Kassaby Sarah S, Hicks Alexander, Leicht Stuart, Youngberg George A
Department of Pathology, East Tennessee State University, Quillen College of Medicine, Johnson City, TN.
James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN.
Am J Dermatopathol. 2017 Dec;39(12):932-934. doi: 10.1097/DAD.0000000000000943.
Direct immunofluorescence (DIF) using frozen section material from a fresh/preserved perilesional biopsy is the gold standard for the immunopathologic diagnosis of bullous pemphigoid (BP). DIF in BP shows linear dermoepidermal junction (DEJ) staining for C3, with or without staining for IgG. In some situations, only a formalin-fixed lesional biopsy is obtained (with no fresh/preserved perilesional biopsy for DIF). In this setting, paraffin section C4d immunohistochemistry has proven to be diagnostically useful, demonstrating linear DEJ positivity for C4d. We present a novel use of C4d staining for the diagnosis of BP, specifically analyzing C4d perilesional frozen section DIF in a case where standard perilesional frozen section DIF for IgG/C3 was available, but was negative. An 80-year-old woman presented with a pruritic bullous lesion on her left upper extremity, clinically thought to represent BP. Lesional histologic findings were typical for BP, but perilesional frozen section DIF staining was negative for IgG and C3. A second set of biopsies processed at a different laboratory yielded the same result. A diagnosis of bullous scabies was considered. Subsequently, perilesional frozen section DIF for C4d was obtained, which showed strong linear DEJ positivity, confirming the diagnosis of BP. DIF for C4d is widely used in transplant pathology, since C4d is persistent in tissue, versus C3. Our case demonstrates that perilesional frozen section DIF staining for C4d may be positive and diagnostic in BP, even when conventional DIF staining for IgG and C3 is negative.
使用新鲜/保存的病损周围活检组织的冰冻切片进行直接免疫荧光（DIF）检查是大疱性类天疱疮（BP）免疫病理诊断的金标准。BP的DIF表现为C3在真皮表皮交界处（DEJ）呈线性染色，IgG染色可阳性或阴性。在某些情况下，仅获得福尔马林固定的病损活检组织（没有用于DIF的新鲜/保存的病损周围活检组织）。在这种情况下，石蜡切片C4d免疫组化已被证明具有诊断价值，显示C4d在DEJ呈线性阳性。我们报告了C4d染色在BP诊断中的一种新用途，具体是在一个病例中分析病损周围冰冻切片DIF的C4d，该病例有可用的IgG/C3病损周围冰冻切片DIF，但结果为阴性。一名80岁女性左上肢出现瘙痒性水疱性皮损，临床考虑为BP。病损组织学表现符合BP，但病损周围冰冻切片DIF染色IgG和C3均为阴性。在另一个实验室处理的另一组活检组织得到了相同结果。曾考虑诊断为大疱性疥疮。随后，进行了病损周围冰冻切片C4d的DIF检查，结果显示DEJ呈强烈线性阳性，从而确诊为BP。C4d的DIF在移植病理学中广泛应用，因为与C3不同，C4d在组织中持续存在。我们的病例表明，即使传统的IgG和C3的DIF染色为阴性，病损周围冰冻切片C4d的DIF染色在BP中也可能为阳性且具有诊断价值。
