Analysis of the frequency and nature of hyaline ring granulomas in inflammatory odontogenic cysts.
OBJECTIVE
To determine the prevalence of hyaline ring granulomas (HRGs) in a large case series of inflammatory odontogenic cysts, and to investigate the nature of these structures.


METHODS
All records from the patients diagnosed with inflammatory odontogenic cysts between January 1970 and April 2009 were reviewed. Histologic sections were evaluated by light microscopy and cases with HRGs for which sufficient biological material was available were submitted to histochemical analysis (Masson's trichrome) and immunohistochemistry (CD34, CD68 and collagen IV).


RESULTS
Twenty-two (3.3%) of the 661 cases of inflammatory odontogenic cysts diagnosed during the study period presented HRGs. The relative frequency of HRGs was higher amongst residual radicular cysts (6.1%), followed by paradental cysts (5.6%) and radicular cysts (3.0%). HRGs appeared as roughly circular homogeneous/fibrillar masses in 14 (63.6%) cases and as round structures enclosing amorphous material in 3 (13.6%) cases. Most (77.8%) roughly circular homogeneous/fibrillar masses were positive for collagen, whereas all (100.0%) round structures enclosing amorphous material were negative for this protein. Immunohistochemistry showed that most mononucleated cells and all multinucleated giant cells were positive for CD68, but negative for CD34, in all cases. In addition, collagen IV immunostaining was negative in amorphous structures and weakly positive in homogeneous/fibrillar masses.


CONCLUSIONS
The present results suggest a very low frequency of HRGs in inflammatory odontogenic cysts and support the hypothesis that these structures arise from the implantation of foreign material, most likely food particles of plant or vegetable origin. The diverse microscopic features of HRG possibly represent different developmental stages of this structure.
Department of Dentistry, Federal University of Rio Grande do Norte, Natal, RN, Brazil.
A C G
AC
Henriques
J S
JS
Pereira
C F W
CF
Nonaka
R A
RA
Freitas
L P
LP
Pinto
M C C
MC
Miguel
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001391:Azo Compounds; D002114:Calcinosis / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000032:analysis; D024141:Collagen Type IV / Q000032:analysis; D004396:Coloring Agents; D003238:Connective Tissue / Q000473:pathology; D004801:Eosine Yellowish-(YS); D005260:Female; D015726:Giant Cells / Q000473:pathology; D015745:Granuloma, Foreign-Body / Q000473:pathology*; D006801:Humans; D006818:Hyalin / Q000737:chemistry*; D008264:Macrophages / Q000473:pathology; D008297:Male; D008739:Methyl Green; D008875:Middle Aged; D009807:Odontogenic Cysts / Q000473:pathology*; D010509:Periodontal Cyst / Q000473:pathology; D011842:Radicular Cyst / Q000473:pathology; D012189:Retrospective Studies; D055815:Young Adult; D000097382:CD68 Molecule
D015703:Antigens, CD; D018952:Antigens, CD34; D015214:Antigens, Differentiation, Myelomonocytic; D001391:Azo Compounds; D003094:Collagen; D024141:Collagen Type IV; D004396:Coloring Agents; D004801:Eosine Yellowish-(YS); D008739:Methyl Green; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C017768:trichrome stain