Primary alveolar rhabdomyosarcoma of the bone: two cases and review of the literature

Cytological diagnosis of patients with embryonal rhabdomyosarcoma of the cervix: case report and literature review

Cervical embryonal rhabdomyosarcoma(ERMS) is a rare malignancy. To date, no cases of ERMS diagnosed by cervical cytology have been reported. In this study, we report a case of cervical ERMS identified by a liquid-based cytology test and cell blocks in a 46-year-old postmenopausal woman. We describe the cytological features of ERMS, with the aim of helping cytopathologists recognize this rare cervical tumor.

Rhabdomyosarcoma with unknown primary tumor site: A report from European pediatric Soft tissue sarcoma Study Group (EpSSG)

BACKGROUND

Rhabdomyosarcoma (RMS) is an aggressive malignancy, and 20% of children present with metastases at diagnosis. Patients presenting with disseminated disease very occasionally have no clear evidence of a primary tumor mass. As these patients have rarely been investigated, we report on a series of patients with RMS and unknown primary tumor site registered in the Metastatic (MTS) RMS 2008 protocol (October 2008 to December 2016) coordinated by the European pediatric Soft tissue sarcoma Study Group.

METHODS

Patients were administered nine cycles of induction chemotherapy, and 48 weeks of maintenance chemotherapy. Surgery and/or radiotherapy were planned after the first assessment of tumor response, and implemented after six cycles of chemotherapy. If feasible, radiotherapy to all sites of metastasis was recommended.

RESULTS

We identified 10 patients with RMS and unknown primary site, most of them adolescents (median age 15.8 years, range: 4.6-20.4). Nine had fusion-positive alveolar RMS. Multiple organ involvement was identified in seven patients, two only had bone marrow disease, and one only had leptomeningeal dissemination. All patients were given chemotherapy, four were irradiated, and none had surgery. Three patients underwent allogeneic bone marrow transplantation. At the time of this analysis, only two patients are alive in complete remission: one had received radiotherapy; and one had a bone marrow transplant.

CONCLUSIONS

RMS with unknown primary tumor occurs mainly in adolescents and is typically fusion-positive alveolar. Radiotherapy may be important, but survival is poor and patients should be offered enrollment in investigational trials.

Hyperactive Akt1 Signaling Increases Tumor Progression and DNA Repair in Embryonal Rhabdomyosarcoma RD Line and Confers Susceptibility to Glycolysis and Mevalonate Pathway Inhibitors

In pediatric rhabdomyosarcoma (RMS), elevated Akt signaling is associated with increased malignancy. Here, we report that expression of a constitutively active, myristoylated form of Akt1 (myrAkt1) in human RMS RD cells led to hyperactivation of the mammalian target of rapamycin (mTOR)/70-kDa ribosomal protein S6 kinase (p70S6K) pathway, resulting in the loss of both MyoD and myogenic capacity, and an increase of Ki67 expression due to high cell mitosis. MyrAkt1 signaling increased migratory and invasive cell traits, as detected by wound healing, zymography, and xenograft zebrafish assays, and promoted repair of DNA damage after radiotherapy and doxorubicin treatments, as revealed by nuclear detection of phosphorylated H2A histone family member X (γH2AX) through activation of DNA-dependent protein kinase (DNA-PK). Treatment with synthetic inhibitors of phosphatidylinositol-3-kinase (PI3K) and Akt was sufficient to completely revert the aggressive cell phenotype, while the mTOR inhibitor rapamycin failed to block cell dissemination. Furthermore, we found that pronounced Akt1 signaling increased the susceptibility to cell apoptosis after treatments with 2-deoxy-D-glucose (2-DG) and lovastatin, enzymatic inhibitors of hexokinase, and 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR), especially in combination with radiotherapy and doxorubicin. In conclusion, these data suggest that restriction of glucose metabolism and the mevalonate pathway, in combination with standard therapy, may increase therapy success in RMS tumors characterized by a dysregulated Akt signaling.

Fusion-negative rhabdomyosarcoma with diffuse bony metastases and remarkable chemosensitivity

In this report, we describe the case of an adolescent male with an unusual case of fusion-negative, paratesticular alveolar rhabdomyosarcoma who presented with spontaneous tumour lysis syndrome and diffuse bony metastases throughout the axial and appendicular skeleton with additional significant bone marrow involvement. Both spontaneous tumour lysis syndrome and diffuse bony metastases are extremely unusual for rhabdomyosarcoma. On the backbone of standard vincristine, dactinomycin and cyclophosphamide (VAC) chemotherapy, the only local control was orchiectomy at 15 weeks, with no radiation administered due to the initially diffuse nature of the disease and rapid response to chemotherapy. Following 43 weeks of VAC, a year-long maintenance phase with pazopanib was given which was well tolerated. The patient remains in remission now 4 years after completion of therapy.

Miscellaneous Tumours of Bone

There are several tumors that do not easily fit into the specific classifications of primary bone tumors. These tumors include tumors of neural, adipocytic, smooth muscle lineage, and some of uncertain lineage. The pathologic features with recent updates of these tumors are discussed here.

