Cystic degeneration in glioblastoma multiforme: trapped-air sign.

Abstract

THE SIGN IN roentgen diagnosis is born when certain details of the roentgenogram are repeatedly found to bear a positive correlation to a given clinical diagnosis. A sign springs, then, from regular follow-up of the patient to the operating room or the autopsy laboratory, where puzzling or poorly understood roentgen findings can be explained in terms of the underlying pathologic anatomy. Such signs are almost never 100 per cent accurate; further, their presence may be entirely of academic interest, since the final diagnosis is often promptly established by other means. It is always challenging and stimulating, however, to attempt to push the diagnostic frontier as far as possible; also, the roentgen sign occasionally permits redirection of therapy into more appropriate channels. To this end, this paper will describe a roentgen sign of glioblastoma multiforme, namely, the presence of trapped air within multiple small, uneven cysts in the center of the tumor. Two cases illustrative of this sign will be reported. Material While a Fellow in the Registry of Radiologic Pathology, Armed Forces Institute of Pathology, the author collected the roentgenograms from 500 cases of primary tumor of the brain and spinal cord to be screened for accessioning in the Registry. In each case the clinical history, the gross and histologic findings, and the roentgenograms were carefully related. In 3 instances, multiple radiolucencies, interpreted as bubbles of gas within brain substance, were observed in the ventriculograms. The histologic diagnosis in each of these 3 cases proved to be glioblastoma multiforme. Observation of this sign in 3 additional cases has proved its usefulness. Illustrative Cases CASE I (Armed Forces Institute of Pathology): A 52-year-old white male complained of headaches, lethargy, stupor, and right homonymous hemianopsia of two months duration. A ventriculogram was interpreted as showing pronounced displacement of the ventricular system to the right. Multiple gas-filled cysts were visualized in the left parietal region (Figs. 1 and 2). At operation a large tumor was removed from the left temporoparietal area. Multiple hemorrhagic areas were present. Histologic diagnosis: Glioblastoma multiforme. CASE II (State University of Iowa). B. S., a white woman aged 68, complained of difficulty in swallowing. Three months previously her husband had noticed that she was having difficulty in thinking of words. Shortly thereafter severe headaches and right-sided weakness developed and, somewhat later, vomiting and difficulty in swallowing. Physical examination showed right homonymous hemianopsia, right hemihypesthesia, and severe right hemiparesis with spasticity. An electrocardiogram indicated an abnormal focal process, possibly due to an expanding lesion in the left temporal region. Spinal fluid protein was 178 mg. per cent.