Immunostaining For S-100 Protein Research Articles

Differential diagnosis in Rosai-Dorfman disease: A rare case of isolated hepatic presentation mimicking a metastatic tumor with positive 18-FDG uptake.

Rosai-Dorfman disease (RDD) is also called sinus histiocytosis with massive lymphadenopathy, and it is caused by a histiocytic disorder with unclear etiology. It usually involves cervical lymph nodes, but it may also present with extranodal involvement. We report a rare condition of isolated hepatic RDD without nodal involvement, clinically manifested with three-month abdominal pain and tenderness of the right hypochondrium. CT- and PET-CT scans were compatible with a secondary lesion from an unknown primary tumor. Therefore, the patient underwent an atypical liver resection. Immunohistochemistry and histological results were compatible with a diagnosis of RDD. RDD is characterized by phenomena of emperipolesis, histiocytic proliferation and positive immunostaining for CD14, CD68 and S-100 protein. Cases of isolated gastrointestinal localization of RDD are particularly rare, especially in the liver. Instrumental exams might confuse RDD with other malignancies. RDD is a rare entity, which might be misdiagnosed using PET-CT due to its similarities with malignant tumors. An accurate multidisciplinary approach may help to clear diagnostic clues of this uncommon disease.

Gastric Schwannoma: The Masquerader amongst Gastric Mesenchymal Tumours

Introduction: Gastric Schwannoma (GS) is a rare gastrointestinal mesenchymal tumour and needs to be distinguished from other common mesenchymal tumours like Gastrointestinal Stromal Tumour (GIST). GS is composed of Antoni A areas with peritumoural lymphoid cuff unlike conventional schwannomas. GS are difficult to differentiate from other mesenchymal submucosal tumours like GIST. The histological features and strong positive immunostaining for S100 protein along with CD117 (Cluster of Differentiation) and Discovered on GIST 1 (DOG1) immunonegativity is required to confirm the diagnosis. Aim: To analyse the histopathological, immunohistochemical, radiological characteristics and follow-up data of GS. Materials and Methods: This was a retrospective descriptive study conducted in a tertiary care hospital in Southern India. There was a total of eight cases of GS retrieved from the Pathology archives from January 2010 to December 2019. The clinical information along with radiology reports were retrieved from the electronic database. The retrieved slides were analysedfor clinicopathological features. The descriptive analysis of the data was done, and the results were presented as mean, frequencies, and percentages. Results: All eight cases of GS presented in the fifth to eighth decade of life with a female preponderance (male to female ratio of 1:3). Six out of eight cases were symptomatic (75%). Radiologically, a differential diagnosis of GIST was considered in all 8 cases (100%). Microscopically, all 8 cases (100%) exhibited fascicles of spindle cells with mild nuclear pleomorphism, prominent peritumoural lymphoid cuff, and few secondary changes. S100 immunohistochemistry was done in six cases of GS and all showed diffuse strong positivity. The remaining two cases were positive for SRY-related High Mobility Group (HMG)-box 10 (SOX). Conclusion: Preoperative diagnosis of GS is difficult due to non-specific endoscopic or radiological findings. In gastric submucosal tumours, GS should be considered as one of the differential diagnosis. The histopathological and immunohistochemical features are considered the gold standard to diagnose GS.

Stem Cell Transcription Factor Sox2 Is Expressed in a Subset of Folliculo-stellate Cells of Growth Hormone-Producing Pituitary Neuroendocrine Tumours and Its Expression Shows No Association with Tumour Size or IGF1 Levels: a Clinicopathological Study of 109 Cases.

