Brown Ryanne A, Cloutier Jeffrey M, Bahrani Eman, Liman Agnes, Tasso David, Palmer Adrian, Manning Melanie A, Galperin Ilana, Rieger Kerri E, Novoa Roberto A, Lau Hubert, Louie Christine Y
Department of Pathology, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA.
Department of Pathology, Stanford University School of Medicine, Stanford, CA.
Am J Dermatopathol. 2021 Nov 1;43(11):831-834. doi: 10.1097/DAD.0000000000001931.
Atypical fibroxanthoma (AFX) is a neoplasm that most commonly occurs on sun-damaged skin of the head and neck in elderly patients and that usually exhibits indolent clinical behavior with complete excision. The granular cell variant of AFX demonstrates overlapping histopathologic features with dermal non-neural granular cell tumor (NNGCT), which typically arises on the extremities of young to middle aged adults with rare reports of regional metastasis. A subset of NNGCT harbors ALK rearrangements and expresses ALK by immunohistochemistry. Here, we present 2 cases of granular cell AFX occurring on the scalp of males aged 73 and 87 with ALK expression by immunohistochemistry and no evidence of an ALK rearrangement on fluorescence in situ hybridization, representing a diagnostic pitfall for NNGCT.
非典型纤维黄色瘤（AFX）是一种肿瘤，最常见于老年患者头颈部受阳光损伤的皮肤，通常通过完整切除表现出惰性临床行为。AFX的颗粒细胞变体表现出与皮肤非神经颗粒细胞瘤（NNGCT）重叠的组织病理学特征，后者通常发生在中青年成人的四肢，区域转移的报道罕见。一部分NNGCT存在ALK重排并通过免疫组织化学表达ALK。在此，我们报告2例发生于73岁和87岁男性头皮的颗粒细胞AFX，免疫组织化学显示ALK表达，荧光原位杂交未发现ALK重排证据，这代表了NNGCT的一个诊断陷阱。
