Positivity For S-100 Protein Research Articles

Mammary analogue secretory carcinoma: a rare salivary gland tumor

<p>Mammary analogue secretary carcinoma are salivary gland tumors similar to secretary carcinoma of breast histologically. It usually affects adults with mean age group of 45 years. Clinically it is usually slow growing, low grade malignancy with favorable prognosis. We are reporting a case of 47 years old female presented with complaints of swelling behind left ear for last 7 years. It was slow growing, painless and persistent. On examination, 4 x 3 cm swelling was present just below left ear lobule. It was nontender, firm, irregular in shape with smooth surface with slight mobility and overlying skin pinchable. Fine needle aspiration cytology suggested benign tumor with cystic change. On contrast enhanced computed tomography scan, there was a lobulated hypodense lesion measuring 24×35×32 mm with internal septations and enhancement of wall in expected location of superficial as well as deep lobe of left parotid gland. Patient underwent left total conservative parotidectomy and histopathology came out to be secretory analogue mammary carcinoma. Subsequently she received post-operative radiotherapy. Patient is on regular follow up and disease free till date. Usually mammary analogue secretory carcinoma is a low-grade malignancy with good prognosis. Immunohistochemistry is confirmatory which shows positivity for S-100 protein and mammaglobin.</p>

Rosai-Dorfman disease with pulmonary involvement mimicking bronchogenic carcinoma

BackgroundRosai-Dorfman disease is a histiocytic lesion that affects lung rarely.Case presentationWe present a 52-year-old female diagnosed with right intrabronchial mass invading the bronchial wall and the extrabronchial tissues with lymphadenopathy. Multiple bronchoscopic biopsies were not diagnostic. Pneumonectomy was performed and postoperative histology revealed marked mucin impaction and bronchial dilatation. The pulmonary tissue showed areas of hemorrhage and chronic inflammation. The mass exhibited an excessive number of lymphocytes, plasma cells, and numerous histiocytes engulfing them (lymphocytophagocytosis). These histiocytes were S100 protein and CD68 positive. These features are consistent with Rosai-Dorfman disease.ConclusionRosai-Dorfman Disease with pulmonary affection can be misdiagnosed as malignancy. Careful histological examination of the specimen for emperipolesis or lymphocytophagocytosis together with S100 protein and CD68 positivity are the clue for proper diagnosis.

Leg myxoid liposarcoma: correlation between image and anatomopathological tests

ABSTRACT A 41-year-old male patient refers to a painful tumor on the lateral side of the right leg. Ultrasonography visualized a predominantly hypoechoic well-delineated large heterogeneous mass in the subcutaneous tissue, showing an internal hyperechoic area. Magnetic resonance imaging (MRI) demonstrated an oval and lobulated tumor with well-defined margins at the anterolateral part of the leg, with contrast enhancement. The anatomopathological evaluation revealed a neoplasm with an extensive chondromyxoid matrix. The immunohistochemical study demonstrated positive vimentin (V9 clone), positive S-100 protein and negative desmin (D33 clone), smooth muscle actin (1A4), CD68 (KP1 clone) and caldesmon. The set of findings is compatible with myxoid liposarcoma.

Rektumun Benign Tümörünün Malign Görüntüsü

Rectal schwannomas are rare mesenchymal tumour of the gastrointestinal tract. They are scarcely identified in the low rectum as compared to the proximal tract. If present, huge tumour tends to be symptomatic leading to obstruction, bleeding, and tenesmus. We highlight a 74-year-old man with malignant presentations mimicking low rectal cancer. Colonoscopy revealed a huge pedunculated polyp measuring 10 x 8 cm with a diagnosis of benign tumour of schwannoma upon punch biopsy. Transanal excision was made after failure of endoscopic resection. Microscopic evaluation of the tumour showed a benign nerve sheath tumour of schwannoma supported by positive S100 protein expression. His recovery was excellent, hence he was discharged on the following day. There are no similar symptoms and tumour recurrence on follow up. A huge rectal tumour is not always malignant. Despite their rarity, schwannomas can manifest as malignant features. In case of tumour that mimics rectal carcinoma, preoperative diagnosis is very important for a management plan. The definitive histological diagnosis is based on the morphological features with diffuse positivity of S100 from immunohistochemical study. Surgical resection either endoscopic or transanal approach is the mainstay of treatment, especially when dealing with local complication caused by the huge bulk of tumour.