Sox2 is one of the transcription factors responsible for the maintenance of stem cell phenotype. It has been implicated as a marker of stem cells in normal pituitaries and pituitary neuroendocrine tumours. To explore the clinical significance of Sox2 expression in histological sections, we performed immunohistochemical detection of Sox2 in 113 pituitary neuroendocrine tumours from 109 patients with acromegaly. In 11 tumours, we performed double immunostaining for Sox2, annexin A1 and S100 protein. Tumours were characterised using the WHO classification system. Proliferative activity and invasion were assessed. The amount of immunoreactive cells was evaluated and correlated with tumour size and biochemical features (levels of IGF1, GH, prolactin, βTSH). Sox2+ cells were identified in 35/38 normal pituitaries adjacent to the tumours. In 36 tumours (33%), ≥ 1% of the cells expressed Sox2, in 24 cases (22%), Sox2+ cells comprised < 1% and 49 cases (45%) were negative. We found no significant differences between Sox2+ and Sox2- groups with respect to the age, initial levels of GH, IGF1, prolactin, βTSH, tumour size, invasion, proliferative activity or histological features. We observed a positive correlation between Sox2+ cell count and βTSH immunoreactive cells (r = 0.459, p< 0.001) that was further verified by multivariate analysis. Using double stain, the majority of Sox2+ cells coexpressed annexin A1 (average 89%) and S100 protein (average 76.2%) and showed morphological features of folliculo-stellate cells. Sox2+ cells are thus commonly present in growth hormone-producing tumours and normal pituitaries, and their amount does not have any prognostic significance. Most of these cells represent a subpopulation of folliculo-stellate cells, pointing out to their role as a possible stem cell population.

Diagnosis of Hirschsprung's Disease by Immunostaining Rectal Suction Biopsies for Calretinin, S100 Protein and Protein Gene Product 9.5.

Hirschsprung's disease (HD) is a congenital intestinal disease that is clinically manifested as an inability to pass meconium in infants or as long-term constipation in children. Rectal suction biopsy (RSB) to determine the absence of ganglion cells and neural hypertrophy is the most accurate test for the diagnosis of HD at present. Traditional hematoxylin-eosin staining lacks sensitivity and specificity. Acetylcholinesterase staining cannot be widely used due to its complex process. Our novel protocol of immunostaining for calretinin, S100 protein, and protein gene product 9.5 (PGP9.5), which we conducted on RSBs, exhibits high sensitivity and specificity rates of 96.49% (95% confidence interval, 0.88-0.99) and 100% (95% confidence interval, 0.97-1.00), respectively. The HD-affected segments often present as the absence of the expression of calretinin, S100 protein, and PGP9.5, which are markers of neural hypertrophy in the submucosal tissue. This protocol describes the detailed operating process of this new diagnostic method.

A dedifferentiated solitary fibrous tumor of the parotid gland: a case report with Cytopathologic findings and review of the literature

BackgroundSolitary fibrous tumor (SFT) is a ubiquitous mesenchymal neoplasm but it rarely occurs in the parotid gland. The histological features are variable, with the majority having spindle cell morphology and non-specific branching (staghorn) ecstatic vascular pattern. SFT ranges from benign to overtly malignant. Dedifferentiation within SFTs represents an abrupt transition from a well-differentiated component to a high-grade area, the latter most often including poorly differentiated epithelioid/round cell or high-grade spindle cell morphology. To the best of our knowledge, dedifferentiated SFT in the parotid gland has not been previously reported.Case presentationA 33-year-old woman presented with a soft tissue tumor in the right parotid gland that had been present for 6 months. Fine needle aspiration (FNA) cytology indicated epithelioid morphology in the dedifferentiated component of the tumor, along with metachromatic myxoid matrix. The tumor was initially interpreted as a salivary gland neoplasm of uncertain malignant potential (SUMP).Right partial parotidectomy was performed, and microscopic examination of the resected specimen revealed a malignant spindle cell tumor with a central epithelioid/anaplastic component. The tumor cells were diffusely positive for CD34, STAT-6 and FLI-1, and negative for pan-cytokeratin, CAM5.2, p63, S100 protein, CD31, SMA, and calponin.ERG and Ki67 immunostaining showed an accentuated nuclear staining pattern in the central dedifferentiated area. There was no overexpression of p53 or p16. The patient is currently undergoing regular follow-up and is 11 months postresection with no evidence of recurrence or distant metastasis.ConclusionsUnlike the typical spindle cell morphology of conventional SFTs, malignant SFTs can show areas of dedifferentiation mimicking an epithelial neoplasm. FNA of dedifferentiated SFTs of the parotid gland may show, a combination of atypical epithelioid cells and metachromatic myxoid/collagenous matrix, which is a less emphasized cytological feature of SFT and may lead to misdiagnosis as a more common parotid gland epithelial neoplasm.

