Epithelial Membrane Antigen Staining Research Articles

Superficial Papular Neuroma: Two Cases of a Distinctive Dermal Neoplasm.

Superficial papular neuroma is a rare cutaneous spindle cell lesion, with only 5 cases reported in 2 studies. We document 2 additional cases in a 45-year-old man and a 43-year-old woman (the first case identified in a woman). Clinically, superficial papular neuromas appear as a single, non-specific papule on the head, neck, or back. Histologically, these lesions are within the papillary and superficial reticular dermis, with nerve-like structures composed of bland spindle-shaped cells intersecting normal tissue with mild reactive acanthosis. The cells are SOX10 positive with neurofilament protein staining multiple axons within. The nerve-like structures in this study were occasionally surrounded by a thin rim of CD34 positivity, with no epithelial membrane antigen staining, similar to normal sensory neurons. Superficial papular neuroma are rare benign neoplasms with no reports of recurrence, even when incompletely excised.

What is new in intraneural perineurioma?

Since the initial description of intraneural (IN) perineurioma in 1964, advances in the understanding of the clinical presentation, diagnostic imaging, pathologic features, and genetic underpinnings have changed how this pathology is managed. IN perineuriomas are rare, benign peripheral nerve sheath tumors, most frequently coming to clinical attention when patients present with painless, progressive weakness or sensory loss in adolescence or young adulthood. The gold standard of diagnosis has traditionally been with targeted tissue biopsy demonstrating "pseudo-onion bulb" formation with positive epithelial membrane antigen (EMA) staining. However, modern magnetic resonance imaging is allowing some patients to forgo biopsy. Recent genetic studies of IN perineuriomas have demonstrated common TRAF7 point mutations and rare NF2 mutations, which may present targets for diagnosis or therapy in the future. Current advances have allowed for us to provide improved patient counseling with informed understanding for various clinical scenarios. With the workup and diagnosis now clearly defined, the next frontier is for improving the lives of patients with IN perineuriomas through the interaction between restoration of functional deficits and advances in our understanding of the genetics of this entity.

DP18 Extraocular sebaceous carcinoma in situ

Abstract Extraocular sebaceous carcinoma in situ (SCIS) is exceedingly rare with < 10 cases reported in the literature (Jeong KM, Seo JY, Kim A et al. Extraocular sebaceous carcinoma in situ concurrent with actinic keratosis: a case report and review of the literature. Korean J Dermatol 2021; 59:307–9). An 80-year-old man reported a 3-month history of a right forehead lesion that had been bleeding. This was a subtle 5 × 5 mm papule on clinical examination, and dermoscopy showed arborizing telangiectasia. Past medical history was significant for 20 basal cell carcinomas, one squamous cell carcinoma, Bowen disease and actinic keratoses. Histology showed sun-damaged skin with a partially eroded neoplasm of lobular architecture, with surface and infundibular epithelium containing atypical sebocytes and squamous cells with no infiltrative growth pattern, which was consistent with SCIS and was fully excised. Immunohistochemistry revealed patchy adipophilin and androgen receptor staining and stronger epithelial membrane antigen staining. Furthermore, there was preserved expression of MSH2, MSH6, MLH1 and PMS2. Sebaceous carcinoma in situ is a debated entity not formally recognized in the classification of sebaceous neoplasms. Kazakov et al. reported five cases of dermal sebaceous tumours with ‘benign’ architectural features (well-circumscribed and no evidence of invasion) but with cytological atypia (abnormal mitoses and pleomorphism) (Kazakov D, Kutzner H, Spagnolo DV et al. What is extraocular cutaneous sebaceous carcinoma in situ? Am J Dermatopathol 2010; 32:857–8). The authors questioned whether these cases represented sebaceous adenomas with atypia or sebaceous carcinomas (Kazakov et al.). In response, it has been argued that such architectural–cytological discordant tumours can be regarded as SCIS owing to the fact that, by definition, carcinoma in situ is a cancer that remains wholly at the site of origin. However, it is argued that these lesions have an unclear origin and may not arise from sebaceous glands in the skin, unlike the more common aggressive periorbital sebaceous carcinomas that arise from meibomian glands and glands of Zeis (Kazakov et al.). It has been postulated that a SCIS diagnosis should be reserved for intraepidermal tumours not extending beyond the epidermal basement membrane, which is a vanishing minority of sebaceous neoplasms (Kazakov et al.). Similar to our case, a 2021 case report identified SCIS without any connection to an adnexal component but concurrent with actinic keratosis. These authors proposed that the tumour cells of intraepidermal squamous neoplasia can differentiate towards malignant sebocytes (Jeong et al.). Although controversial, SCIS appears to have reasonable, clear histological criteria for diagnosis and an excellent prognosis, with no reports of recurrence following surgical excision. We feel it is important to increase identification to avoid the overtreatment of such lesions.