NCOA4-RET and TRIM27-RET Are Characteristic Gene Fusions in Salivary Intraductal Carcinoma, Including Invasive and Metastatic Tumors: Is "Intraductal" Correct?

Intraductal carcinoma (IC) is the new WHO designation for tumors previously encompassed by "low-grade cribriform cystadenocarcinoma" and "low-grade salivary duct carcinoma." The relationship of IC to salivary duct carcinoma (SDC) is controversial, even though they are considered to be distinct entities. IC is a rare low-grade malignant salivary gland neoplasm with histopathological features reminiscent of atypical ductal hyperplasia or ductal carcinoma in situ of the breast, showing diffuse S100 protein and mammaglobin positivity, while it is partially defined genetically. Recently, RET rearrangements including NCOA4-RET and TRIM27-RET have been described in IC. Here, we genetically characterize the largest cohort of IC to date (33 cases) including 8 cases with focal or widespread invasive growth and 1 case with lymph node metastasis. Thirty-three cases of IC were analyzed by next-generation sequencing (NGS) using the FusionPlex Solid Tumor kit (ArcherDX). Identified gene fusions were confirmed using fluorescence in situ hybridization break-apart and fusion probes and an reverse transcription polymerase chain reaction designed specifically for the detected breakpoints. Ten cases of SDC were analyzed for comparison using NGS panels that detect mutations and fusion transcripts. NGS analysis detected an NCOA4-RET fusion transcript in 11 cases of intercalated duct-type IC joining exon 7 or 8 of NCOA4 gene and exon 12 of the RET gene. Eight cases of IC had an invasive growth pattern, including one with widespread invasion and lymph node metastasis. Three invasive ICs harbored an NCOA4-RET fusion transcript, while 1 case was negative, and 2 cases were not analyzable. In addition, a novel TRIM27-RET fusion transcript between exon 3 of TRIM27 and exon 12 of RET was identified in 2 cases of IC with apocrine features, and one of them displayed invasive growth. Two IC cases with invasive growth harbored novel fusions TUT1-ETV5 and KIAA1217-RET, respectively. A total of 42.4% of the cases in this series of IC harbored fusions involving RET. Such fusion transcripts were not detected in any of the 10 SDC cases. We have confirmed NCOA4-RET as a predominant fusion in intercalated duct-type IC, including 3 cases with invasive growth pattern. A novel finding in our series was a case of widely invasive intercalated duct-type IC, with a single lymph node metastasis that revealed an NCOA4-RET fusion transcript. We also demonstrated that a subset of apocrine ICs harbored a TRIM27-RET gene fusion, including one case with invasive growth. In contrast, neither NCOA4-RET nor TRIM27-RET fusions were detected in any tested SDCs. Thus, the distinct molecular findings in IC and SDC support that the tumors are separate malignant salivary tumor entities. The presence of tumor-type-specific NCOA4-RET or TRIM27-RET translocations in a subset of widely invasive carcinomas with intercalated duct-like immunoprofiles suggests that a recharacterization of IC including its redesignation as "intercalated duct carcinoma, invasive or noninvasive" may be appropriate.

Macrocystic (Mammary Analogue) Secretory Carcinoma: An Unusual Variant and a Pitfall in the Differential Diagnosis of Cystic Lesions in the Head and Neck.

