Beatriz Vera-Sirera

Intraosseus plexiform schwannoma of the mandible: immunohistochemical differential diagnosis.

Schwannomas and neurofibromas are the most common benign tumors derived from peripheral nerves, and whereas the head and neck region is the most common location for the occurrence of benign neural sheath neoplasms, origin within the oral cavity is uncommon, and occurrence centrally in the jaws is most unusual. Plexiform (multinodular) schwannoma is an anatomically unique variant of schwannoma characterized grossly and/or microscopically by intraneural plexiform and often multinodular growth. In current report, we present the first reported case of intraosseous plexiform schwannoma of the mandible, an extremely rare benign neurogenic tumor, diagnosed by optical and immunohistochemical procedures, showing the importance of differential diagnosis of these unusual intraosseous mandibular tumors.

Differential expression of Cyclin D1 in keratin-producing odontogenic cysts

Objetives: The aim of the present study was to analyze the expression levels of Cyclin D1 (CCD1), a nuclear protein that plays a crucial role in cell cycle progression, in a series of keratin-producing odontogenic cysts. Study Design: A total of 58 keratin-producing odontogenic cysts, diagnosed over ten years and classified according to the WHO 2005 criteria, were immunohistochemically analyzed in terms of CCD1 expression, which was quantified in the basal, suprabasal and intermediate/superficial epithelial compartments. The extent of immunostaining was measured as a proportion of total epithelial thickness. Quantified immunohistochemical data were correlated with clinicopathological features and clinical recurrence. Results: Keratin-producing odontogenic cysts were classified as 6 syndromic keratocystic odontogenic tumors (S-KCOT), 40 sporadic or non-syndromic KCOT (NS-KCOT) and 12 orthokeratinized odontogenic cysts (OOC). Immunohistochemically, CCD1 staining was evident predominantly in the parabasal region of all cystic lesions, but among-lesion differences were apparent, showing a clear expansion of parabasal compartment especially in the S-KCOT, followed to a lesser extent in the NS-KCOT, and being much more reduced in the OOC, which had the greatest average epithelial thickness. Conclusions: The differential expression of CCD1 noted in the present study suggests that dysregulation of cell cycle progression from G1 to the S phase contributes to the different aggressiveness of these lesions. However, CCD1 expression levels did not predict NS-KCOT recurrence, which is likely influenced by factors unrelated to lesion biology. Key words:Keratin-producing odontogenic cyst, keratocyst, keratocystic odontogenic tumor, nevoid basal cell carcinoma syndrome, orthokeratinized odontogenic cyst, cyclin D1, immunohistochemistry.

Estudio clínicopatológico e inmunohistoquímico de la pigmentación oral por amalgama

Amalgam tattoo, the most common exogenous oral pigmentation, can sometimes be confused with melanotic lesions, being then biopsied. We present the clinicopathological characteristics of 6 biopsied cases (5 females and 1 male) of oral amalgam pigmentation. The most common location was the gingival mucosa, followed by the buccal and palatal mucosa. Morphology and distribution (stromal, perivascular, perineural, endomysial) of pigmentation was variable; there was only 1 case with fibrous capsular reaction and likewise only a single case of granulomatous foreign body reaction. Morphological variability is conditioned by the timing and amount of the pigment deposit, which is often associated with infiltration by mast cells (CD117+), as well as overexpression of metallothionein and HLA-DR at different tissue levels.

