Abstract：
The NONO::TFE3 fusion has been described in MiT family translocation renal cell carcinomas as well as extracutaneous perivascular epithelioid cell tumors (PEComas). PEComas are known to express myogenic and melanocytic markers but SOX10 and p63 positivity has never been reported. We report two primary cutaneous tumors that morphologically and molecularly fit PEComas, both harboring the NONO::TFE3 fusion, but with an unusual immunophenotype of SOX10 and p63 positivity. One case was on an 80-year-old male\'s finger, and the other one was on a 72-year-old female\'s thigh. Both were well-circumscribed multinodular dermal tumors composed of nests of monotonous epithelioid to spindled cells with pale to vacuolated cytoplasm, some of which were arranged around blood vessels. Both tumors were positive for SOX10, S100, and p63, focally positive for Melan-A, and negative for myogenic markers. There are very little data regarding the molecular findings of primary cutaneous PEComas. While the NONO::TFE3 fusion has been identified in extracutaneous PEComas, it has never been reported in primary cutaneous cases. We believe these cases represent a previously undescribed subtype of cutaneous tumor which shows some immunophenotypic expression of melanocytic markers and we named these cases NONO::TFE3 fusion cutaneous epithelioid and spindle cell tumor. Further, we raise the question of whether this tumor should fall under the rubric of PEComa because of its morphology, partial expression of melanocytic markers, and the presence of the NONO::TFE3 fusion, or whether these tumors represent a separate novel class of tumors since the immunophenotypic expression of SOX10 and p63 is unusual for PEComas.
摘要：
已在MiT家族易位肾细胞癌以及血管周围上皮样细胞肿瘤（PEComas）中描述了NONO::TFE3融合。已知PEComas表达生肌和黑素细胞标记，但从未报道过SOX10和p63阳性。我们报告了两种在形态和分子上符合PEComas的原发性皮肤肿瘤，两者都拥有NONO::TFE3融合，但具有不寻常的SOX10和p63阳性免疫表型。一个案例是在一个80岁的男性手指上,另一个在72岁的女性大腿上。两者都是界限清楚的多结节性真皮肿瘤，由单调的上皮样细胞至梭状细胞的巢组成，细胞质苍白至液泡状，其中一些排列在血管周围。两种肿瘤均为SOX10，S100和p63阳性，局部为Melan-A阳性，生肌标记呈阴性。关于原发性皮肤PEComas的分子发现的数据很少。虽然NONO::TFE3融合已经在皮肤外PEComas中被发现，在原发性皮肤病例中从未报道过。我们认为这些病例代表了以前未描述的皮肤肿瘤亚型，该亚型显示了黑素细胞标志物的一些免疫表型表达，我们将这些病例命名为NONO::TFE3融合皮肤上皮样和梭形细胞肿瘤。Further,我们提出了一个问题，这个肿瘤是否应该因为它的形态而属于PEComa的范畴，黑素细胞标志物的部分表达，以及NONO::TFE3融合的存在，或者这些肿瘤是否代表了一个单独的新类型的肿瘤，因为SOX10和p63的免疫表型表达对于PEComas来说是不寻常的。
