denticles !
DESCRIPTION
Denticles !. Equine Odontogenic Tumors Accessions: 128549, 128572. Jewel. 3 yo Belgian Filly Presents for undescribed abnormalities noted on routine dental exam, no dysphagia PE: palpable asymmetry to the hemimandibles , mild right mandibular lymphomegaly - PowerPoint PPT PresentationTRANSCRIPT
DENTICLES!
Equine Odontogenic TumorsAccessions: 128549, 128572
Jewel 3 yo Belgian Filly Presents for undescribed abnormalities noted
on routine dental exam, no dysphagia PE: palpable asymmetry to the
hemimandibles, mild right mandibular lymphomegaly
Orally, the occlusal surface of 410 is replaced by cobblestone-like surface of multiple "dental islands" with deep periodontal and intradental pocketing
Local feed impaction with fermented odor
Insert CT images
P.M. Dixon, I. Dacre / The Veterinary Journal 169 (2005) 165–187
2 wks after surgery
Pre-surgical Post-surgical
Symptoms of oral tumors Dysphagia, wt. loss, oral bleeding, grossly
abnormal tissue, facial asymmetry and respiratory distress (maxillary tumors may impinge on the nasal passages)
Primary oral tumors in horses: Odontogenic
Pure epithelial, mixed epithelial and mesenchymal Slow growing masses
Osteogenic Soft tissue origin
FNA may not achieve representative samples to allow for an accurate diagnosis
Odontogenic tumors Calcified tumors
ODONTOMA=Dentinal tissue Combinations of all dental components=compound odontoma or
ameloblastic odontoma CEMENTOMA=Cementum Usually slow growing, hard focal mandibular or maxillary masses,
very radio-opaque Usually do not have draining tracts and the swelling exceeds that
of periapical abscessation Px depends on border definition and surgical resectability
Non-calcified tumors AMELOBLASTOMA
Derived from epithelium that forms enamel Do not induce connective tissue formation Freq expansile soft tissue mass with resorption of adjacent teeth and
boneP.M. Dixon, I. Dacre / The
Veterinary Journal 169 (2005) 165–187
Calcified massesOdontomas (including ameloblastic odontomas) and Cementomas
JAVMA, Vol 225, No. 9, November 1, 2004
Odontomas=Dentinal tissues
Rare, benign, locally expansive tumors of dental origin Odontomas are classified as hamartomas instead of neoplasms:
normal tissues in a chaotic arrangement: enamel, dentin, cementum and occas pulp
Complete surgical excision is curative Odontomas
epithelial and mesenchymal elements, induce connective tissue proliferation within the tumor (induction separates these from ameloblastomas)
Young, no known sex predilection, maxilla>mandible Classification
Compound-reported, rarely, in horses, dogs, and cattle have all the features of normal tooth formation Well-organized tooth-like structures known as denticles are often found
Complex-more differentiated than ameloblastic, w/ dental tissues arranged in a disorganized structure
Ameloblastic-most undifferentiated form, not common in horses
JAVMA, Vol 225, No. 9, November 1, 2004
Compound odontomas PE: Young animals (<1 year), epulis-like
growth or firm bony mass, no oral mucosal defect, non painful, no soft tissue swelling, may affect nasal airflow if maxillary
Rads: Well-marginated osseous-like mass encircling the alveolus, or centered around teeth. Tooth may be abnormally shaped and positioned, with indistinct alveolus. No evidence of lysis or fracture
JAVMA, Vol 225, No. 9, November 1, 2004
Compound Odontoma Histopathology
Multiple tooth-like structures and foci of normal bone; Denticles consist of a core of primitive mesenchyme resembling dental pulp, surrounded by a disorganized layer of odontogenic epithelium and a distinct zone of dentin, with an outer border that is disorganized and discontinuous of primitive ameloblasts
Aggressive surgical excision required for cure
Radiographic differentials: • Primary bone tumor
• Osteoma• Ossifying fibroma
• Primary dental tumor• Complex or compound odontoma• Ameloblastic odontoma• Ameloblastoma (usually not as mineralized)
