Rebeca De Souza Azevedo

Oral myofibromas: report of two cases and review of clinical and histopathologic differential diagnosis

Myofibroma is a benign mesenchymal neoplasm composed of myofibroblasts which has been described with different synonyms since the first report in 1951. It may show clinical and histologic features that may be misinterpreted as a malignancy. We describe 2 cases of oral myofibromas affecting infants; the first one showed a rapid growth with teeth displacement and ulceration; the second one presented a relatively slow growth with an indolent course. Differential diagnosis included benign and malignant mesenchymal neoplasms, salivary gland tumors, and reactive processes. Microscopic analysis of both lesions revealed a spindle cell tumor with immunoreactivity for vimentin, muscle-specific actin, and specific smooth muscle isoform alpha-actin, rendering the diagnoses of myofibroma. The patients were treated with surgical excision, and both are in follow-up without any signs of recurrence. Myofibroma presents a wide range of differential diagnosis, including benign and malignant neoplasms. Therefore, accurate diagnosis may avoid an unnecessary aggressive therapy.

Comparative Cytokeratin Expression in the Different Cell Types of Salivary Gland Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma is the most common malignant salivary gland tumor, composed of several different cell types, with controversial histogenesis. The aim of this study was to assess the expression of cytokeratins in mucoepidermoid carcinoma, comparing to cytokeratin expression in normal salivary glands, in order to establish a possible correlation between tumor cells immunostaining and mucoepidermoid carcinoma histogenesis and differentiation. Eighty cases of salivary gland mucoepidermoid carcinoma were immunohistochemically examined with the use of antibodies against cytokeratins 6, 7, 8, 13, 14, 18, and 19. Cytokeratin expression varied according to the cellular type: squamous cells presented high expression of cytokeratins 6, 7, 8, 14, 18, and 19; intermediate and mucous cells of cytokeratin 7; clear and columnar cells of cytokeratins 6, 7, 8 and the latter also expressed cytokeratin 18. Cytokeratin 13 expression was low in all cell types. Cytokeratin immunoexpression in mucoepidermoid carcinoma was variable according to the cellular type; but regardless of the cellular type studied, cytokeratins 7 and 13 were, respectively, constantly high and low expressed. The immunoprofile of the normal salivary glands was variable according to the component but, in general, cytokeratin profile in mucoepidermoid carcinoma showed similarity to the immunoexpression on the excretory duct unit of normal salivary glands.

Clinical, histological and immunohistochemical features of ectomesenchymal chondromyxoid tumor

OBJECTIVE Ectomesenchymal chondromyxoid tumor is a rare oral soft tissue neoplasm that should be differentiated from other neural and chondromyxoid entities. The aim of this study was to report the clinical, histological, and immunohistochemical features of 3 additional cases of this condition. METHODS Clinical data were obtained from the clinical records and all cases were evaluated through light microscopy and immunohistochemistry to cytokeratins, vimentin, S100 protein, desmin, smooth muscle actin, and glial fibrilary acidic protein. RESULTS All 3 cases affected the tongue as a long-lasting submucosal swelling and were managed through conservative surgery. They all showed myxoid and chondroid histological patterns, and vimentin, S100, and glial fibrilary acidic protein immunoexpression. CONCLUSIONS These findings reinforce the typical features of ectomesenchymal chondromyxoid tumor previously described, helping to confirm and establish the clinical, histopathological, and immunohistochemical profile of this uncommon lesion.

Metastatic renal cell carcinoma to the oral cavity and clear cell mucoepidermoid carcinoma: comparative clinicopathologic and immunohistochemical study.

BACKGROUND Metastatic clear cell renal cell carcinoma (CCRCC) should be considered in differential diagnosis of intraoral clear cell tumors, including mucoepidermoid carcinoma (MEC). OBJECTIVE AND STUDY DESIGN We compared the clinical, histologic, histochemical, and immunohistochemical characteristics of 9 oral metastatic CCRCCs and 8 intraoral clear cell MECs. RESULTS Oral metastatic CCRCC affected salivary-gland containing tissues in 7 cases (78%). Microscopically, oral metastasis revealed a proliferation of neoplastic clear cells arranged in an alveolar pattern with central blood vessels, features that were not seen in any intraoral clear cell MEC. Mucicarmine staining was positive only in clear cell MEC. Immunohistochemistry showed similarities in cytokeratin expression; vimentin and CD10 were expressed in all oral metastatic CCRCCs but in only 1 clear cell MEC each. CONCLUSIONS Besides clinical history, the alveolar pattern, vessel distribution, absence of mucicarmine staining, and vimentin and CD10 immunoexpression are useful in histologic differential diagnosis of CCRCC and clear cell MEC.

Lichen sclerosus of the oral mucosa: clinicopathological features of six cases

Lichen sclerosus is a chronic inflammatory mucocutaneous disease, rarely involving the mouth. There are only 20 well-documented cases of oral lichen sclerosus reported in the English-language literature. This report describes the clinicopathological features of 6 cases of oral lichen sclerosus; 5 in women. There were 12 lesions, mainly on the lips (50%) and buccal mucosa (25%). The affected areas appeared as irregular whitish patches, harder than the surrounding tissue. Half of the patients were symptomatic and presented with no associated skin and/or genital lesions. All cases were biopsied, and histopathological features were evaluated using hematoxylin-eosin and Verhoeffs stains, S-100 immunohistochemical reaction and transmission electron microscopy. Management of the oral lesions consisted of surgical excision, intralesional triamcinolone acetonide, oral colchicine, and regular follow-up. There is no effective curative treatment, but there are some options for patient management; and colchicine may be considered an additional choice.

