Jeng-Tzung Wang

Odontoma: A clinicopathologic study of 81 cases

BACKGROUND AND PURPOSE Odontoma is the most common odontogenic tumor. It includes 2 types, the compound and complex odontomas. There has not been a series study of the clinical and histologic features of odontomas from Taiwan. This study evaluated the clinicopathologic features of odontoma in Taiwanese. METHODS Cases of odontoma treated from 1998 to 2002 identified from medical records were included. The microscopic features, radiographic features, and clinical history of the patients were reviewed and analyzed. RESULTS A total of 81 odontomas in 81 patients (36 males and 45 females) were included. There were 62 compound and 19 complex odontomas. The mean age of the patients was 18 years with the majority of odontomas occurring in the first (32%) and second decade (38%) of life. Odontomas had a marked predilection for the maxilla (70%) and for the anterior region of the jaw (83%), particularly for the anterior maxilla (62%). Sixty four (79%) of the 81 odontomas were associated with 80 impacted teeth, including 71 permanent teeth, 2 deciduous teeth, and 7 supernumerary teeth. Of the 71 impacted permanent teeth, the maxillary central incisor (27%) was most commonly affected, followed by the maxillary canine (26%) and mandibular canine (24%). Histologic examination revealed enamel matrix in 90%, dentin in 100%, cementum in 88%, pulp tissue in 96%, fibrous capsule in 93%, ghost cells in 83%, reduced enamel epithelium in 86%, and nests of odontogenic epithelium in 58% of odontomas. Dentigerous cyst was associated with 9% of odontomas. CONCLUSIONS In this series, odontomas occurred most often in the first and second decade of life. Although complex odontomas are usually found in the posterior jaw, in this Taiwanese series they were most commonly found in the anterior maxilla. Odontoma is frequently associated with an impacted tooth and occasionally with a dentigerous cyst. No recurrence of odontomas was found after surgical excision with follow-up of 1 to 15 years.

Nuclear Expression of metastasis-associated Protein 1 (MTA1) is Inversely Related to Progression of Oral Squamous Cell Carcinoma in Taiwan

Overexpression of metastasis-associated protein 1 (MTA1) has been demonstrated in a variety of human cancers and found to be significantly associated with the tumor size, lymph node metastasis, clinical stage, tumor invasion, and prognosis of these cancers. In this study, we examined the expression of MTA1 in 74 specimens of oral squamous cell carcinoma (OSCC), 100 specimens of oral epithelial dysplasia (OED; 33 mild, 44 moderate, and 23 severe OED cases), and 21 specimens of normal oral mucosa (NOM) by immunohistochemistry. The cytoplasmic and nuclear MTA1 labeling indices (LIs) in OSCC, OED, and NOM samples were calculated and compared among these groups. Correlations of the cytoplasmic and nuclear MTA1 LIs in OSCC with clinicopathological parameters and survival of OSCC patients were statistically analyzed. We found that the mean cytoplasmic MTA1 LIs were all over 95% for the NOM, OED, and OSCC samples. There were no significant associations of the cytoplasmic MTA1 LI with any of the clinicopathological parameters of OSCC patients. The mean nuclear MTA1 LIs significantly decreased from NOM (73%±13%) to mild OED (71%±16%), moderate OED (60%±22%), and severe OED (46%±25%) and OSCC samples (30%±30%, p＜0.001). A significant correlation was found between the lower mean nuclear MTA1 LIs and OSCCs located on the buccal mucosa and tongue (p=0.001), with larger tumor sizes (T3 and T4, p=0.020), with regional lymph node metastases (N1, N2, and N3, p=0.024), and with more-advanced clinical stages (stages 3 and 4, p=0.045). Our results suggest that MTA1 is universally expressed in the cytoplasm of normal, dysplastic, and malignant oral epithelial cells. The nuclear expression of MTA1 significantly dropped from NOM through OED to OSCC samples, and was inversely related to the T status, N status, and clinical staging of OSCCs. Therefore, the nuclear MTA1 LI can be used to predict the progression of OSCCs in Taiwan.

