This document discusses various types of pseudocysts and true cysts found in the body. It begins by defining the key differences between a true cyst and a pseudocyst. Pseudocysts are lined by granulation and/or fibrous tissue rather than an epithelial cell layer. The document then classifies and describes different types of pseudocysts including traumatic bone cysts, aneurysmal bone cysts, and developmental cysts. It provides details on the etiology, location, patient demographics, clinical presentation, radiographic features, histopathology and treatment for each type.

1. Pseudosoft tissue
Cyst
By
Dr . Wael Mohamed Swelam
Dr. Wael Swelam
Monday, January 20, 2014

2. References
Dr. Wael Swelam
Monday, January 20, 2014

3. pseudo cyst ╳ true cyst
Type
Lining
True cyst
Pseudo cyst
The wall of a true cyst consists of a The wall of a pseudocyst consists of
clearly defined epithelial cell layer granulation and/or fibrous tissue
(origin: odontogenic X non odontogenic)
(which is present secondary to inflammation)
Classification of Pseudo cysts
Traumatic
Aneurysmal
Dr. Wael Swelam
Traumatic
Developmental
Static bone cyst
bone
marrow
defect
Monday, January 20, 2014

4. 1. Aneurysmal bone cyst
Etiology and pathogenesis:
1. Traumatic event result in an area of haemorrhage that maintain connection
with the original with the disrupted feeding vessels. Subsequently giant cell
granuloma-like can develop after loss of connection with the original
vascular source
2. Frequently develops secondary within another lesion of bone as a result of
disrupted vascular dynamics in pre-existing intrabony lesion
ex. Central giant cell tumors
Dr. Wael Swelam
Monday, January 20, 2014

5. Aneurysmal bone cyst
Age :
 Young
adults < 30 Years
Location:
 Shaft
of long bones
 Vertebral
 2%
column
Jaw bone; posterior mandibular is more common
Sex : No predilection
Manifestations:
 Rapidly
 Painful
Dr. Wael Swelam
growing swelling
frequently with parathesia
Monday, January 20, 2014

6. Aneurysmal bone cyst
 Radiographic features:




Malocclusion
Mobility
Migration
Root resorption
 Maxillary lesions:

Nasal manifestations




Bulging into adjacent sinus
Nasal obstruction
Nasal bleeding
Optical manifestations


Proptosis
Diplopia
Dr. Wael Swelam
Monday, January 20, 2014

7. Aneurysmal bone cyst
 Surgical Histopathology:

At operation
Intact periosteum
B. Shell cortex often with perforation
C. After removal of A & B dark venous blood wells up
A.

Surgeon impression:
 Blood
soaked sponge
Histopathological features:
 Spaces
of varying size
 Filled with blood
 Surrounded by cellular fibroblastic tissue
 Wall contain multinucleated giant cells and osteoid tissue
 Might be associated with other pathosis mostly fibrous dysplasia
Dr. Wael Swelam
Monday, January 20, 2014

8. Traumatic bone cyst
Etiology and pathogenesis:
1. Trauma-hemorrhage theory:
Traumatic event that is insufficient to cause bone fracture result in an
intraosseous hematoma. If hematoma doesn’t undergo organization and
repair the clot breaks down (liquefy) leaving an empty bony cavity.
2. Altered bone metabolism theory:
Inability to of interstitial fluid to exit the bone because of
* Inadequate venous drainage
* Local disturbance of in bone growth
* Ischemic marrow necrosis
Result in Osteolysis
Dr. Wael Swelam
Monday, January 20, 2014

9. Traumatic bone cyst
Age :
 10-20
Years
Location:
 Essentially
 More
 Sex
restricted to the mandible
common in premolar – molar region
: 60% ♂
Manifestations:
 Asymptomatic
 20%
and usually discovered accidentally
might have painless swelling
 Associated with vital teeth
 At
operation the lesion appear as an empty cavity
Dr. Wael Swelam
Monday, January 20, 2014

10. Traumatic bone cyst
Radiographic features :
 Well
delineated, radiolucent defect
 Unilocular,
or Multilocular
 When
several teeth are involved in the lesion, the
defect shows domelike projections that scallop upward
between the roots, NO root resorption of related teeth
Location:
 Essentially
 More
 Sex
restricted to the mandible
common in premolar – molar region
: 60% ♂
Dr. Wael Swelam
Monday, January 20, 2014

11. Traumatic bone cyst
Histopathological features:




Empty spaces of varying size
Surrounded by thin band of vascular fibrous connective tissue cellular
fibroblastic tissue
Wall occasionally contain multinucleated giant cells and osteoid tissue
Might be associated with other pathosis mostly fibrous dysplasia
Dr. Wael Swelam
Monday, January 20, 2014

12. Static bone cyst
Stafne’s bone defect
Definition:
Lingual mandibular Salivary Gland Depression:
A developmental concavity of the lingual cortex of the mandible, usually in the
third molar area, that forms around an accessory lateral lobe of submandibular
gland and has the radiographic appearance of a well-circumscribed cystic
lesion within the bone, usually below the inferior alveolar canal.
canal
Etiology and pathogenesis:
The pathogenesis is unknown exactly
1. Entrapment of salivary gland tissue during the development of the mandible
2. Lingual cortical erosion from hyperplastic salivary gland tissue, both
demographic and anatomic findings are consistent with this hypothesis
Dr. Wael Swelam
Monday, January 20, 2014