Atretic cephalocele and encephalocele: A single-institution clinicopathological study.

Encephaloceles are neural tube defects characterized by herniation of meninges, neural tissue and cerebrospinal fluid, while atretic cephaloceles denote a rudimentary connection to the intracranial space with absence of herniated neural tissue and represent an infrequent dermatopathologic diagnosis. Limited reports of these entities confound the challenge in their histopathologic distinction. Accurate classification is important given associated anomalies and neurologic manifestations that impact prognosis. We describe the clinicopathological and immunohistochemical [glial fibrillary acidic protein (GFAP), S100, epithelial membrane antigen (EMA), and somatostatin receptor subtype 2A (SSTR2A)] features in a retrospective series encountered at a single institution between 1994 and 2020. We identified 13 cases classified as atretic cephalocele (n=11) and encephalocele (n=2). Hamartomatous changes and multinucleated cells were unique to atretic cephaloceles while myxoid areas were unique to encephaloceles. At least focal staining for SSTRA was seen in all atretic cephaloceles with the majority (87.5%) staining for EMA; negative staining for GFAP and S100 confirmed absence of neural tissue. Encephaloceles were GFAP and S100 positive, and negative for SSTR2 and EMA. Atretic cephaloceles had a favorable prognosis compared to encephaloceles, with severe morbidity present in both encephalocele cases. Our study raises awareness of atretic cephalocele and encephalocele among dermatopathologists and reveals a mutually exclusive immunophenotype that facilitates their distinction for prognostication and management.

Diagnostic Accuracy of GATA6 Immunostaining in Sebaceous Tumors of the Skin

The accurate diagnosis of skin adnexal neoplasms is sometimes challenging but is necessary because medical management and follow-up may differ between tumors. GATA6 transcription factor has been identified as a new marker of the upper folliculosebaceous compartment (lower infundibulum, junctional zone and isthmus, and upper sebaceous gland) in the human skin. We aimed to determine the diagnostic accuracy of GATA6 immunostaining to diagnose sebaceous tumors compared with that to diagnose other adnexal and nonadnexal cutaneous neoplasms. We conducted a retrospective, evaluator-nonblinded study comparing the reference standard (diagnosis by an expert dermatopathologist) with GATA6 immunostaining to identify sebaceous tumors in a cohort containing 234 different tumors. The GATA6 expression score was significatively higher in sebaceous than that in nonsebaceous tumors. In addition, tumors originating from the upper hair follicle showed positive results for GATA6 staining; however, they showed lower GATA6 expression scores. Detection of sebaceous tumors using GATA6 positivity had a sensitivity of 95.7% (95% CI, 85.8-99.2), specificity of 80.8% (95% CI, 74.5-85.8), positive predictive value of 55.6% (95% CI, 44.7-65.9), and negative predictive value of 98.7% (95% CI, 95.4-99.8). GATA6 showed similar sensitivity to adipophilin, the reference marker; however, the specificity of GATA6 was higher, as observed in a cohort of 106 tumors enriched in squamous cell carcinomas with clear-cell histology. In addition, GATA6 positivity was assessed in 39 sebaceous carcinomas and compared with epithelial membrane antigen (EMA), CK7, and androgen receptor (AR) staining results. Although CK7 staining displayed lower diagnostic performances, GATA6 staining showed comparable results as EMA and AR. Finally, we found GATA6 expression in skin metastases of gastrointestinal origin, whereas GATA6 was absent in metastases originating from breast or lung cancers. Overall, our work identified GATA6 immunostaining as a new diagnostic tool for sebaceous tumors.

Label-free detection of invasive micropapillary carcinoma of the breast using multiphoton microscopy.