Intratumoral Translocation Positive Heterogeneity in Pediatric Alveolar Rhabdomyosarcoma Tumors Correlates to Patient Survival Prognosis

Alveolar rhabdomyosarcoma (ARMS) is characterized by one of three translocation states: t(2;13) (q35;q14) producing PAX3-FOXO1, t(1;13) (p36;q14) producing PAX7-FOXO1, or translocation-negative. Tumors with t(2;13) are associated with greater disease severity and mortality than t(1;13) positive or translocation negative patients. Consistent with this fact, previous work concluded that a molecular analysis of RMS translocation status is essential for the accurate determination of prognosis and diagnosis. However, despite this knowledge, most diagnoses rely on histology and in some cases utilize fluorescence in situ hybridization (FISH) probes unable to differentiate between translocation products. Along these same lines, diagnostic RT-PCR analysis, which can differentiate translocation status, is unable to determine intratumoral translocation heterogeneity, making it difficult to determine if heterogeneity exists and whether correlations exist between this heterogeneity and patient outcomes. Using newly developed FISH probes, we demonstrate that intratumoral heterogeneity exists in ARMS tumors with respect to the presence or absence of the translocation product. We found between 3 and 98% of cells within individual tumor samples contained a translocation event with a significant inverse correlation (R² = 0.66, p = 0.001) between the extent of intratumoral translocation heterogeneity and failure-free survival of patients. Taken together, these results provide additional support for the inclusion of the molecular analysis of these tumors and expand on this idea to support determining the extent of intratumoral translocation heterogeneity in the diagnosis of ARMS to improve diagnostic and prognostic indicators for patients with these tumors.

Characterization of mTOR Activity and Metabolic Profile in Pediatric Rhabdomyosarcoma

mTOR activation has been observed in rhabdomyosarcoma (RMS); however, mTOR complex (mTORC) 1 inhibition has had limited success thus far. mTOR activation alters the metabolic pathways, which is linked to survival and metastasis. These pathways have not been thoroughly analyzed in RMSs. We performed immunohistochemistry on 65 samples to analyze the expression of mTOR complexes (pmTOR, pS6, Rictor), and several metabolic enzymes (phosphofructokinase, lactate dehydrogenase-A, β-F1-ATPase, glucose-6-phosphate dehydrogenase, glutaminase). RICTOR amplification, as a potential mechanism of Rictor overexpression, was analyzed by FISH and digital droplet PCR. In total, 64% of the studied primary samples showed mTOR activity with an mTORC2 dominance (82%). Chemotherapy did not cause any relevant change in mTOR activity. Elevated mTOR activity was associated with a worse prognosis in relapsed cases. RICTOR amplification was not confirmed in any of the cases. Our findings suggest the importance of the Warburg effect and the pentose-phosphate pathway beside a glutamine demand in RMS cells. The expression pattern of the studied mTOR markers can explain the inefficacy of mTORC1 inhibitor therapy. Therefore, we suggest performing a detailed investigation of the mTOR profile before administering mTORC1 inhibitor therapy. Furthermore, our findings highlight that targeting the metabolic plasticity could be an alternative therapeutic approach.

Upfront surgical resection for primary bone tumors: rationale and potential benefits

Local control for the treatment of primary bone tumors is generally delayed following neoadjuvant chemotherapy. This was born out of the historical need to manufacture custom implants when performing limb-salvage resection. There is increasing reason to reconsider the timing of local control in the setting of primary bone tumors. In this report, we describe two cases in which upfront surgery was utilized and review rationale, prior literature, and potential benefits of this approach.

Alveolar Rhabdomyosarcoma Following Mandibular Distraction Osteogenesis

The authors present a rare case of anaplastic alveolar rhabdomyosarcoma (ARMS) occurring after Mandibular Distraction Osteogenesis. A 16-month-old male presented with a rapidly enlarging left lower jaw mass after removal of mandibular distractors placed shortly after birth for Pierre Robin Sequence and severe obstructive sleep apnea. Incisional biopsy of the mass revealed ARMS with anaplastic features. Although ARMS is an extremely rare entity, craniofacial surgeons should have a low threshold for seeking further diagnostic modalities of a growing mass postmandibular distraction.

Spindle cell rhabdomyosarcoma in a lumbar vertebra with FUS-TFCP2 fusion

A 70-year-old woman developed severe buttock pain that progressed to a walking disturbance. Radiographs and computed tomography scans revealed an osteolytic lesion with osteosclerosis extending from the body to the arch of the fifth lumbar vertebra. Magnetic resonance imaging showed multinodular masses in the fifth lumbar vertebral body extending into the spinous processes and right transverse process. The masses were hypointense to isointense on T1-weighted images and hypointense to hyperintense on T2-weighted images. Histologic examination of biopsy specimens showed destruction of the trabecula of the vertebral bone by a fascicular and solid proliferation of spindle tumor cells and scattered rhabdomyoblasts, in a fibrotic background. The tumor cells were immunoreactive for keratins, vimentin, desmin, MyoD1, myogenin, and anaplastic lymphoma kinase. Fluorescence in situ hybridization detected split signals for FUS and TFCP2 in 80% and 64% of the tumor cells, respectively, suggesting FUS-TFCP2 fusion. Reverse transcription-polymerase chain reaction revealed a FUS-TFCP2 fusion. The final diagnosis was spindle cell rhabdomyosarcoma of a lumbar vertebra with a FUS-TFCP2 fusion. A spindle cell rhabdomyosarcoma with a FUS-TFCP2 fusion in a vertebral bone is rare and should be differentiated from metastatic carcinoma, particularly in the elderly.