Abstract：
Diseases in which cutaneous plasma cell infiltrates predominate are rare and usually of unknown etiology, including those that transition from benign to malignant, such as cutaneous plasmacytosis, multicentric Castleman disease, and extramedullary plasmacytoma. These diseases may present as purplish, reddish-brown cutaneous plaques or nodules. Here, we report an exceptional case of lichen planus (LP) in which the patient had classic histopathological features, but the infiltrating inflammatory cells were plasma cells with restricted light chain expression. The patient presented with severe rashes, including purplish-red plaques and nodules, erythema, and erosions in the palmoplantar area, verrucous hyperplasia of the oral mucosa, and anonychia of the toes. These findings suggest a possible role of plasma cells with restricted light chain expression in the LP. Clinicians should closely follow patients for changes in their rash, perform repeat biopsies if necessary, and regularly conduct multisystemic evaluations.
摘要：
以皮肤浆细胞浸润为主的疾病很少见，通常病因不明。包括那些从良性转变为恶性的，例如皮肤浆细胞增多症，多中心Castleman病,和髓外浆细胞瘤.这些疾病可能呈现为紫色，红棕色皮肤斑或结节。这里,我们报告了一例扁平苔藓（LP）的特殊病例，其中患者具有经典的组织病理学特征，但浸润的炎症细胞是轻链表达受限的浆细胞。病人出现严重的皮疹，包括紫红色斑块和结节，红斑,和掌足底区域的侵蚀，口腔粘膜疣状增生，和脚趾的甲沟炎。这些发现表明浆细胞在LP中具有限制性轻链表达的可能作用。临床医生应密切关注患者皮疹的变化，如有必要，进行重复活检，并定期进行多系统评估。
