鉴别诊断(1)胚胎性横纹肌肉瘤.

鉴别诊断(2)婴幼儿纤维肉瘤.

*    免疫组化：Vim阳性；一般不表达desmin等 

鉴别诊断(3)脂肪母细胞瘤.

鉴别诊断(4)炎性肌纤维母细胞瘤.

请继续关注和发言。谢谢！

 原单位的诊断合适。

最后诊断：（颈项部）间叶性恶性小细胞肿瘤，结合免疫组化，倾向未分化肉瘤。

Primitive myxoid mesenchymal tumor of infancy

 最后的诊断不是原单位的诊断。王坚老师的诊断个人觉得比较合适。

1. J Pediatr Hematol Oncol. 2013 May 9. [Epub ahead of print]

A Case With Sacrococcygeal Primitive Myxoid Mesenchymal Tumor of Infancy: A Case Report and Review of the Literature.

Saito A, Taketani T, Kanai R, Kanagawa T, Kumori K, Yamamoto N, Ishikawa N, Takita J, Yamaguchi S.

Source

Departments of *Pediatrics §Radiology ∥Organ Pathology, Shimane University Faculty of Medicine †Division of Blood Transfusion, Shimane University Hospital ‡Department of Digestive and General Surgery, Shimane University School of Medicine, Shimane ¶Department of Cell Therapy and Transplantation Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.

Abstract

A girl, aged 19 months, presented with a sacrococcygeal tumor that developed at 5 months after birth and gradually enlarged. Serum tumor marker levels were negative. Ultrasound imaging showed abundant blood flow in the tumor. However, neither computed tomography (CT) nor magnetic resonance imaging (MRI) showed contrast agent incorporation. The surgically resected tumor consisted of immature cells with myxoid stroma and proliferating small blood vessels. Immunostaining showed extensive vimentin expression. However, smooth muscle actin, muscle-specific actin, and S-100 protein expression was negative. Neither the ETV6-NTRK3 fusion gene nor the FUS gene rearrangement was detected. Thus, the patient was diagnosed with a primitive myxoid mesenchymal tumor of infancy. This tumor primarily consisted of a mucosal stroma with a low absorption on CT, a low signal on T1-weighted MRI, and a high signal on T2-weighted MRI. A diagnosis of primitive myxoid mesenchymal tumor of infancy should be considered in cases of soft tissue tumors in infants that show prominent vascularity but little contrast enhancement on MRI or CT.

2. Med Mol Morphol. 2013 Jun;46(2):109-13. doi: 10.1007/s00795-013-0032-1. Epub 2013 Mar 5.

A rare malignant tumor of scalp in a 3-month-old Taiwanese infancy: case report of primitive myxoid mesenchymal tumor of infancy with molecular study.

Su TC, Hwang MJ, Li CF, Wang SC, Lee CH, Chen CJ.

Source

Department of Surgical Pathology, Changhua Christian Hospital, 135 Nanxiao Street, Changhua, Taiwan.

Abstract

Primitive myxoid mesenchymal tumor of infancy is an extremely rare and recently recognized soft tissue tumor entity with a tendency for multiple recurrences. Only ten cases have been described in the literature and most cases are reported in Western countries. This tumor ranges in size from 2 to 15 cm and is characterized microscopically by a diffuse growth of primitive cells in a myxoid background with focal fascicles or a herringbone pattern. In this study, we describe a primitive myxoid mesenchymal tumor of infancy on the scalp of a 3-month-old Taiwanese boy. The histology showed typical morphology and the tumor cells showed vimentin and CD99 immunoreactivities. The translocation t(12,15)(p13;q25) was not found by fluorescence in situ hybridization. After complete surgical excision, no recurrence was noted during an 18-month follow-up.

3. Pathol Int. 2012 Aug;62(8):549-53. doi: 10.1111/j.1440-1827.2012.02836.x. Epub 2012 Jun 21.

Primitive myxoid mesenchymal tumor of infancy: report of two cases and review of the literature.

Gong Q, Wang Z, Li X, Fan Q.

Source

Department of Pathology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.

Abstract

Primitive myxoid mesenchymal tumor of infancy is a recently recognized soft tissue tumor with only a few cases reported. Here, we reported another two cases of the lesion, a 5-month-old boy presenting with a soft tissue mass in the neck region that recurred 2 months later and a 3-day-old girl with a congenital superficial dorsal lumbar mass that extended to the spinal canal 1 month later. They shared similar histological patterns, such as unusual diffuse myxoid background, delicate vascular network, small cystic spaces, low to moderate cellularity, and primitive mesenchymal tumor cells. Immunohistochemically, the tumor cells showed positive for vimentin, CD99, CD117 and nestin, negative for myoid, lipoblastic, histiocytic, and neural markers. In conclusion, primitive myxoid mesenchymal tumor of infancy is a distinctive entity with its own clinical pathological features. Expression of CD99, CD117 and nestin may be consistent with the primitive nature of the tumor and may serve as ancillary markers for differential diagnosis from the other infantile tumors.