Mammary analogue secretory carcinoma (MASC) is a relatively recently described salivary gland adenocarcinoma characterized by ETV6-NTRK3 gene fusion and in most cases indolent clinical behavior. The majority of tumors show an admixture of microcystic, solid, and tubular growth patterns but only a few cases with dominant macrocystic growth have been reported. We report 15 cases of macrocystic MASC. There were 11 men and 4 women (17 to 88 y age range, average 47 y). The patients presented with a painless cystic mass, the majority in the region of the parotid gland (n=13), as well as in submandibular gland (n=1) and the neck (n=1). All tumors were circumscribed measuring 1.0 to 4.0 cm in greatest diameter (mean: 1.75 cm). Twelve tumors were unilocular, while 3 were multilocular. The cystic spaces were predominantly lined by a single epithelial cell layer with focal areas in which the epithelium was multilayered with papillary and hobnail features. In 3 of the cases there were more solid foci of intracystic tumor characterized by papillary and/or microcystic growth. The neoplastic cells were round to oval with hyperchromatic to vesicular nuclei with centrally located nucleoli and eosinophilic or vacuolated cytoplasm. Tumor cells showed strong positivity for S100 protein and mammaglobin, while DOG1 was uniformly negative. A minority of cases showed focal p63 reactivity predominantly limited to the periphery of the cystic lining. ETV6 gene rearrangement was identified in 9 cases. Macrocystic MASC can simulate benign and malignant salivary gland lesions and needs to be included in the differential diagnosis of cystic lesions in the head and neck. To the best of our knowledge, our report represents the first series of macrocystic MASCs wholly focusing on this unusual variant.

MULTIFOCAL AMELANOTIC MELANOMA OF THE HEAD AND NECK: A CHALLENGING CASE

Introduction Primary malignant melanoma evolves from melanocytic precursors via the formation of intermediate lesion of varying stability. Less than 1% of all malignant melanomas arise in the head and neck area, the anterior maxilla and alveolar mucosa being the most frequently affected sites. Males and females are equally affected, with an age range between adolescence and senescence. The prognosis is usually poor, with a 5-years survival rate of 30-35% and a median survival of 36 months. Several cases of primary malignant melanoma of the head and the neck area have been reported in the literature but in most cases no clear evidence was shown whether such lesions were primary or metastatic in origin. Case Report We present a case of malignant melanoma in a 50-years old male, who complained for a rapidly growing maxillary nodular lesion, involving the ethmoid sinus and the orbital base. Histopathological intraoperative examination revealed a poorly differentiated malignancy, with spindle-shaped cells showing prominent nucleoli. Subsequent immunohistochemical stains highlighted pan-CK (dot-like) and S100 protein positivity but HMB-45 and melan-A were negative, supporting the diagnosis of malignant melanoma. The tumour was treated by en-block resection with mapping-margins and additional histopathological examination showed an intra-mucosal hyper-melanotic lesion, consistent with an acral lentiginous-type melanoma, which was considered the primary neoplastic focus. Conclusions Primary malignant melanomas in the oral cavity are rare and usually asymtomatic at early stages, thus leading to delayed diagnosis. This must rely upon accurate histopathological and extensive immunohistochemical evaluation as the morphological features often are misleading or non-specific. It is worth to emphasise that melanocyte-specific antigens (Melan-A and HMB-45) frequently are negative in such neoplasm and unexpected cytokeratin positivity may occur, which may result in an inappropriate diagnosis.

Primary Malignant Melanoma of the Breast: A Report of Two Cases.

Primary malignant melanoma of the breast (PMMB) is a rare tumor with only a few case reports available in the literature. We report two cases of PMMB, one derived from the breast parenchyma and the other from the breast skin. The first case consisted of atypical epithelioid cells without overt melanocytic differentiation like melanin pigments. The tumor cells showed diffuse positivity for S100 protein, tyrosinase, and BRAF V600E. However, the tumor cells were negative for cytokeratin, epithelial membrane antigen, and HMB-45. The second case showed atypical melanocytic proliferation with heavy melanin pigmentation. The tumor cells were positive for S100 protein, HMB-45, tyrosinase, and BRAF V600E. These two cases represent two distinct presentations of PMMB in terms of skin involvement, melanin pigmentation, and HMB-45 positivity. Although PMMB is very rare, the possibility of this entity should be considered in malignant epithelioid neoplasms in the breast parenchyma.

Molecular Profiling of Salivary Gland Intraductal Carcinoma Revealed a Subset of Tumors Harboring NCOA4-RET and Novel TRIM27-RET Fusions: A Report of 17 cases.