Characteristics of calcifying odontogenic cyst in Taiwanese

BACKGROUND AND PURPOSE Calcifying odontogenic cyst (COC) is a rare type of odontogenic cyst. This retrospective study analyzed the clinical, radiographic, and histopathologic features of COC in Taiwanese. METHODS Ten cases of COC in 2 male and 8 female patients with a mean age of 29 years (range, 11 to 48 years) treated from January 1985 to December 2002 were included. Microscopic slides, clinical histories, and radiographic features of these 10 COC cases were reviewed and analyzed. RESULTS COCs occurred in the maxilla in 3 cases and in the mandible in 7 cases. COCs were associated with impacted teeth in 6 cases and with odontomas in 3 cases. All COCs appeared as either unilocular (9 cases) or multilocular (1 case) radiolucencies. In 7 cases, spotty radiopaque materials were scattered throughout the radiolucency. Histologically, all of the lesions were at least partially lined by epithelium with cuboidal to columnar basal cells and stellate reticulum-like suprabasal cells. Variable numbers of ghost cells, some of which were calcified, were observed in the lining epithelium or in the fibrous connective tissue wall of all 10 cases. Juxta-epithelial dentinoid was also found in all cases. However, proliferation of ameloblastoma-like tumor nests was observed in only 1 case. Based on the above histologic findings, 6 COC lesions were classified as simple unicystic type, 3 as unicystic odontoma-producing type, and 1 as unicystic ameloblastomatous proliferating type. CONCLUSIONS COC occurs frequently in the second and third decades and is commonly associated with an impacted tooth or an odontoma. It usually appears as a mixed radiolucent and radiopaque lesion radiographically. Simple unicystic type is the most common type of COC. No recurrences were found after conservative surgical removal in this series.

Oral Nevi-A Clinicopathological Study of 29 Cases

Oral nevi are uncommon oral mucosal lesions. Twenty-nine cases of oral nevi including 21 intramucosal, 2 compound, and 6 common blue nevi were analyzed in this study. These 29 nevi were excised from 8 male and 19 female patients. Two patients each had 2 nevi. The mean age of patients at the time of diagnosis was 33 (range, 7~56) years. The more-common sites for oral nevi were the hard palate (12 cases) and vermilion border (9 cases). All 6 common blue nevi were located on the hard palate. The greatest dimension of the lesion was ≧1 cm in 3 cases and ＜1 cm in 24 cases. Excisional biopsy was the treatment of choice in 27 cases and wide excision in 2 cases. No recurrence of these lesions was found after surgical excision. Type A, type B, type C, and multinucleated giant nevus cells were found in 23 (100%), 19 (83%), 14 (61%), and 12 (52%) of 23 cases of intramucosal and compound nevi. The mean percentages of type A, type B, and type C nevus cells in total nevus cells were 73%±25%, 17%±15%, and 11%±18% in 23 cases of intramucosal and compound nevi, respectively. All 23 cases of intramucosal and compound nevi more or less contained nevus cells with pigmentation which varied from 1% to 91% (mean, 20%±26%). We concluded that the most-common type of oral nevi is an intramucosal nevus. Intramucosal and compound nevi were composed of approximately 3/4 of type A and 1/4 of type B and type C nevus cells. Oral nevi in this study occurred more often in female patients and in the third and fourth decades of life. The more-commonly affected sites were the hard palate and vermilion border. About 90% of these oral nevi were smaller than 1 cm.

Apical Periodontal Cyst: A Clinicopathologic Study of 405 Cases

This clinicopathological study of apical periodontal cysts included 405 specimens obtained from a total of 394 patients. The patients, 207 males and 187 females, ranged from 6 to 77 years old in their age. Approximately three fourths of the patients were in their third to sixth decades of life with the third decade as the age group of peak incidence (25.6%). Two hundred forty-seven lesions (61%) occurred in the maxilla while the remaining 158 (39%) in the mandible. The anterior region of the maxilla and the molar region of the mandible were the two sites of most frequent occurrence. Most lesions (400 out of 405) were associated with permanent teeth, while the remaining 5 involved deciduous teeth. Of the 311 lesions in which the affected teeth were specified, the upper lateral incisors were most frequently affected, followed in descending order by the lower first molars, upper central incisors, lower second molars, and lower central incisors. Histologic features of apical periodontal cysts were analyzed based on 377 lesions with available tissue sections. Most of the cysts (367 out of 377, 97.3%) were lined by nonkeratinized stratified squamous epithelium. Among these, 19 (5.0%) were partially lined by pseudostratified ciliated columnar epithelium and 3 (0.8%) partially lined by mucoepidermoid cell type epithelium. There were also 1 cyst (0.3%) completely lined by pseudostratified ciliated columnar epithelium and 9 cysts (2.4%) completely lined by keratinized stratified squamous epithelium. Acute and/or chronic inflammatory cell infiltrates were seen in the lining epithelium and/or fibrous cystic wall. In general, in the epithelium acute inflammatory cell infiltration predominated (50.4%) and chronic inflammatory cell infiltration most commonly occurred in the fibrous cystic wall (97.3%). In addition, hyaline bodies, odontogenic epithelial rests, foam cells, and cholesterol slits were found in 4.5%, 13.0%, 22.3%, and 30.8% of the cysts, respectively. Most lesions were treated by enucleation or curettage after root canal therapy of the affected teeth. Recurrences after surgery were noted in 5 cases.