4. Pediatr Dermatol. 2010 Nov-Dec;27(6):635-7. doi: 10.1111/j.1525-1470.2010.01323.x. Epub 2010 Nov 16.

Primitive myxoid mesenchymal tumor of infancy in a preterm infant.

Lam J, Lara-Corrales I, Cammisuli S, Somers GR, Pope E.

Source

Department of Pediatrics, Department of Dermatology, University of British Columbia, Vancouver, British Columbia, Canada. joseph.mc.lam@gmail.com

Abstract

Primitive myxoid mesenchymal tumor of infancy is a recently recognized entity that has been added to the differential diagnosis of myxoid tumors of the soft tissue. Few cases have been reported of this entity in the literature, but none presenting in a preterm infant. We present the case and clinical course of a preterm boy with a primitive myxoid mesenchymal tumor of infancy that occurred following excision of a congenital juvenile xanthogranuloma.

5. Pediatr Dev Pathol. 2011 Jan-Feb;14(1):75-9. doi: 10.2350/09-12-0770-CR.1. Epub 2010 May 13.

Primitive myxoid mesenchymal tumor of infancy: a report of a further case with locally aggressive behavior.

Mulligan L, O'Meara A, Orr D, Eadie P, Hayes R, McDermott M.

Source

Department of Histopathology, Our Lady's Children's Hospital Crumlin, Dublin, Ireland.

Abstract

We report a case of an 8-month-old child with a primitive myxoid mesenchymal tumor of infancy arising in the thenar eminence. The lesion recurred after conservative excision and was ultimately nonresponsive to chemotherapy, necessitating partial amputation. The patient remains free of disease 5 years after this radical surgery. This is the 1st report of such a tumor since it was initially described by Alaggio and colleagues in 2006. The pathologic differential diagnosis is discussed.

6. Am J Surg Pathol. 2006 Mar;30(3):388-94.

Primitive myxoid mesenchymal tumor of infancy: a clinicopathologic report of 6 cases.

Alaggio R, Ninfo V, Rosolen A, Coffin CM.

Source

Department of Oncology and Surgery, Section of Pathology, University of Padova, Padova, Italy.

Abstract

Soft tissue sarcomas in the first year of life are rare, and the most common sarcomas in infancy are embryonal rhabdomyosarcoma, Ewing sarcoma/primitive neuroectodermal tumor, congenital infantile fibrosarcoma, and primitive sarcomas such as undifferentiated sarcoma. In this study, we report 6 cases of a primitive myxoid mesenchymal tumor of infancy (PMMTI), which previously may have been included under the diagnostic categories of congenital-infantile fibrosarcoma or infantile fibromatosis. PMMTI occurred in 6 infants, 3 of whom had a congenital presentation of a soft tissue mass. All patients were otherwise healthy. The tumors occurred on the trunk, extremities, and head and neck. Grossly, the tumors were nonencapsulated and had a multinodular appearance with focal infiltrative growth, a white fleshy cut surface, and a tumor diameter ranging from 2 to 15 cm. Histologically, a diffuse growth of primitive spindle, polygonal, and round cells occurred in a myxoid background. The tumor cells were arranged in a vaguely nodular pattern with peripheral collagenized stroma, higher cellularity at the periphery, and a delicate vascular network in the background. Immunohistochemically, the tumors displayed diffuse reactivity for vimentin and no reactivity for smooth muscle actin, muscle specific actin, desmin, S-100 protein, or myogenin. Electron microscopy documented a poorly differentiated fibroblastic proliferation. Four cases tested negative for the ETV6-NTRK3 gene fusion by RT-PCR. One tumor had a complex karyotypic abnormality with rearrangements involving chromosomes Y, 9, and 3. Three patients had recurrences or metastasis treated with a combination of surgery and chemotherapy. One patient is alive with persistent locally aggressive disease, 2 are alive with no evidence of recurrence, 1 had a recurrence treated surgically without further follow-up information, 1 patient died with persistent tumor and sepsis 6 weeks after diagnosis, and 1 patient was lost to follow-up. The morphologic appearance combined with the ultrastructural features and absence of the typical gene rearrangement of congenital-infantile fibrosarcoma are unique, and we propose that PMMTI represents a new category of pediatric fibroblastic-myofibroblastic tumor.

1. Am J Surg Pathol. 2006 Mar;30(3):388-94.

Primitive myxoid mesenchymal tumor of infancy: a clinicopathologic report of 6 cases.

Alaggio R, Ninfo V, Rosolen A, Coffin CM.

