O'Keeffe F N, Swischuk L E, Stansberry S D
Department of Radiology, University of Texas Medical Branch, Child Health Center C-65, Galveston 77550.
AJR Am J Roentgenol. 1991 Jan;156(1):145-8. doi: 10.2214/ajr.156.1.1898549.
We studied the radiographs of 115 neonates with anterior pneumothoraces to determine how often the pneumothorax created the impression of a mediastinal pseudomass. The pseudomass results from compression of the thymus gland by air under pressure. To the unwary, the resulting configuration can lead to an erroneous diagnosis of a mediastinal mass. In experienced hands, however, it can serve as a strong clue to the presence of an underlying anterior pneumothorax. A pseudomass was present in 27 (33%) of 82 neonates with unilateral pneumothoraces and in 29 (88%) of the 33 patients with bilateral anterior pneumothoraces. A free lung edge was visualized in 26% of the patients with a unilateral pseudomass and in 55% of the neonates with a bilateral pseudomass. The pseudomass was large enough to potentially lead to a misdiagnosis in one third of the cases. In the other neonates the mass was smaller and not particularly problematic. The majority of the neonates with pseudomasses were large, not intubated, and not on positive-pressure assisted ventilation. Over half had no underlying pulmonary disease. The appearance of a mediastinal pseudomass on radiographs of neonates can obscure a pneumothorax, and lead to an erroneous diagnosis. Recognition of the pseudomass as a manifestation of pneumothoraces is important.
我们研究了115例患有前气胸的新生儿的X光片，以确定气胸造成纵隔假性肿块影像的频率。假性肿块是由受压空气对胸腺的压迫所致。对于粗心的人来说，由此产生的形态可能会导致对纵隔肿块的错误诊断。然而，在经验丰富的医生手中，它可作为潜在前气胸存在的有力线索。82例单侧气胸的新生儿中有27例（33%）出现假性肿块，33例双侧前气胸的患者中有29例（88%）出现假性肿块。单侧假性肿块的患者中有26%可看到游离肺边缘，双侧假性肿块的新生儿中有55%可看到游离肺边缘。在三分之一的病例中，假性肿块大到足以导致误诊。在其他新生儿中，肿块较小，问题不大。大多数有假性肿块的新生儿体型较大，未插管，也未接受正压辅助通气。超过半数没有潜在肺部疾病。新生儿X光片上纵隔假性肿块的出现可能会掩盖气胸，并导致错误诊断。认识到假性肿块是气胸的一种表现很重要。
