This document reports on 3 cases of unicystic ameloblastoma that were initially misdiagnosed. Case 1, in a 58-year-old female, was diagnosed clinically as a residual cyst but was found to be a unicystic ameloblastoma. Case 2, in a 25-year-old female, was diagnosed as a dentigerous cyst but was also a unicystic ameloblastoma. Case 3, in a 13-year-old female, was diagnosed as a keratocystic odontogenic tumor but was additionally a unicystic ameloblastoma. The document emphasizes that unicystic ameloblastoma can mimic features of odontogenic cysts and should

1. Unicystic Ameloblastoma,
A missed diagnosis -
Report of 3 cases
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2. Introduction
 Unicystic Ameloblastoma is a variant of ameloblastoma first described by
Robinson and Martinez in 1977.
 Unicystic variant of ameloblastoma is believed to be less aggressive,
tends to occur in younger age, and its response to enucleation or
curettage is more favorable than the classic solid or multicystic
ameloblastoma.
 High percentage of these lesions are associated with impacted tooth and
most commonly occur in posterior mandible.
 It is asymptomatic and remains undetected until seen on the routine
radiograph.
 It is second and far less frequent growth pattern of intra osseous
ameloblastoma.
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3.  It accounts less than 10-15% of all intra osseous ameloblastomas.
 Though uni cystic ameloblastoma have clinical and radiographic
characteristics of an odontogenic cyst, histopathologically it shows an
ameloblastomatous epithelium lining part of the cyst cavity with or
without luminal or mural proliferation.
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4. case 1 case 2 case 3
56yrs female
Swelling since 10 to 11
months. No HO pain
25yrs female
Swelling since 6months.
HO of pain
13yrs female, swelling
since 2 to 3 months. No
pain.
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5. Case 1 case 2 case 3
Swelling with diffuse margins
irregular in shape
Non tender, hard,
Diffuse swelling extending
from Zygomatic arch to sub
mandibular region. irregular in
shape. Tender, firm to hard,.
Diffuse swelling, non tender,
hard and irregular in shape
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6. Case 1 case 2 case 3
More buccal & minimal
lingual plate expansion,
missing 37, 38. swelling non
tender, firm to hard.
More lingual & less buccal
plate expansion, impacted
48, swelling is tender, firm
to hard.
.Buccal & lingual plate
expansion. Non tender,
hard, non fluctuant.
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7. Case 1 case 2 case 3
Purulent brown liquid Thin, yellow straw colored
fluid
Thick, yellow straw
colored fluid
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8. ORTHOPANTOMOGRAM
Case 1 case 2 case 3
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9. RADIOGRAPHIC FINDINGS
case 1 case 2 case 3
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10. Case 1 case 2 case 3
Hb % 11.5
ESR 25
TLC, DLC, CT, BT,
RBS are within
normal range.
Hb %, TLC, DLC,
CT, BT, ESR are
within normal limits
Hb % 11.5, TLC,
DLC, CT, BT, ESR
are within normal
limits
Vitality test results;
35 and 36 are non
vital
Teeth associated
with cystic lesion are
vital
Teeth associated
with cystic lesion are
vital
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11. Differential diagnosis; case 1
Provisional diagnosis; Residual cyst involving
left body and ramus of mandible.
