The autosomal dominant genetic disease NF1 affects approximately 1 in 3,000 births . Patients often suffer from malignant neoplasms and various other comorbidities [4–6], thus requiring continuous medical support. Vasculopathy is a less common though lethal complication with an incidence of only 3.6% . The occurrence of hemothorax in the perinatal period has been reported in only three cases of NF1, all postpartum [5, 6]. We report, to our knowledge, the first case of massive hemothorax in a pregnant patient with NF1.
In small arteries such as the intercostal artery, invasion by neurofibroma causes intimal thinning of the media, elastic fragmentation, and aneurismal dilatation, which are influenced by the fragile nature of the vascular tissue . Vascular lesions of small arteries are often asymptomatic and thus may go undetected before lethal complications occur.
Hemothorax develops when other factors, such as tumors and aneurysms, overlap with vascular vulnerability . Furthermore, pregnancy might be considered a precipitating factor for hemothorax in patients with NF1. Pregnancy exacerbates NF1 itself [5.6]; furthermore, increased intrathoracic pressure, blood volume, and cardiac output lead to increased blood pressure. Elevated steroid hormone levels also increase vascular fragility.
Blood volume increases in late pregnancy, so hemorrhagic shock may be overlooked. However, the fetus is directly affected by decreased blood flow. In this case, the patient was hemodynamically stable because bleeding was restricted by a massive hematoma. We decided to perform emergency cesarean section with adequate infusion management because there was a possibility of saving both the patient and the fetus. If the mother’s general condition had been unstable owing to persistent bleeding, endovascular coil embolization would have been performed first.
There have been several treatments reported for hemothorax, including conservative treatment with drainage, thoracotomy, and endovascular coil embolization . In this case, the bleeding site was detected on contrast-enhanced CT; therefore, endovascular treatment was feasible. Surgical repair would not have been safe as the field of view would have been obscured by the massive hematoma and dural ectasia. Furthermore, the proximity of the site of bleeding to the dural ectasia meant that there was a risk of perforation during the procedure. In cases where the site of bleeding extends further to the proximal side, intrathoracic surgical repair is impossible. Therefore, considering the fragility of the artery, the site of bleeding, and the presence of dural ectasia, surgical repair would have been extremely risky.
This case demonstrates that, even in cases without gross lesions such as tumors and aneurysms, patients with NF1 patients have the potential to develop massive hemothorax during the perinatal period. Since this outcome is difficult to prevent, strict hospitalization or blood pressure control, especially late in pregnancy and postpartum, should be considered in these patients. When massive hemothorax does occur, immediate endovascular treatment and fetal lifesaving should be instituted.