Intraductal carcinoma (IC) is the new World Health Organization designation for tumors previously called "low-grade cribriform cystadenocarcinoma" and "low-grade salivary duct carcinoma." The relationship of IC to salivary duct carcinoma is controversial, but they now are considered to be distinct entities. IC is a rare low-grade malignant salivary gland neoplasm with features similar to mammary atypical ductal hyperplasia or ductal carcinoma in situ, that shows diffuse S100 protein and mammaglobin positivity and is only partially defined genetically. (Mammary analogue) secretory carcinoma harboring ETV6-NTRK3, and in rare cases ETV6-RET fusion, shares histomorphologic and immunophenotypical features with IC. Recently, RET rearrangements and NCOA4-RET have been described in IC, suggesting a partial genetic overlap with mammary analogue secretory carcinoma. Here, we genetically characterize the largest cohort of IC to date to further explore this relationship. Seventeen cases of IC were analyzed by next-generation sequencing using the FusionPlex Solid Tumor kit (ArcherDX). Identified fusions were confirmed using fluorescence in situ hybridization break apart and, in some cases, fusion probes, and a reverse transcription polymerase chain reaction designed specifically to the detected breakpoints. All analyzed cases were known to be negative for ETV6 rearrangement by fluorescence in situ hybridization and for ETV6-NTRK3 fusion by reverse transcription polymerase chain reaction. Next-generation sequencing analysis detected a NCOA4-RET fusion transcript joining exon 7 or 8 of NCOA4 gene and exon 12 of RET gene in 6 cases of intercalated duct type IC; and a novel TRIM27-RET fusion transcript between exons 3 and 12 in 2 cases of salivary gland tumors displaying histologic and immunohistochemical features typical of apocrine IC. A total of 47% of IC harbored a fusion involving RET. In conclusion, we have confirmed the presence of NCOA4-RET as the dominant fusion in intercalated duct type IC. A novel finding in our study has been a discovery of a subset of IC patients with apocrine variant IC harboring a novel TRIM27-RET.

The localization of CD3, CD79a, CD68 and S100 protein immunoreactive cells in hemal nodes of Saanen goat (Capra hircus)

We investigated the structure of hemal nodes in Saanen goats using immunohistochemical staining. We examined the distribution of CD3 positive T lymphocytes, CD79a positive B lymphocytes, CD68 positive macrophages and S100 protein positive follicular dendritic cells. Hemal nodes of six healty adult female goats were used. Hemal nodes were removed from the thoracic and abdominal cavities. The oval to round hemal nodes were observed especially between the abdominal aorta and vena cava, and near the kidneys and adrenal glands. Tissue sections were stained with Crossmon’s modified triple stain to demonstrate general histological structure. The avidin-biotin-peroxidase technique using anti-CD3, anti-CD79a, anti-CD68 and anti-S100 primary antibodies was used for immunohistochemistry. Many CD3 positive T lymphocytes were found in the germinal center of the lymph follicles and in the lymphatic cords of hemal nodes; CD3 positive cells also were observed in the sinuses. CD79a and CD68 positive cells were found at the germinal center of the lymph follicles. In the lymph follicles near the subcapsular sinuses, CD79a and CD68 positive cells were found especially in e areas bordering the mantle zone. S100 positive cells were found in the lymph follicles, lymphatic cords and sinuses.

Diagnostic pitfall: primary myoepithelial carcinoma of the lacrimal gland, case report and literature review

