Clinical Features and Differential Diagnoses in Laryngeal Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma is the most common malignant tumor of salivary glands. However, it is a rare entity in larynx. Laryngeal cases are frequently misdiagnosed with other malignancies and they are under-reported. So, recognizing the clinical and histological features of this tumor is essential. Laryngeal mucoepidermoid carcinoma can arise in supraglottis, glottis and subglottis. Generally, it presents as a submucosal mass; therefore, progressive symptoms without any identifiable lesion in laryngoscopy must be well considered. The prognosis is somehow dependent on the histological features. In high-grade tumors, recurrence is more common and radical surgery with radiotherapy is recommended. In this paper, we provide a thorough literature review on mucoepidermoid carcinoma in the larynx. The most important distinguishing features of mucoepidermoid carcinoma and its two major differential diagnoses (squamous cell carcinoma and adenosquamous carcinoma) are clearly stated and pitfalls in true diagnosis of this tumor are discussed

Benign neural tumors of the oral cavity: A comparative immunohistochemical study

To determine if immunohistochemistry can be used as adjunct to the diagnosis and classification of oral benign neural tumors, we stained 77 neurally differentiated tumors with a panel of neural-associated antibodies (S-100 protein, CD57, epithelial membrane antigen, factor XIIIa, CD34, CD68, collagen IV). Using standard histologic criteria, we identified 13 schwannomas, 16 neurofibromas, 23 traumatic neuromas, 16 palisaded and encapsulated neuromas, and 9 granular cell tumors from archived oral pathology specimens. Silver stains showed that neurofibromas, traumatic neuromas, and palisaded and encapsulated neuromas consistently contained axon filaments. Although all neural tumors contained S-100-positive cells, schwannomas and palisaded and encapsulated neuromas contained the most. All tumors expressed CD57; traumatic neuromas were stained intensely and the others stained weakly. The consistent epithelial membrane antigen capsular staining of schwannomas and the absence of factor XIIIa-positive dendritic/spindle cells helped distinguish these tumors from others. Many CD34-positive cells were found in schwannomas, and few were found in palisaded and encapsulated neuromas. Variable numbers CD68-positive cells were seen in all neural tumor types; some of these cells appeared to be macrophages and mast cells, but many were thought to be Schwann cells expressing this antigen. Collagen IV staining, apparently representing basement membrane, was generally a feature of all benign neural tumors. The immunophenotype of the granular cells of the GCTs was S-100+, CD57+, and collagen IV+ supporting the putative neural origin of these tumors. We conclude that neural origin/differentiation of a connective tissue tumor can be confirmed with stains for S-100 protein, epithelial membrane antigen, CD57, and collagen IV. Staining patterns and intensities associated with the panel of antibodies tested can be useful in tumor classification

Apoptosis in oral erythema multiforme

Objective. Cell death was evaluated in oral erythema multiforme to test the hypothesis that apoptosis may be a mechanism by which keratinocytes die in this condition. Study design. Ten erythema multiforme and five control oral mucosa biopsy specimens were evaluated in immunohistochemically stained sections for apoptosis-regulating proteins Bcl-2, Bcl-x, Bax, p53, Fas, and Fas-ligand. Apoptotic keratinocytes, determined by a detection method for DNA fragmentation (TUNEL) and by conventional morphologic criteria were counted per high power field. Results. Keratinocyte staining for Bcl-2 protein was comparable in erythema multiforme and controls. Bcl-x expression was reduced in five erythema multiforme cases. Staining for Bax protein differed in six erythema multiforme cases and showed variable intensity in layers under the parakeratin. Only slight differences in staining patterns of Fas and Fas-ligand proteins were noted between erythema multiforme and controls. The number of apoptotic keratinocytes evaluated by morphologic examination was significantly higher in erythema multiforme (mean per high power field, 0.90 ± 0.2; controls, 0.06 ± 0.04; p < 0.05, Mann-Whitney test) and was limited in significance by the TUNEL method (erythema multiforme, 0.43 ± 0.1; controls, 0.02 ± 0.02). Overexpression of p53 protein was seen in basal keratinocytes in five erythema multiforme specimens (mean, 17.5 ± 4.03 per high power field; controls 1.2 ± 0.3). Conclusions. There is evidence that cell death in erythema multiforme is at least in part due to apoptosis. The apoptotic mechanism may be related to an altered expression of apoptosis-regulating proteins. Although measurable alterations in the phenotypic expression of Fas and Fas-ligand proteins were not apparent, activation of Fas/Fas-ligand system could still be involved in the induction of apoptosis in erythema multiforme

p53, p21, Rb, and MDM2 proteins in tongue carcinoma from patients <35 versus >75 years

Relatively rare squamous cell carcinomas of the tongue in young patients may be associated with different etiologic factors and pathogenetic mechanisms than carcinomas from the same site in older patients. Alterations in cell cycle proteins likely contribute to the biologic behavior of these neoplasms. The purpose of this investigation was to evaluate cell cycle proteins (p53, p21, Rb, MDM2) in lateral tongue cancers from patients at the two ends of the age spectrum. All available archived lateral tongue carcinomas from patients <35 years (n = 36, 23 males and 13 females) were sectioned, immunohistochemically stained, and evaluated. Protein expression was scored as percent positive nuclei. An equal number of sequentially accessioned lateral tongue specimens from patients >75 years (23 males and 13 females) were stained and compared. Positive p53 staining was seen in 18/36 of the <35-year group versus 24/36 of the >75-year group (p = 0.149). Increased p21 staining (both percent of positive cells and intensity) was evident in 25/32 of the <35-year group versus 24/32 of the >75-year group (p = 1.0). Increased p21 expression was seen in both p53-positive and -negative cases in both age groups. Rb protein was increased in 16/29 of the <35-year group versus 17/26 of the >75-year group (p = 0.58). Fourteen cases (4/35 vs 10/36, p = 0.135) showed positive MDM2 staining; MDM2-positive cases were also p53 positive in 4/4 younger and 8/10 older patients. We conclude that p53, p21, Rb, and MDM2 are over-expressed in lateral tongue cancers, and that immunohistochemical profiles are heterogeneous. A p53-independent pathway of p21 induction is supported by the results; p53 suppression may be associated with MDM2 protein expression in a subset of cancers. Significant differences in the expression of p53, p21, Rb, and MDM2 proteins are not evident in lateral tongue carcinomas from patients <35 years as compared to patients >75 years