Oral Neurilemmomas-A Clinicopathological Study of 21 Cases

Oral neurilemmomas (ON) are rare oral lesions. Twenty-one cases of ONs diagnosed and treated in our institute during the period from January 1991 to June 2004 were analyzed in this study. There were 14 male and 7 female patients. The mean age of the 21 patients at the time of diagnosis was 30 (range, 14-67) years with a peak incidence of tumor occurrence in the third decade. The more-common sites for an ON were the tongue (8 cases) and buccal mucosa (5 cases). The clinical appearance of ONs was frequently a pink, movable mass. In only 1 case was palpation tenderness noted. The greatest dimension of the lesion was 2 cm with a mean of 1.0±0.5 cm. The duration of the lesion ranged from 10 days to 10 years with a median of 6 months. Of the 21 cases, the clinical diagnosis was a fibroma in 6, a mucocele in 4, a tongue or buccal tumor in 5, and others in 6. Surgical excision was the treatment of choice for all 21 lesions. None of the lesions showed recurrence after surgical excision. On the average, our 21 ONs contained 77%±16% Antoni A tissue and 23%±16% Antoni B tissue. We conclude that ONs occur most often in the third decade. The more-commonly affected sites are the tongue and buccal mucosa. ONs often present as a painless and movable mass which is very difficult to diagnose just based on their clinical features. Our ONs were mostly composed of Antoni A tissue, with much-smaller content of Antoni B tissue.

A Clinicopathological Study of 22 Cases of Oral Melanotic Macule

Oral melanotic macules, or melanosis, are uncommon oral mucosal lesions. Twenty-two cases of oral melanotic macule diagnosed and treated in our institute during the period from January 1989 to June 2004 were analyzed in this study. There were 8 male and 14 female patients. The mean age of patients at the time of diagnosis was 41.2 (range, 5~80) years. The most-common sites for melanotic macule were the buccal mucosa (7 cases) and lower lip (6 cases). Multiple lesions were noted in 5 cases. The clinical appearance of the lesion was frequently a black macule (19 cases). The greatest dimension of the lesion was 1.5cm with a mean of 0.5cm. Of the 22 cases, the clinical diagnosis was oral melanosis in 12, oral melanotic macule in 6, intramucosal nevus in 2, and others in 2. Excisional biopsy was the treatment of choice in 21 cases and incisional biopsy in 1 case. Recurrence of the lesion was found in 3 cases. We found that buccal mucosal lesions had a significantly lower mean density of pigmented basal epithelial cells/mm of the basement membrane (14±26 cells/mm) than of the lower lip (89±62 cells/mm, p=0.014) or gingival lesions (76±62 cells/mm, p=0.041). In contrast, buccal mucosal lesions had a significantly higher mean density of melanophages/mm of basement membrane(52±29 cells/mm) than gingival lesions (14±2 cells/mm, p=0.031). However, there was no significant difference ii the mean density of melanophages/mm of the basement membrane between buccal mucosal lesions and lower lip lesions (28±16 cells/mm, p=0.1). We concluded that oral melanotic macules in this study occurred most often in the fifth decade. The most-commonly affected sites were the buccal mucosa and lower lip. The black pigmentation of these buccal mucosal melanotic macules might have been due to an increase in the number of melanophages in the subepithelial connective tissue, and the black pigmentation of lower lip or gingival melanotic macule might have been due to an increase in the number of melanin-pigmented basal epithelial cells.