BackgroundIn lacrimal gland, lymphomas and inflammatory lesions predominate. Primary epithelial tumours represent less than 30% of lacrimal gland lesions. Myoepithelial carcinoma of lacrimal gland is rare. To the best of our knowledge, only nine cases have been reported in the literature. This lesion presents diagnostic difficulties: non-specific clinical and radiological findings and histological polymorphism. This is well illustrated by the diagnostic pathology errors described in the literature.We report a new case of lacrimal myoepithelial carcinoma with a review of others published cases to try to assess clinico-pathological features and outcome whenever possible of this rare tumour.Case presentationAn 80-year-old Arabian female presented with a 2-month history of swelling over the right eyebrow, pain, proptosis of the right eye and diplopia. Computed tomography demonstrated an ill-defined, homogeneous, contrast-enhancing mass attached to the medial rectus. A biopsy was performed. Microscopic examination showed malignant spindle cells tumour, most consistently to sarcoma or sarcomatoid carcinoma. Immunohistochemical study was not possible because neoplastic material has been exhausted. Subsequently, total exenteration of the right orbit was performed. Immunohistochemical study revealed diffuse positive staining for pancytokeratin AE1/AE3, epithelial membrane antigen (EMA) and smooth muscle actin (SMA) and focal positivity for S100 protein. The lesion was immunonegative for desmin, h-cladesmon, CD34, Melan-A and HMB-45. The tumour was extending to the surgical margins. The patient was lost to follow-up until she developed local tumour progression 3 months after removal. The patient was again lost to follow-up and therefore did not receive any other treatment in our hospital.ConclusionWe present this rare tumour with an unusual location. The use of a complete immunohistochemical panel with epithelial and myoepithelial markers positivity helped us for classification of this poorly differentiated tumour.

An unusual finding in a desmoid-type fibromatosis of the pancreas: a case report and review of the literature

BackgroundDesmoid-type fibromatoses are rare benign and fibrous tumors that account for approximately 0.03% of total neoplasms. Within this category of neoplasms, pancreatic desmoid-type fibromatosis is an extremely rare subgroup, accounting for approximately 5% of desmoid-type fibromatoses. Although the etiology is unknown, some risk factors include trauma, surgery, family history of desmoid tumor, pregnancy, use of contraceptives, genetic mutation, and familial adenomatous polyposis or Gardner syndrome. Desmoid-type tumors are primarily diagnosed by pathological and immunohistochemical studies. The treatment of choice is surgical resection of the tumor. Systemic chemotherapy and radiotherapy are optional treatment approaches for patients with high risk for surgery.The following is a report of an unusual case of a pancreatic desmoid-type fibromatosis in which a very rare variation in the immunohistochemistry findings was demonstrated: slides were immunopositive for S100 protein and not immunonegative. Most desmoid tumors are immunonegative for S100 protein with just a few cases being positive for this protein.Case presentationWe describe the case of a 15-year-old boy, a Chinese national, who was diagnosed as having a pancreatic desmoid-type fibromatosis. He was a healthy individual who was incidentally diagnosed with an abdominal mass. His chief complaints were mild generalized abdominal pain for 1 week, nausea, vomiting, and a low-grade fever. An enhanced computed tomography scan of his abdomen showed a large cystic mass in the anterior surface of the body of his pancreas. He underwent a radical resection of the pancreatic mass, partial pancreatectomy, splenectomy, segmental resection of transverse colon and distal jejunum, and subsequently a one-stage jejunojejunostomy and colonic anastomosis. Postoperatively, he was diagnosed as having a desmoid-type fibromatosis of the pancreas by pathological and immunohistochemical studies.ConclusionsThe diagnosis of desmoid-type fibromatosis is usually incidental and challenging. Pathological and immunohistochemical testing are essential for confirming diagnosis where demonstration of β-catenin nuclear staining is probably the single most important characteristic. Other markers, such as vimentin, are usually positive, while S100 protein is usually negative. Our case however, confirms that there are rare cases that can be S100 positive. This is the first diagnosed case of pancreatic desmoid-type fibromatosis with S100 protein positivity.

A Case of Primary Gastric Melanoma Exhibiting a Rare BRAF V600R Mutation.