Invasive micropapillary carcinoma of the breast (IMPC) is a rare form of breast cancer with unique histological features, and is associated with high axillary lymph node metastasis and poor clinical prognosis. Thus, IMPC should be diagnosed in time to improve the treatment and management of patients. In this study, multiphoton microscopy (MPM) is used to label-free visualize the morphological features of IMPC. Our results demonstrate that MPM images are well in agreement with hematoxylin and eosin staining and epithelial membrane antigen staining, indicating MPM is comparable to traditional histological analysis in identifying the tissue structure and cell morphology. Statistical analysis shows significant differences in the circumference and area of the glandular lumen and cancer nest between the different IMPC cell clusters with complete glandular lumen morphology, and also shows difference in collagen length, width, and orientation, indicating the invasive ability of different morphologies of IMPC may be different.

Establishment and characterization of meningioma patient-derived organoid

Meningioma is a central nervous system tumor originated from arachnoid cells. 2D cell culture is widely used as a platform for tumor research as it enables us to culture cells in in vitro and a controlled environment. However, in 2D culture condition, 3D architecture of in vivo tumor mass is lost and phenotypic change may occur. Due to the drawbacks of 2D cell culture, organoid culture is seen as an alternative platform for disease modeling, drug testing and personalized medicine. The objective of this study was to establishing protocol for culturing cells from patient meningioma tissue in in vitro 3D environment. Eight meningiomas were collected for the 3D organoid culture. Cells of 5 meningioma tissues survived and proliferated. Under 3D culture condition, cell aggregates were formed and cytoplasmic processes linking the cell aggregates could be observed. In H&E staining, ovaloid cells and spindle cells were observed. Resembling cultured organoids observed under the light microscope, cell aggregates were also observed in the H&E staining. Epithelial Membrane Antigen (EMA) staining was positive. In 4 (80%) cultured organoids, low Ki67 index (≤6%) were measured. In one cultured organoid, a high Ki67 index (12.8%) was seen. The result of this study revealed the feasibility of culturing meningioma cells in in vitro 3D culture condition. Organoid technology showed its potential as an alternative platform for meningioma research.

Cervical malignant mixed mesonephric tumour: A case report with local recurrence after six-years and next-generation sequencing analysis with particular reference to the ataxia telangiectasia mutated gene.

Malignant mixed mesonephric tumours (MMMsT) of the female genital tract are extremely rare, and the majority are located in the wall of the cervix uteri. At present, there are no reports of the molecular characterisation of MMMsT of the female genital tract. Herein, we report the morphological, immunohistochemical and molecular features of this rare malignancy using next-generation sequencing (NGS) analysis. A 58-year-old woman presented with vaginal bleeding. In 2013, she had been diagnosed with a cervical carcinosarcoma of probable mesonephric origin and International Federation of Gynaecology and Obstetrics (FIGO) stage IB that had been treated by total hysterosalpingo-oopherectomy without adjuvant chemo-radiotherapy. Ultrasonography showed a vaginal mass measuring 25 mm in the maximum dimension. Biopsy was performed and showed a biphasic neoplasm composed of adenocarcinoma and sarcoma. Immunohistochemistry showed positive staining for epithelial membrane antigen (EMA), pancytokeratin (MNF116), paired box 8 (PAX-8), β-catenin, cytokeratin 7, cyclin D1, GATA3 and CD10. Androgen receptor positivity was detected in very limited areas. Cytokeratin 20, carcinoembryonic antigen (CEA), oestrogen receptor (ER), progesterone receptor (PR), transcription termination factor 1 (TTF1), Wilm's tumour antigen-1 (WT-1), calretinin and p16 were negative. The immunohistochemical profile was consistent with mesonephric origin. NGS analysis identified a variant of the ataxia-telangiectasia mutated (ATM) gene (p.Phe858Leu; c.2572 T>C; COSM21826). The number of detected allele frequency reads of ATM mutation following clinical relapse was higher, compared to its baseline: 65 vs. 96%. The differential diagnosis of MMMsT includes mesonephric hyperplasia, malignant mixed Mullerian tumour (carcinosarcoma), endometrioid adenocarcinoma and endometrial stromal sarcoma. The clinical significance of the observed ATM variant in the case reported herein is unknown. The present findings need further verification, as the mutation in ATM may result in chemotherapy resistance or conversely, may be exploited for targeted therapies.

Epithelial-Stromal Polyps of the Colon Are Not Perineuriomas.

