DSRCT has significant IHC expression of AR and c-Kit in heavily pre-treated patients. The presence of significant AR expression in 37% suggests that these patients could possibly respond to CAB. The significance of c-Kit expression in 35% of DSRCT patients is unknown and warrants further investigation.

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Rhabdomyosarcoma is the most common pediatric soft tissue malignancy. Two major subtypes, alveolar rhabdomyosarcoma and embryonal rhabdomyosarcoma, constitute 20 and 60% of all cases, respectively. Approximately 80% of alveolar rhabdomyosarcoma carry two signature chromosomal translocations, t(2;13)(q35;q14) resulting in PAX3-FOXO1 fusion, and t(1;13)(p36;q14) resulting in PAX7-FOXO1 fusion. Whether the remaining cases are truly negative for gene fusion has been questioned. We are reporting the case of a 9-month-old girl with a metastatic neck mass diagnosed histologically as solid variant alveolar rhabdomyosarcoma. Chromosome analysis showed a t(8;13;9)(p11.2;q14;9q32) three-way translocation as the sole clonal aberration. Fluorescent in situ hybridization (FISH) demonstrated a rearrangement at the FOXO1 locus and an amplification of its centromeric region. Single-nucleotide polymorphism-based microarray analysis illustrated a co-amplification of the FOXO1 gene at 13q14 and the FGFR1 gene at 8p12p11.2, suggesting formation and amplification of a chimerical FOXO1-FGFR1 gene. This is the first report to identify a novel fusion partner FGFR1 for the known anchor gene FOXO1 in alveolar rhabdomyosarcoma. Rhabdomyosarcoma accounts for 4-10% of pediatric malignancies. Four pathological subtypes have been traditionally defined: alveolar rhabdomyosarcoma, embryonal rhabdomyosarcoma, botyroid rhabdomyosarcoma, and pleiomorphic rhabdomyosarcoma. 1,2 Alveolar rhabdomyosarcoma and embryonal rhabdomyosarcoma have distinct clinical manifestations, biological behavior, genetic alterations, and account for B20 and B60% of all cases, respectively. 1 Alveolar rhabdomyosarcoma is most often seen in older children and is associated with a poor outcome, while embryonal rhabdomyosarcoma primarily occurs in children younger than 4 years of age and is usually associated with a better prognosis. 2 A rare solid variant of alveolar rhabdomyosarcoma has been described that is often morphologically indistinguishable from poorly differentiated embryonal rhabdomyosarcoma and may be confused with other 'small, round, blue cell tumors'. 3 A study of a large pediatric cohort of 171 patients with rhabdomyosarcoma by the children's oncology group (COG) has demonstrated the role of genetics in the development of rhabdomyosarcoma. 4 In the subtype of alveolar rhabdomyosarcoma, approximately 80% of cases harbored two signature chromosomal translocations, t(2;13)(q35;q14) in 60%, and t(1;13) (p36;q14) in 20% of cases. These translocations resulted in the formation and overexpression of chimerical genes PAX3-FOXO1

This report describes the youngest patient to develop a malignant peripheral nerve sheath tumor arising from a ganglioneuroma (MPNST ex Ganglioneuroma). The patient, a 6-year-old boy, was never irradiated and had no history or stigmata of neurofibromatosis. The report also includes a review of the previously published related cases, and an analysis of the immunohistochemistry and electron microscopy data available to date on the subject.