[Head and neck paragangliomas. Embryological origin and anatomical characteristics: topographic distribution and vascularization pattern].
Paragangliomas are tumors that arise in the extraadrenal paraganglia and result from migration of neural crest cells during embryonic development. Based on their anatomical distribution, innervation and microscopic structure, these tumors can be classified into interrelated families: branchiomeric paraganglia (related to the branchial clefts and arches), intravagal, aortic-sympathetic and visceral-autonomic. Head and neck paragangliomas belong mainly to the first two of these families. The present article is divided into two parts. The first part reviews the embryological origin of these tumors. Special emphasis is placed on the process of neurulation or neural tube formation, neurosegmentation (with a summary of the mechanisms involved in the initial segmentation of the neural tube and of the hindbrain and spinal medulla), and the development of the sensory placodes and secondary inductions in the cranial region. Subsequently, the neural crest is analyzed, with special attention paid to the cranial neural crest. The embryonogenesis of paragangliomas is also described. The second part describes the topographical distribution of head and neck paragangliomas according to their localization: jugulotympanic, orbit, intercarotid, subclavian and laryngeal. The embryonogenesis and most important anatomical characteristics are described for each type.
Carretero González
José
J
Departamento de Anatomía Humana, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain. jcar@usal.es
Blanco Pérez
Pedro
P
Vázquez Osorio
María Teresa
MT
Benito González
Fernando
F
Sañudo Tejedo
José Ramón
JR
D006258:Head and Neck Neoplasms / Q000098:blood supply / Q000196:embryology* / Q000473:pathology*; D006801:Humans; D010235:Paraganglioma / Q000098:blood supply / Q000196:embryology* / Q000473:pathology*