Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Acknowledgment
- Section 1 Head and neck
- Case 1 Trilateral retinoblastoma
- Case 2 Fibromatosis colli
- Case 3 Craniopharyngioma
- Case 4 Labyrinthitis ossificans
- Case 5 Branchio-oto-renal syndrome
- Case 6 Medulloblastoma
- Case 7 Ectopic cervical thymus
- Case 8 X-linked adrenoleukodystrophy
- Case 9 Langerhans cell histiocytosis
- Case 10 PHACES syndrome (Posterior fossa malformations, Hemangiomas of the face, Arterial anomalies, Cardiovascular anomalies, Eye anomalies, and Sternal defects or supraumbilical raphe)
- Section 2 Thoracic imaging
- Section 3 Cardiac imaging
- Section 4 Vascular and interventional
- Section 5 Gastrointestinal imaging
- Section 6 Urinary imaging
- Section 7 Endocrine - reproductive imaging
- Section 8 Fetal imaging
- Section 9 Musculoskeletal imaging
- Index
- References
Case 7 - Ectopic cervical thymus
from Section 1 - Head and neck
Published online by Cambridge University Press: 05 June 2014
- Frontmatter
- Contents
- List of contributors
- Preface
- Acknowledgment
- Section 1 Head and neck
- Case 1 Trilateral retinoblastoma
- Case 2 Fibromatosis colli
- Case 3 Craniopharyngioma
- Case 4 Labyrinthitis ossificans
- Case 5 Branchio-oto-renal syndrome
- Case 6 Medulloblastoma
- Case 7 Ectopic cervical thymus
- Case 8 X-linked adrenoleukodystrophy
- Case 9 Langerhans cell histiocytosis
- Case 10 PHACES syndrome (Posterior fossa malformations, Hemangiomas of the face, Arterial anomalies, Cardiovascular anomalies, Eye anomalies, and Sternal defects or supraumbilical raphe)
- Section 2 Thoracic imaging
- Section 3 Cardiac imaging
- Section 4 Vascular and interventional
- Section 5 Gastrointestinal imaging
- Section 6 Urinary imaging
- Section 7 Endocrine - reproductive imaging
- Section 8 Fetal imaging
- Section 9 Musculoskeletal imaging
- Index
- References
Summary
Imaging description
A five-month-old boy presented with a palpable left neck mass. MRI shows a left parapharyngeal mass that is isointense to muscle on T1-weighted imaging (Fig. 7.1a) and hyperintense to muscle and homogeneous in signal on T2-weighted imaging (Fig. 7.1b). A coronal contrast-enhanced T1-weighted image (Fig. 7.1c) shows mild enhancement of this mass and again shows homogeneous signal. The MR imaging characteristics are similar to intrathoracic thymus but there is not definite contiguity. The diagnosis of normal thymic tissue was confirmed following CT-guided fine-needle aspiration.
Importance
The primordial thymus arises from the third and fourth pharyngeal pouches during the sixth week of gestational life. During the seventh week, thymic primordia migrate medially and caudally, forming the thymopharyngeal duct, to their final anatomic location in the anterior mediastinum. Ectopic and accessory thymic tissue may occur anywhere along the descending pathway of the thymopharyngeal duct (from the angle of the mandible to the superior mediastinum) due to arrest in migration, sequestration, or failure of involution. Ectopic thymic tissue and remnants are congenital lesions that may be solid and/or cystic in nature. Most ectopic cervical thymic tissue is unilateral and usually on the left for reasons that are unclear. Manifestation of ectopic thymic tissue as a neck mass may be mistaken for a pathologic process.
- Type
- Chapter
- Information
- Pearls and Pitfalls in Pediatric ImagingVariants and Other Difficult Diagnoses, pp. 20 - 22Publisher: Cambridge University PressPrint publication year: 2014