The purpose of the present paper was to describe the range of lesions histologically diagnosed in an oral pathology laboratory in southern Brazil. A retrospective study of 8,168 specimen analyses recorded between 1995 and 2004 was conducted. The records were retrieved from the Oral Pathology Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, RS, Brazil. A total of 6,831 valid cases (83.63%) were examined. Of these, inflammatory lesions were the most common occurrences (n = 4,320; 63.24%). Benign and malignant tumors accounted for 7.66% (n = 523) and 1.9% (n = 130) of the occurrences, respectively. Significant associations were observed between nonneoplastic proliferative disorders and benign mesenchymal tumors in females, and between squamous cell carcinoma and leukoplakia in males. Most diagnoses were benign in nature and had an inflammatory etiology. The association of some demographic characteristics with the occurrence of lesions suggests that these characteristics should be considered in performing differential diagnoses.

O objetivo deste estudo foi o de investigar a distribuição de linfócitos CD8+ e CD20+ em lesões inflamatórias periapicais. Para tanto foram estudados 90 casos entre abscessos crônicos, cistos abscedados e cistos inflamatórios. A tecnica de imunohistoquímica pelo método da estreptavidina-biotina foi utilizada para identificar linfócitos T citotóxico/supressor (CD8) e linfócito B (CD20). Dentre os resultados encontrados notou-se uma distribuição das células CD8+ da seguinte forma: 1) difusa na capsula fibrosa dos abscessos crônicos (58,8%) e ausente nos cistos abscedados (64,1%) e cistos inflamatórios (70,6%); 2) zona infiltrativa: difusa nos cistos abscedados (100%) e cistos inflamatórios (82,4%); 3) zona subepitelial: ausente nos cistos inflamatórios (53,0%) e difusa nos cistos abscedados (56,4%); 4) zona de supuração: difusa nos abscessos crônicos (100%) e cistos abscedados (97,5%). As células CD20+ apresentavam a seguinte distribuição: 1) cápsula fibrosa: ausente nos cistos inflamatórios (100%), cistos abscedados (94,8%) e abscessos crônicos (88,3%); 2) zona infiltrativa: difusa nos cistos abscedados (100%) e cistos inflamatórios (53%); 3) zona subepitelial: ausente nos cistos inflamatórios (58,8%) e focal nos cistos abscedados (46,2%); 4) zona de supuração: difusa nos cistos abscedados (100%) e abscessos crônicos (100%). Em conclusão é possível afirmar que a distribuição linfocitária é predominantemente difusa para ambos os tipos de linfócitos.

The objective of this study was to investigate the distribution of CD8+ and CD20+ lymphocytes in chronic periapical inflammatory lesions. A total of 90 periapical inflammatory lesions (chronic abscesses, abscessed cysts, and inflammatory cysts) were evaluated. The biotin-streptavidin immunohistochemical technique was used to identify cytotoxic/suppressor T-lymphocytes (CD8) and B-lymphocytes (CD20). Age ranged from 10 to 67 years. Patients between 26 and 45 years old (54.4%), females (52.2%), and white patients (74.4%) were more frequently affected. CD8+ cell distribution was as follows: 1) fibrous capsule: diffuse in 58.8% of chronic abscesses and absent in 64.1% of abscessed cysts and in 70.6% of inflammatory cysts; 2) infiltration zone: diffuse in 100% of abscessed cysts and in 82.4% of inflammatory cysts; 3) sub-epithelial zone: absent in 53.0% of inflammatory cysts and diffuse in 56.4% of abscessed cysts; 4) suppurative zone: diffuse in 100% of chronic abscesses and in 97.5% of abscessed cysts. CD20+ cell distribution was as follows: 1) fibrous capsule: absent in 100% of inflammatory cysts, in 94.8% of abscessed cysts, and in 88.3% of chronic abscesses; 2) infiltration zone: diffuse in 100% of abscessed cysts and in 53% of inflammatory cysts; 3) sub-epithelial zone: absent in 58.8% of inflammatory cysts and focal in 46.2% of abscessed cysts; 4) suppurative zone: diffuse in 100% of abscessed cysts and in 100% of chronic abscesses. The distribution of the lymphocytic infiltrate in the lesions was usually diffuse for both types of lymphocytes.