ALK-positive histiocytosis is a recently described entity with few reported cases in literature. Herein, we report an unusual case of ALK-positive histiocytosis showing an Erdheim-Chester disease (ECD)-like presentation, occurring in a 37-year-old woman with a 2-year history of chronic lymphocytic leukaemia (CLL). Our CLL patient relapsed 6 months after the end of fludarabine, cyclophosphamide and rituximab frontline therapy and complained of lower limb pains. A bone marrow biopsy was performed and showed concomitant CLL/small lymphocytic lymphoma and ALK-positive histiocytosis with an identical immunoglobulin heavy-chain gene rearrangement in both neoplasms, suggesting clonal relationship. After 4 years under ibrutinib therapy, our patient remains free of both diseases. This report extends the spectrum of composite hematolymphoid neoplasms and shows that ALK rearrangement should be considered in all histiocytosis subtypes. Moreover, both tumours eradication under ibrutinib suggests that BTK inhibitors may also be effective in histiocytic neoplasms.

ALK阳性组织细胞增生是最近描述的实体，文献中报道的病例很少。在此，我们报告了一个不寻常的ALK阳性组织细胞增生症病例，显示了类似Erdheim-Chester病（ECD）的表现，发生在一名2年慢性淋巴细胞性白血病（CLL）历史的37岁女性中。我们的CLL患者在氟达拉滨，环磷酰胺和利妥昔单抗一线治疗结束后6个月复发，主诉下肢疼痛。进行了一次骨髓活检，发现伴有CLL /小淋巴细胞淋巴瘤和ALK阳性组织细胞增生，两种肿瘤均具有相同的免疫球蛋白重链基因重排，提示克隆关系。在接受依鲁替尼治疗4年后，我们的患者仍然没有这两种疾病。所有组织细胞增多症亚型均应考虑ALK重排。此外，在依鲁替尼治疗下根除两种肿瘤均表明BTK抑制剂在组​​织细胞性肿瘤中也可能有效。