Kempf und Pfaltz Histologische Diagnostik, Seminarstrasse 1, CH-8042 Zurich, Switzerland.
Am J Surg Pathol. 2012 Jul;36(7):1021-9. doi: 10.1097/PAS.0b013e31824f4f66.
Pityriasis lichenoides comprises a clinicopathologic spectrum of cutaneous inflammatory disorders, with the 2 most common variants being pityriasis lichenoides et varioliformis acuta (PLEVA) and pityriasis lichenoides chronica. The aim of the study was to describe 13 cases of a unique PLEVA variant characterized in the conspicuous CD30 component and thus mimicking lymphomatoid papulosis (LyP), a condition currently classified in the spectrum of CD30 lymphoproliferative disorders. The cohort included 10 female and 3 male patients whose ages at diagnosis ranged from 7 to 89 years (mean 41 y; median 39 y). The clinical manifestation was that of PLEVA, with small erythematous macules quickly evolving into necrotic papules. No waxing and waning was seen on follow-up in any of the cases. Histopathologically, typical features of PLEVA were present, but an unusual finding was occurrence of a considerable number of CD30 small lymphocytes as detected immunohistochemically. Over half of the cases also displayed a large number of CD8 cells and showed coexpression of CD8 and CD30 in the intraepidermal and dermal component of the infiltrate. Of the 11 cases of PLEVA studied for T-cell receptor gene rearrangement, 6 evidenced a monoclonal T-cell population, and 5 were polyclonal. Parvovirus B19 (PVB19) DNA was identified in 4 of 10 cases investigated, and positive serology was observed for PVB19 in 2 patients, altogether suggesting that PVB19 is pathogenetically linked to PLEVA at least in a subset of cases. The presence of CD30 lymphocytes and CD8 lymphocytes would be consistent with an inflammatory antiviral response, as CD30, even atypically appearing lymphoid cells have been identified in some viral skin diseases. The main significance of the PLEVA variant is, however, its potential confusion with LyP or some cytotoxic lymphomas. Admittedly, the CD30 PLEVA variant described herein and LyP show considerable overlap if one takes into account all known variations of the 2 conditions recognized in recent years, thus suggesting that LyP and PLEVA may be much more biologically closely related entities than currently thought or can even occur on a clinicopathologic spectrum.
pityriasis lichenoides 包括一组皮肤炎症性疾病的临床病理谱，其中最常见的两种变异型为 pityriasis lichenoides et varioliformis acuta (PLEVA) 和 pityriasis lichenoides chronica。本研究的目的是描述 13 例具有明显 CD30 成分的独特 PLEVA 变异型，这些病例表现类似于蕈样肉芽肿（LyP），这是一种目前被归类为 CD30 淋巴增生性疾病谱的疾病。该队列包括 10 名女性和 3 名男性患者，诊断时的年龄从 7 岁到 89 岁不等（平均年龄 41 岁；中位数 39 岁）。临床表现为 PLEVA，表现为小的红斑性斑疹，迅速发展为坏死性丘疹。在任何病例中，随访时均未出现病情的时好时坏。组织病理学上，存在典型的 PLEVA 特征，但一个不寻常的发现是存在相当数量的 CD30 小淋巴细胞，这些细胞通过免疫组化检测到。超过一半的病例还显示出大量的 CD8 细胞，并在浸润的表皮和真皮成分中显示出 CD8 和 CD30 的共表达。在研究的 11 例 PLEVA 中，有 6 例进行了 T 细胞受体基因重排，结果显示存在单克隆 T 细胞群，5 例为多克隆。在 10 例研究的 PVB19 中，有 4 例检测到 PVB19 DNA，有 2 例患者的 PVB19 血清学呈阳性，这表明 PVB19 与 PLEVA 至少在某些病例中存在病因学联系。CD30 淋巴细胞和 CD8 淋巴细胞的存在与炎症性抗病毒反应一致，因为 CD30 甚至在一些病毒性皮肤病中也已被鉴定为异常出现的淋巴细胞。然而，PLEVA 变异型的主要意义在于，它可能与 LyP 或某些细胞毒性淋巴瘤混淆。诚然，如果考虑到近年来公认的这两种疾病的所有已知变异型，本文描述的 CD30 PLEVA 变异型和 LyP 之间存在相当大的重叠，这表明 LyP 和 PLEVA 可能比目前认为的更具有密切的生物学关系，或者甚至可能存在于临床病理谱中。