IntroductionMalignant melanoma of the gastrointestinal tract is usually a metastasis from a cutaneous source. Primary gastric melanoma is an extremely rare clinical entity, with few reported cases worldwide. It is often advanced at time of diagnosis and is associated with a dismal outcome.BackgroundA 76 year old gentleman presenteded with a one month history of fatigue and exertional dyspnoea. Laboratory investigations indicated an anaemia, with a haemoglobin level of 11.0g/dl. Subsequent gastroscopy visualised a large, atypical, crater-like ulcerated lesion distal to the cardia in the proximal stomach.Provisional histology was suggestive of a poorly differentiated adenocarcinoma but subsequent cyto-morphology and immunophenotyping were consistent with melanoma, with positive S100 protein, HMB45 and Melan A. Further molecular genetic testing revealed a V600R mutation in the BRAF gene, which is the first primary gastric melanoma with this mutation to be reported in the literature. Given the rarity of the findings, an extensive secondary work-up was undertaken, which concluded the diagnosis primary gastric melanoma.DiscussionPrimary gastric melanoma is a rare disease that can present similarly to other upper gastrointesinal lesions, with weight loss, abdominal pain, malena, and anaemia. Given its rarity, the pathogenesis is poorly understood. Lesions are often endoscopically atypical. Important points to note would include the absence of a primary lesion, as supported by a full skin examination and PET-CT findings, which can help to delineate the limitation to the stomach, thus helping to inform subsequent management.LEARNING POINTSPrimary gastric melanoma (PGM) is a rare clinical entity.Work-up including skin and ophthalmic examination is important to exclude a primary cutaneous source, as this helps dictate both prognosis and subsequent management, including whether surgical resection is advisable.Immunophenotyping and genetic testing inform management but, despite advances in therapy, the prognosis of PGM and other mucosal melanomas remains poor.

Gastric schwannoma: report of two cases and review of the literature

IntroductionGastrointestinal schwannomas are benign, slow-growing and usually asymptomatic tumors. In some cases bleeding, epigastric pain and palpable mass may be occurring. Preoperative diagnosis is challenging due to the difficulty of differentiation from other submucosal tumors. Diagnosis is most often provided through the histology report. Case presentationIn this study we report two cases of gastric tumors with the suspicion of a GIST preoperatively but histologically confirmed to be gastric schwannomas. Two patients of our study gave to us their written consent for publication. Research work has been reported with the PROCESS criteria. DiscussionSurgical resection should be considered the mainstay of treatment in patients with gastric schwannomas. Possible complications such as bleeding or pyloric stenosis can be presented. The size and location of the tumor, as well as its relation to the surrounding organs, are essential factors in determining the type of resection. ConclusionGastric schwannomas are usually presented us submucosal mass. Preoperative diagnosis is challenging due to the difficulty of differentiation from other submucosal tumors. Endoscopic Esophagogastroduodenoscopy with biopsy and endoscopic ultrasound is essential to determine the nature of these lesions. Resection of the lesion in healthy borders is the treatment of choice. Patho-logical examination usually revealed positive S-100 protein and negative CD34, CD117, Actin and desmin strains.

Case report and immunohistochemical study of a malignant peripheral nerve sheath tumor in a dog

Malignant peripheral nerve sheath tumor is rare and rarely reported in dogs. The term neurofibroma/sarcoma is classically used when the tumor is composed of Schawann and perineural cells. This work describes the clinical, histopathological, and immunohistochemical case of a subcutaneous malignant peripheral nerve sheath tumor, most likely a malignant neurofibroma located in the pelvic member of a Rottweiler dog. Histopathological features and immunohistochemical analysis corroborated the diagnosis, showing positivity for S-100 protein, vimentin, and CD57, and was useful to distinguish this type of neoplasm from other malignancies of similar morphologies.

Base of tongue schwannoma on a 22 year old lady: a rare case

Schwannomas are benign tumours arising from the Schwann cells. Around 25-45% schwannomas have been reported occured in head and neck region, but only 1% located intraoral. We report a case of 22 year old woman who presented with foreign body sensation in throat, dysphagia, change of voice, and snoring. There was a slowly growing, solitary, encapsulated, painless, mass on the tongue base. Microscopically, it had the typical features of schwannoma, the diagnosis being supported by a strong positivity for S-100 protein. Ki67 staining showed low proliferative index (<5%) indicated benign schwannoma. CT-scan of oropharynx demonstrated a well-circumscribed soft tissue density mass, oval shape, connected with the left portion base of tongue, homogenous, and strong enhancement mass. The entire mass was removed in general anesthesia with conservative surgical excision via trans-oral route, histopathologic reported consistent as schwannoma. The patient remained disease-free, without any residual problems. Although the rarity of schwannoma on the tongue base, this case highlights the importance of including it in the differential diagnosis of mass from the tongue base. To the best of our knowledge, our case is only the twentieth of schwannoma at the base of tongue that reported in the literature. <p> </p>