Clinicopathologic and molecular characterization of mammary analogue secretory carcinoma of salivary gland origin

BackgroundMammary analogue secretory carcinoma (MASC) is a newly recognized salivary gland tumor that harbors a characteristic balanced chromosomal translocation t (12; 15) (p13; q25) resulting in an ETV6-NTRK3 fusion gene. MethodsRetrospective study of 111 salivary gland carcinomas revealed 37 cases with secretory features and growth patterns resembling secretory carcinoma of breast. These 37 cases were originally diagnosed as acinic cell carcinoma, adenocarcinoma not otherwise specified and cystadenocarcinoma. Positive immunostaining for S-100 protein and mammaglobin, followed by detection of ETV6 gene rearrangement by FISH and/or ETV6-NTRK3 fusion transcript by RT-PCR were used to identify MASCs. ResultsIn the cohort of 37 salivary carcinomas with secretory features we have identified 10 cases of MASC. All 10 MASCs were positive for mammaglobin, S-100 protein and SOX10, while staining for DOG1 and p63 protein were mostly absent. In 7/10 cases, both FISH and RT-PCR were positive while three remaining cases showed break of ETV6 gene by FISH analysis and the RT-PCR was negative. Clinical follow-up data were obtained in 6 out of 10 patients with MASC. In 3 patients cervical lymph node metastases developed, one patient with high grade transformed MASC died with multiple distant bone metastases, and local recurrence was observed in three patients. ConclusionOur clinicopathological data are in keeping with previous studies; in most cases, MASC is a low-grade malignancy with overall favorable prognosis. In rare cases, however, MASC with high-grade transformation may behave aggressively, and these patients could benefit from targeted biological treatment using tyrosine kinase inhibitors.

Histological identification of nasopharyngeal mechanoreceptors.

The auditory tube plays a fundamental role in regulating middle ear pressure. A "system" sensitive to a pressure gradient between the middle ear and the ambient environment is necessary. The presence of mechanoreceptors in the middle ear and the tympanic membrane has been studied, but the presence of these receptors in the nasopharyngeal region remains unclear. The aim of this study is to confirm the presence of pressure sensitive corpuscles in the nasopharynx. An experimental study was conducted on five fresh and unembalded human cadavers. The pharyngeal ostium of the auditory tube and its periphery was removed in one piece by video-assisted endonasal endoscopy. Samples were fixed in formaldehyde solution, embedded in paraffin, and cut. Slides were analyzed by HES (Hematoxyline Eosine Safran) coloration, by S100 protein and neurofilament protein immunostaining. Encapsulated nerve endings were researched and identified by slides analysis. Eight samples were included in our study. On seven samples, Ruffini corpuscles were identified in the mucosa of the posterior area of the pharyngeal ostium, with a higher concentration in the pharyngeal recess and in the posterior nasopharyngeal wall. Our study identified nasopharyngeal mechanoreceptors that could detect the nasopharyngeal pressure and, by extension, the atmospheric pressure. These findings support the theory of the neuronal reflex arc of isobaric system of the middle ear, based on the existence of a "system" sensitive to a pressure gradient between the middle ear and the ambient environment. Understanding of this system has been helpful in the diagnosis and management of middle ear diseases.

EXTENDED CYTOPROTECTIVE EFFECT OF AUTOPHAGY IN THE LATE STAGES OF SEPSIS AND FLUCTUATIONS IN SIGNAL TRANSDUCTION PATHWAYS IN A RAT EXPERIMENTAL MODEL OF KIDNEY INJURY.

