Odontogenic Disorders PDF

9 020 corrector : Lubna Adilly Hana Khasawneh Dana Al-Toum Faleh 1|P age ODONTOGENIC DISORDERS We will face some patients presenting with a swelling of the alveolar bone whether in the maxilla or in the mandible, and we have to take some points into considerations while dealing with this enla...

9 020 corrector : Lubna Adilly Hana Khasawneh Dana Al-Toum Faleh 1|P age ODONTOGENIC DISORDERS We will face some patients presenting with a swelling of the alveolar bone whether in the maxilla or in the mandible, and we have to take some points into considerations while dealing with this enlargement as it could be a result to many things: - Odontogenic or non-odontogenic cysts Odontogenic tumors Bone tumors Bone lesions: fibro-osseous lesions, giant cell lesions - Inflammatory like: chronic osteomyelitis Usually rare Epithelial origin Newly classified Mesenchymal origin The recent 2017 WHO classification of odontogenic tumors, which sometimes is not included in the textbooks, divides odontogenic tumors into benign and malignant. 2|P age And in addition to the tumors /lesions mentioned above, we have another two of possible odontogenic origin Tumors of debatable origin: ▪ Melanotic neuroectodermal tumor of infancy ▪ Congenital gingival granular cell tumor (congenital epulis) If we take a look at the prevalence of odontogenic tumors in this study for e.g. we can see that 45% of tumors were ameloblastoma. So, it has the highest prevalence and thus most important type to concentrate on. 2nd most common are complex and compound odontoma And the third one is odontogenic myxoma. 3|P age Epithelial origin: 1. Ameloblastoma (conventional) Used to be called Solid, multicystic ameloblastoma or the conventional ameloblastoma that arise within the bone (intraosseous). ▪ Most common • Clinically: ➢ Age (30-60) wide age group & X gender (no gender predilection). ➢ Site: most commonly affecting: Post. mandible, the molar region and the ascending ramus. ➢ Teeth: could present around impacted teeth OR replacing the site of missing teeth (third molar region). Ameloblastoma affecting the mandible ➢ Asymptomatic swelling: slowly enlarging asymptomatic swelling, and because of this it can reach a significant size and may perforate the alveolar bone and extends to the soft tissues. 4|P age ➔ Slowly growing ➔ May perforate bone Once it extends to the soft tissues it becomes difficult to treat. • Rx: To confirm the diagnosis, we need to take radiographs, and we will find that the lesion is growing within the bone, and usually there is: ➢ Multilocular “soap bubble” appearance, so it’s multicystic radiolucency. ➢ Root resorption that is seen in adjacent teeth. ➢ And it could be associated with an Impacted tooth as we said, and usually it’s the third molar. In some ameloblastomas, the radiographic appearance will be unilocular. ➔ So mostly it’s multilocular but could be seen as unilocular radiolucency. 5|P age After the resection of the tumor, if we look grossly to it, we will find that it’s solid but usually it’s composed of multicystic spaces, that’s why it’s called multicystic ameloblastoma. • Hist: It has many patterns: 1. Follicular pattern: Islands or follicles of the epithelium against fibrous connective tissue stroma. The epithelium is composed of two areas: - The peripheral part can be seen as → columnar or cuboidal cells - The central part has → angular cells, same as those found in developing teeth stellate reticulum like cells 6|P age The peripheral cells (cuboidal or columnar) are seen with reversed polarity, the nucleus is seen away from the basement membrane, and this is opposite to the usual arrangement, as the nucleus is usually close to the basement membrane in normal columnar cells. Also, these cells resemble the ameloblasts (cells seen in developing teeth). Reversed polarity Cystic spaces are seen within the follicle. Degeneration of the stellate reticulum like cells (angular cells) will form → microscopic cystic spaces, that can coalesce to form → large cystic spaces that we see in the macroscopic appearance. Cystic changes 7|P age 2. Acanthomatous pattern Some variance of the tumor, sometimes the angular cells (stellate reticulum like cells) change into squamous cells, and sometimes form keratin and due to this acanthomatous pattern form. 3. Granular cell variant And sometimes the angular cells change into granular cells, and so they call it granular cell variant of ameloblastoma. 