopsy only and three subtotal resection. All patients were treated with multiple-agent chemotherapy and external beam radiotherapy. In 8 patients, all of whom had intracranial tumor extension, the tumor and whole brain were treated as the initial volume. In the remaining patients, most of those treated before 1992 were treated to the prechemotherapy (CMT) tumor volume for the entire treatment up to the total dose, which ranged from 45 to 59.4 Gy (median dose 57.9). In contrast, patients treated after 1992 generally received radiation initially to the pre-CMT volume (30.6-40 Gy; median dose 36) followed by a conedown to the post-CMT volume to a final dose of 41.4-55.2 Gy (median 50.4).

RESULTS

With a median follow-up of 6.2 years (range 2.1-13.3), the actuarial 5-year overall survival, progression-free survival, and local control rate for the entire group was 82%, 76%, and 76%, respectively. Seven failures and five deaths have been documented. In univariate analysis, histologic type, tumor size, and age at diagnosis were found to be predictive of overall survival and local control. No statistically significant difference in overall survival or local control was seen between patients who received a conedown to the post-CMT volume (n = 13) and patients in whom the pre-CMT volume was included for the entire treatment (n = 9).

CONCLUSION

Radiotherapy delivered to children with PM-RMS using a shrinking field technique with a post-CMT volume boost was effective and appears to give results comparable to those of patients in whom the pre-CMT volume was treated for the entire course. The use of such tailored treatment fields is likely to lead to fewer late effects and warrants further investigation.

Detection of the PAX3-FKHR fusion gene in paediatric rhabdomyosarcoma: a reproducible predictor of outcome?

Rhabdomyosarcoma has 2 major histological subtypes, embryonal and alveolar. Alveolar histology is associated with the fusion genes PAX3-FKHR and PAX7-FKHR. Definition of alveolar has been complicated by changes in terminology and subjectivity. It is currently unclear whether adverse clinical behaviour is better predicted by the presence of these fusion genes or by alveolar histology. We have determined the presence of the PAX3/7-FKHR fusion genes in 91 primary rhabdomyosarcoma tumours using a combination of classical cytogenetics, FISH and RT-PCR, with a view to determining the clinical characteristics of tumours with and without the characteristic translocations. There were 37 patients with t(2;13)/PAX3-FKHR, 8 with t(1;13) PAX7-FKHR and 46 with neither translocation. One or other of the characteristic translocations was found in 31/38 (82%) of alveolar cases. Univariate survival analysis revealed the presence of the translocation t(2;13)/PAX3-FKHR to be an adverse prognostic factor. With the difficulties in morphological diagnosis of alveolar rhabdomyosarcoma on increasingly used small needle biopsy specimens, these data suggest that molecular analysis for PAX3-FKHR will be a clinically useful tool in treatment stratification in the future. This hypothesis requires testing in a prospective study. Variant t(1;13)/PAX7-FKHR appears biologically different, occurring in younger patients with more localised disease.

Near-precise interchromosomal recombination and functional DNA topoisomerase II cleavage sites at MLL and AF-4 genomic breakpoints in treatment-related acute lymphoblastic leukemia with t(4;11) translocation

We analyzed the der(11) and der(4) genomic breakpoint junctions of a t(4;11) in the leukemia of a patient previously administered etoposide and dactinomycin by molecular and biochemical approaches to gain insights about the translocation mechanism and the relevant drug exposure. The genomic breakpoint junctions were amplified by PCR. Cleavage of DNA substrates containing the normal homologues of the MLL and AF-4 translocation breakpoints was examined in vitro upon incubation with human DNA topoisomerase IIalpha and etoposide, etoposide catechol, etoposide quinone, or dactinomycin. The der(11) and der(4) genomic breakpoint junctions both involved MLL intron 6 and AF-4 intron 3. Recombination was precise at the sequence level except for the overall gain of a single templated nucleotide. The translocation breakpoints in MLL and AF-4 were DNA topoisomerase II cleavage sites. Etoposide and its metabolites, but not dactinomycin, enhanced cleavage at these sites. Assuming that DNA topoisomerase II was the mediator of the breakage, processing of the staggered nicks induced by DNA topoisomerase II, including exonucleolytic deletion and template-directed polymerization, would have been required before ligation of the ends to generate the observed genomic breakpoint junctions. These data are inconsistent with a translocation mechanism involving interchromosomal recombination by simple exchange of DNA topoisomerase II subunits and DNA-strand transfer; however, consistent with reciprocal DNA topoisomerase II cleavage events in MLL and AF-4 in which both breaks became stable, the DNA ends were processed and underwent ligation. Etoposide and/or its metabolites, but not dactinomycin, likely were the relevant exposures in this patient.