13. Stafne’s bone defect
Age :

Adults
Sex:
 80-90%
♂
 Clinical features:
 Anterior
defects are related to sublingual SG
 Posterior
defects are related to submandibular SG
 Might
interrupt the continuity of the inferior border of
the mandible
 Rarely;
increase in size over time which indicate
that these lesions are nor congenital
Dr. Wael Swelam
Monday, January 20, 2014

14. Osteoporotic bone marrow defect
Etiology
 Abnormal
 Residual
 Focus
healing following tooth extraction
remnants of fetal marrow
of extramedullary haematopoiesis
Sex
 Female
70%
Clinical features
 Site:
Angle/ posterior mandible
Histopathological features:
 Predominance
of haematopoietic cells with fewer fat cells
 Lymphoid
aggregates within cellular marrow &
megakaryocytes
Dr. Wael Swelam
Monday, January 20, 2014

15. Dr. Wael Swelam
Monday, January 20, 2014

16. Embryological review
Development of pharyngeal pouches
Development of Tongue
Dr. Wael Swelam
Monday, January 20, 2014

17. Branchial cyst
Cervical lymphoepithelial cyst
Etiology and pathogenesis
Fusional lesion hypothesis



Incomplete obliteration of the fetal branchial arches, i.e. the lack of
degeneration of the cervical sinus created by the growth of the second arch
over the third and fourth arches is the proposed cause.
The third and fourth arches thus overlaid by the second arch persist as small
pockets with their ectodermal epithelium.
These pockets usually fill in during fetal development; however, when they
do not, cysts, sinuses and fistulas.
Dr. Wael Swelam
Monday, January 20, 2014

18. Branchial cyst
Cervical lymphoepithelial cyst
Clinical features
 Age
20:40 Y
 Usually unilateral, rarely bilateral
 Soft, fluctuant, asymptomatic, enlargement
 Along anterior margin of sternomastoid
 Some lesions appear as sinus or fistulae on the skin
Histological features
90% are lined by stratified squamous epithelium
may/may not be keratinized
 Cyst wall typically contain lymphoid tissue with
germinal centers

Dr. Wael Swelam
Monday, January 20, 2014

19. Oral Lymphoepithelial cyst
Cystic changes in entrapped lymph node epithelial islands
Etiology:
 Epithelial invagination into tonsillar
tissue, result in blind pouches or tonsillar
crypts
Clinical features:
 Small submucosal nodule covered by
normal overlying mucosa.
Microscopic features:
 Epithelial lined space with lymphoid
tissue in the surrounding c.t. wall.
Dr. Wael Swelam
Monday, January 20, 2014

20. Thyroid gland development
Dr. Wael Swelam
Monday, January 20, 2014

21. Thyroglossal tract cyst
 Most common 75% of developmental cyst of the neck
 As thyroid anlage grow downward from foramen caecum to its
permanent location in the neck. Residual epithelial elements
along this pathway may give rise to cysts
Dr. Wael Swelam
Monday, January 20, 2014

22. Thyroglossal tract cyst







Mostly occur in midline, Below the level of hyoid bone
2% occur within the tongue itself (lingual thyroid nodule)
Sinus tract formation if secondary infected
Rarely undergo malignant transformation
50% occur before 20 years
No sex predilection
Painless, fluctuant, movable swelling
 Retract on swallowing if it maintain an attachment to hyoid
 Retract on tongue movement if it maintain attachment with tongue
Histopathological features:
Cyst lining with ciliated or columnar epithelial lining
Thyroid tissue might be seen within CT
Dr. Wael Swelam
Monday, January 20, 2014

23. Dermoid cyst
 Developmental cystic malformation,
 Due to entrapment of totipotent blastomeres, which can
produce derivatives of all three germ layers
 Oral lesions affect anterior portion of oral cavity,
 Appear on midline
 If develop above geniohyoid ms sublingual swelling will
displace tongue = difficulty in eating, speaking, berating
 If develop below geniohyoid ms will result in submental
swelling ‘double chin appearance’
Teratoid cyst
is a term used to describe a cystic form of teratoma that
contain a variety of germ layer derivatives:

Skin appendages ex. Hair follicle, sebaceous gland, sweet gland

Connective tissue elements ex. Muscle, blood vessel, bone

Endodermal structures ex. GIT lining
Dr. Wael Swelam
Monday, January 20, 2014

24. Epidermoid cyst
 Usually follow localized inflammation of the hair follicle and
represent non neoplastic proliferation of epithelium resulting from
healing process
 Oral lesions are very rare, the lesion mainly affect skin
Clinical features




Common in acne-prone areas of the head and neck,
Unusual before puberty
Usually associated with Gardner Syndrome
Appear as nodular fluctuant subcutaneous lesion
Histopathological features




Cavity lined by stratified squamous epithelium,
Well developed granular cell layer
Lumen filled with orthokeratin
Prominent inflammatory reaction including multinucleated giant cells
Dr. Wael Swelam
Monday, January 20, 2014

25. Dr. Wael Swelam
Monday, January 20, 2014