Facial Mass: Ameloblastoma in Adult and Holoprosencephaly in Neonate

1. CASES Dr Satish R2, Dept of Radiodiagnosis, SSGH, Vadodara, 28-11-08

2. Case 1

3. History • A 47yrs old male having facial abnormality in the form of a large mass in the region of jaw. • The enlargement was slow & progressive without any pain or discharge.

6. DIFFERENTIAL DIAGNOSIS: • Ameloblastoma • Odontogenic Keratocyst • Dentigerous Cyst

7. Cystic lesion of Jaw Non Odontogenic Odontogenic Non mineralized Mineralized Ameloblastoma Radicular Cyst Odontoma Odontogenic Myxoma Odontogenic Keratocyst Dentigerous Cyst

8. Non Odontogenic Cyst Benign Fibro-osseous Lesions Traumatic Bone Cyst Central Giant Cell Granuloma Lingual Inclusion Defect (Stafne’s simple bone cyst) Brown Tumor Arteriovenous Malformation Mucoepidermoid Carcinoma

9. Points to look for… • History • Location of the lesion within the mandible. • its borders. • Internal architecture. • Effects on adjacent structures • Displacement, • Resorbtion of teeth. • Surrounding bony changes. • Other associated findings.

10. Radiologically the odontogenic & non odontogenic cysts have a number of features in common.

11. Jaw Cyst MULTILOCULAR UNILOCULAR • RADICULAR CYST • DENTIGEROUS CYST • STAFNE’S CYST • SOLITARY BONE CYST • FIBROUS DYSPLASIA(EARLY) • ODONTOGENIC KRATOCYST(LARGE) • AMELOBLASTOMA(LARGE) • CENTRAL GIANT CELL GRANULOMA • BROWN’S TUMOUR • ANEURYSMAL BONE CYST

13. Ameloblastoma • slow-growing, painless tumour arising from dental follicular lining epithelium & occurring in 4th-5th decade of life. • Involves ramus and posterior body of the mandible (80%). • are typically expansile mutilocular with a well defined osseous shell that represents the involved bone. The involved teeth are usually displaced. • CT findings usually show soft tissue attenuation although lower attenuation cystic appearance can also be seen. It can perforate the lingual cortex of the mandible and extend into the adjacent soft tissues.

14. Odontogenic Keratocyst • Arise from dental lamina & represent 5%–15% of all jaw cysts, occurring in adolescents . • Site - body and ramus of the mandible • Occurs as multilocular lesion with corticated margins and causes cortical thinning, tooth displacement, and root resorption.

15. Because it grows by epithelial proliferation it lacks the ballooning of radicular or dentigerous cysts & expansion extends to be more AP than buccolingual. • Multiple odontogenic keratocysts, along with nevoid basal cell carcinomas and bifid ribs, are components of the Basal cell nevus syndrome (Gorlin-Goltz syndrome) .

16. Dentigerous Cyst • the most common type of noninflammatory odontogenic cyst associated with an impacted tooth. • Occurs in adolescents and young adults & form around the crown of an unerupted mandibular third molar.

17. Dentigerous Cyst

18. So the diagnosis in our case is AMELOBLASTOMA

19. Case 2

20. History • A newborn with abnormal facial features with a proboscis on the forehead. • The baby died soon after birth. • No similar maternal history.

21. US image of fetal head showing a large single cavity with two thalami which are fused.

22. US image showing closely spaced orbits with a small round structure on the forehead.

24. Diagnosis • Alobar holoprosencephaly

25. Discussion • Holoprosencephaly is a disorder of ventral induction in which there is failure of lateral cleavage into distinct cerebral hemispheres & failure of transverse cleavage into diencephalon & telencephalon. • Associated facial anomalies result from a lack of induction of the midline segments of the face. • They are divided into three types by degree of brain cleavage.

