CTNNB1 somatic mutations drive Wnt pathway activation in a case of incidental intranodal palisaded myofibroblastoma / Mutaciones somáticas de CTNNB1 inducen la activación de la vía Wnt en un caso incidental de miofibroblastoma en empalizada de localización intraganglionar

Intranodal palisaded myofibroblastoma (IPM) is a rare stroma-derived spindle-cell neoplasm of the lymph node with myofibroblastic differentiation and CTNNB1 (β-catenin gene) somatic mutations. We present a case of IPM found incidentally in the staging of lung adenocarcinoma. We describe the major histopathological and phenotypic features, including a palisaded bland spindle cell proliferation with myofibroblastic differentiation and Wnt pathway activation by immunohistochemistry, including β-catenin expression. Production of osteoid-like collagen directly from tumor cells was observed. We confirmed p.Gly34Arg CTNNB1 mutation by direct sequencing. We also reviewed the literature for similar cases.(AU)

El miofibroblastoma en empalizada intraganglionar linfático (MEIG) es una neoplasia infrecuente de células fusiformes del estroma del ganglio linfático con diferenciación miofibroblástica y mutaciones en CTNNB1 (gen de la β-catenina). Aquí mostramos el caso de un paciente con MEIG encontrado incidentalmente en la estadificación por un adenocarcinoma de pulmón. Se describen las características histopatológicas principales de la entidad, incluyendo una proliferación de células fusiformes con escasa atipia, empalizadas celulares y diferenciación miofibroblástica con activación de la vía Wnt, incluyendo expresión inmunohistoquímica de β-catenina. Se observó producción de colágeno de tipo osteoide por parte de las células tumorales. Se confirmó la presencia de la mutación p.Gly34Arg de CTNNB1 mediante secuenciación directa. Se recogen adicionalmente publicaciones de casos similares al nuestro.(AU)

CTNNB1 somatic mutations drive Wnt pathway activation in a case of incidental intranodal palisaded myofibroblastoma.

Intranodal palisaded myofibroblastoma (IPM) is a rare stroma-derived spindle-cell neoplasm of the lymph node with myofibroblastic differentiation and CTNNB1 (ß-catenin gene) somatic mutations. We present a case of IPM found incidentally in the staging of lung adenocarcinoma. We describe the major histopathological and phenotypic features, including a palisaded bland spindle cell proliferation with myofibroblastic differentiation and Wnt pathway activation by immunohistochemistry, including ß-catenin expression. Production of osteoid-like collagen directly from tumor cells was observed. We confirmed p.Gly34Arg CTNNB1 mutation by direct sequencing. We also reviewed the literature for similar cases.

Myofibroblastoma of the male breast: A case report / Miofibroblastoma en la mama de un varón, descripción de un caso clínico

Myofibroblastoma (MFB) is a rare spindle stromal tumour of the breast that predominates in 60–80 years-old adult males. Its imaging features are nonspecific, leading to misdiagnosis. Thus, core biopsy is needed for definitive diagnosis. Macroscopically, MFB is usually a well-circumscribed, firm and rubbery, unencapsulated, pale white to grey round mass. Microscopically, it consists on spindle cells arranged in haphazardly intersecting fascicles or clusters, thick hyalinized collagen bundles and low mitotic activity with a lack of myoepithelial component and necrosis. Immunohistochemistry shows consistently positive immunoreactivity to vimentin and CD34, while expression of desmin, SMA, bcl-2 and CD99 varies. Oestrogen, progesterone and androgen receptors are usually expressed. They are constantly negative to cytokeratins, EMA, S100 protein, HMB-45 and c-kit (CD117). These differentiate them from fibroadenoma, phyllodes tumour, round pattern gynecomastia, carcinoma and sarcoma, since they present infiltrative growth and are negative to CD34. Wide local excision is curative, with no need of sentinel lymph node biopsy, since local recurrence is extremely low and has been reported to be less than 1.5%. No distant metastases have been described on the literature. We report a rare case MFB on a 73-year-old male attended at our institution presenting with a nodule on the right breast. (AU)

El miofibroblastoma (MFB) es un tumour estromal de células fusiformes que aparece en varones de 60-80 años. Las características radiológicas son inespecíficas, por lo que es necesaria la realización de biopsia para el diagnóstico definitivo. Macroscópicamente se trata de una lesión bien circunscrita, firme, no encapsulada. Microscópicamente consiste en células fusiformes organizadas en fascículos entremezclados con bandas de colágeno hialino, con baja actividad mitótica y ausencia de componente mioepitelial y necrosis. La inmunohistoquímica muestra la expresión constante de vimentina y CD34, con expresión variable de desmina, AML, bcl-2 y CD99. Los receptores de estrógenos, progesterona y andrógenos normalmente son positivos, mientras que la expresión de citoqueratinas, EMA, S100, HMB-45 y c-kit (CD117) es negativa. Estas características lo diferencian del fibroadenoma, tumour filodes, ginecomastia, carcinoma y sarcoma, ya que la mayoría de ellos se caracterizan por ser negativos para CD34 y presentar crecimiento infiltrativo. La tumorectomía es considerada curativa, sin necesidad de realizar biopsia selectiva de ganglio centinela, dado que la recurrencia local es baja (menos del 1,5%). No se ha descrito la presencia de metástasis a distancia en la literatura. Presentamos el caso de MFB en un varón de 73 años que debutó con un nódulo en la mama derecha. (AU)

Tumor miofibroblástico inflamatorio del colon / Inflammatory Myofibroblastic Tumor of the Colon