Some colorectal polyps contain serrated or tubular crypts surrounded by whorls of spindle cells that expand the mucosa. These epithelial-stromal polyps have been termed benign fibroblastic polyps or, more commonly, perineuriomas. We hypothesized that these lesions are pathogenetically heterogeneous polyps that share in common exuberant fibroblastic proliferations derived from the pericryptal sheath. Forty-six epithelial-stromal polyps containing serrated crypts (n = 21) and nonserrated crypts (n = 25) were evaluated with epithelial membrane antigen and BRAF V600E immunohistochemical stains, and a subset was subjected to next-generation sequencing for BRAF mutations. Polyp morphology and immunohistochemical results were correlated with clinical information. Epithelial-stromal polyps containing serrated crypts were significantly associated with other sessile serrated polyps (43%, P = .01) and hyperplastic polyps (29%, P = .006). They also showed BRAF V600E abnormalities (95%) and strong, patchy epithelial membrane antigen staining of spindle cells (95%). In contrast, polyps with nonserrated crypts lacked BRAF alterations and infrequently showed robust EMA staining of stromal cells (16%, P < .01). Benign epithelial-stromal polyps with serrated epithelium are biologically similar to sessile serrated polyps and should be classified as such to ensure appropriate clinical surveillance. The nature of polyps without serrated crypts is less clear, but evidence that they are perineuriomas is circumstantial at best.

Malignant Perivascular Epithelioid Cell Tumor Mimicking Renal Cell Carcinoma: A Diagnostic Pitfall

Abstract We describe a case of metastatic malignant renal perivascular epithelioid cell tumor in a 56-year-old male. Computed tomography initially revealed bilateral heterogeneous enhancing kidney masses, the right one significantly larger than the left. The patient underwent a right radical nephrectomy. Upon gross examination, the mass was infiltrating into the surrounding fat and had a heterogeneous cut surface with multiple hemorrhagic foci. Histologically, majority of cells were highly atypical with abundant clear cytoplasm, pleomorphic nuclei, and enlarged prominent nucleoli. Extensive lymphovascular invasion was noted. Based on morphology, the diagnosis of renal cell carcinoma, Fuhrman grade 4, with extensive rhabdoid and focal sarcomatoid features was rendered. Follow-up computed tomography demonstrated a hypodense area within the right hepatic lobe, which upon resection showed identical morphology to the renal mass, except for focal areas of prominent epithelioid cells with abundant eosinophilic cytoplasm. Immunohistochemistry of both resection specimens (kidney and liver) demonstrated positive staining for Melan-A, HMB-45, and epithelial membrane antigen, focal positive staining for TFE3, and negative staining for PAX8 and cytokeratin. The initial diagnosis of renal cell carcinoma was amended to malignant epithelioid angiomyolipoma with hepatic metastasis. The diagnosis of angiomyolipoma/perivascular epithelioid cell tumor is particularly problematic owing to the large number of potential mimics. Immunohistochemistry for myomelanocytic differentiation should be considered in the context of kidney lesions with epithelioid and spindled cell morphology.

Immunoexpression of epithelial membrane antigen in canine meningioma: Novel results for perspective considerations.

Epithelial membrane antigen (EMA) is one of the most widely used diagnostic immunohistochemical markers for human meningioma. To date, no published study on EMA expression in formalin-fixed paraffin-embedded (FFPE) tissue samples of canine meningioma is available. Here, we describe the results of an immunohistochemical study on 25 FFPE canine meningiomas using a monoclonal anti-human EMA antibody. All meningiomas showed positive staining for EMA with cytoplasmic pattern, in nine cases associated with membranous staining. Area and intensity of staining were highly variable among cases. No clear relationships between tumour subtype/grade and area/intensity of staining were found. However, epithelial-like patterns showed a higher affinity for EMA compared to the mesenchymal one. The present study provides the basis to explore the potential diagnostic application of this marker in canine meningioma. To investigate EMA expression in other central nervous system tumours of dogs are necessary to assess the specificity of this marker.

