430 likes | 870 Views
The Pediatric Central Skull Base. Gary L. Hedlund, D.O. Primary Children ’ s Medical Center Salt Lake City, Utah. The Chondrocranium. Portion of the neocranium formed by endochondral ossification 25 centers of ossification 18 sutures and/or synchondroses
E N D
The Pediatric Central Skull Base Gary L. Hedlund, D.O. Primary Children’s Medical Center Salt Lake City, Utah
The Chondrocranium • Portion of the neocranium formed by endochondral ossification • 25 centers of ossification • 18 sutures and/or synchondroses • Anatomic variants and developmental anomalies abound
Central Skull Base Jinkins JR . Atlas of Neuroradiologic Embryology, Anatomy, and Variants. 2000: LW&W
Newborn Newborn Central Skull Base
Sphenooccipital Synchondrosis NB 3 yrs 5 yrs
10 yrs 14 yrs Sphenooccipital Synchondrosis
Neonatal Central Skull Base 6 Mo Newborn
Craniopharyngeal Canal 5 yrs
Craniopharyngeal Canal Larsen WJ. Human Embryology, 2ND ed. Saunders; 1997
Craniopharyngeal Canal Courtesy Bronwyn E. Hamilton, MD
Age Related T1WI Marrow Changes Newborn 3 yrs 7 yrs
Sphenoid Bone Pneumatization • Follows marrow conversion • Begins at about 1 – 2 years • Reaches the sella by about 7 years • Mature by 15 years • Asymmetric pneumatization is common • Lateral recess pneumatization • Splays distance between f. rotundum & vidian canal
11-year-old boy with headache and lethargy Leukemic marrow infiltration - ALL
Diagnostic Considerations? • Metastasis • Rhabdomyosarcoma • LCH • Chordoma • Chondrosarcoma
Langerhans’ Cell Histiocytosis • Denditic cell proliferation • Skull (calvarium>orbit>skullbase) • Mandible> ribs> femur> pelvis> spine • Imaging • Punched-out, beveled, lack of sclerosis • Sequestration +/- • T1 hyper - isointensity ~ lipid laiden histiocytes • T2 signal variable
Metastatic Disease • Leukemia • Neuroblastoma • Sarcomas • Rhabdomyosarcoma • Soft part sarcoma • Clear cell sarcoma
Rhabdomyosarcoma • Most common childhood soft tissue sarcoma • More common in African American children • H&N involvement in 50% • Orbit • Parameningeal • Nasal cavity, NP, sinuses, parapharyngeal, masticator, pterygopalatine fossa, middle ear • Other • Cervical nonparameningeal
Imaging of Rhabdomyosarcoma • CT • Bony lysis • ST attenuation • MR T1 hypo to isointense T2 hyperintense Variable enhancement
NonrhabdomyosarcomaSoft Tissue Sarcomas (NRSTSs) • Fibrosarcoma • Primitive neuroectodermal tumor (PNET) • Malignant peripheral nerve sheath tumor • Ewing sarcoma • Synovial sarcoma
Clival Chordoma • Primitive notocord remnant • Location • 35% skull base • 50% sacrococcygeal • 15% vertebral body
Clival Chordoma • T1WI • Intermediate to low signal • Focal hemorrhage • T2WI • High signal intensity • Heterogeneous • T1 C+ • Honeycomb enhancement Hemorrhage ~ 30%
Chordoma and TSC • TSC is a harmatoneoplastic syndrome • Autosomal dominant trait • Nonsense mutations in TSC1 (9q34) • Found in: • Symptomatic father • Clival chordoma of the son Borgel J et al. Eur J Pediatr (2001) 160:138
Neurenteric Cyst Kapoor V et al AJNR 23: 476-479, March 2002
Paraclival Neurenteric Cyst • Dysgenesis of notocord & neurenteric canal. Similar to Rathke cleft and colloid cysts • Most involve • Craniovertebral junction and posterior fossa • Histopathiology • Type A, resemble respiratory or GI epithelium • Type B, smooth muscle, glandular, and lymphoid • Type C, like Type B + glial elements
Summary • Review age related ossification and maturation • Identify anatomic variants • Review anomalies of development • Highlight pseudolesions and tumefactions of the central skull base
Thank you gary.hedlund@imail.org