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Diagnosis Please |
1 Department of Radiology, Thomas Jefferson University Hospital, Gibbon Bldg 3350AB, 111 S 11th St, Philadelphia, PA 19107.
Index terms: Brain, abnormalities • Brain, growth and development • Fetal, abnormalities • Diagnosis please
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HISTORY |
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 TOP HISTORY IMAGING FINDINGSDISCUSSIONReferences |
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IMAGING FINDINGS |
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TOPHISTORYIMAGING FINDINGSDISCUSSIONReferences |
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Two days after delivery, CT of the newborn's head was performed without intravenous contrast material (Fig 2). A disrupted falx was noted. No normal cortical mantle except some occipital cortex could be identified. At the level of the normal thalami, normal choroid plexuses were seen posteriorly. The posterior fossa including the cerebellum was normal.
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DISCUSSION |
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TOPHISTORYIMAGING FINDINGSDISCUSSIONReferences |
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Hydranencephaly occurs after the brain and ventricles have fully formed, usually in the second trimester. The brain destruction is complete or almost complete in a bilateral internal carotid artery distribution, with the cerebral hemispheres replaced by fluid covered with leptomeninges and dura. During the destructive phase, unusual "masses" of hemorrhage and soft tissue may be seen (4). Because the ventricles have already been formed, the falx cerebri is present. The cerebellum, midbrain, thalami, basal ganglia, choroid plexus, and portions of the occipital lobes, all fed by the posterior circulation, are typically preserved.
With most of the cerebral cortex absent, the fetal head would be expected to be small. Although this may occur, the head is more often normal or increased in size because the choroid plexuses within the lateral ventricles continue to produce cerebral spinal fluid that is not adequately absorbed. This causes increased pressure, which may expand the head and lead to rupture of the falx cerebri. Both of these findings were present in this case.
While the pathogenesis of hydranencephaly is thought to be a vascular accident, this cannot always be confirmed because internal carotid arteries are not always occluded at autopsy (1). Intrauterine infections, particularly toxoplasmosis and viral infections (enterovirus, adenovirus, parvovirus, cytomegalic, herpes simplex, Epstein-Barr, and respiratory syncytial viruses), have been implicated in a number of cases. Toxic exposures and cocaine abuse have been reported, and hydranencephaly has been described in rare syndromes (5). In monochorionic twin pregnancies, death of one twin in the second trimester may cause a vascular exchange to the living twin through the placental circulation, leading to hydranencephaly in the surviving fetus (6).
Hydranencephaly may, on first impression, mimic severe hydrocephalus (dilated lateral ventricles)(2). Depending on the level of obstruction, concomitant dilatation of the third and fourth ventricles may be seen. The incidence of hydrocephalus approaches 1 in 1,000 births. Although there are many causes, the most common is an Arnold-Chiari type II malformation secondary to a spina bifida. The most severe cases, however, are usually secondary to aqueductal stenosis. Hydrocephalus is often not an isolated anomaly and can be associated with other intracranial abnormalities, multiple anomaly syndromes, and abnormal karyotype (7).
With hydrocephalus, as with hydranencephaly, the head is normal to enlarged with an identifiable falx cerebri, which may be disrupted in severe cases. Unlike in hydranencephaly, an intact rim of cortex is always present even in the most severe forms of hydrocephalus (Fig 3). It may, however, be difficult to identify prenatally. In aqueductal stenosis, a dilated third ventricle can often also be identified.
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Holoprosencephaly is a developmental anomaly resulting from absent or incomplete diverticulation of the forebrain (prosencephalon) and occurs in 1 in 16,000 live births worldwide. Alobar, its most severe form, shows no separation of the ventricles, an absent falx, and partial fusion of the thalami (Fig 4). The head is often considerably smaller than the body, and there are often additional and marked abnormalities.