Residual cyst
Primordial cyst
Unicystic
ameloblastoma
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12. Differential diagnosis; case 2
Provisional diagnosis; Dentigerous cyst involving right body and
ramus of mandible
Dentigerous cyst
Kerato cystic
odontogenic tumor
[OKC]
Primordial cyst
Unicystic
ameloblastoma
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13. Differential diagnosis; case 3
Provisional diagnosis; Keratocystic odontogenic tumor [OKC] involving
left mandible
Keratocystic
odontogenic tumor
[OKC]
Dentigerous cyst
Primordial cyst
Unicystic
ameloblastoma
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14. HISTOPATHOLOGICAL
FINDINGS
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15. 5X
10X
40X
case 1 case 2 case 3
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16. RED- EPITHELIAL LINING
GREEN- CONNECTIVE
TISSUE CAPSULE
RED- EPITHELIAL
LINING
BLUE-FOLLICLE
PROLIFERATING INTO
THE CONNECTIVE
TISSUE
PINK-CONNECTIVE
TISSUE CAPSULE
RED- EPITHELIAL LINING
GREEN- CONNECTIVE TISSUE
CAPSULE
BLUE- CYSTIC
DEGENERATION
WHITE-CONNETIVE
TISSUE CAPSULE
PINK- FOLLICLE WITH
STELLATE RETICULUM
YELLOW-DENTAL
FOLLICLE WITH
STELLATE RETICULUM
INTO THE CONNECTIVE
TISSUE
WHITE-CONNETIVE TISSUE
CAPSULE
PINK-EPITHELIUM WITH
LOOSELY ARRANGED
ODONTOGENIC CELLS
PINK- DENTAL FOLLICLE
WITH STELLATE
RETICULUM
BLUE-FOLLICLE WITH
CYSTIC DEGENARATION
RED- DENTAL FOLLICLE
WITH STELLATE
RETICULUM SHOWING
DEGEGNERATION
PINK-EPITHELIUM WITH
LOOSELY ARRANGED
ODONTOGENIC CELLS
WHITE-CONNETIVE TISSUE
CAPSULE
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17. UNI CYSTIC
AMELOBLASTOMA
INTRA MURAL
TYPE-3a (follicular)
UNICYSTIC
AMELOBLASTOMA
INTRA MURAL
VARIETY
UNICYSTIC
AMELOBLASTOMA
LUMINAL VARIETY
HISTOPATHOLOGICAL DIAGNOSIS
Case 1 case 2 case 3
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18. DISCUSSION
It was first described by Robinson in 1977, who reviewed the literature
concerning ameloblastoma.
The unicystic ameloblastoma is less frequently encountered variant of
ameloblastoma. It accounts less than 10-15% of all intra osseous
ameloblastomas.
It appears more frequently in the second or third decade with no
sexual or racial predilection. It is almost found asymptomatically in the
posterior mandible. It appears radio graphically as a well defined
unilocular radiolucency with corticated borders. On aspiration it yields
amber colored fluid. Histopathologically, there are three different
variants of unicystic ameloblatomas; luminal, intraluminal and mural
variety. Enucleation is the definitive treatment with recurrence rate
less than 10%.
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19. Continued….
 Here there are three reported cases of unicystic ameloblastoma, in
which clinical diagnosis is missed. In first case, 58yrs female
patient was giving history of surgical extraction of impacted tooth
20 yrs back, asymptomatic swelling in posterior mandible, on
aspiration purulent brown liquid, radio graphically well defined
unilocular radiolucency with corticated borders and root resorption
irt 35 & 36 region. Based on this findings a clinical diagnosis of
residual cyst is given.
 In second case, 25yrs female patient was giving history of swelling
with pain, yellow straw colored fluid on aspiration, radio graphically
multilocular radiolucency with impacted tooth 48 displaced
inferiorly. Based on this findings a clinical diagnosis of dentigerous
cyst is given.
 In third case, 13yrs female patient was giving history of swelling in
left mandible, yellow straw colored fluid, radio graphically well
defined radiolucency with displacement of tooth between 34 & 35.
based on this findings a clinical diagnosis of Kerato cystic
odontogenic tumor [OKC] is given.
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20. conclusion
 There are three cases of unicystic ameloblastoma with different
clinical presentation are reported. The cases presented with
features atypical of the commonly reported literature mimicking one
of the odontogenic cysts which mislead the clinical diagnosis.
 It may arise from any cystic lesion, especially dentigerous cyst and
hence it has to be considered in the differential diagnosis of all
odontogenic cysts even in the absence of salient features.
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21. REFERENCES
 Recurrence of unicystic ameloblastoma; A case report
and review of literature[ Arch pathol,lab.med
1998;122:371-379]
 Unicystic ameloblastoma; a clinico pathologic study of 33
Chinese patients [AMJ Surg pathol 2000]
 Text book of oral and maxillofacial pathology; 2nd
edition.
Neville, Damm, Allen, Bouqnot.
 Text book of differential diagnosis of oral and
maxillofacial lesions; Norman K. Wood, Paul W. Goaz
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22. Continued….
 Text book of oral pathology; Shafer’s ; 5th
edition.
 Text book of diagnostic surgical pathology of head and
neck.
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23. Thank you
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