1 - Neuroradiology Department, Hospital de São José e Hospital Dona Estefânia, Centro Hospitalar de Lisboa Central, Lisbon, Portugal
- 46th ESNR Annual Meeting, 20 a 24 setembro 2023, Viena
- Neuroradiology (2023) 65 (Suppl 1):S1–S146
- https://doi.org/10.1007/s00234-023-03203-z
Introduction: Pontocerebellar hypoplasias represent a rare and diverse group of disorders characterized by reduced volume of the pons and cerebellum. Moreover, a considerable number of other diseases exhibit similar imaging patterns, further highlighting the need for careful differentiation and precise diagnosis. Applying a pattern recognition approach, particularly based on imaging, aids in narrowing the differential diagnosis and, when considered alongside clinical context, can guide targeted genetic investigation. This case report focuses on Hoyeraal-Hreidarsson syndrome, a severe variant of dyskeratosis congenita, a hereditary telomere maintenance defect involving telomerase dysfunction and impaired proliferation of hematopoietic stem cells. Clinical presentation includes intrauterine growth retardation, bone marrow failure, immunodeficiency, and neoplasias. Imaging features encompass cerebellar hypoplasia, supratentorial calcifications, delayed myelination, thin corpus callosum, and small pituitary gland. A comprehensive approach integrating imaging findings, clinical context, and laboratory investigation is crucial for diagnosis of Hoyeraal-Hreidarsson syndrome.
Case Report: Here, we present a case of a boy born by emergency cesarean section at 30 weeks of gestation due to complications including pre-eclampsia, placental abruption, severe oligohydramnios, and decreased fetal movement. The newborn had a low birth weight and microcephaly, with an Apgar score of 7/8. He required a 34-day stay in the neonatal Intensive Care Unit due to respiratory distress syndrome, sepsis and severe anemia. At 8 months of age, he was admitted to our hospital with a three-week history of oral and skin lesions, irritability, and fever for the last two days. Physical examination revealed microcephaly, developmental delay, poor ponderal progression and leukoplakia. Laboratory tests revealed pancytopenia and elevated inflammatory markers, prompting the onset of empiric antibiotic therapy due to the suspicion of sepsis. Head CT scan showed a very small cerebellum and pons, calcifications in the internal capsule, ventricular and subarachnoid space enlargement. Brain MRI confirmed pons and cerebellar hypoplasia, involving the cerebellar hemispheres and vermis, and revealed discrete hyperintensity of the white matter, particularly in the internal capsule and central region of the centrum semiovale. Other findings included a hypoplastic corpus callosum and a simplified gyral pattern. The prominent pontocerebellar hypoplasia, alongside with the clinical history and supra-tentorial calcifications suggested Hoyeraal-Hreidarsson syndrome as a potential diagnostic hypothesis. Subsequent genetic testing confirmed two mutations in the RTEL1 gene, one of which was likely pathogenic.
Conclusion: Cerebellar hypoplasia is a key characteristic of Hoyeraal-Hreidarsson syndrome. Clinical features and other imaging characteristics, namely brain calcifications can aid in the diagnosis of this syndrome.
Keywords: Pontocerebellar hypoplasia; Hoyeraal-Hreidarsson syndrome; brain calcifications