Acinic cell carcinoma of the oral and maxillofacial region: an international multicenter study

Abstract The aim of this study was to describe the prevalence, clinicopathological, and prognostic features of acinic cell carcinoma (AciCC) of the oral and maxillofacial region. AciCC cases were retrospectively retrieved from 11 pathology centers of three different countries. Medical records were examined to extract demographic, clinical, pathologic, and follow-up information. A total of 75 cases were included. Females (65.33%) with a mean age of 45.51 years were mostly affected. The lesions usually presented as an asymptomatic (64.28%) nodule (95.66%) in the parotid gland (70.68%). The association of two histopathological patterns was the most common finding (48.93%) and the tumors presented mainly conventional histopathological grades (86.11%). Surgical treatment was performed in the majority of the cases (59.19%). Local recurrence was observed in 20% of the informed cases, regional metastasis in 30.43%, and distant metastasis in 12.50%. The statistical analysis showed that the cases with a solid histopathological pattern (p=0.01), high-grade transformation (p=0.008), recurrence (p=0.007), and regional metastasis (p=0.03) were associated with poor survival. In conclusion, high histopathological transformation, presence of nodal metastasis, and recurrence were prognostic factors for AciCC of the oral and maxillofacial region.

Comparative histological and immunohistochemical study of ameloblastomas and ameloblastic carcinomas

BACKGROUND: This study aimed to compare the histological and immunohistochemical characteristics of ameloblastomas (AM) and ameloblastic carcinomas (AC). MATERIAL AND METHODS: Fifteen cases of AM and 9 AC were submitted to hematoxilin and eosin (H&E) and immunohistochemical analysis with the following antibodies: cytokeratins 5,7,8,14 and 19, Ki-67, p53, p63 and the cellular adhesion molecules CD138 (Syndecan-1), E-cadherin and β-catenin. The mean score of the expression of Ki-67 and p53 labelling index (LIs) were compared between the groups using the t test. A value of p < 0.05 was considered to be statistically significant. RESULTS: All cases were positive for CKs 5, 14 and 19, but negative for CKs 7 and 8. CKs 5 and 19 were positive mainly in the central regions of the ameloblastic islands, while the expression in AC was variable in intensity and localization. CK14 was also variably expressed in both AM and AC. Ki-67 (P=.001) and p53 (P=.004) immunoexpression was higher in AC. All cases were positive for p63, but values were higher in AC. CD138 was mainly expressed in peripheral cells of AM, with a weak positivity in the central areas, while it was positive in most areas of ACs, except in less differentiated regions, where expression was decreased or lost. E-cadherin and β-catenin were weakly positive in both AM and AC. CONCLUSIONS: These results shows that Ki-67, p53 and p63 expression was higher in AC as compared to AM, suggesting that these markers can be useful when considering diagnosis of malignancy, and perhaps could play a role in malignant transformation of AM. Pattern of expression of CKs 5 and 19 in AC were different to those found in AM, suggesting genetic alterations of these proteins in malignant cells. It was confirmed that CK19 is a good marker for benign odontogenic tumors, such as AM, but it is variably expressed in malignant cases

Pleomorphic adenoma with extensive squamous metaplasia and keratin cyst formations in minor salivary gland: a case report

Pleomorphic adenoma (PA), the most common salivary gland tumor, accounts for 54 to 65 percent of all salivary gland neoplasias and 80 percent of the benign salivary gland tumors. It most frequently affects the parotid gland, followed by the submandibular and the minor salivary glands. Microscopically, mucous, sebaceous, oncocytic and squamous metaplasia, sometimes with the formation of keratin pearls, may be present, but the latter rarely results in the formation of extensive keratin-flled cysts lined by squamous epithelium. Extensive squamous metaplasia can be mistaken for malignancy, including mucoepidermoid carcinoma and squamous cell carcinoma. Here, we present an unusual case of PA with extensive squamous metaplasia and keratin cyst formations in a minor salivary gland, and discuss its microscopic features, including the immunohistochemical characteristics, and differential diagnosis of this uncommon presentation.

Peripheral developing odontoma in newborn. Report of two cases andliterature review

Extra-osseous odontogenic tumors are rarely observed. However, it is widely accepted that the remains of odontogenicepithelium entrapped in the oral soft tissues may be a possible source for peripheral odontogenic tumorsdifferentiation. Peripheral developing odontoma is considered exceptionally rare, since few similar cases are describedin the English-related literature under diverse nomenclature, such as irregular eruption, ectopic tooth, ectopicsoft-tissue mesiodens, ectopic odontoma and extra-osseous tooth germ. Previously reported cases invariablyaffected children and surgical exploration revealed tooth germs exclusively embedded in the soft tissue withoutbone involvement. Microscopically, all these cases exhibited developing tooth germs composed of ameloblasts,enamel matrix, odontoblastic layer, dentin and dental papilla and the morphological findings seem to depend onthe developmental stage of each tooth germ at discovery. Thus, we believe that it is relevant to report two additionalcases that were recently diagnosed in Brazil and Guatemala, focusing on their nomenclature, correctdiagnosis and further treatment (AU)

Oral melanoacanthoma and oral melanotic macule: a report of 8 cases, review of the literature, and immunohistochemical analysis

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Oral melanoacanthoma (MA) is a rare, benign pigmented lesion, similar to cutaneous MA, characterized by hyperplasia of spinous keratinocytes and dendritic melanocytes. The pathogenesis of oral MA remains uncertain, although its clinical behavior is suggestive of a reactive origin. The most common intraoral sites are the buccal mucosa, lip, palate and gingiva. The average age of presentation is 28 years, mainly in blacks, with a strong female predilection. The oral melanotic macule (MM) is a small, well-circumscribed brown-to-black macule that occurs on the lips and mucous membranes. The etiology is not clear and it may represent a physiologic or reactive process. The average age of presentation is 43 years, with a female predilection. A biopsy is recommended to distinguish these lesions from each other and from other oral melanocytic lesions. We depict four cases each of oral MA and MM, affecting Caucasian and Latin American mestizo patients. The clinicopathological features of these cases reflect its ample spectrum, and to the best of our knowledge, it is the first example of oral MA affecting a Caucasian boy reported in the English literature. Therefore oral MA and MM should be considered in the differential diagnosis of pigmented lesions in the oral mucosa in these populations