Department of Pathology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510000, People's Republic of China.
Department of Medical Imaging, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, 510000, People's Republic of China.
Diagn Pathol. 2019 Jun 1;14(1):51. doi: 10.1186/s13000-019-0829-x.
As a new entity included in the 4th edition of the WHO classification of tumours of soft tissue and bone in 2013, hybrid peripheral nerve sheath tumours are benign composite neoplasms that demonstrate features of more than one type of nerve sheath tumour, with a wide age distribution and a predilection for superficial location. Those involving deep sites are relatively rare. To the best of our knowledge, only one case of primary intraosseous hybrid peripheral nerve sheath tumours has been documented. In this article, we report another case of hybrid peripheral nerve sheath tumours occurring in bone with different clinical, radiological and pathological features from those in the previously reported cases.
A 28-year-old female presented with a painful nodule in the right tibia. Radiological examination revealed an oval eccentric osteolytic lesion in the proximal tibia. Histologically, the circumscribed but unencapsulated lesion demonstrated biphasic cellular differentiation. Bland, small epithelioid cells arranged in clusters in the myxoid or collagenous stroma and inconspicuous spindle cells scattered in the hypercellular areas were suggested to originate from Schwann cells according to the detection of S100. Both the elongated spindle cells with thin, wavy nuclei and the spindle cells in fascicular or storiform pattern in hypercellular areas showed a positive immunoreaction for epithelial membrane antigen, indicating perineurial differentiation. Based on histological and immunochemical examinations, the patient was diagnosed with hybrid epithelioid schwannoma/perineurioma. The lesion was resected and has not recurred for 8 months since resection.
The present case is the second primary intraosseous hybrid peripheral nerve sheath tumour to be reported. This is also the first reported intraosseous tumour composed of epithelioid schwannoma and perineurioma with hypercellularity, indicating diverse involvement sites and a wide range of histological features among hybrid peripheral nerve sheath tumours. Awareness of such diversity is critical for accurate diagnoses. The morphological overlap with other spindle and epithelioid cell neoplasms, especially pure peripheral nerve sheath tumours, requires that immunochemical and molecular examinations be used as objective tools to provide the necessary information for a differential diagnosis.
作为 2013 年世界卫生组织软组织和骨肿瘤分类第四版中的一个新实体，混合性外周神经鞘瘤是良性复合性肿瘤，具有超过一种神经鞘瘤的特征，发病年龄广泛，好发于表浅部位。涉及深部部位的相对少见。据我们所知，仅有一例原发性骨内混合性外周神经鞘瘤的病例被报道。本文报道了另 1 例发生在骨内的混合性外周神经鞘瘤病例，其临床表现、影像学和病理学特征与以往报道的病例不同。
一位 28 岁女性因右胫骨疼痛性结节就诊。影像学检查显示胫骨近端呈卵圆形偏心溶骨性病变。组织学上，边界清楚但无包膜的病变表现为双相细胞分化。根据 S100 的检测结果，在黏液样或胶原基质中排列成簇的小而幼稚的上皮样细胞和在细胞丰富区散在分布的不明显梭形细胞提示来源于施万细胞。细胞丰富区中长梭形细胞具有薄而波浪状核，束状或席纹状排列的梭形细胞均对上皮膜抗原呈阳性免疫反应，提示有神经周围分化。根据组织学和免疫化学检查，患者被诊断为混合性上皮样施万细胞瘤/神经鞘瘤。病变被切除，自切除以来 8 个月未复发。
本例是第二例被报道的原发性骨内混合性外周神经鞘瘤。这也是首例报道的由上皮样施万细胞瘤和神经鞘瘤组成的骨内肿瘤，伴有细胞丰富性，表明混合性外周神经鞘瘤在不同的发病部位和广泛的组织学特征上存在多样性。认识到这种多样性对于准确诊断至关重要。与其他梭形和上皮样细胞肿瘤的形态学重叠，特别是纯外周神经鞘瘤，需要使用免疫化学和分子检查作为客观工具，提供鉴别诊断所需的信息。
