Banerjee S S, Agbamu D A, Eyden B P, Harris M
Department of Histopathology, Christie Hospital, Manchester, UK.
Histopathology. 1997 Oct;31(4):355-66. doi: 10.1046/j.1365-2559.1997.2770865.x.
To study the clinical and pathological features of primary malignant peripheral primitive neuroectodermal tumours (PNETs) of the skin and subcutaneous tissue, to discuss the differential diagnosis, and to review the existing literature on these tumours.
Eight cases of PNETs presenting in the skin and subcutaneous tissue were identified from the pathology records of the Christie Hospital, Manchester. Detailed immunohistochemical studies were performed on all cases and seven tumours were subjected to electron microscopic examination. Detailed clinical and follow-up information was obtained on seven cases. Six tumours occurred in children and adolescents and two were seen in young adults (age range, 8-36 years). No sex or site predilection was observed. Five tumours occupied the dermis and subcutis and three were entirely located in the subcutaneous tissue. Microscopically, they were composed of small round cells and seven tumours contained glycogen. Only one tumour focally exhibited Home-Wright rosettes and neuropil. Two tumours contained rhabdoid or plasmacytoid cells in places and all cases showed microcystic and pseudovascular spaces. Immunostains revealed MIC2 (8/8), NSE (7/8), PGP9.5 (7/8), beta 2 microglobulin (7/8), neurofilament protein (6/8), S100 protein (3/8), synaptophysin (2/8) and Leu-7 (1/8) positivity. Anomalous cytokeratin (4/8), desmin (2/8), myoglobin (2/8), NKIC3 (4/8) and GFAP (1/8) staining was also noted. Ultrastructurally, neuroendocrine granules were detected in five cases and one case exhibited microtubules in processes. Adequate follow-up information was available in four cases. One patient died of metastatic disease. One child developed axillary lymph node metastasis but is alive with no evidence of disease 96 months after treatment. Two other patients are alive with no residual or recurrent disease 44 and 52 months after excision and radio/chemotherapy.
PNETs are rare malignant small round cell tumours of the skin and subcutaneous tissue which are probably underdiagnosed. A correct diagnosis can be made on light microscopic features, demonstration of neuroendocrine granules on electron microscopy and a combination of MIC2, beta 2 microglobulin, and more than one neural marker positivity. These neoplasms should be differentiated from other cutaneous neoplasms composed of small round cells. The number of cases of cutaneous PNETs studied so far is rather small, and no firm conclusion can be drawn about their behaviour but long-term survival is possible in some cases.
研究皮肤及皮下组织原发性恶性外周原始神经外胚层肿瘤（PNETs）的临床和病理特征，探讨鉴别诊断方法，并复习有关这些肿瘤的现有文献。
从曼彻斯特克里斯蒂医院的病理记录中识别出8例发生于皮肤及皮下组织的PNETs。对所有病例进行了详细的免疫组织化学研究，7例肿瘤进行了电子显微镜检查。获得了7例病例的详细临床和随访信息。6例肿瘤发生于儿童和青少年，2例见于年轻成人（年龄范围8 - 36岁）。未观察到性别或部位偏好。5例肿瘤累及真皮和皮下组织，3例完全位于皮下组织。显微镜下，它们由小圆形细胞组成，7例肿瘤含有糖原。仅1例肿瘤局灶性显示霍姆 - 赖特菊形团和神经毡。2例肿瘤局部含有横纹肌样或浆细胞样细胞，所有病例均显示微囊和假血管腔隙。免疫染色显示MIC2（8/8）、NSE（7/8）、PGP9.5（7/8）、β2微球蛋白（7/8）、神经丝蛋白（6/8）、S100蛋白（3/8）、突触素（2/8）和Leu - 7（1/8）阳性。还注意到异常细胞角蛋白（4/8）、结蛋白（2/8）、肌红蛋白（2/8）、NKIC3（4/8）和GFAP（1/8）染色。超微结构上，5例检测到神经内分泌颗粒，1例在突起中显示微管。4例有足够的随访信息。1例患者死于转移性疾病。1名儿童发生腋窝淋巴结转移，但治疗96个月后存活且无疾病证据。另外2例患者在切除及放化疗后44和52个月存活，无残留或复发性疾病。
PNETs是皮肤及皮下组织罕见的恶性小圆形细胞肿瘤，可能诊断不足。根据光镜特征、电镜下神经内分泌颗粒的显示以及MIC2、β2微球蛋白和一种以上神经标志物阳性的组合可做出正确诊断。这些肿瘤应与其他由小圆形细胞组成的皮肤肿瘤相鉴别。目前研究的皮肤PNETs病例数较少，关于其行为尚无确凿结论，但某些病例可能长期存活。
