脂母

 结果：考虑为Primitive_Myxoid_Mesenchymal_Tumor_of_Infancy  婴儿原始黏液性间叶肿瘤。本例经澳太中心软组织学会主席Allen教授会诊。

Gross Pathology
The six primary tumors were unencapsulated and
had a multinodular but demarcated appearance with
focal infiltrative growth. The cut surface was white with
fleshy central areas and a firm periphery. Tumor diameter
ranged from 2.5 to 15.0 cm, with a mean of 8.8 cm.
Light Microscopy
All tumors were characterized histologically by a
diffuse growth of primitive spindled, polygonal, and
round cells in a myxoid background (Figs. 1A–D). The
tumor cells were often arranged in a vaguely nodular
pattern with a peripheral collagenized stroma and greater
cellularity at the periphery. Cellularity was low to
moderate. A delicate vascular network with a lacy
appearance was seen in many areas. Medium-sized
arterioles and venules surrounded by a cuff of densely
packed tumor cells were randomly distributed within the
tumors. The tumor cells had bland uniform nuclei with
even chromatin, inconspicuous nucleoli, and variable
amounts of pale eosinophilic to clear vacuolated cytoplasm
(Fig. 1E). In some areas, the vacuolated mesenchymal
cells were arranged in small aggregates. An Alcian
blue stain in 1 case demonstrated cytoplasmic acid mucins
in the vacuolated cells. Highly cellular areas were located
at the periphery of tumor nodules and were composed of
spindle cells arranged in bundles or fascicles with a focal
herringbone pattern (Fig. 1F). Infiltrative growth into

adjacent soft tissue was noted in 3 cases (Fig. 1G). In
three tumors, small cystic spaces were noted and were
lined by tumor cells and contained finely granular
eosinophilic material with a degenerative appearance
(Fig. 1H). Necrosis was identified in 1 case. An
inflammatory infiltrate was absent to sparse. The mitotic
rate varied from less than 1 to 10 mitoses per 10 high
power fields, with a mean of 4 mitoses per 10 high power
fields. No atypical mitoses were observed.
In 2 cases, slides were available from recurrences.
The recurrent tumors had increased cellularity and
increased cellular atypia in comparison with the original
tumors. The recurrent tumor cells were sometimes
elongated or epithelioid and arranged in clusters or
slender fascicles had pale to clear cytoplasm, and had
darker chromatin and more prominent nucleoli.
Immunohistochemistry
Results of immunohistochemical stains are summarized
in Table 2. The tumors showed diffuse reactivity
for vimentin and no reactivity for smooth muscle actin,
muscle specific actin, desmin, S-100 protein, myogenin,
cytokeratin, or bcl-2. Two cases showed indistinct weak
cytoplasmic CD99 reactivity. CD31 and CD34 stains
highlighted the delicate vascular background (Fig. 2) but
did not decorate tumor cell.
Ultrastructural Findings
Electron microscopy was available in 3 cases. All
showed a homogeneous population of poorly differentiated
fibroblasts with nuclei characterized by coarsely
distributed chromatin and cytoplasm devoid of intermediate
filaments, but with Golgi apparatus, free ribosomes,
scanty rough endoplasmic reticulum, and rare
hemidesmosomes and lysosomes (Fig. 3). The tumor cells
were noncohesive and embedded in a collagen-containing
matrix.
Molecular and Cytogenetic Results
Case nos. 1, 2, 3, and 6 were negative for the ETV6-
NTRK3 gene fusion by RT-PCR (2 cases with frozen
tissue and 2 cases with paraffin-embedded samples).
Cytogenetic analysis of tumor tissue from case no. 1
revealed 46, X der (Y)t(Y;9)(q12;p11) der (9)t(3;Y;9)
(p13;q12;p11) or t(3;9)(p12;p11), der (18)t(1;18)(q12;q23).
Cytogenetic analysis of tumor tissue from case no. 2
showed a 46, XY karyotype.

我可是大力支持你了，不但给你加了三分，而且还把你的帖子设置成了精华帖子。

这个病例还真不知道从什么地方下手分析、学习了

从未见过的好病例，学习了。謝謝！

脂母

 学习了 谢谢您的分享！

谢谢支持！有好东西就应该大家分享！

我以为是脂肉？

学习啦，盼望楼主更多的好病例分享

其实是挺好的病例，怎么没人回复，讨论讨论呢？本例是国外专家会诊后才得出的结论，我们也是不认识。

希望大家热烈讨论，明天我会把结果和文献上传，大家一起学习啊！

 是图片太大了还是怎么回事，点击图片打不开

罕见，好病例！

 国外工作还是做的细……

 没见过 学习了！！

 目的 探讨婴儿原始黏液样间叶性肿瘤(PMMTI)的临床病理学特征、免疫表型和鉴别诊断.方法 回顾性分析3例PMMTI的临床资料、病理学形态和免疫学表型.结果 男性2例,女性1例,年龄分别为4岁、2d和3个月,均因家长发现肿块就诊,2例位于颈部,1例位于腰部,肿块最大径分别为6.5、5.5、2.8 cm.镜下肿瘤由小卵圆形、短梭形和小多边形的瘤细胞组成,胞质稀少嗜伊红色或呈空泡状,瘤细胞轻度异型性,核分裂象(0 ～2)/10 HPF.瘤细胞呈弥漫性生长,部分区域呈结节状分布,结节周边为胶原化基质.肿瘤间质呈黏液样,富含纤细的血管,1例部分区域可见小囊腔样结构.免疫组织化学染色显示瘤细胞主要表达波形蛋白,不表达平滑肌肌动蛋白、结蛋白、肌生成素、S-100蛋白、CD34和细胞角蛋白.3例均行手术切除,1例术后复发2次,与原发肿瘤相比,复发肿瘤中瘤细胞密度明显增高,异型性明显,核分裂象易见(10/10 HPF),该患儿2年后死亡;另2例术后无瘤生存.结论 PMMTI是一种好发于婴儿的少见软组织肿瘤,由原始间叶性细胞和黏液样基质组成,主要发生于躯干、头颈部和四肢,切除不净易复发,极少数可发生转移或导致患儿死亡.熟悉这一新病种有助于避免将其误诊为先天性纤维肉瘤和脂肪母细胞瘤等好发于婴幼儿的间叶性肿瘤.

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