4. Plexiform pattern: Second most important histological pattern of amelobalstoma. ▪ Characterized by a “Fishnet” arrangement. ▪ Same cell layers: Peripheral → columnar, and cuboidal epithelium. The center → angular cells. ▪ Cystic changes (spaces) are seen. But here they won’t be within the follicle, instead, they will be within the surrounding fibrous connective tissue stroma. 8|P age 5.Desmoplastic variant 6. Basal cell variant 5 & 6 → rare variants. ▪ Pathogenesis: ✓ Resemble Enamel organ The tumor looks like developing enamel organ, so they said that the origin of the epithelium is from the enamel organ. ✓ Dental lamina While others say that the epithelium origin is from the dental lamina, others say it’s from the surface epithelium, or sometimes it could be from the lining of odontogenic cysts. Thus, there are different theories regarding the origin of the epithelium forming the ameloblastoma. ✓ Pre-ameloblast But here the ameloblast of ameloblastoma, the peripheral columnar cells, they are considered as pre-ameloblast, because they’re not inducing the surrounding tissue to form dentine, so it’s still in the immature form (Pre-ameloblast) 9|P age ▪ Behavior (prognosis): Benign but locally invasive. You will not find capsule around the developing tumor, so it’s locally invasive within the bone marrow spaces. ➔ Usually there is a need for a clear margins of the tumor, in order to make sure that the whole tumor is removed and to decrease its local recurrence rate. Q: Site of poorest prognosis of ameloblastoma. From google : posterior maxilla 10 | P a g e 2. Metastasizing ameloblastoma: In rare occasions ameloblastoma with a typical histology (as the conventional ameloblastoma) is seen within the lung. ▪ Typical histology Lung ▪ Pulmonary metastasis ▪ Aspiration ➔ It’s found in patients who already have conventional ameloblastoma who usually had multiple surgeries and multiple local recurrences. ➔ It’s considered as aspiration from the same tumor to the lung and the aspirated tissue proliferate to form another focus within the lung. → So, it’s not a typical metastasizing, as metastases usually occurs throughout the blood but in here aspiration from the conventional tumor to the lung has occurred. → Thus, it’s not a malignant tumor (as it has the same histology of conventional ameloblastoma) 3. Unicystic ameloblastoma Another important variant of odontogenic ameloblastoma. ▪ Clinically: ✓ 5-15% of AM cases ✓ This tumor arises in Younger patients, usually in the second decade of life. ✓ The most common site is also the molar region of the mandible. 11 | P a g e ▪ Rx: ✓ In here the tumor is unilocular And with three arrangements (three variances): 3 Types of growth in unicystic ameloblastoma: 1. Luminal: the ameloblasts like cells are seen lining the cystic spaces. (They are seen within the lining of the cystic space). 2. Or this ameloblastic tissue could proliferated inside the cystic space (as num 2 in the figure) resulting in the → intraluminal. 3. Or the proliferation could be outside the capsule → Mural. • Hist: - Dense FCT capsule surrounding a solitary, fluid-filled lumen So, there is a cystic space filled with fluids and surrounded by capsule. 12 | P a g e Here is the luminal type, there are ameloblast like cells with a reversed polarity, surrounding a cyst in the basal region lining this cystic space. Also, stellate reticulum like cells are seen toward the lumen of the cyst. Basal layer: columnar Other layers: stellate reticulum The intraluminal type: proliferation of the plexi form like ameloblastoma inside the cystic space. Intraluminal And in the mural: the ameloblastic tissue proliferate toward the capsule (invading the capsule), or there could be islands of ameloblastic tissue within the capsule of the cystic space. The mural type has the poorest prognosis in comparison to the luminal and intraluminal because the proliferation occurs outside, toward the bone and consequently care in the removal of ameloblastoma should present as it will increase the local recurrent rate. Mural 13 | P a g e 4. Peripheral ameloblastoma: ▪ Clinically: ➢ Gingival firm sessile nodule Usually present or it can be seen as a firm nodule within the gingiva with the same histology of conventional ameloblastoma ▪ Origin: Basal oral epithelium, or remnants of the dental lamina of the gingiva ▪ Hist: = intraosseous. Same histology, and the same arrangement of the tumor whether plexi form or follicle pattern ▪ Rx: ± saucerization Peripheral ameloblastoma cannot be seen on radiographs, but it