Histology-specific expression of a DNA repair protein in pediatric rhabdomyosarcomas

PURPOSE

DNA repair enzymes have a critical role in cellular maintenance and survival. The enzyme apurinic/apyrimidinic endonuclease/redox factor 1 (APE/ref1), a key protein in the base excision repair pathway, displays both repair and redox control. We examined the role of APE/ref1 in pediatric embryonal and alveolar rhabdomyosarcomas (ARMS).

MATERIALS AND METHODS

Using an immunohistochemical method, fixed tissue from 31 newly diagnosed pediatric rhabdomyosarcomas were evaluated for expression of APE/ref1. Tissue was obtained from Indiana University and the Cooperative Human Tissue Network.

RESULTS

We demonstrated high levels of expression within the localized and metastatic embryonal rhabdomyosarcomas. This contrasted with both localized and metastatic ARMS, which had low levels of APE/ref1 expression. This histology-specific difference proved to be significant (P = 0.003). Furthermore, the expression within all tumors examined was localized to the nucleus and did not differ between localized and metastatic tumors.

CONCLUSIONS

We propose several hypotheses to explain this histology-specific expression of APE/ref1 in pediatric rhabdomyosarcomas. Because the majority of ARMS expressed either the PAX3/FKHR or PAX7/FKHR fusion transcript, the low level of expression may be related to the redox activity of APE/ref1. The low levels may also be related to the bioreductive activity of APE/ref 1.

Up-front window trial of topotecan in previously untreated children and adolescents with metastatic rhabdomyosarcoma: an intergroup rhabdomyosarcoma study

PURPOSE

To investigate the antitumor activity and toxicity of topotecan, used alone and in combination with conventional therapy, in patients with metastatic rhabdomyosarcoma (RMS).

PATIENTS AND METHODS

Forty-eight patients younger than 21 years of age with newly diagnosed metastatic RMS received 2.0 to 2.4 mg/m(2) of topotecan intravenously daily for 5 days every 21 days before standard therapy. Two courses were given in the absence of progressive disease or excessive toxicity and response was assessed. Patients with at least a partial response (PR) to topotecan proceeded to therapy with alternating courses of vincristine 1.5 mg/m(2), dactinomycin 1.5 mg/m(2), and cyclophosphamide 2.2 g/m(2) (VAC) and vincristine 1.5 mg/m(2), topotecan 0.75 mg/m(2) daily x 5, and cyclophosphamide 250 mg/m(2) daily x 5. Patients who did not respond to topotecan received continuation therapy with VAC alone.

RESULTS

The overall response rate to topotecan was 46% (complete response, 4%; partial response 42%). Unexpectedly, patients with alveolar RMS had a higher rate of response (65%) than those with embryonal RMS (28%; P: = .08). The most common grade 3 or 4 toxicities were neutropenia (67%), anemia (33%), thrombocytopenia (25%), and infection (21%). Two-year failure-free survival and survival estimates were 24% and 46%, respectively. Response to window therapy did not correlate with survival.

CONCLUSION

The high response rate and acceptable toxicity profile of topotecan in children with advanced RMS support further evaluation of this agent in phase III trials. The superior responses in alveolar RMS are of interest.

High-dose thiotepa and hematopoietic stem cell transplantation in pediatric malignant mesenchymal tumors: a phase II study

The prognosis of metastatic malignant mesenchymal tumors (MMT) remains poor. Given the chemosensitivity of these neoplasms, a phase II study of high-dose thiotepa (HDT) was performed to evaluate the efficacy of this drug in this particular subset of pediatric tumors. Between 1986 and 1998, 18 patients, previously treated with conventional therapy for metastatic or refractory MMT, entered the study. Thiotepa was administered at a daily dose of 300 mg/m2 for 3 consecutive days. Hematopoietic stem cell rescue, consisting of bone marrow transplantation or peripheral stem cell transplantation, was performed 2 days after completion of HDT. A response exceeding 50% was observed in 6/18 patients (response rate 33%). Toxicity was severe but never led to death. HDT used at a dose of 900 mg/m2 yields measurable anti-tumor activity in previously treated patients. The next step in these particularly poor prognosis metastatic MMT will be to investigate HDT combined with other drugs, known to be efficient at high doses.