ORPTH ADONS ODNTGN CYSTS TUMRS Flashcards

Question

25. Histological features of thin epithelial lining, ameloblast-like basal cell layer with overlying layers resembling stellate reticulum and abundant ghost cell within the epithelial lining are suggestive of (a) Dentigerous cyst (b) Radicular cyst (c) Calcifying odontogenic cyst (d) Odontogenic keratocyst

Answer 1

(c) The lining of COC consists of odontogenic epithelium of 4–10 cells in thickness. The basal cells of the epithelial lining may be cuboidal or columnar and are similar to ameloblasts. The overlying layer of loosely arranged epithelium may resemble the stellate reticulum of an ameloblastoma. The most characteristic histopathological feature of the COC is the presence of variable numbers of ghost cells within the epithelial component

Answer 2

(b) The nasolabial cyst is a rare developmental (fissural) cyst that occurs in the upper lip lateral to the midline. The enlargement often elevates the mucosa of the nasal vestibule and obliterates the maxillary mucolabial fold.

Answer 3

(c) The gingival cyst of adults is a developmental odontogenic cyst derived from the remnants of dental lamina and shows a striking predilection to occur in the mandibular canine and premolar area

Answer 4

(d) The buccal bifurcation cyst is classified as an inflammatory odontogenic cyst that characteristically develops on the buccal aspect of the mandibular first permanent molar. It has been speculated that when the tooth erupts, an inflammatory response may occur in the surrounding follicular tissues that stimulates cyst formation.

Answer 5

(a) The most characteristic histopathological feature of COC is presence of ghost cells within the epithelial component These eosinophilic ghost cells are altered epithelial cells characterized by the loss of nuclei with preservation of the basic cell outline.

Answer 6

(c) The glandular odontogenic cyst is a rare developmental odontogenic cyst that can show aggressive behavior. Generally accepted as being of odontogenic origin, it also shows glandular features. The GOC is lined by squamous epithelium of varying thickness. The fibrous cyst wall is usually devoid of any inflammatory cell infiltrate. The superficial epithelial cells lining the cyst cavity appear cuboidal or columnar and have an irregular and sometimes papillary surface. Occasionally cilia may be noted. Due to presence of mucous cells and pools of mucin in the wall, features of low grade mucoepidermoid carcinoma are mimicked

Answer 7

(a) Ameloblastomas are slow-growing, locally invasive tumors that run a benign course in most cases. Theoretically, they may arise from rests of dental lamina, from a developing enamel organ, from the epithelial lining of an odontogenic cyst, or from the basal cells of the oral mucosa.

Answer 8

(d) Odontoma/odontome is the most common odontogenic tumor, while ameloblastoma is the most common odontogenic neoplasm. A tumor refers to any swelling, which in case of odontoma is developmental in nature, i.e. a hamartoma.

Answer 9

(b) Although originally this variant was considered to represent an aging or degenerative change in long-standing lesions, this variant has been seen in young patients and in clinically aggressive tumors.

Answer 10

(c) Radiographically, this type usually resembles a fibroosseous lesion because of its mixed radiolucent/radiopaque appearance. This mixed radiographic appearance is due to osseous metaplasia within the dense fibrous septa that characterize the lesion and not because the tumor itself is producing a mineralized product.

Answer 11

(b) Follicular and plexiform patterns are the most common histological subtypes. Less common histopathological patterns include the acanthomatous, granular cell, desmoplastic, and basal cell types

Answer 12

(d) Conventional ameloblastoma usually shows “soap bubble” appearance when the radiolucent loculations are large and as being “honeycombed” when the loculations are small. Buccal and lingual cortical expansion is frequently present. Resorption of the roots of teeth adjacent to the tumor is common. In many cases, an unerupted tooth is associated with the radiolucent defect. The margins of these radiolucent lesions often show irregular scalloping.

Answer 13

(a) Three histopathological variants of unicystic ameloblastoma are described. First type called luminal unicystic ameloblastoma, is confined to the luminal surface of the cyst. In the second variant called intraluminal, one or more nodules of ameloblastoma project from the cystic lining into the lumen of the cyst. In the third variant known as mural unicystic ameloblastoma, the fibrous wall of the cyst is infiltrated by typical follicular or plexiform ameloblastoma.

Answer 14

(d) Metastases from ameloblastomas are most often found in the lungs. Cervical lymph nodes are the second most common site for metastasis of an ameloblastoma. Spread to vertebrae, other bones and viscera has also occasionally been confirmed.

Answer 15

(b) Histochemical and ultrastructural studies show that the clear cells, which are the prominent feature of this neoplasm, have similarities to glycogen rich pre-secretory ameloblasts.

Answer 16

(d) The adenomatoid odontogenic tumor represents 3% to 7% of all odontogenic tumors. This lesion was previously considered to be a variant of the ameloblastoma and was designated as “adenoameloblastoma.” However, its clinical features and biologic behavior indicate that it is a separate entity.

Answer 17

(b) In many of the cases, the tumor appears as a well-defined, unilocular radiolucency involving the crown of an unerupted tooth, most often a canine. This type of follicular adenomatoid odontogenic tumor may be impossible to differentiate radiographically from the more common dentigerous cyst

Answer 18

(d) Some authorities feel that, given the slow growth and circumscription of the lesion, it is best classified as a hamartoma (developmental tumor-like swelling) rather than a true neoplasm.