can cause pressure on the bone resulting in a saucerization which can be seen in the radiograph. ▪ Prognosis: less aggressive It’s less aggressive in comparison to the conventional ameloblastoma 14 | P a g e 5. Adenomatoid odontogenic tumor: Another important odontogenic tumor. ▪ Clinically: ✓ It can be seen in the 2nd decade of life. ✓ Seen as a swelling over un-erupted tooth (Upper Canine usually) ▪ Rx: ✓ Unilocular radiolucency containing a tooth (the impacted tooth “canine”) ✓ Sometimes Faint flecks of radio-opacities are seen within the radiolucency. ▪ DDx: (Differential Diagnosis) Will include “the dentigerous cyst.” But you have to be careful, look at the distribution of the radiolucency, as the radiolucency should extend beyond the CEJ in adenomatoid tumors in contrast with dentigerous cysts as this is not found in it. In addition to that, the radiopaque spots within the radiolucency can also aid in differentiating between them. ▪ Prognosis: Is usually very good, and the incubation will result with a low recurrent rate. 15 | P a g e ▪ Hist: ✓ The tumor is composed of capsule so it’s a capsulated tumor (FCT capsule) ✓ Usually it’s solid but cystic spaces might be found as well. ✓ The tumor is composed of sheets, or whorls/rosettes of epithelium with central spaces containing homogenous eosinophilic material. ✓ Sometimes tubular arrangement like ducts might be seen, as in this section, and because of this presence of ducts in the tumor it’s called adenomatoid (resembling the gland) Also, spherical calcification may be seen within the tumor, and it is responsible for the radiopacity that is seen in the radiographs. Spherical calcifications 16 | P a g e 6. Squamous Odontogenic tumor: ▪ Clinically: ✓ Usually it affects: Young adults ✓ Site: Anterior to molars (PM region, or canine PM region). ✓ Causes a painless swelling ✓ ± Tenderness & loosening of the associated teeth ▪ Rx: ✓ Unilocular, semilunar ✓ Ñ-shaped or triangular radiolucency It could be mixed with deep pockets or deep/angular resorption of the alveolar bone. Might be mixed with periodontitis, or you might think that this is a lateral periodontal cyst or lateral radicular cyst. ▪ Hist: Histological section will confirm the diagnosis. ✓ It’s composed of rounded & elongated islands ✓ With a normal appearing well differentiated squamous cells. ✓ In a fibrous CT stroma ✓ And these squamous cells may form keratin, or cystic space (microcysts) might be found within follicles. Origin: RC of Malassez 17 | P a g e • Calcified structures Or sometimes we may find calcification within these structures It’s of a good prognosis. 7. Calcifying epithelial odontogenic tumor (Pindborg tumor) ▪ Clinically: ✓ Rare (1%), Adults ✓ Slowly enlarging painless mass ✓ 2/3 of the cases occurs in the Mand, in the molar & premolar region. ✓ Peripheral CEOT (6%). Sometimes it’s peripheral in the gingiva but usually it’s intraosseous. ▪ Prognosis: infiltrative but LRR <20% The tumor is infiltrative inside the bone and usually there is a local recurrence rate in less than 20% in comparison with conventional ameloblastoma. Convectional ameloblastoma has the highest local recurrence rate of odontogenic tumors. 18 | P a g e ▪ Rx: ✓ Irregular radiolucent area ✓ Radio-opaque bodies So there is formation of calcification within the tumor. ✓ Can be associated with unerupted teeth In mature lesion the calcification will increase, and you can find the appearance of driven snow appearance in the mandible here. “Driven-snow” ▪ Hist ✓ The tumor is composed of sheets of large polyhedral epithelial Cs ✓ With abundant eosinophilic cytoplasm ✓ The cells will be connected with each other with a prominent intercellular bridges. ✓ Pleomorphism you can find these cells variable in size and shape, multinucleation, hyperchromatism deep color of the nuclei. Note that these features do resemble malignancy but it’s a benign tumor not malignant. 19 | P a g e We can also see with the tumor, the presence of homogenous like material, amyloid like material, if you add Congo red stain (special stain) it will give apple green appearance indicating that this is an amyloid material within the tumor and this may help to confirm the diagnosis. Congo Red Stain Amyloid-like material Also, in histology you can see that the tumor has spherical calcifications that increase with time Spherical calcifications IIII ‫تالتالت‬ to .. ‫"قلبي تعبان" حصريا‬ https://drive.google.com/file/d/1azgYIWOeWS2Ey8ZrgYn0fwfDfRT90suh/view?usp=sharing 20 | P a g e