The impact of a potential autophagy (LC3a/b) deregulation in hyper and in hypo stages during sepsis-induced kidney injury and the temporal profile of phosphorylated extracellular signal-related kinase, P38 (pP38), Akt (pAKT), and 13-3-3β protein were investigated in the current study, using a rat cecal ligation and puncture (CLP) model, by means of flow cytometry and immunohistochemistry. Cell viability was assessed by protein C zymogen concentrate (PC), 7-aminoactinomycin D (7-AAD) staining and inflammation by S100 protein immunostaining. The impact of reduced kidney inflammation in autophagy was assessed by PC administration, an anti-inflammatory and cytoprotective substance. Sepsis induction increased LC3a/b expression, which presented two peaks at 6 and 36 h after CLP, both in the percentage of positive cells (P = 0.024, P = 0.025, respectively) and in fluorescence intensity. At 6 h when inflammation was already apparent, LC3a/b increase was escorted by phosphorylated extracellular signal-related kinase stimulation and high cell viability (65%), designating autophagy as a cytoprotective mechanism against microbial infection. The phosphorylation of P38 was delayed to 12 h after CLP, when autophagy was reduced. pAkt and 14-3-3β expression was stimulated between 6 and 36 h after CLP, although a slight inhibition of pAkt within each cell was detected (lower MnIX value). During the second peak, inflammation was intensified, necrosis was significantly increased with LC3a/b+/7-AAD + cells to present a 1.5-fold increase. Protein C zymogen concentrate administration declined autophagy at 6 and 36 h after CLP and reduced necrosis, whereas double positive LC3a/b and 7-AAD cells were increased by 1.68 and 2.78-fold, respectively. These data open new prospectives in sepsis treatment, since they further support that autophagy represents a cytoprotective mechanism triggered by stress conditions, rather than an alternative cell death pathway.

Lymphoepithelioma-like Carcinoma of the Skin in the Cheek with a Malignant Metastatic Cervical Lymph Node.

Lymphoepithelioma-like Carcinoma of the Skin in the Cheek with a Malignant Metastatic Cervical Lymph Node.

Morphological studies and immunohistochemical detection of leptin and s-100 protein on the uropygial gland of baladi duck

Immunoperoxidase methods for the demonstration of leptin and S-100 protein were applied in routinefixedparaffin sections on the uropygial gland of baladi duck. Intact uropygial glands from twenty adulthealthy duck were used after slaughter. The glands were removed then the tissue specimens were fixedin 10% buffered neutral formalin. This study showed that the uropygial gland formed from two lobes,which were encapsulated by a connective tissue capsule. Each lobe composed of peripheral tubules andcentral tubules that separated by connective tissue septa. The epithelial cells of the secretory tubuleswere consisted of four layers, the germinative, intermediate, secretory and degenerative cells.Immunohistochemical examination revealed that the leptin immunoreactivity was distributed in both theperipheral and the central tubules. The leptin immunostaining was strong in the basement membrane,the cytoplasm of germinative cells, secretory cells and degenerative cells. In addition, strong reaction toleptin antibody was seen in the lumen or central cavity of central tubules. Additionally, S100immunoreactivity was detected strong in the capsule and with moderate reaction on the cytoplasm ofperipheral and central tubules. This study emphasized that the strong positive reaction to leptinimmunostaining in the secretion of central tubules reflect the nature of secretion of the preen wax. Inaddition, the expression of S100 protein immunostaining may indicate specific functions.

Hypersecretory Thyroid-like Adenosis of the Breast: A Distinct Benign Entity Devoid of Myoepithelial Cells