Primary Oral Malignant Melanoma-A Clinicopathological Study of 6 Cases

Oral malignant melanomas (OMMs) are a rare entity, comprising less than 1% of all malignant melanomas. Six patients with an OMM diagnosed and/or treated in our institute during the period from 1988 to 2003 were analyzed in this study. There were 4 female and 2 male patients. The mean age of the 6 patients at the time of diagnosis was 64 years. Of the 6 OMMs, 4 occurred on the hard palate, 1 on both the hard palate and maxillary gingiva, and 1 on the mandibular gingiva. The greatest dimension of the lesions ranged from 1.5 to 8cm with a mean of 4cm. The more-common clinical symptoms and signs were black-pigmented tumors with ulceration, pain, or bleeding. Of the 5 patients whose dental status was available, 4 had either a denture or a bridge near or impinging on the tumor. At the time of initial presentation, 3 patients were in clinical stage Ⅰ (localized disease), and the other 3 were in clinical stage Ⅱ (OMM with regional lymph node metastasis). Two patients who received surgical excision of the primary OMM with or without modified radical neck dissection survived for 25 and 14 months, respectively; 2 patients who were treated by chemotherapy with or without radiotherapy survived 54 and 48 months, respectively; and the remaining 2 patients who received no treatment survived 8 and 2 months, respectively. We concluded that OMMs occur more often in the sixth and seventh decades. The more-common affected sites are the hard palate and maxillary gingiva. The more-frequent clinical presentation is a pigmented mass. The mean survival of our 6 OMM patients was 25 months. Certain treatments do prolong the life of OMM patients.

Expression of Cytokeratins in the Lining Epithelium and Ghost Cells of Calcifying Odontogenic Cyst

Calcifying odontogenic cyst(COC) is a rare type of odontogenic cyst. The most characteristic feature of COC is the presence of ghost cells (GS) in the lining epithelium. Previous immunohistochemical studies on the expression of cytokeratins in the lining epithelial cells (LEC) and GC of COC showed controversial results. In addition, several investigators used antibodies that recognize a mixture of cytokeratins in their studies, resulting in a difficulty in understanding what specific cytokeratins are present in the LEC and GC of COC. In this study, we used an immunohistochemical technique to investigate the expression of pan cytokeratins (pan CK), cytokeratin 10(CK 10), cytokeratin 13(CK1 3), cytokeratin 14(CK 14), and cytokeratin 19(CK 19) in the LEC and GC of 4 cases of COC. The immunostaining results were expressed in a semiquantitative fashion according to the estimated percentage of positively stained cells: 0%, negative (-); 1-25%, focally positive(+); 26-75%, variably positive(++); and 76-100%, uniformly positive(+++). We found that the LEC of COC were variably (++) or uniformly positive(+++) for pan CK and CK19, focally(+) or variably positive(++) for CK 14, and negative(-) for CK 10 and CK 13. The GC of COC were uniformly positive (+++) for pan CK and CK 19, focally positive(+) for CK 13 and CK 14, and negative (-) for CK 10. The expression of CK 14 and CK 19 in the LEC of COC indicates that the LEC of COC have skin or oral basal and odontogenic epithelial cell properties, respectively. Furthermore, the presence of CK 13, CK 14 and CK 19 in the GC of COC suggests that the GC of COC possess the specific CKs originally existing in non-keratinizing stratified squamous and odontogenic epithelial cells.

Merkel Cell Carcinoma Arising in the Oral Mucobuccal Fold: A Case Report with Immunohistochemical Study

Merkel cell carcinoma (MCC) is an unusual primary cutaneous small cell neuroendocrine carcinoma that occurs predominantly in the head and neck region, but rarely in the oral cavity. A review of the English-language literature revealed only 2 cases of MCC that occurred intraorally and the present case was the second reported case of oral MCC arising in the oral mucobuccal fold. The patient, a 62-year-old Taiwanese female, noted a firm and painful swelling at her right cheek for three months. Intraoral examination of the lesion revealed an erythematous bulging mass involving both the right lower posterior mucobuccal fold and the right lower retromolar area. Incisional biopsy of the lesion via intraoral approach showed numerous uniform, small round cells with scanty cytoplasm and frequent mitoses, either typical or atypical. These cells were densely packed into nests infiltrating in a loose connective tissue stroma. The Merkel cell origin of the tumor is suggested by results from immunohistochemical studies. In these studies, most neoplastic cells showed a paranuclear, globular, and inclusion-like pattern of immunostaining with the antibodies to pancytokeratin (AE1+AE3) and neuron-specific enolase, features that are characteristic of MCC. The aggressiveness of the tumor was characterized by rapid growth, frequent regional lymph node and distant metastases. The patient died 8 months after the initial diagnostic biopsy.