Answer 19

(c) The tumor cells bear a close morphologic resemblance to the cells of the stratum intermedium of the enamel organ. However, some investigators have recently suggested that the tumor arises from dental lamina remnants based on its anatomic distribution in the jaws.

Answer 20

(b) Squamous odontogenic tumor is a rare benign odontogenic neoplasm. Most of these are usually located within bone, although a few peripheral examples have been described. This lesion was initially believed to represent an atypical acanthomatous ameloblastoma or even a squamous cell carcinoma. The squamous odontogenic tumor may arise from neoplastic transformation of dental lamina rests or the epithelial rests of Malassezia

Answer 21

(c) CEOT shows discrete islands, strands, or sheets of polyhedral epithelial cells in a fibrous stroma along with large areas of amorphous, eosinophilic, amyloid-like extracellular material. Calcifications, which are a distinctive feature of the tumor, develop within the amyloid like material and form concentric rings (Liesegang ring calcifications).

Answer 22

(b) Consist of varying shaped islands of bland appearing squamous epithelium in a mature fibrous connective tissue stroma. The peripheral cells of the epithelial islands do not show the characteristic polarization seen in ameloblastomas, thus helping in distinguishing this neoplasm from ameloblastoma

Answer 23

(d) All such cases will be diagnosed initially as a dentigerous cyst. The surgical findings may also suggest that the lesion in question is a cyst and the diagnosis of ameloblastoma is made only after microscopic study of the specimen.

Answer 24

(c) The ameloblastic fibroma is considered to be a true mixed tumor in which the epithelial and mesenchymal tissues are both neoplastic, thereby being classified as a mixed odontogenic tumor

Answer 25

(d) The most common epithelial pattern consists of long, narrow cords of odontogenic epithelium, often in an anastomosing arrangement. These cords are usually only two cells in thickness and are composed of cuboidal or columnar cells.

Answer 26

(d) Microscopically, the tumor is composed of a cell rich mesenchymal tissue resembling the primitive dental papilla admixed with proliferating odontogenic epithelium in the form of discrete rests or islands. The mesenchymal portion of the ameloblastic fibroma consists of plump stellate and ovoid cells in a loose matrix which closely resembles the developing dental papilla.

Answer 27

(c) Patients with granular cell odontogenic tumors have all been adults at the time of diagnosis, with over half being older than 40 years of age. The tumor occurs primarily in the mandible and most often in the premolar and molar region. Some lesions are completely asymptomatic; others present as a painless, localized expansion of the affected area.

Answer 28

(a) AOT occurs most frequently in the anterior maxilla region usually in association with an impacted or unerupted tooth.

Answer 29

(a) AOT is the only lesion amongst the given lesions, that most commonly occurs in anterior maxillary region, usually in association with impacted maxillary canine. Also, radiologically, AOT is unilocular compared to other given lesions.

Answer 30

(c) All other given lesions are mixed odontogenic tumors, i.e. derived from both epithelium and mesenchyme, while the squamous odontogenic tumor is an odontogenic tumor derived from odontogenic epithelium only.

Answer 31

(b) Odontoameloblastoma is an extremely rare odontogenic tumor that contains an ameloblastomatous component and odontoma-like elements. This tumor was previously called “ameloblastic odontoma” and was confused with the more common lesion currently designated as ameloblastic fibro-odontoma

Answer 32

(d) Odontomas are the most common odontogenic tumors. Fully developed odontomas consist chiefly of enamel and dentin with variable amounts of pulp and cementum. They are further subdivided into compound and complex types. Compound odontoma is composed of multiple, small tooth-like structures. Complex odontoma consists of a conglomerate mass of enamel and dentin which bears no anatomic resemblance to a tooth. Radiographically, the compound odontoma appears as a collection of tooth-like structures of varying size and shape surrounded by a narrow radiolucent zone.

Answer 33

(a) In ameloblastic fibroma, the epithelial component proliferates in the form of long anastomosing cords, rosettes or finger-like strands, while desmoplastic fibroma does not contain any epithelial islands and the peripheral odontogenic fibroma occurs in the soft tissues.

Answer 34

(d) Odontogenic fibroma is a rare, controversial lesion, occurring in patients of ages between 4–80 years with a 2.2 to 1 female predilection. About 45 percent of cases usually occur in maxilla, anterior to the first molar. In mandible, however, about half of the tumors are located posterior to the first molar. They are microscopically composed of stellate fibroblasts, often arranged in a whorled pattern with fine collagen fibrils and considerable ground substance. Small foci of odontogenic epithelial rests may or may not be present.

Answer 35

(a) Cementoblastoma is an odontogenic neoplasm of cementoblasts, and is believed to represent the only true neoplasm of cementum. More than 75 percent tumors arise in the mandible with 90 percent arising in the molar-premolar region. Pain and swelling are present in approximately 2/3rd of patients. Radiographically, it appears as a radiopaque mass fused to one or more tooth roots and surrounded by a thin radiolucent rim. The outline of the root or roots of the involved tooth is usually obscured as a result of root resorption.

Answer 36

(d) This type of ameloblastoma contains small islands and cords of odontogenic epithelium in a densely collagenized stroma. Peripheral columnar ameloblast like cells are inconspicuous around the epithelial islands.

ORPTH ADONS ODNTGN CYSTS TUMRS Flashcards

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