Duodenal Gangliocytic Paraganglioma: A Rare Neuroendocrine Tumor

Gangliocytic paragangliomas, predominantly found in the second part of duodenum, are rare, usually benign tumors with occasional lymph node metastasis. Clinical presentation varies from incidental finding upon endoscopy, or abdominal pain and upper gastrointestinal bleeding. A 73-year old woman with past medical history of non-Hodgkin's lymphoma, presented with intermittent post-prandial epigastric pain, radiating to right upper quadrant, without any weight loss or melena. Physical examination was unremarkable. Laboratory analysis was normal. Cross-sectional imaging of abdomen revealed a possible duodenal diverticulum. Esophagogastroduodenoscopy revealed 17mm, sessile polyp in second part of duodenum. Endoscopic ultrasound (EUS) showed a hypoechoic mass, measuring 17mm x 13mm, extending from mucosa to submucosa and having well-defined margins. EUS-guided fine needle aspiration (FNA) cytology was consistent with a neuroendocrine tumor with immunohistochemical stains positive for synaptophysin, chromogranin and CD56 antibodies. A decision was made to proceed with endoscopic mucosal resection (EMR) which revealed a hypoechoic intramural lesion, appearing to originate from submucosa, overlaid by focal ulcerating flattened duodenal mucosa. The pathology was remarkable for variable admixture of bundles of spindle cells, clusters of ganglion cells and epithelial cells. Immunohistochemical stains showed positive S100 protein in the spindle cells; the epithelioid cells were positive for synaptophysin and CD56 consistent with neuroendocrine differentiation; and the ganglion cells positive for calretinin. Gangliocytic paragangliomas, first reported by Dahl et al. in 1957, is a peculiar neuroendocrine tumor thought to be derived from neural crest with 88% reported lesions located in the second part of duodenum. These tumors are benign and consist of variable admixture of spindle cells, epithelioid cells, and ganglion cells. Rare malignant cases have been reported with regional lymph node metastasis. The epithelioid component was found to be present in the patients with lymph node metastasis; the causal relationship of which is unclear. Due to the submucosal location of the tumor, diagnosis is difficult on endoscopic biopsy which emphasizes the role of EMR in the diagnosis. As most of these tumors are benign and non-functional, EMR is therefore the treatment of choice especially in cases in which the tumor may be removed in its entirety with negative margins.Figure: A 17mm x 13mm, hypoechoic intramural lesion, appearing to originate from submucosa.Figure: Duodenal mass showing variable admixture of ganglion cells, spindle cells, and epithelioid cells (arrow shows ganglion cell). H&E X 100.Figure: Well-controlled immunostain with antibody to synaptophysin shows strong positivity for epithelioid cells. Synaptophysin X 100.

Schwannoma of the vagina - a common tumor but a rare location: A case report.

Schwannomas are nerve sheath tumors arising from Schwann cells. These tumors usually present as benign, relatively slow-growing, solitary, encapsulated, painless masses. Schwannomas rarely occur in the vagina, and have not been fully recognized as gynecological tumors. We herein describe the case of a patient who presented with a schwannoma occurring in the wall of vagina, with non-specific symptoms lasting for ~1 year. The vaginal mass was incidentally detected during a sonographic examination and the patient was referred for surgical resection. The surgery was uncomplicated and the vaginal tumor was diagnosed as benign schwannoma. The immunohistochemical examination revealed positivity for vimentin, S-100 and glial fibrillary acidic protein, whereas discovered on GIST-1, CD117, CD34, desmin, smooth muscle actin and cytokeratin were negative. Tumors occurring in the vagina are common and are of variable histological types, with a wide range of pathological characteristics and complications. Schwannoma should be considered in the differential diagnosis in patients presenting with atypical symptoms from the gynecological tract. Immunohistochemical staining is required for confirmation of the diagnosis of schwannoma, and for distinguishing this entity from other homologous tumors.