Multiple granular cell tumors with metachronous occurrence in tongue and vulva. Clinicopathological and immunohistochemical study

Granular cell tumor (GCT) usually occurs as a single tumor, although sometimes multiple lesions can occur. In present report we analyze the clinicopathological and immunohistochemical features of a multiple GCT involving the tongue of a 14-year-old girl, with no other abnormalities, with a metachronous occurrence of a second GCT in vulva, after a period of 10 years. Both tumors revealed S-100, vimentin and CD57 positivity. In addition, over expression of calretinin was observed in tumor cells located in the vicinity of pseudoepitheliomatous hyperplasia (PEH) of the tongue. Tumor vasculature situated close to the PEH showed marked CD105 reactivity, data not described so far, suggesting an interaction between PEH cells and underlying stroma, since GCT completely lacks CD105 vessels. Our study emphasizes that patients with GCT, especially young patients, should be followed long-term, looking for multiple tumors or other abnormalities suggestive of a systemic syndrome, given the associations described in multiple GCT.

Palatal ancient schwannoma: optical, immunohistochemical and ultrastructural study with literature review

Schwannoma or neurilemmoma is a benign encapsulated slow-growing tumor that originates from a Schwann cell of a nerve, and is rare at intraoral locations. Different histological variants of schwannomas have been described, of these degenerative or ancient schwannoma is probably one of the least common in the oral cavity with only 16 previously reported cases, of which only one has been described in palatal location. Although ancient schwannoma shows particular characteristics, it is difficult to diagnose based on clinical and imaging appearance alone; as a result, morphological examination assisted by ancillary techniques is necessary to establish a definite diagnosis. We present a clinicopathological description of this rare variant of schwannoma, located in an unusual intraoral site, of a 26-year-old female. We illustrate the optical, immunohistochemical and ultrastructural characterization that aid diagnosis, as well as providing a review of the relevant published data of this unusual tumor.

NCAM (CD56) Expression in keratin-producing odontogenic cysts: aberrant expression in KCOT

ObjectiveTo investigate immunohistochemically the expression of neural cell adhesion molecule (NCAM), which has been identified as a signaling receptor with frequent reactivity in ameloblastomas (AB), in a series of keratin-producing odontogenic cysts (KPOCs).Material and methodsImmunohistochemical expression of NCAM, using a monoclonal antibody, was determined in a series of 58 KPOCs comprising 12 orthokeratinized odontogenic cysts (OOCs) and 46 keratocystic odontogenic tumors (KCOTs), corresponding to 40 non-syndromic KCOT (NS-KCOTs) and 6 syndromic KCOT (S-KCOTs), associated with nevic basocellular syndrome (NBCS).ResultsNCAM expression was negative in all OOCs, but 36.45% of KCOTs exhibited focal and heterogeneous expression at the basal cell level, as well as in basal budding areas and the basal cells of daughter cysts. The latter two locations were especially applicable to S-KCOTs, with focal NCAM reactivity occurring in 66.66% of cases.ConclusionsAberrant NCAM expression, in KCOTs but especially in S-KCOTs, together with its immunomorphological location, suggests that this adhesion molecule and signaling receptor plays a role in the pathogenesis of KCOTs, with a probable impact on lesional recurrence.

Adult rhabdomyoma with oncocytic changes affecting the floor of the mouth: optical, immunohistochemical, and ultrastructural study.

Adult rhabdomyoma (AR) is an extremely uncommon benign neoplasm with mature skeletal muscle differentiation comprising approximately 2% of muscle tumors, usually affecting the soft tissue of the head and neck. Although histology of AR is characteristic, several differential diagnoses (granular cell tumor, hibernoma, oncocytoma) should be considered, and one needs to be familiar with this rare entity to exclude other neoplastic diseases. We present a case of AR, in a 54-year-old man, affecting the floor of the mouth, and call attention to the oncocytic appearance (including antimitochondrial and peroxiredoxin I immunoreactivity) of this case and its differential diagnosis analyzed at the optical, immunohistochemical, and ultrastructural level, showing the morphological and immunohistochemical features that can be confused with a salivary oncocytoma.