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Our congratulations to the 139 individuals who submitted the most likely diagnosis (hydranencephaly) for Diagnosis Please, Case 7. Their names and locations, as submitted, are as follows:
Gholamali Afshang, MD, Tinley Park, Ill
S. I. Al-Agha, MD, Gaza, Israel
S. Manucher Alavi, MD, Richmond, Va
David R. Anderson, MD, Richmond, Va
Roger L. Antonelli, MD, Dayton, Ohio
Majed Ashour, MD, Dhahran, Saudi Arabia
A. Rhett Austin, MD, Kingsport, Tenn
Edward L. Baker, MD, San Francisco, Calif
Kenneth Baliga, Rockford, Ill
Zubin N. Balsara, MD, Fort Smith, Ark
Cynthia A. Barone, DO, Shrewsbury, NJ
John Bennett, MDCM, FRCPC, London, Ontario, Canada
Steven L. Bezinque, DO, Williamsville, NY
Tom Bonk, MD, Seattle, Wash
Nikos P. Bontozoglou, MD, Athens, Greece
Eric L. Bressler, MD, Minnetonka, Minn
Steve Burbidge, MD, St Louis Park, Minn
Joseph W. Burke, MD, Huntingdon, Pa
Can Cevikol, Antalya, Turkey
Ercument Ciftci, MD, Houston, Tex
Frederick U. Conard III, MD, Hartford, Conn
Philippe A. Coquel, MD, Cran-Gevrier, France
Mark T. DiMarcangelo, DO, MSc, Cherry Hill, NJ
Vinay Duddalwar, Aberdeen, United Kingdom
Peter English, FRACR, Hong Kong, China
Keith D. Epperson, MD, Milwaukee, Wis
Kate A. Feinstein, MD, Chicago, Ill
Laura Zindell Fenton, MD, Denver, Colo
Sylvia H. Ford, MD, Green Bay, Wis
Jonathan Foss, MD, St Louis, Mo
Michael A. Foster, MD, Cherry Hills Village, Colo
Mary C. Frates, MD, Boston, Mass
Jeffrey Friedland, Glendale, Colo
Arnold C. Friedman, MD, New York, NY
Stuart A. Fruman, MD, Vienna, Va
Akira Fujikawa, Tokyo, Japan
Douglas Gardner, MD, Windsor, Ontario, Canada
Ronald B. J. Glass, MD, New York, NY
Ishikawa Goemon, Shiga, Japan
Jacob A. Goldenberg, MD, Fargo, ND
Dulce Gomez-Santos, MD, Madrid, Spain
Devang Gor, DMRD, Costa Mesa, Calif
Daniel S. Gordon MD, MAJ USA MC, Sanford, NC
Dr. Rajesh Gothi, New Delhi, India
Athanassios D. Gouliamos, Athens, Greece
D. Joseph Grunz, MD, Creve Coeur, Mo
Mark Guelfguat, Flushing, NY
Dr Arunima Gupta, Ludhiana, India
Sunita Gupta, MD, Francistown, Botswana
David C. Harrison, MD, Cambridge, Mass
Rufus W. Head, MD, North Bridgton, Me
Maureen Heldmann, MD, Shreveport, La
Elizabeth Hingsbergen, MD, Richmond, Va
Carlos Holguera Blazquez, MD, Madrid, Spain
Lowrey H. Holthaus, MD, Richmond, Va
Kamil Karaali, Antalya, Turkey
Aake Karlsson Douglas S. Katz, MD, Mineola, NY
Ji Chang Kim, MD, Taejon, Korea
Mitchell Klein, MD, Milwaukee, Wis
Arlene M. Klink, MD, Bronx, NY
John D. Knudtson, MD, Wichita, Kan
Craig D. Korbin, MD, Weston, Mass
Dawna J Kramer, MD, Seattle, Wash
Dr. Renee G. Kulkarni, New Delhi, India
Yu-Ting Kuo, MD, Taiwan, ROC
Dong Lin Kwak, MD, Roanoke, Va
Kathleen M. Lazzarini, MD, Branford, Conn
Jong Beum Lee, MD, Seoul, Korea
Ronaldo Lessa, Jr, MD, Recife, Brazil
Julio Loureiro, MD, Buenos Aires, Argentina
David R. Ludwig, MD, Amherst, NY
António José Madureira, MD, Porto, Portugal
