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男,56岁 头皮肿物 灰红碎组织4×3×3cm一堆,切面灰白,质地细腻。
免疫组织化学结果:
EMA局灶(+)、Vimentin(+)、BCL-2(+)、CK(-)、CD34(-)、S100(-)、HMB45(-)、Desmin(-)、Ki67约20%阳性。
高倍镜仔细观察,每10个高倍视野核分裂像大于5个。
本例有2种区域,细胞稀少区和细胞密集区,稀少区内宽带较一致的胶原纤维互相交织,细胞密集区血管外皮瘤样改变明显。肿瘤细胞较为一致,胞浆淡染,可见核分裂,可考虑HPC/SFT。免疫组化表达也支持,因为本例以HPC细胞形态为主,SFT的梭形形态极为少见。Weiss & Goldblum: Enzinger and Weiss's Soft Tissue Tumors, 5th ed.中提到Many hemangiopericytomas express CD34 but usually in a smaller percentage of cases and to a lesser degree than solitary fibrous tumors。最难以抉择的就是纤维组织细胞瘤。胶原化、血管外皮瘤样改变、较多核分裂这些都是纤维组织细胞瘤会出现的形态,同时细胞核具有多形性,但是同时出现在一个病变中就属于比较少见的。另外本例的具体位于皮肤的层次,边缘情况都没有显示,我想这些对于鉴别诊断还是很重要的。免疫组化CD68及13因子可能有用,毕竟免疫组化不是万能的。
第二个鉴别是滑膜肉瘤,因为滑膜肉瘤也可以出现HPC改变,并且本例EMA似乎阳性。但本例细胞胖、短梭形,细胞间胶原化明显,细胞间距不等,细胞多形性明显,与一般滑膜肉瘤细胞紧致排列的特点不符合。Sternberg's Diagnostic Surgical Pathology, 5th Edition中提到The monophasic variant may easily simulate fibrosarcoma, MPNST, SFT/HPC, and mesenchymal chondrosarcoma. In other words, because of the high degree of cellularity, a herringbone pattern or an HPC pattern may predominate. However, clues to the real nature of the tumor include the presence of small, oval, overlapping nuclei。
至于隆突,本例形态似乎不支持,隆突的典型特点席纹状或车幅状排列不存在,血管外皮瘤及间质显著胶原化不是隆突的特点。免疫组化CD34阴性也不支持。
如大家一样,我觉得鉴别诊断主要在HPC/SFT、滑膜肉瘤、富于细胞性纤维组织细胞瘤这3种肿瘤实体之间。本例没有皮肤切除?也没见正常与肿瘤交界处,肿块对周围组织生物学行为如何,具体解剖位置等尚未知,感觉要100%下结论尚未成熟
Weiss Enzinger——“monophasic fibrous synovial sarcoma” PK “HPC”:
Many synovial sarcomas exhibit a prominent hemangiopericytoma-like vascular pattern, which can result in an erroneous diagnosis of hemangiopericytoma. The latter tumor is quite uncommon and by definition is a diagnosis of exclusion. Typically, this vascular pattern is present as a focal phenomenon in synovial sarcoma, whereas, by definition, hemangiopericytoma has this vasculature throughout the entire neoplasm, including myxoid and hyalinized zones. In addition, hemangiopericytoma lacks immunohistochemical evidence of epithelial differentiation and expresses CD34 in up to 80% of cases, a marker typically absent in synovial sarcomas.
呵呵,当我引用了上面的话并仔细阅读之后,现在回过头来想,本例还是符合滑膜肉瘤的——毕竟,血管周细胞的形态本例只是局灶有,粘液和硬化区不明显!CD34毕竟也阴性,EMA我认为还是算阳性的,所以滑膜肉瘤是优先考虑
至于富于细胞性纤维组织细胞瘤,刚开始还没想到这个,网友提起这个倒是可以作为鉴别诊断,但细胞形态本例是小圆形,束状结构不明显
还是看看Weiss Enzinger怎么说:
VARIANTS OF BENIGN FIBROUS HISTIOCYTOMA
There are a number of histologic variants of benign fibrous histiocytoma. With the exception of the cellular and epithelioid forms, these designations are of minor importance. Cellular fibrous histiocytoma appears to have a higher risk of local recurrence and often poses a diagnostic challenge to distinguish it from more aggressive lesions such as fibrosarcoma, whereas the epithelioid fibrous histiocytoma can be confused with tumors of melanocytic lineage.
Cellular fibrous histiocytomaCellular fibrous histiocytoma is a designation used for lesions characterized by increased cellularity and a more fascicular (and less storiform) growth pattern. Some cases of “dermatofibroma with subcutaneous extension”[32,][33] and “dermatofibroma with potential for local recurrence”[26] are examples of this variant. Occurring in an age range and anatomic location similar to those for ordinary benign fibrous histiocytoma, these lesions are composed of a relatively monomorphic population of plump spindle cells arranged in longer fascicles with fewer inflammatory cells and giant cells (Figs 12-24, 12-25). In addition, mitotic activity is usually somewhat higher (mean 3 mitoses/10 high-power fields [HPF]), and subcutaneous extension more common (30%), than in the usual fibrous histiocytoma. About 10% undergo spontaneous central necrosis. Although the local recurrence rate of 25% for this form of fibrous histiocytoma seemingly contrasts with that of the ordinary form, it has not been demonstrated that cellularity is an independent predictor of recurrence. The high incidence of extension into the subcutis by this form of fibrous histiocytoma suggests that this feature might be equally significant. Nonetheless, we believe it is still useful to recognize the cellular form of fibrous histiocytoma as a distinct variant, but we think it is also important to comment on extensive subcutaneous extension when present in fibrous histiocytomas of the usual type as a possible predictor of recurrence. Recently, a distinct chromosomal translocation has been identified in this form of fibrous histiocytoma,[23] but it is not clear whether it uniquely identifies this variant or is a feature of all fibrous histiocytomas.
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