Type 1 neurofibromatosis (NF 1), a rare genetic disease with autosomal dominant transmission, has typical dermatologic manifestations with pathognomonic Lisch nodules, and is rarely known for vascular alterations. Among these, aneurysmal dilatation is the most common form. We report a fatal case of massive hemothorax due to a spontaneous rupture of the left pulmonary artery branch micro-aneurysm in a NF 1 patient. Indeed, spontaneous rupture of these pathologic vessels is very rare in clinical practice and the literature, but, for its potentially life-threatening complications, there is the need for it to be taken into account in differential diagnosis. The origin of bleeding was first confirmed by computed tomography angiography (CTA). The patient’s condition worsened suddenly leading to pulmonary hemorrhage and death. A clinical autopsy was required to assess the definitive cause of death.