Gildo Matta, MD, Cagliari, Italy
James M. McAfee, MD, West Linn, Ore
Jeffrey J. McClure, MD, Grand Rapids, Mich
Steven Medwid, MD, Fall River, Mass
Edward Menges, MD, Aptos, Calif
Frank H. Miller, MD, Chicago, Ill
Manabu Minami, MD, Tokyo, Japan
Hidetoshi Miyake, MD, Oita, Japan
Sergio J. Moguillansky, MD, Rio Negro, Argentina
Silvia Moguillansky, Buenos Aires, Argentina
Eduardo Mondello, Buenos Aires, Argentina
Albert Nizzero, MD, Sudbury, Ontario, Canada
Aksel Ongre, Arendal, Norway
Mahesh R. Patel, MD, Brookline, Mass
Narendrakumar Patel, MD, Newburgh, NY
Eduardo Pavon Tinoco MD, Oaxaca, Mexico
Tim L. Pendergrass, MD, Fairchild AFB, Wash
Dr Roberto E. Perez Gautrin, Sonora, Mexico
Marvin W. Petry, MD, Chicago, Ill
Pedro J. S. Pinto, MD, Gondomar, Portugal
John Plotke, MD, Naperville, Ill
Gary Podolny, MD, Park City, Utah
Carlos H. Previgliano, MD, Salta, Argentina
Anita Price, MD, Mineola, NY
Shawn P. Quillin, MD, Charlotte, NC
M. R. Ramakrishnan, MD, Big Stone Gap, Va
Oswaldo A. Ramos, MD, Estado Trujillo, Venezuela
Lorenz (Larry) Ramseyer, MD, Enid, Okla
Enrique Remartinez Escobar, Melilla, Spain
Marco A. Rocha Mello, MD, Sao Paulo, Brazil
Javier Rodriguez Lucero, MD, Santa Fe, Argentina
Derek J. Roebuck, FRACR, Hong Kong, China
Stuart A. Royal, MD, Birmingham, Ala
Dr Eduardo Sanchez Heras Paul S. Schaefer, MD Steven M. Schultz, MD, Fort Worth, Tex
Anthony J. Scuderi, MD Hassan Semaan, Toledo, Ohio
A. Utku Senol, Antalya, Turkey
Waldo Sepulveda, MD, Santiago, Chile
Matt Shapiro, MD, Boxborough, Mass
Yoshihisa Shimanuki, MD, Yamagata, Japan
L.H. Sie, MD, Beverwijk, the Netherlands
James F. Smith, Columbia, Mo
Eric R. Sover, DO, Brookfield, Wis
Joanne B. Speigle, MD, Richmond, Va
Michael S. Stecker, MD, Iowa City, Iowa
Marius Stellmann, MD, Rotenburg, Germany
Simon Strauss, MBChB, Kfar Shmaryahu, Israel
Jeffrey Y. Sue, MD, Honolulu, Hawaii
Christopher Sweet, MD, Clarkston, Mich
Koyama Takashi, Kyoto, Japan
J. Takasugi, Mercer Island, Wash
Oscar Tenreiro Picon, MD, Maracay, Venezuela
J. Keith Thompson, MD, Richmond, Va
Joseph Z. H. Toutounji, MD, Beirut, Lebanon
Carlos Triana Rodriguez, Santefe de Bogota, Colombia
Herminia Tyminski, MD, Manama, Bahrain
T. E. G. van Zanten, MD, Haarlem, the Netherlands
Andrew L. Wagner, MD, Durham, NC
Chien-Kuo Wang, MD, Taiwan, ROC
Edward W. Williams, FRCR, Cayman Islands, British West Indies
Joseph T. Wroblicka, MD, Iowa City, Iowa
Masanobu Yasuda, MD, Kanagawa, Japan
Dr. Zhang Youbin, Gaborone, Botswana
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Footnotes |
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Received February 17, 1998;
revision requested March 18, 1998; revision received April 8, 1998;
accepted June 10, 1998.
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References |
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TOPHISTORYIMAGING FINDINGSDISCUSSIONReferences |
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