Clinicopathological and immunohistochemical features of oral spindle cell carcinoma

BACKGROUND Oral spindle cell carcinoma (SpCC) is a rare variant of oral squamous cell carcinoma (SCC). The aims of this study were to compare the clinicopathologic and immunohistochemical features of oral SpCC with conventional oral SCC. METHODS Five cases of oral SpCC and 10 cases of oral SCC (five well-differentiated and five poorly differentiated) were evaluated through conventional hematoxylin and eosin staining and immunohistochemical reactions to cytokeratins (CK), vimentin, desmin, smooth muscle actin, muscle-specific actin, S-100 protein, epithelial membrane antigen (EMA), p53, and ki-67. RESULTS Oral SpCC showed predilection for males on their sixth decade of life, presenting clinically as painful infiltrative ulcers or ulcerated exophytic polypoid masses, preferably located on the alveolar mucosa. Mesenchymal markers were expressed in the spindle cell but not in the carcinomatous component of SpCC, and it was negative in all SCC. CKs AE1/AE3, 6, 14, and EMA were positive on both carcinomatous and spindle cell components of most SpCCs. These tumors also presented higher p53 and ki-67 expression and no CK 1 expression in contrast to well-differentiated SCC. CONCLUSION Oral SpCC presented a different clinical profile than conventional SCC and histopathologic features and p53 and ki-67 expression closer to poorly differentiated SCC. Besides mesenchymal markers, CK AE1/AE3, 6, 14, and EMA expression on spindle cells may be useful as an adjunct on microscopical differential diagnosis of SpCC.

Comparative clinicopathological study of intraoral sebaceous hyperplasia and sebaceous adenoma

OBJECTIVE The objective of this study was to compare the clinicopathological features of oral sebaceous hyperplasia and sebaceous adenoma. STUDY DESIGN Clinical data, microscopical characteristics, and ki-67 immunoexpression were comparatively analyzed on 2 intraoral sebaceous adenomas, 6 intraoral sebaceous hyperplasias, and 21 normal intraoral sebaceous glands. RESULTS Clinically, sebaceous glands presented as multiple separated papules, sebaceous hyperplasias as a single enlarged papule, and sebaceous adenoma as a well-defined nodule. Microscopically, sebaceous adenoma presented an increased number of lobules, smaller lobules, and a greater number of germinative/squamous cells. Sebaceous hyperplasia also had an increased number of lobules and fewer number of germinative/squamous cells, as compared to normal oral sebaceous glands. Ki-67 expression was seen only in germinative cells and counts were higher in sebaceous adenomas followed by hyperplasias and normal glands. CONCLUSIONS Sebaceous hyperplasias and adenomas showed different clinical, microscopic, and proliferative characteristics, suggesting the usefulness of the studied criteria on diagnosis of these uncommon oral lesions.

Extraneural Soft Tissue Perineurioma of the Oral Mucosa

A58-year-oldCaucasianfemalepresentedwithapainless,fibroelastic,well-definedmobilesubmucosalnoduleinthelowerbuccalfoldadjacenttotheleftfirstmolar,measuring0.5 cm in diameter. The duration of the lesion was un-knownandthepatientwasotherwisehealthy.Panoramicradiographyshowednobonealterations,buttheassociatedleftfirstmolarwasendodonticallytreated.Withthemainclinicalhypothesisofareactivelymphadenopathy,anexci-sional biopsy was performed under local anesthesia. Thelesionwasayellowishwell-definednodulethatwaseasilydetachedfromtheadjacenttissue(Fig1).Microscopically,itwascomposedofamoderatelycircumscribedbutnonen-capsulated spindle cell proliferation (Fig 2A). The tumorwashypercellularandcomposedofangulatedspindlecellsdisposed in a storiform pattern with some perivascularwhorls (Fig 2B). The cells were thin with scarce eosino-philic cytoplasm, indistinct cell borders, and elongatedwavy-shaped nuclei. Tissue cracking artifact could be ob-servedandtherewerenopleomorphism,mitosis,andne-crosis(Fig2C).Aprovisionaldiagnosisofabenignspindlecellneoplasmofneuraloriginwasestablished,andimmu-nohistochemicalreactionswerecarriedoutusingtheavi-

Immunoexpression of Wnt/β-catenin signaling pathway proteins in ameloblastoma and calcifying cystic odontogenic tumor

Background Wnt/β-catenin signaling pathway is essential for the beginning of odontogenesis and may be involved in the development and progression of some odontogenic tumors. Thus, the aim of this study was to comparatively evaluate the immunohistochemical expression of Wnt/β-catenin signaling pathway proteins in a series of AME and CCOT. Material and Methods Immunohistochemical reactions were performed using antibodies against Wnt1, Wnt5a and β-catenin in 17 cases of solid AME and 6 cases of CCOT. Results In the AME group, Wnt1 and Wnt5a were identified in the epithelium in most of the cases, and β-catenin was mainly identified in the cytoplasm of the tumoral cells. In the CCOT group, Wnt1 and Wnt5a were identified in the epithelium and in the ghost cells in almost all the cases, and β-catenin was mainly identified in the cytoplasm and in the nuclei of the tumoral cells. Conclusions These results contribute to support the importance of Wnt/β-catenin signaling pathway proteins in AME and CCOT tumorigenesis. The abnormal expression of cytoplasmic and/or nuclear β-catenin appears to contribute to the development of both AME and CCOT. In addition, it is possible that Wnt1 and Wnt5a expression in ghost cells can contribute to its histogenesis in CCOT. Key words:Ameloblastoma, β-catenin, calcifying cystic odontogenic tumor, immunohistochemistry, Wnt.