Context: Granulocytic sarcoma (GS) is an extramedullary form of proliferating myeloblasts. It is frequently reported in patients with acute myeloid leukemia (AML) but rarely in patients with chronic myeloid leukemia (CML). Spinal cord compression caused by CML-associated GS is exceedingly rare, with only few cases reported in the literature. To our knowledge, this is the first reported case in which GS caused such extensive compression.

Findings: A 37-year-old man with CML suffered from back pain for 2 months. Notably, he had already achieved molecular remission (MR) after receiving imatinib mesylate for CML; bone marrow aspiration results were consistent with CML in chronic phase. Image examination revealed that developed GS occupied nearly the entire thoracic spinal canal, thereby causing extensive spinal cord compression. The tumor completely diminished after his treatment regimen was upgraded. He showed no signs of recurrence after 1-year follow-up.

Conclusion: Extramedullary infiltration of CML should be taken into consideration when a mass lesion develops and compresses the spinal cord in a CML patient who has been receiving routine and standard treatment modalities; thus, a sudden and unexpected progression mandates a refinement and upgrade of treatment modality.

背景：粒细胞肉瘤（GS）是一种髓外增殖的成髓细胞。在急性髓性白血病 (AML) 患者中经常报道，但在慢性髓性白血病 (CML) 患者中很少见。由 CML 相关的 GS 引起的脊髓压迫极为罕见，文献中报道的病例很少。据我们所知，这是首次报道的 GS 造成如此广泛压缩的案例。

结果：一名患有 CML 的 37 岁男性患有背痛 2 个月。值得注意的是，他在接受甲磺酸伊马替尼治疗 CML 后已经实现了分子缓解 (MR)；骨髓穿刺结果与慢性期 CML 一致。影像检查显示，发达的 GS 几乎占据了整个胸椎管，从而导致广泛的脊髓受压。在他的治疗方案升级后，肿瘤完全消失了。1年后随访未见复发迹象。

结论：当接受常规和标准治疗方式的 CML 患者出现肿块并压迫脊髓时，应考虑 CML 的髓外浸润；因此，突然和意外的进展要求对治疗方式进行改进和升级。