Purpose or Case Report: In preterm infants, caudothalamic lesions on ultrasound usually evoke the presence of a recent germinal matrix bleed. Intraventricular bleeds may also be seen in term infants but usually located near the glomus of the choroid plexus. Because germinal matrix has involuted in term infants, caudothalamic bleeds are infrequent and other possibilities should be considered when caudothalamic lesions are seen. Previous literature has described germinolytic cysts as indistinguishable from lesions resulting from germinal matrix hemorrhage. The pathologic process underlying development of these cysts is not well known and may result from intrauterine injury due to a vascular insult, congenital infections or chromosomal abnormalities. In our practice, we have seen many cases of germinolytic cysts in term infants mimicking germinal matrix bleed but acting as “red flag” raising the suspicion of other pathology, such as CMV infection and Zellweger syndrome. Although germinal matrix bleed and germinolytic cysts appear similar on ultrasound, we believe that key differentiating feature between these lesions is gestational age of the infant at presentation.
Purpose of our educational exhibit is to emphasize these facts and encourage both radiologists and sonologists to consider unusual but important possibilities such as CMV infections or Zellweger syndrome whenever caudothalamic lesions are encountered in a term baby. We discuss other abnormalities and findings to support these diagnoses. Early suspicion and detection of intracranial CMV infection is essential for prompt treatment and better outcome.
Methods & Materials: Cases included term neonates from a tertiary care hospital requiring cranial ultrasound and caudothalamic groove lesions. All infants also had subsequent cross sectional imaging (MRI and or CT).
Results: Other abnormalities, more subtle than caudothalamic lesions, were also detected on the cranial ultrasound and suggestive of CMV or Zellweger syndrome. Subsequent MRI proved that the caudothalamic lesions were not bleeds but rather germinolytic cysts. MRI also confirmed other associated abnormalities suspected on ultrasound.
Conclusions: Presence of caudothalamic lesions resembling bleeds in term newborns on US should immediately raise the suspicion of an alternate diagnosis prompting search for more subtle signs of CMV infection or Zellweger syndrome. While Zellweger is very rare, CMV infection is not infrequent and early detection is essential for prompt initiation of treatment and better outcomes.