Karass Michael, Linder Katherine, Agarwal Anup, Budhai Alexandra, Yusuf Yasmin, Epelbaum Oleg
Internal Medicine, Westchester Medical Center, Valhalla, USA.
Pathology, Westchester Medical Center, Valhalla, USA.
Cureus. 2018 Dec 3;10(12):e3675. doi: 10.7759/cureus.3675.
Extramedullary hematopoiesis, which represents ectopic blood cell production, is usually an incidental finding accompanying hematologic pathology. The liver and spleen are the most common sites of extramedullary hematopoiesis, but thoracic involvement is likewise observed. Pleural effusions in the setting of intrathoracic extramedullary hematopoiesis have been attributed to mechanical interactions between the pleural surface and neighboring paravertebral masses consisting of hematopoietic tissue. Rupture of these highly vascularized lesions into the adjacent pleural space has been the putative mechanism in cases complicated by hemothorax. Histologically proven instances of islets of extramedullary hematopoiesis occurring on the pleural surface itself are exceedingly rare. Our case of a patient with myelofibrosis and massive pleural effusion is only the third such example described in the literature and the second to result in a confirmed hemothorax requiring surgery. As expected, technetium-99m sulfur (Tc-99m sulfur) colloid scanning accurately localized sites of extramedullary hematopoiesis in our patient, and there was a salutary response to radiation therapy.
髓外造血是指异位血细胞生成，通常是伴随血液学病理的偶然发现。肝脏和脾脏是髓外造血最常见的部位，但胸部受累情况也有观察到。胸腔内髓外造血时出现的胸腔积液被认为是胸膜表面与由造血组织构成的邻近椎旁肿块之间机械相互作用的结果。这些高度血管化的病变破裂进入相邻的胸膜腔是并发血胸病例的推测机制。组织学证实胸膜表面本身出现髓外造血岛的情况极为罕见。我们报道的这例骨髓纤维化合并大量胸腔积液的患者是文献中描述的第三例此类病例，也是第二例导致确诊血胸并需要手术的病例。不出所料，锝-99m硫胶体扫描准确地定位了我们患者的髓外造血部位，并且放疗取得了良好效果。
