Abstract：
Immunohistochemistry plays a vital role in the diagnosis of small round cell tumors. CD99 immunonegativity is one of the features, which helps in distinguishing neuroblastoma from other small round cell tumors. NKX2.2 is a specific marker of Ewing sarcoma, which is a differential for poorly differentiated neuroblastoma. Here, we present a case of metastatic neuroblastoma showing immunoreactivity for both CD99 and NKX2.2 on cytology of the metastatic site causing diagnostic dilemma. Biopsy study of the adrenal lesion revealed presence of differentiating cells and neuropil, highlighting the importance of evaluation of the primary site and limitation of cytology.
摘要：
免疫组织化学在小圆细胞肿瘤的诊断中起着至关重要的作用。CD99免疫负性是其特征之一,这有助于区分神经母细胞瘤和其他小圆细胞肿瘤。NKX2.2是尤因肉瘤的特异性标记,这是低分化神经母细胞瘤的差异。这里,我们介绍了一例转移性神经母细胞瘤，显示CD99和NKX2.2对转移部位细胞学的免疫反应性，从而导致诊断困境。肾上腺病变的活检研究显示存在分化细胞和神经纤维，强调评估主要部位的重要性和细胞学的局限性。
