[Alveolar rhabdomyosarcoma: Two fusion-negative cases lacking PAX3-FOXO1 and PAX7-FOXO1]. / Rabdomiosarcoma alveolar. Dos casos negativos para la fusión PAX3-FOXO1 y PAX7-FOXO1.

Rhabdomyosarcoma is the most common soft tissue sarcoma in childhood and adolescence. Morphologically, two major forms are described: alveolar and embryonal rhabdomyosarcoma. The former is generally associated with a poorer prognosis and it usually harbors a characteristic fusion gene, PAX3/7-FOXO1, that is used to confirm the diagnosis. We present two cases, both of which exhibited the classic alveolar histology with immunohistochemical myogenic differentiation (Desmin, MYOD-1 and Myogenin expression) and lacked the characteristic fusion gene PAX3/7-FOXO1. The aim of this report is to highlight the importance of the molecular status in the study and diagnosis of these cases, as it seems to be not only a useful diagnostic tool, but also an important prognostic factor.

Rabdomiosarcoma alveolar. Dos casos negativos para la fusión PAX3-FOXO1 y PAX7-FOXO1 / Alveolar rhabdomyosarcoma: Two fusion-negative cases lacking PAX3-FOXO1 and PAX7-FOXO1

Los rabdomiosarcomas son los tumores de partes blandas más frecuentes en la edad pediátrica y en adultos jóvenes. Morfológicamente se distinguen dos subtipos principales: el rabdomiosarcoma alveolar y el rabdomiosarcoma embrionario. El subtipo alveolar se asocia generalmente con un peor pronóstico y presenta una fusión génica característica que clásicamente se ha utilizado para confirmar el diagnóstico: PAX3/7-FOXO1. Presentamos dos casos que fueron remitidos a nuestro centro. Ambos mostraron morfología alveolar clásica y diferenciación muscular basada en la inmunohistoquímica; no obstante, carecían de la fusión característica PAX3/7-FOXO1. El objetivo de este artículo es resaltar la importancia del estudio molecular de estos casos no solo como herramienta diagnóstica sino también como factor pronóstico importante.(AU)

Rhabdomyosarcoma is the most common soft tissue sarcoma in childhood and adolescence. Morphologically, two major forms are described: alveolar and embryonal rhabdomyosarcoma. The former is generally associated with a poorer prognosis and it usually harbors a characteristic fusion gene, PAX3/7-FOXO1, that is used to confirm the diagnosis. We present two cases, both of which exhibited the classic alveolar histology with immunohistochemical myogenic differentiation (Desmin, MYOD-1 and Myogenin expression) and lacked the characteristic fusion gene PAX3/7-FOXO1. The aim of this report is to highlight the importance of the molecular status in the study and diagnosis of these cases, as it seems to be not only a useful diagnostic tool, but also an important prognostic factor.(AU)

Rabdomiosarcoma del ala nasal en un paciente pediátrico. Un reporte de caso / Nasal ala Alveolar Rhabdomyosarcoma in a pediatric patient. A rare case report

Dada la respiración nasal preferencial que tiene la población pediátrica en los primeros meses de vida, la obstrucción nasal tiene más repercusiones a nivel clínico a diferencia de un adulto, lo cual hace más prioritario su diagnóstico y manejo. Una de las principales causas de obstrucción nasal en niños son las masas nasales, las cuales debido a sus múltiples etiologías causan bastante incertidumbre diagnóstica en el equipo médico. En este artículo se presenta el caso de una paciente de 10 meses con una masa en el ala nasal de crecimiento rápido; se realiza un rápido diagnóstico de rabdomiosarcoma que requiere un adecuado manejo. El rabdomiosarcoma con patrón alveolar se presenta de forma inusual en esta ubicación, es por esto por lo que se considera importante presentar este caso para mantenerlo en el algoritmo diagnóstico como una posibilidad y que, así como en el caso presentado, se pueda tener un diagnóstico temprano, un tratamiento adecuado y un resultado estético y funcional favorable.

Given preferential nasal breathing in the first months of life in the pediatric population, nasal obstruction has more clinical repercussions than it would have in adults, hence the need to give higher priority to its diagnosis and management. One of the main causes of nasal obstruction in children is the presence of nasal masses, which cause considerable diagnostic uncertainty in the medical team, because of their multiple etiologies. In this article, the case of a 10-month-old patient with a rapidly growing mass in the nasal ala is presented. A rhabdomyosarcoma was promptly diagnosed and adequately managed. Rhabdomyosarcoma with an alveolar pattern occurs in an unusual way in this location; for this reason, this case is important in order to include this possibility in the diagnostic algorithm and, as was the case in this patient, reach an early diagnosis and institute adequate treatment resulting in favorable aesthetic and functional results.

Rabdomiosarcoma alveolar con metástasis cardíaca en un paciente pediátrico / Alveolar rhabdomyosarcoma with cardiac metastasis in a pediatric patient

El rabdomiosarcoma es el tumor maligno de partes blandas más frecuente en la edad pediátrica. Puede afectar cualquier localización anatómica. El subtipo histológico alveolar suele causar lesiones en las extremidades en niños de mayor edad. Los sitios metástasicos más frecuentes son el pulmón, la médula ósea, el hueso y los ganglios linfáticos. Describimos el caso de un paciente con rabdomiosarcoma alveolar (RA) con metástasis cardíaca, una presentación poco frecuente de la patología.

Rhabdomyosarcoma is the most common malignant soft tissue tumor in pediatric age. It can affect any anatomical location. Alveolar histological subtype usually presents lesions on the extremities in older children. The most common metastatic sites are the lung, bone marrow, bone and lymph node. We describe a case of alveolar rhabdomyosarcoma with cardiac metastasis in a pediatric patient, a rare presentation of the pathology.