Most infiltrative epithelial proliferations of the breast lacking a myoepithelial cell layer are malignant. The notable exception is Microglandular Adenosis (MGA). Lack of myoepithelial cells has also been noted occasionally in metaplastic apocrine glands. Here, we present a previously undescribed breast lesion that we have termed “Hypersecretory Thyroid-Like Adenosis” (HTLA). HTLA consists of multiple dilated glands of varying sizes preserving a lobulated architecture. The glands are lined by a single layer of bland cuboidal or columnar cells. Some nuclei have cleared chromatin, some exhibit grooves and others contain pseudo-inclusions reminiscent of papillary carcinoma of thyroid. Dense eosinophilic secretions, positive for PAS-Diastase and resembling thyroidal colloid, are present in many of the lumens. A thick basement membrane is present around each gland. There are no Myoepithelial (ME) cells present on H&E examination, immunohistochemistry or ultrastructural study. The immunohistochemical stain for S-100 protein shows weak focal nuclear and cytoplasmic staining of the minority of the luminal cells (<20% of cells). The lesion is ER negative. HTLA has some features similar to, but is overall distinctly different from MGA. In particular, the preserved lobular architecture, macroacinar structures, distinctive nuclear features, and lack of diffusely strong immunostaining for S-100 protein are features unlike MGA. This lesion was an incidental finding in a partial mastectomy performed for invasive ductal carcinoma but showed no spatial relationship, morphological or immunohistochemical similarities to the breast carcinoma.

English

Twenty-five to 45 percent of all schwannomas occur in the head and neck. Most of them arise along the vestibular portion of the eighth cranial nerve (acoustic neurinoma). They rarely originate from the peripheral facial nerve or other nerves within the parotid gland. Less than 4% of schwannomas involve the nasal cavity and paranasal sinuses. They arise from the branches of the trigeminal nerve and autonomic nervous system. We report two cases of schwannomas arising from intraparotid facial nerve and nasal cavity. The first case diagnosed in a 50-year-old-man presented with 4-year-history of painless mass of the parotid gland. The lesion was found to be cystic through the pre-operative examinations and investigations. The histology of the specimen retained an intraparotid cystic schwannoma. The second case concerned a 65-year-old-female presented with episodes of nasal obstruction, rhinorrhea, anosmia and headache. Histological study of the specimen showed fusiform cells with strongly and diffusely immunostaining for S100 protein suggesting a

Two rare schwannomas of head and neck

Twenty-five to 45 percent of all schwannomas occur in the head and neck. Most of them arise along the vestibular portion of the eighth cranial nerve (acoustic neurinoma). They rarely originate from the peripheral facial nerve or other nerves within the parotid gland. Less than 4% of schwannomas involve the nasal cavity and paranasal sinuses. They arise from the branches of the trigeminal nerve and autonomic nervous system.We report two cases of schwannomas arisng from intraparotid facial nerve and nasal cavity. The first case diagnosed in a 62-year-old-man presented with 2-year-history of painless mass of the parotid gland. The lesion was found to be cystic through the pre operative examinations and investigations. The histology of the specimen retained an intraparotid cystic schwannoma. The second case concerned a 75-year-old-man presented with episodes of nasal obstruction, rhinorrhea, anosmia and headache. Histological study of the specimen showed fusiform cells with strongly and diffusely immunostaining for S100 protein suggesting a schwannoma.Virtual Slideshttp://www.diagnosticpathology.diagnomx.eu/vs/1098335216112242.

Tarsal Tunnel Syndrome Secondary to Schwannoma of the Posterior Tibial Nerve

Schwannoma is a benign tumor that arises from the peripheral nerve sheath. It presents as a discrete, often tender, and palpable nodule associated with neurogenic pain or paresthesia when compressed or traumatized. The growth rate is usually slow, and these lesions seldom exceed 2 cm in diameter. We report the case of a large schwannoma arising from the posterior tibial nerve located in the posterior medial ankle. The core needle biopsy findings were suggestive of a schwannoma, with spindle cells strongly and uniformly immunostaining for S-100 protein. The mass was marginally excised. The surgical specimen consisted of a grossly encapsulated white-yellow mass with irregular contours, measuring 3.7 × 3.5 × 2.7 cm. The cut surface showed areas of pin-point hemorrhage. The patient did not encounter any motor deficits; however, early results showed some subjective numbness. Few reports have been published of schwannomas arising from the tibial nerve. Marginal excision appears to be the recommended therapy for this tumor, without any evidence of recurrence at 9 months of follow-up.