SMARCB1/INI1 Loss in Epithelioid Schwannoma

The epithelioid variant of schwannoma is rare, and loss of SMARCB1/INI1 expression has been observed in a subset of cases. Our aim was to further define the clinicopathologic features and to evaluate SMARCB1/INI1 deficiency in a large cohort of 65 epithelioid schwannomas diagnosed between 2002 and 2015, which consisted of 32 men and 33 women with median age at diagnosis of 45 years (range, 13 to 75 y). Most tumors arose in the extremities (upper, 20, lower, 15) and trunk (17); 9 were visceral (8 gastrointestinal). Most somatic tumors were in dermis/subcutis (53/54) and encapsulated (53/54) with an epithelial membrane antigen-positive perineurial capsule in 46 cases; visceral tumors were unencapsulated. No patients were reported to have any neurocristopathy. Three patients had multiple lesions (2 each). Tumor size range was 0.4 to 22.7 cm (median, 1.2 cm). Tumors showed multilobulated growth of uniform epithelioid cells in sheets and nests or singly dispersed within a frequently myxoid or hyalinized stroma. Tumor cells had round vesicular nuclei and abundant palely eosinophilic cytoplasm, usually lacking significant pleomorphism or hyperchromasia. Some tumors showed foci resembling conventional schwannoma (spindled morphology, 29; Antoni B foci or Verocay bodies, 8; hyalinized thick-walled vessels, 16). Mitoses ranged from 0 to 9 per 10 high-power fields (median count, 1). No tumor had necrosis. Twenty-three cases showed degenerative nuclear atypia. Focally striking cytologic atypia was present in 7 tumors, 3 of which showed transformation to epithelioid malignant peripheral nerve sheath tumor. All tumors showed diffuse positivity for S-100 protein and consistent positivity for SOX10 (50/50), while INI1 expression was lost in 24 of 57. Other positive immunohistochemical results were: glial fibrillary acidic protein (15/37) and focal keratin (2/40); epithelial membrane antigen (0/53) and melanocytic markers were negative (Mart-1 0/29; HMB-45 0/23). Most patients underwent local excision (13 complete; 47 marginal/positive margins). Follow-up data available for 31 patients (range, 1 to 108 mo; median, 37) indicated that no patient had developed metastatic disease, including 3 cases with cytologic atypia, one of which showed malignant transformation. One tumor without atypia developed local recurrence 48 months after marginal excision; all other patients were alive with no evidence of disease. Epithelioid schwannoma most commonly occurs as a superficial tumor on the extremities or trunk in adults. Loss of SMARCB1/INI1 expression is seen in 42% of tumors. Tumors follow a generally benign clinical course, although recurrence and malignant transformation are infrequent. Some tumors are characterized by notable cytologic atypia, the significance of which is uncertain but which may indicate a morphologic continuum with low-grade epithelioid malignant peripheral nerve sheath tumor.

Melanotrichoblastoma: A Rare Case Report from B. P. Koirala Institute of Health Sciences, Dharan, Nepal

Melanotrichoblastoma is a variant of pigmented trichoblastoma. It shows heavily pigmented epithelial lobules and differentiaion toward the hair bulb. Abundant dendritic melanocytes are found within the tumor masses. These melanocytes show positivity for S100 protein, HMG45/gp 100 and tyrosinase. The case is being reported because of its rarity.A twenty eight year lady presented to Dermatology OPD with a single nodular lesion on the right temporal region since last five years. Punch biopsy was done. Haematoxylin and eosin stained slides were studied and immunohistochemistry analysis was also done.Variably sized epithelial lobules of basaloid cells spanning the entire dermis was noted on H and E stained slides. Some lobules showed pale looking cells- a reminiscent of follicular germinative cells. Intralesional melanocytes with pigmentation were observed. Immunohistochemistry results showed the melanocytes positive for HMB-45 and S100 and the stroma positive for CD 34. Hence, a definitive diagnosis of Melanotrichoblastoma was made.This case is being presented to emphasize the difficulty posed by adnexal tumors in clinical diagnosis due to their clinical similarity with malignant lesion and rarity.Birat Journal of Health Sciences Vol.2/No.1/Issue 2/ Jan - April 2017