Nonaka Daisuke, Chiriboga Luis, Rubin Brian P
Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
J Cutan Pathol. 2008 Nov;35(11):1014-9. doi: 10.1111/j.1600-0560.2007.00953.x. Epub 2008 Jun 10.
Desmoplastic melanoma (DM) may simulate various benign and malignant lesions, including benign peripheral nerve sheath tumors (BPNSTs) and malignant peripheral nerve sheath tumors (MPNSTs). The latter case is diagnostically challenging because DM generally show only S100 protein expression but no reaction to melanocytic markers. S100 family of proteins consists of over 20 members. We report on S100 subtypes in malignant melanomas (MMs), and BPNSTs and MPNSTs to investigate differential expression.
S100A1, S100A2, S100A4, S100A6 and S100B immunostains were performed on 80 MMs including conventional and desmoplastic types, 86 BPNSTs and 77 MPNSTs.
S100A1 expression was seen in > 91% of MMs in a diffuse reaction, whereas BPNSTs showed focal or no reaction. Sixteen percent of MPNSTs focally expressed S100A1 except for one case with diffuse reaction. S100A2 staining was negative or focal in all three groups whereas S100A4 reaction was variable in all three. S100A6 was diffusely expressed in MMs, BPNSTs and MPNSTs. S100B was stained diffusely in MMs and BPNSTs, but its reaction was observed in 30% of MPNSTs in a focal fashion.
S100A1 expression was diffuse in most of MMs but absent or focal in BPNSTs and MPNSTs. This may be helpful to distinguish between the two entities.
促纤维增生性黑色素瘤（DM）可能会模拟各种良性和恶性病变，包括良性外周神经鞘瘤（BPNST）和恶性外周神经鞘瘤（MPNST）。后一种情况在诊断上具有挑战性，因为DM通常仅显示S100蛋白表达，而对黑素细胞标记物无反应。S100蛋白家族由20多个成员组成。我们报告恶性黑色素瘤（MM）、BPNST和MPNST中的S100亚型，以研究差异表达。
对80例MM（包括传统型和促纤维增生型）、86例BPNST和77例MPNST进行S100A1、S100A2、S100A4、S100A6和S100B免疫染色。
超过91%的MM可见弥漫性S100A1表达，而BPNST显示局灶性反应或无反应。除1例弥漫性反应外，16%的MPNST局灶性表达S100A1。三组中S100A2染色均为阴性或局灶性，而三组中S100A4反应各不相同。S100A6在MM、BPNST和MPNST中均弥漫性表达。S100B在MM和BPNST中弥漫性染色，但在30%的MPNST中呈局灶性反应。
S100A1在大多数MM中呈弥漫性表达，但在BPNST和MPNST中缺失或呈局灶性表达。这可能有助于区分这两种实体。