Kba.62 and S100 protein expression in cytologic samples of metastatic malignant melanoma

The diagnosis of melanoma can be challenging, especially in metastatic lesions, due to the ability of melanoma cells to morphologically mimic carcinoma, sarcoma and even lymphoma cells. Moreover, melanomas can exhibit negative immunostaining for the melanoma markers HMB-45 and MART-1/Melan-A, often used in the diagnosis of this tumor. KBA.62 is a recently described antibody that reacts with benign and malignant melanocytic proliferations. In this study, we report our experience with KBA.62 and S100 protein immunostaining in the diagnosis of metastatic melanoma on fine-needle aspiration and effusion samples. We reviewed 60 cytology samples from 58 patients with metastatic melanoma. Our results showed that KBA.62 stained 75% of the cases and S100 protein 87% of the cases. KBA.62 and S100 protein stained the majority of metastatic melanomas that were negative for HMB-45 and MART-1; KBA.62 stained 73% of the cases and S100 protein 73% of the cases. The majority (85%) of the cases negative for HMB-45 and MART-1 were positive for KBA.62 and/or S100 protein. Additionally, we also observed that KBA.62 staining was positive in the majority of epithelioid and spindle cell type melanoma cells. In conclusion, the performances of KBA.62 and S100 protein were similar and both markers are useful in the diagnosis of metastatic melanoma in cytology material, especially when the tumor cells lack expression of HMB-45 and MART-1.

Rosai–Dorfman Disease (Sinus Histiocytosis with Massive Lymphadenopathy) of the Pancreas: Third Reported Occurrence

Sinus histiocytosis with massive lymphadenopathy (SHML) was first described in 1969 by Rosai and Dorfman [1]. It is a rare inflammatory disorder with key clinicopathological characteristics such as emperipolesis and positive immunostaining for S-100 protein [2] and CD68. Rosai–Dorfman disease (RDD) is primarily manifested in the lymph nodes, yet extranodal disease has been reported in as many as half of patients [3]. Such cases affect primarily the head and neck, upper respiratory tract, and central nervous system, although the disease has been found in almost every organ system. The gastrointestinal tract is rarely involved, and only two cases of primary involvement of the pancreas have been previously described [4, 5].

Recurrent Rearrangement of the PHF1 Gene in Ossifying Fibromyxoid Tumors

Ossifying fibromyxoid tumor (OFMT) is a soft tissue tumor of unknown lineage. Although most cases are histologically and clinically benign, some show malignant morphological features and local recurrences are not uncommon; a few may even metastasize. In the present study, cytogenetic analysis identified different structural rearrangements of chromosome band 6p21 in tumor cells from three cases of OFMT, including one with typical, one with atypical, and one with malignant morphological features. Mapping of the 6p21 breakpoint by fluorescence in situ hybridization (FISH) indicated that the PHF1 gene was rearranged in all three cases. Further FISH, 5'-rapid amplification of cDNA ends, and RT-PCR analyses disclosed an EP400/PHF1 fusion transcript in one of the cases. Interphase FISH on tumor sections from 13 additional cases of OFMT showed rearrangement of the PHF1 locus in four of four typical, two of three atypical, and one of six malignant lesions. Thus, the PHF1 gene, previously shown to be the 3'-partner of fusion genes in endometrial stromal tumors, is also recurrently involved in the pathogenesis of OFMTs, irrespective of whether they are diagnosed as typical, atypical, or malignant lesions. The PHF1 protein interacts with the polycomb-repressive complex 2 (PRC2), which, in turn, regulates the expression of a variety of developmental genes. Thus, the results indicate that deregulation of PRC2 target genes is crucial for OFMT development.