26. Alobar Holoprosencephaly (severe form) • Semi lobar Holoprosencephaly (moderate form) • Lobar Holoprosencephaly (mildest form)

27. Alobar Holoprosencephaly • Is characterized by nearly complete lack of ventricular & hemispheric cleavage. • Imaging reveals a large crescent-shaped holoventricle with a completely unsegmented rim of brain. • Thalami are fused with absence of the interhemispheric fissure, falx cerebri & septum pellucidum.

28. a large dorsal cyst which occupies more than half of the volume of the calvarium is usually present. • Patients have severe midline facial deformities & hypotelorism, resulting from absence or hypoplasia of the premaxillary segment of the face. • In most extreme form, cyclopia (fused orbits, single eyeball) and forehead proboscis are present. • Most fetuses are spontaneously (or therapeutically) aborted while infants that are carried to term are stillborn or have a very short life span

29. Semilobar Holoprosencephaly • a less severe anomaly with normal facies or mild facial anomalies. • There is partial but interrupted attempt at brain diverticulation. • A H-shaped monoventricle with partially developed occipital & temporal horns is common. • A rudimentry falx, incompletely formed interhemspheric fissure is seen. • There is usually partial or complete fusion of basal ganglia with a small third ventricle.

30. Semilobar Holoprosencephaly H-shaped monoventricle with partially developed occipital & temporal horns

31. Lobar Holoprosencephaly • There is near complete brain cleavage. • Ventricles appear well lobulated. Absent septum pellucidum gives a box like configuration to the frontal horns. • Basal ganglia are separate. • A nearly completely formed falx & interhemispheric fissure is present although the most anteroinferior part may be absent & the frontal lobes fused inferiorly in the midline. • The optic vesicles & olfactory bulbs may be hypoplastic but severe facial abnormalities are rare.

32. Coronal image: absent CSP & frontal horn flattening

34. Other differentials include: • Hydranencephaly • Severe hydrocephalus • Corpus callosal agenesis with a large midline cyst.

35. Hydranencephaly is believed to be the result of bilateral occlusion of ICA during fetal development. • There is almost total destruction of cerebral cortex with calvarium filled with CSF but little else. • Structures receiving blood supply from PCA & vertebral atrery as thalamus, cerebellum, brainstem & posterior choroid plexus are normally seen. • Falx is typically present.

36. Hydranencephaly

37. Hydranencephaly

38. Severe hydrocephalus may mimic alobar holoprosencephaly but there is always a thin rim of cortex surrounding the ventricles. • Other features like presence of normal thalami, falx dangling choroid are also helpful.

39. Corpus callosal agenesis with dorsal interhemispheric cyst : • the falx & interhemispheric fissure is complete & the frontal horns have a bicornuate appearance. • Thalami & BG are normal.

40. Case 3

41. History • A 5 yr old boy complaining of dimness of vision with irregular constriction of visual fields. • No other positive history.

42. These axial and coronal CT scans show a soft-tissue mass extending along the path of the left optic nerve (arrow).

43. The coronal MR image shows an area of high signal intensity along the left optic nerve.

44. Orbit mass lesions Within or Involving the globe Arising from the Muscle cone Arising from the orbital wall Within the muscle cone (Intraconal) Outside the muscle cone (Extraconal)

45. Orbital mass Within or involving the globe RETINOBLASTOMA MELANOMA

46. Intraconal masses Optic nerve glioma Optic nerve meningioma Hemangioma & AV Malformations Inflammatory Pseudotumour Hematoma Lymphoma & metastases

47. Arising from the muscle cone INFLAMMATORY PSEUDOTUMOUR THYROID OPHTHALMOPATHY RHABDOMYOSARCOMA

48. Extraconal Mass Orbital Cellulitis & Abscess Lymphoma & Metastases Dermoid & Teraroma Lymphangioma

49. Masses arising From the orbital wall Spread of ethmoidal & antral tumours & infection Metastases & lymphoma LCH

50. INTRACONAL MASSES Without optic. N involvement With optic. N involvement • Cavernous hemangioma • AV Malformations • Hematoma • Orbital varix • lymphangioma • Optic nerve glioma • Optic nerve meningioma • Pseudotumour • Lymphoma