RESUMEN Introducción: Los tumores miofibroblásticos son tumores benignos de origen mesenquimal, de etiología incierta, y frecuente en niños y jóvenes. Objetivo: Describir un nuevo caso de tumor miofibroblástico abdominal. Caso clínico: Se presenta una paciente de 20 años con antecedentes de salud con dolor en abdomen derecho, se realiza tomografía de abdomen contrastada que informa una masa hiperdensa no homogénea en flanco derecho. Se realiza resección quirúrgica del tumor y el estudio anatomopatológico informa un tumor miofibroblástico inflamatorio. Su pronóstico es favorable porque es una entidad benigna y no metastiza. Conclusiones: Los tumores miofibroblásticos de colon son infrecuentes, benignos, que al diagnosticarlos deben resecarse ampliamente para evitar la recidiva(AU)

ABSTRACT Introduction: Myofibroblastic tumors are benign tumors of mesenchymal origin, of uncertain etiology, and frequent in children and young people. Objective: To describe a new case of abdominal myofibroblastic tumor. Clinical case: The case is presented of a 20-year-old female patient with a health history and pain in the right abdomen. Contrasted abdominal tomography is performed, which shows an inhomogeneous hyperdense mass in the right flank. Surgical resection of the tumor was performed. The pathological study reported an inflammatory myofibroblastic tumor. Its prognosis is favorable because it is a benign entity that does not metastasize. Conclusions: Colon myofibroblastic tumors are infrequent, benign, and when diagnosed, they must be widely removed to avoid recurrence(AU)

FEMALE BREAST MYOFIBROBLASTOMA: CASE REPORT / Miofibroblastoma de mama feminina: relato de caso

The myofibroblastoma of the breast is rare, being even less frequent in women. It is a benign mesenchymal tumor of uncertain etiology. The present study reports the case of a 47-year-old patient with a palpable nodule on the right breast, non-painful, having appeared approximately one year before, and with slow growth, located in an inferolateral quadrant. The biopsy pathology product describes a firm, yellowish white tissue that microscopically exhibited fusocellular proliferation without atypia, including small ductal structures with epithelial hyperplasia, suggesting immunohistochemistry which revealed expression of desmin and smooth muscle actin. Based on the morphological and anatomopathological picture, the diagnosis of breast myofibroblastoma was confirmed. Sectorectomy surgery was performed as treatment

O miofibroblastoma de mama é raro, sendo menos frequente ainda em mulheres. Trata-se de um tumor mesenquimal benigno de etiologia incerta. A presente descrição relata o caso de uma paciente de 47 anos, apresentando um nódulo palpável na mama direita, não doloroso, com surgimento há aproximadamente um ano e de crescimento lento, localizado em quadrante ínferolateral. O anatomopatológico de biópsia produto de core biopsy descreve tecido branco amarelado, de consistência firme, que microscopicamente apresenta proliferação fusocelular sem atipias, incluindo pequenas estruturas ductais com hiperplasia epitelial, sugerindo imuno-histoquímica, a qual revelou expressão de desmina e actina de músculo liso. Com base no quadro morfológico e anatomopatológico, confirmou-se o diagnóstico de miofibroblastoma de mama. Foi realizada setorectomia como tratamento

Miofibroblastoma de la mama femenina: reporte de un caso / Miofibroblastoma of the female breast: a case report

El miofibroblastoma constituye una entidad benigna de la mama de presentación muy infrecuente, que afecta principalmente la mama masculina. Su principal característica histológica es su estirpe mesenquimal caracterizada por la proliferación de células fusiformes rodeadas de colágeno y que derivan de los fibroblastos. El tratamiento principal es la cirugía, con tendencia a la preservación de la glándula sobre todo en la mujer. Presentamos el caso de una paciente femenina de 64 años de edad, con un tumor solitario, de crecimiento progresivo durante 5 años, hasta que decide solicitar asistencia médica, planteándose el diagnóstico preoperatorio de una lesión de tipo mesenquimal; la cual posterior al tratamiento quirúrgico y mediante estudios inmunohistoquímicos se confirma la presencia de un miofibroblastoma clásico, siendo estos tumores infrecuentes en la práctica clínica diaria, debiendo ser considerados al momento de hacer diagnóstico diferencial.

The miofibroblastoma is a benign tumor of the breast of very infrequent presentation that mainly affects the male breast. The main histological characteristic is the mesenchymal ancestry characterized by the proliferation of plump and spindle cells surrounded by collagen and that derive from fibroblasts. The surgery is the main treatment with preservation of the breast in female patients. We presented a case of a female patient of 64 years old, which presents a solitary tumor with progressive growth by 5 years, until she decides to ask for medical aid, considering the preoperating diagnosis of an tumor of mesenchymal type; which subsequent to the surgical treatment and confirmed by immunohistochemistry the presence of miofibroblastoma of the breast, being this finding very unusual in the clinical practice, and to be considered at the time of making differential diagnosis.

Miofrioblastoma mamário em axila / Mammary myofibroblastoma in axila

Miofibroblastoma é um tumor benigno raro de mama, de origem mesenquimal. A localização em região axilar é ainda mais incomum. Tendo em vista a dificuldade em se estabelecer o diagnóstico diferencial baseado apenas nos achados clínicos e imaginológicos, a confirmação histopatológica é imprescindível no diagnóstico diferencial com tumor oculto de mama.

Myofibroblastoma is a rare and benign mesenchymal breast neoplasm. The axillary topography is further more uncommon. The histologic identification is important because the differencial diagnosis with malignant tumours of the breast. This report a case of mammary myofibroblastoma in axilla, wich was initially diagnosticated as an occult lobular carcinoma.