Melanoma amelanótico em cães: estudo retrospectivo de 35 casos (2004-2010) e caracterização imuno-histoquímica

Melanomas são tumores agressivos de melanócitos que ocorrem principalmente na cavidade oral, nas junções mucocutâneas e na pele de cães. Este tipo de neoplasma pode apresentar diversos graus de pigmentação melânica, incluindo total ausência (melanomas amelanóticos [MA]). Os arquivos de biópsia do SPV-UFRGS, que compreendem o período de 2004 a 2010, foram revisados e levantados os casos de neoplasias melanocíticas em cães. Realizou-se estudo retrospectivo de 35 casos de MA e caracterização pela imuno-histoquímica (IHQ). As principais raças acometidas foram o Poodle, Dachshund e Cocker Spaniel, mas o maior número de casos foi observado em cães sem raça definida (SRD). A idade média desses cães foi de 10,7 anos (variação de 5 a 18 anos) e não houve predileção por sexo. As principais localizações incluíram cavidade oral (57,1%) e dígitos (17,1%). Histologicamente, 40% dos MA foram classificados como epitelioides, 34,3% como mistos e 25,7% como fusiformes. Na avaliação IHQ, 86,6% dos casos foram positivos para a vimentina, 70% para a proteína S-100 e 56,6% para o melan-A. Os resultados obtidos neste trabalho possibilitam concluir que os cães com MA caracterizavam-se por serem velhos. A forma celular mais observada foi a epitelioide. Devido a pouca diferenciação desses tumores, ressalta-se a importância da realização do painel imuno-histoquímico, sobretudo da proteína S-100, que apresentou melhor marcação que o melan-A.

Intoxicação experimental por Trema micrantha (Cannabaceae) em equinos

O objetivo desse estudo foi confirmar a toxidez e caracterizar os aspectos clínicos e patológicos da intoxicação por Trema micrantha em equinos. Três equinos, pôneis, com idade entre 2 e 7 anos consumiram espontaneamente folhas de T. micrantha em doses únicas de 30g/kg, 25g/ kg e 20g/kg. Os três animais adoeceram e evoluíram para morte. Outro equino recebeu 15 e 25g/kg da planta com intervalo de 30 dias entre as doses e não apresentou alteração clínica. Coletas diárias de sangue foram realizadas para análises bioquímicas. Os principais sinais clínicos apresentados foram apatia, desequilíbrios, dificuldade de deglutição, decúbito esternal, decúbito lateral, movimentos de pedalagem, coma e morte. Os três equinos afetados apresentaram elevação da atividade sérica de gama-glutamil transferase, dos níveis séricos de amônia e diminuição da glicemia. Esses animais foram necropsiados e fragmentos de diversos órgãos foram coletados para análise histopatológica e imuno-histoquímica. Os principais achados patológicos foram encontrados no fígado e no encéfalo dos três animais. O fígado apresentava, macroscopicamente, acentuação do padrão lobular; enquanto que, no encéfalo havia áreas amareladas na superfície de corte, mais evidentes na substância branca do cerebelo. Microscopicamente, o fígado apresentava tumefação hepatocelular, necrose de coagulação predominantemente centrolobular e hemorragia associada. No encéfalo, havia edema perivascular generalizado e astrócitos Alzheimer tipo II na substância cinzenta. Esses astrócitos apresentaram marcação fraca ou negativa na imuno-histoquímica anti-GFAP e marcação positiva do antígeno S-100. A dose letal mínima de folhas de T. micrantha estabelecida nesse experimento foi de 20g/kg. A ampla distribuição e palatabilidade desta planta, associadas à alta sensibilidade da espécie equina, constatada nesse experimento, reforçam a importância da planta em casos acidentais de intoxicação em equinos.

Extraneural Sclerosing Perineurioma of the Buccal Mucosa: A Case Report and Clinicopathologic Review

The perineurioma is an infrequently encountered benign peripheral nerve sheath tumor composed of a clonal proliferation of perineurial cells. Rare cases of perineurioma have been reported in the oral cavity. An extraneural sclerosing perineurioma arising in the buccal mucosa of a 17-year-old male is presented. Histopathologically, the tumor is composed of a well circumscribed nodular proliferation of spindle cells arranged in a storiform growth pattern, in some areas subtly arranged around vascular channels. The tumor cells reveal positive immunostaining for epithelial membrane antigen (EMA), collagen type IV and vimentin, and negative immunostaining for S-100 protein, consistent with a perineurial origin. To the best of our knowledge, this case represents the first report of an extraneural sclerosing perineurioma involving the oral cavity.