Source

Department of Oncology and Surgery, Section of Pathology, University of Padova, Padova, Italy.

Abstract

Soft tissue sarcomas in the first year of life are rare, and the most common sarcomas in infancy are embryonal rhabdomyosarcoma, Ewing sarcoma/primitive neuroectodermal tumor, congenital infantile fibrosarcoma, and primitive sarcomas such as undifferentiated sarcoma. In this study, we report 6 cases of a primitive myxoid mesenchymal tumor of infancy (PMMTI), which previously may have been included under the diagnostic categories of congenital-infantile fibrosarcoma or infantile fibromatosis. PMMTI occurred in 6 infants, 3 of whom had a congenital presentation of a soft tissue mass. All patients were otherwise healthy. The tumors occurred on the trunk, extremities, and head and neck. Grossly, the tumors were nonencapsulated and had a multinodular appearance with focal infiltrative growth, a white fleshy cut surface, and a tumor diameter ranging from 2 to 15 cm. Histologically, a diffuse growth of primitive spindle, polygonal, and round cells occurred in a myxoid background. The tumor cells were arranged in a vaguely nodular pattern with peripheral collagenized stroma, higher cellularity at the periphery, and a delicate vascular network in the background. Immunohistochemically, the tumors displayed diffuse reactivity for vimentin and no reactivity for smooth muscle actin, muscle specific actin, desmin, S-100 protein, or myogenin. Electron microscopy documented a poorly differentiated fibroblastic proliferation. Four cases tested negative for the ETV6-NTRK3 gene fusion by RT-PCR. One tumor had a complex karyotypic abnormality with rearrangements involving chromosomes Y, 9, and 3. Three patients had recurrences or metastasis treated with a combination of surgery and chemotherapy. One patient is alive with persistent locally aggressive disease, 2 are alive with no evidence of recurrence, 1 had a recurrence treated surgically without further follow-up information, 1 patient died with persistent tumor and sepsis 6 weeks after diagnosis, and 1 patient was lost to follow-up. The morphologic appearance combined with the ultrastructural features and absence of the typical gene rearrangement of congenital-infantile fibrosarcoma are unique, and we propose that PMMTI represents a new category of pediatric fibroblastic-myofibroblastic tumor.

2. Genes Chromosomes Cancer. 1996 Feb;15(2):115-21.

Fusion of an ETS-family gene, EIAF, to EWS by t(17;22)(q12;q12) chromosome translocation in an undifferentiated sarcoma of infancy.

Kaneko Y, Yoshida K, Handa M, Toyoda Y, Nishihira H, Tanaka Y, Sasaki Y, Ishida S, Higashino F, Fujinaga K.

Source

Department of Cancer Chemotherapy, Saitama Cancer Center Hospital, Japan.

Abstract

EIAF is a newly isolated ETS-family gene that is located on 17q21 and codes for the adenovirus EIA enhancer-binding protein. In our chromosome analysis of 18 of the Ewing family of tumors and undifferentiated sarcomas, we found t(17;22)(q12;q12) in an MIC2 antigen-positive undifferentiated sarcoma of infancy. On Southern blot analysis, EWS and EIAF cDNA probes hybridized to the same rearranged band, indicating that an EWS-EIAF fusion gene was formed in the tumor. Further Southern blot analysis using four EIAF cDNA probes of different sizes showed that the breakpoint lies in the region upstream to the ETS domain of the EIAF gene. EIAF may be the fourth ETS-family gene to be identified forming a fusion gene with EWS. We assume that the RNA binding domain of EWS may have been replaced by the DNA binding domain of EIAF in the EWS-EIAF fusion protein as in other fusion proteins previously characterized in Ewing sarcoma and other types of sarcomas.

3. J Am Coll Cardiol. 1985 Dec;6(6):1362-4.

Intracardiac undifferentiated sarcoma in infancy.

Ludomirsky A, Vargo TA, Murphy DJ, Gresik MV, Ott DA, Mullins CE.

Abstract

A rare case of an intracardiac undifferentiated sarcoma in a 3 month old infant is described together with the clinical, angiographic, echocardiographic, surgical and histopathologic findings. The tumor was successfully removed surgically, and monthly echocardiographic follow-up is being performed.

细胞形态还是支持胚横的，但是结构上没有典型的“形成层”。

我倒是还想原单位补充一下，患儿是否有HIV感染？其母是否吸毒？

病史中没有HIV感染和吸毒记载。

本例肌源性标记阴性，不支持胚胎性横纹肌肉瘤。

婴幼儿粘液性间叶肿瘤(PMMTI)。谢谢！学习了

这个S100背景太黄了，不可靠。。。

Ki67指数也并不高，未分化肉瘤　恶性程度很高的

学习了