Alveolar rhabdomyosarcoma: origin and prognostic implications of molecular findings / Rabdomiosarcoma alveolar: origen de los hallazgos moleculares e implicaciones pronósticas

Abstract: We present the case of a 2-year-old male patient with a facial tumor partially treated with chemotherapy before his admission to our institution. The tumor involved from the frontal region to the maxillary floor, the orbit, and the maxillary and sphenoid sinuses. The histopathological diagnosis revealed a stage IV alveolar rhabdomyosarcoma with infiltration to bone marrow and cerebrospinal fluid. He was managed with four cycles of adriamycin, actinomycin, cyclophosphamide and vincristine; cisplatin and irinotecan were added to the last cycle. The tumor had a 50% size reduction, but the patient died after a neutropenia and fever episode. The aggressive behavior of alveolar rhabdomyosarcoma has been associated with the expression of oncogenic fusion proteins resulting from chromosomal translocations, particularly t(2;13) (q35;q14) PAX3/FOXO1, and t(1;13) (p36;q14) PAX7/FOXO1 which were present in this patient.

Resumen: Se presenta el caso de un niño de dos años de edad con un tumor facial tratado parcialmente con quimioterapia anterior a su admisión en este hospital. El tumor abarcaba desde la región frontal hasta el piso maxilar, la órbita y los senos esfenoidales y maxilares. El diagnóstico histopatológico reveló un rabdomiosarcoma alveolar estadio IV con infiltración a la médula ósea y fluido cerebroespinal. El paciente fue tratado con cuatro ciclos de adriamicina, actinomicina, ciclofosfamida y vincristina; al último ciclo se añadieron cisplatino e irinotecan. El tumor se redujo en 50% de su tamaño, pero el paciente murió tras un episodio febril y neutropénico. La agresividad del rabdomiosarcoma alveolar se ha asociado con la expresión de proteínas oncogénicas de fusión provenientes de translocaciones cromosomales, particularmente t(2;13) (q35;q14) PAX3/FOXO1 y t(1;13) (p36;q14) PAX7/FOXO1, presentes en este paciente.

Childhood rhabdomyosarcoma. / Rabdomiosarcoma infantil.

Rhabdomyosarcoma is the most common soft-tissue sarcoma in children; it can appear in any part of the body. Its biological behavior varies widely, and despite the absence of specific clinical or radiological characteristics, rhabdomyosarcoma should be taken into account in the differential diagnosis of solid tumors in children. This review focuses primarily on the imaging findings and anatomical distribution of the histological subtypes of childhood rhabdomyosarcoma and secondarily on the differential findings in histological studies.

Alveolar rhabdomyosarcoma: origin and prognostic implications of molecular findings.

We present the case of a 2-year-old male patient with a facial tumor partially treated with chemotherapy before his admission to our institution. The tumor involved from the frontal region to the maxillary floor, the orbit, and the maxillary and sphenoid sinuses. The histopathological diagnosis revealed a stage IV alveolar rhabdomyosarcoma with infiltration to bone marrow and cerebrospinal fluid. He was managed with four cycles of adriamycin, actinomycin, cyclophosphamide and vincristine; cisplatin and irinotecan were added to the last cycle. The tumor had a 50% size reduction, but the patient died after a neutropenia and fever episode. The aggressive behavior of alveolar rhabdomyosarcoma has been associated with the expression of oncogenic fusion proteins resulting from chromosomal translocations, particularly t(2;13) (q35;q14) PAX3/FOXO1, and t(1;13) (p36;q14) PAX7/FOXO1 which were present in this patient.

[Orbital alveolar rhabdomyosarcoma masked by ethmoid sinusitis in a 25-year-old]. / Rabdomiosarcoma alveolar orbitario enmascarado por sinusitis etmoidal en un adulto de 25 años.

CASE REPORT: A 25-year-old woman with right subacute sinusitis, complained about discomfort in her right eye. Clinical manifestations and computed tomography were suggestive of sub-periosteal orbital ethmoid wall abscess, for which the patient underwent urgent drainage. A solid tumor was found, with a positive biopsy for alveolar rhabdomyosarcoma. Complete remission and resolution of orbital symptoms were achieved with chemotherapy and radiation therapy. DISCUSSION: Alveolar orbital rhabdomyosarcoma in adults is uncommon. Rhabdomyosarcoma has a high risk of spreading. It can simulate a sinusitis, as in our patient, early diagnosis and early treatment being especially important in these patients.

Rabdomiosarcoma alveolar de patrón sólido nasal, a propósito de un caso / Pattern alveolar rhabdomyosarcoma nasal solid, on the subject of a case

El rabdomiosarcoma (RMS) es considerado el sarcoma infantil más frecuente, y se origina a partir de células precursoras mesenquimatosas embrionarias del músculo estriado. El compromiso cutáneo se da por metástasis o por invasión local y es poco frecuente. El 41% de los RMS en los niños se localiza en cabeza y cuello, y las formas embrionaria y alveolar son las variantes más frecuentes. Presentamos un caso de RMS nasal de rápido crecimiento variante alveolar de patrón sólido, debido a la presentación en edad temprana para esta variante (AU)

Rhabdomyosarcoma (RMS) is one of the most common pediatric sarcoma, originated of the mesenquimal embryonal smooth muscle precursor cells.This tumor is unusual, when it involves the skin is by metastasis or local invasion. 41% of the pediatric RMS occurs in the head and neck.The alveolar and embryonal forms are the most common variants.We report a case of RMS alveolar form of solid pattern with rapid growth on nasal area (AU)