Expresión de SDHB en el tumor de Warthin

INTRODUCTION Succinic dehydrogenase subunit B (SDHB) is an enzyme belonging to the mitochondrial complex II. The aim of this study is to analyse SDHB expression in a series of Warthins tumours, studying its relationship with oncocytic changes, constantly present in this form of tumour. MATERIAL AND METHODS In resection tumour specimens from a series of ten Warthins tumours (all from the parotid gland), immunohistochemical expression of SDHB was analysed using a commercially-available monoclonal antibody. RESULTS The Warthins tumours studied affected 10 men (mean age: 64.2 yrs, range 40-80), all with smoking habits, and 2 with metachronous bilateral involvement. Two patients presented associated urothelial carcinoma. Our SDHB study showed marked reactivity (++/+++) in all cases in the oncocytic epithelial component and also in striated duct cytoplasm (+) from non-tumorous parotid tissue. Expression was not influenced by age, smoking intensity or bilateral character. One of the tumours showed squamous metaplasia foci with SDHB-negativity at this level. DISCUSSION AND CONCLUSIONS Due to the constant and intense SDHB reactivity in oncocytic cells in our observations, oncocytic changes are not considered to be associated with defective enzyme activity in the mitochondrial complex II. Strong SDHB reactivity is an additional marker of oncocytic changes in Warthins tumour. Neither of these facts has been described previously.

Ultrastructural findings from paraffin embedded tissue in intraoral lesions caused by Leishmania infantum

Fetuin-A regulation of calcified matrix metabolism. Circ Res 2011;108:1494–1509. 4. Viegas CS, Rafael MS, Enriquez JL, et al. Gla-rich protein acts as a calcification inhibitor in the human cardiovascular system.Arterioscler ThrombVasc Biol 2015;35:399–408. 5. Bobrie A, Colombo M, Krumeich S, Raposo G, Thery C. Diverse subpopulations of vesicles secreted by differentintracellular mechanisms are present in exosome preparations obtainedby differential ultracentrifugation. J Extracell Vesicles 2012;1:18397–18408. 6. Théry C, Clayton A, Amigorena S, Raposo G. Curr Protoc Isolation and Characterization of Exosomes from Cell Culture Supernatants and Biological Fluids Curr Protoc Cell Biol 2006, John Wiley & Sons, Inc, chap 3(Sup30) 3.22.1–29.

Immunohistochemical expression of glucose transporter 1 in keratin-producing odontogenic cysts

BackgroundKeratin-producing odontogenic cysts (KPOCs) are a group of cystic lesions that are often aggressive, with high rates of recurrence and multifocality. KPOCs included orthokeratinised odontogenic cyst (OOC) and parakeratotic odontogenic cysts, which are now considered true tumours denominated keratocystic odontogenic tumours (KCOTs). GLUT1 is a protein transporter that is involved in the active uptake of glucose across cell membranes and that is overexpressed in tumours in close correlation with the proliferation rate and positron emission tomography (PET) imaging results.MethodsA series of 58 keratin-producing odontogenic cysts was evaluated histologically and immunohistochemically in terms of GLUT1 expression. Different data were correlated using the beta regression model in relation to histological type and immunohistochemical expression of GLUT1, which was quantified using two different morphological methods.ResultsKPOC cases comprised 12 OOCs and 46 KCOTs, the latter corresponding to 6 syndromic and 40 sporadic KCOTs. GLUT1 expression was very low in OOC cases compared with KCOT cases, with statistical significant differences when quantification was considered. Different GLUT1 localisation patterns were revealed by immunostaining, with the parabasal cells showing higher reactivity in KCOTs. However, among KCOTs cases, GLUT1 expression was unable to establish differences between syndromic and sporadic cases.ConclusionsGLUT1 expression differentiated between OOC and KCOT cases, with significantly higher expression in KCOTs, but did not differentiate between syndromic and sporadic KCOT cases. However, given the structural characteristics of KCOTs, we hypothesised that PET imaging methodology is probably not a useful diagnostic tool for KCOTs. Further studies of GLUT1 expression and PET examination in KCOT series are needed to confirm this last hypothesis.