Department of Internal Medicine, Komatsu Hospital, Neyagawa, Osaka, Japan.
Department of Internal Medicine, Higashi-Osaka Hospital, Osaka, Japan.
Am J Case Rep. 2023 Sep 28;24:e938547. doi: 10.12659/AJCR.938547.
BACKGROUND Essential thrombocytosis (ET) is a myeloproliferative neoplasm variant that leads to excessive platelet production in the bone marrow. Janus kinase 2 (JAK2) mutation is observed in 60% of ET cases. The risk of thrombosis increases with the presence of this mutation. ET can cause systemic thrombosis, including extra-portal vein thrombosis (EHPVT). In patients with ET-induced EHPVT, varied symptoms generally occur. However, our case was asymptomatic. This condition is relatively rare. CASE REPORT A 49-year-old woman presented to our hospital for a detailed clinical examination 1 month after a health examination, and blood tests revealed microcytic anemia and thrombocytosis. The patient had no current concerns and had no relevant medical or alcohol consumption history. Esophagogastroduodenoscopy demonstrated esophageal varices, with portal hypertension suspected as the underlying cause. Contrast-enhanced computed tomography scans revealed a thrombus in the portal vein, but liver cirrhosis and a tumor were ruled out. JAK2 mutation was positive, which led to myeloproliferative neoplasms being considered as the differential diagnosis. Bone marrow biopsy demonstrated many mature megakaryocytes with large and irregular nuclei and platelet aggregation in the field of view, leading to the diagnosis of ET. CONCLUSIONS This case study describes a patient with EHPVT caused by JAK2-positive ET. This case report emphasizes that physicians should consider myeloproliferative neoplasms as part of their differential diagnosis when presented with EHPVT.
特发性血小板增多症（ET）是一种骨髓增生性肿瘤，可导致骨髓中血小板过度生成。60%的 ET 病例存在 JAK2 突变。存在这种突变会增加血栓形成的风险。ET 可导致全身性血栓形成，包括门静脉以外血栓形成（EHPVT）。在 ET 引起的 EHPVT 患者中，通常会出现各种症状。然而，我们的病例患者无症状。这种情况相对罕见。
一名 49 岁女性在健康检查后 1 个月因详细临床检查就诊于我院，血液检查显示小细胞性贫血和血小板增多。患者目前无任何不适，也无相关医疗或饮酒史。食管胃十二指肠镜检查显示食管静脉曲张，疑为门静脉高压所致。增强 CT 扫描显示门静脉内有血栓，但排除了肝硬化和肿瘤。JAK2 突变阳性，考虑为骨髓增生性肿瘤的鉴别诊断。骨髓活检显示视野中有许多成熟的巨核细胞，细胞核大且不规则，血小板聚集，诊断为 ET。
本病例研究描述了一例 JAK2 阳性 ET 引起的 EHPVT 患者。本病例报告强调，当遇到 EHPVT 时，医生应将骨髓增生性肿瘤作为鉴别诊断的一部分。
