Frontal horn cysts in normal neonates

Inspired by a patient

Nakamura N, Miyazaki C, Hasegawa Y, Onodera M, Sugiura M, Kubo K, Nakajima T, Hattori S, Terae S. [Neonatal cystic structure adjacent to frontal horn--MRI features]. Nihon Igaku Hoshasen Gakkai Zasshi. 2005 Oct;65(4):368-72. Japanese. PMID: 16334388.

Abstract

Purpose: To evaluate the incidence and features of cystic structures adjacent to the frontal horns of neonates using MRI, and to assess the clinical features of the neonates.

Materials and methods: Between April 2001 and January 2005, MRI examinations were performed at our hospital in 352 neonates and infants whose postconceptional age was less than 48 weeks. We retrospectively evaluated the MRI findings and the clinical records.

Results: Seventeen babies (8 males and 9 females) showed cystic structures adjacent to frontal horns, hemilaterally or bilaterally. The incidence of the cysts was 4.8% in total, and was 1.4% (1/74), 9.2% (6/65), and 4.7% (10/213)in term infants, preterm infants born at 33-36 weeks of gestational age, and at less than 32 weeks, respectively. The cysts ranged from 1 to 8 mm in diameter, and were located in the white matter adjacent to ventricular walls and in the portion cephalad to the frontal horns. The cysts resolved in 5 cases (with follow-up ranging from 3 months to 2 years of age), causing slight dilatation of the frontal horn. Developmental disturbances were not observed in patients without other abnormalities.

Conclusion: Cystic structures near the frontal horns in neonates are detected by MRI at a rate of 4.8%. They will resolve spontaneously without causing developmental abnormalities.

Chang CL, Chiu NC, Ho CS, Li ST. Frontal horn cysts in normal neonates. Brain Dev. 2006 Aug;28(7):426-30. doi: 10.1016/j.braindev.2006.01.002. Epub 2006 Feb 28. PMID: 16503391; PMCID: PMC7125929.

Abstract

Frontal horn cysts (FHCs) are elliptical, smooth, thin-walled cysts adjacent to the tip of the anterior horns of the lateral ventricles. Among 3,545 terms or near term healthy babies who underwent cranial ultrasound examination in our hospital over a 2-year 5-month period, 18 were found to have FHCs (17 typical and one atypical; seven bilateral and 11 unilateral, of which seven were on the left and four on the right). The female to male ratio was 2:1. The incidence of FHCs in normal term babies was thus 0.5%. Six children had resolution of the cyst within 1 month, and 6 more had resolution on repeat scan from 2 to 11 months of age. Four children did not have subsequent ultrasonography to document resolution, but they had normal growth and development. Two were lost to follow up. The infant with an atypical FHC had an enlarged left frontal horn cyst with a midline shift on follow up, but he had normal development. Our study suggests that FHC may be a normal physiologic variant or a benign pathologic condition that can be expected to resolve spontaneously within a few months. It is reasonable to follow typical FHC by cranial ultrasound examinations at 1 or 2 and 6 months of age. In the case of an atypical cyst, more frequent follow up and further image studies like CT or MRI are necessary.