Supplementary Material for: Multiple Primary Cutaneous Anaplastic Large Cell Lymphoma: A Case Report

Introduction: Anaplastic large cell lymphomas (ALCL) are a subtype of non-Hodgkin lymphoma categorized into systemic and cutaneous (cALCL) subtypes. cALCL are frequently characterized by their lack of ALK receptor expression, which differentiates them from their systemic counterparts. cALCLs present as solitary or grouped skin lesions. Due to their rarity, cALCLs are frequently misdiagnosed as other skin conditions.
Case presentation: We report the case of a female with a 30-year history of expanding skin lesions on the upper and lower limbs, abdomen, and back. During her initial presentation, the lesions were thought to be due to an arthropod bite. However, lesion biopsy revealed ALK-negative cALCL and methicillin-resistant Staphylococcus aureus. A full workup excluded systemic ALCL and, therefore, confirmed the diagnosis of primary cALCL. The patient was placed on methotrexate to treat the lesions and sulfamethoxazole/trimethoprim to treat the infection.
Conclusion: Our case highlights the need to consider cALCL in the differential diagnosis of patients with persistent skin lesions.

引言：间变性大细胞淋巴瘤（Anaplastic large cell lymphomas, ALCL）是非霍奇金淋巴瘤（non-Hodgkin lymphoma）的一个亚型，可分为系统性与皮肤型（cutaneous, cALCL）两个亚型。皮肤型ALCL通常以ALK受体表达缺失为特征，这一差异使其与系统性ALCL相区分。皮肤型ALCL表现为单发或多发的皮肤损害。由于该病较为罕见，常被误诊为其他皮肤疾病。病例报告：本文报告1例女性患者，其上下肢、腹部及背部出现进行性扩大的皮肤损害，病程长达30年。初次就诊时，皮损被初步考虑为虫咬所致。但皮损活检结果显示为ALK阴性皮肤型ALCL，且合并耐甲氧西林金黄色葡萄球菌（methicillin-resistant Staphylococcus aureus）感染。经全面检查排除系统性ALCL后，确诊为原发性皮肤型间变性大细胞淋巴瘤。患者接受甲氨蝶呤治疗皮损，并予磺胺甲噁唑/甲氧苄啶抗感染治疗。结论：本病例提示，对于持续性皮肤损害患者，在鉴别诊断中需将皮肤型ALCL纳入考量范畴。