JAVMA, Vol 225, No. 9, November 1, 2004
JAVMA, Vol 225, No. 9, November 1, 2004
v
Complex Odontoma Less differentiated than compound odontomas Reported appearance in a case series:
Firm, smoothly rounded, raised mass Mass centered over the crown, with a radio-opaque rim
interspersed with lucent and mineralizing opaque areas (similar to that of enamel)
Normal dental sac structures present in all cheek teeth Differential diagnoses
Periapical abscessation Cyst Ossifying fibroma Malignant neoplasia-SCC and myomatous tumors Odontogenic tumors
Complex Odontoma Reported radiographic appearance
includes: Multilobulated masses within a well-
differentiated cyst-like structure Differentiated from compound odontomas in
that compound odontomas are organized into recognizable tooth structures
Locally aggressive, but complete surgical excision is curative
Complex Odontoma At surgery, mass was cystic containing white,
mineralized tissue suspended within HxPx: Odontogenic epithelium and stellate
reticulum. Material resembling cementum with nests of epithelial rests and chords of cells with early differentiation into ameloblastic cells with abnormal looking enamel matrix
Epithelial components: ameloblasts and stellate reticulum
Mesenchymal components: cementum and pulp
Cementomas=Cementum Rare odontogenic neoplasm of mesenchymal origin
(Not an odontoma since not epithelial component) Excessive deposition of cementum-like tissues Slow-growing tumor of cementoblasts, deposit
differentiated cemental matrix around the root, proliferation of cementoblasts and destruction of the lamina dura
Well-circumscribed, rounded, radio-opaque masses surrounding the roots of several incisors or premolars; deformation of surrounding alveolar bone and effacement of lamina dura (effacement of lamina dura differentiates this from hypercementosis)
Cementoma
Cementomas Histopathologically
Prominent, well-differentiated and demarcated proliferation of cementum-like material with collagen and abn lacunae surrounding normal dental structures, including dental pulp, dentin, and cementum
Etiology Possibly hereditary in humans, or due to a
reactive/hyperplastic response after periodontal trauma May occur any age (2-17 yr range) Differential: hypercementosis=non-neoplastic process
Excessive cementum accumulation in continuation with the normal radicular cementum, lamina dura is usu preserved
Usually not as disruptive
Non-calcified massesAmeloblastoma
Ameloblastoma Ameloblastomas: major Ddx for odontomas Characterized by a predominance of odontogenic
epithelium Large amts of odontogenic epithelial tissue, lack inductive
differentiation of dentin and enamel More common in the mandible of older horses, but can be
seen in foals Tend to be osteolytic and uni- or multilocular Keratinizing ameloblastoma: lg amounts of epithelial
keratin throughout the lesion Ameloblastic carcinomas: more differentiation toward
ameloblastic epithelium Ameloblastic odontomas: radiolucent or partially
mineralized with occas foci of enamel***
Histopathology on Jewel
Right mandible, teeth: The majority of the mass is composed of disorganized extracellular matrix associated with a dense band of inflamed fibrovascular connective tissue which contains a few small islands of epithelial cells consistent for rests of Malassez. Adjacent to this mass is a large tooth composed of degenerate, variably mineralized and disorganized, and possibly necrotic dentin. The mass is composed predominantly of matrix consistent for cementum, but is poorly organized into large aggregates with anastomosing, irregular cords. The matrix is pink with lacunae-trapped cells and multiple blue resting lines. In one section the matrix forms a plexiform arrangement with clear spaces in between creating a swiss-cheese like mass.� �
We shared slides with two pathologists and favor a diagnosis of cementoma. Cementoma is a benign lesion and does not metastasize. The lesion extends to the tissue margins.