Gallbladder metastasis of renal cell carcinoma presenting as a hypervascular polypoid lesion: case report of two cases with immunohistochemical analysis

BackgroundMetastasis of renal cell carcinoma (RCC) to the gallbladder is rare, and its clinicopathological feature remains poorly understood. We here present two cases of gallbladder metastasis from RCC presenting as a hypervascular polypoid lesion.Case presentationThe first case was a 73-year-old man who had undergone right nephrectomy for clear cell RCC. Imaging studies detected a hypervascular polypoid lesion in the gallbladder 6 years after nephrectomy. Laparoscopic cholecystectomy was done. The pathological findings of the polypoid lesion showed proliferation of clear cells in the submucosal layer. Immunohistochemically, the tumor was positive for carbonic anhydrase 9 (CA9) but negative for cytokeratin 7 (CK7), suggestive of metastatic RCC. The second case was a 43-year-old man who had undergone right nephrectomy for clear cell RCC. Imaging studies revealed a hypervascular polypoid lesion of 20 mm in diameter in the gallbladder 1 year after nephrectomy. The patient underwent expanded cholecystectomy and extra-hepatic bile duct resection with lymphadenectomy. Microscopically, the polypoid lesion of the gallbladder was composed of clear cells in the submucosal layer. Immunohistochemical analysis showed positive staining for epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA) but negative staining for CK7, leading to the diagnosis of metastatic RCC.ConclusionsGallbladder metastasis from RCC is rare but should be considered when a hypervascular polypoid lesion in the gallbladder is detected during the follow-up period after RCC treatment.

Clinicopathologic Characterization of Hidradenoma on Acral Sites: A Diagnostic Pitfall With Digital Papillary Adenocarcinoma.

Hidradenomas are benign sweat gland tumors that typically present as small nodules in adulthood. Their anatomic distribution is wide and rarely includes acral sites. In this setting, reliable separation from digital papillary adenocarcinoma is important, but notoriously difficult. Hematoxylin and eosin-stained sections of 25 hidradenomas on acral skin were retrieved. The clinical presenting features and morphologic findings were recorded, and follow-up was obtained. Immunohistochemistry was performed for AE1/3, CK5/6, EMA, CEA, SMA, S100, p40, and p63. The tumors presented as solitary nodules on the hands (n=17) and feet (n=8) of adults (age range: 20 to 81 y; median: 50 y), with an equal sex distribution. Histologically, the well-circumscribed tumors were lobular, with a solid and cystic growth within dermis. Duct and squamous differentiation and vascularized hyaline stroma were frequent. The majority (n=18) were poroid hidradenomas. Scattered cytologic atypia and mitotic activity (median: 2/10 HPF) were common, and a pseudoinfiltrative growth of strands in a hyaline to sclerotic matrix was noted in 5 tumors. No papillary structures, atypical mitoses, or tumor necrosis were present. Immunohistochemically, all tumors expressed AE1/3, CK5/6, p40, and p63 strongly and diffusely. Luminal differentiation was highlighted by epithelial membrane antigen and carcinoembryonic antigen staining. S100 and SMA staining was absent. Follow-up (1 to 288 mo; median: 61 mo), available for 20 patients, showed no local recurrences and no disease-related mortality. Acral hidradenomas and digital papillary adenocarcinomas share a well-circumscribed dermal growth pattern containing solid, cystic, and tubular areas with mitotic activity and at least focal cytologic atypia. Lack of papillary structures and the diffuse positivity for p40 and p63 in the absence of S100 and SMA expression are helpful features in favor of acral hidradenoma.

Colloid cyst of third ventricle: Histopathological and ultrastructural study

Cysts occupying the third ventricle are rare lesions and may appear as an unusual cause of hydrocephalic crisis. A 40-year old woman with headache and one episode of fainting attack was diagnosed with a cystic lesion in the third ventricle after brain MRI study. She was operated with the pre-operative diagnosis of a colloid cyst. A yellowish, thick and mucoid cyst was observed intra-operatively. The total removal of the cyst was done along with the cyst wall. On histopathological evaluation, the cyst wall was lined by ciliated cuboidal to pseudostratified columnar epithelium resting on an eosinophilic basement membrane. The ultrastructural study showed the characteristic 9+2 pattern of cilia. Immunohistochemistry showed positive staining for epithelial membrane antigen (EMA), cytokeratin (CK), and negative staining for Glial fibrillary acidic protein (GFAP). Histopathological and ultrastructural findings confirm the diagnosis of a colloid cyst of third ventricles favoring the endodermal origin of the cyst.

Desmoplastic trichoepithelioma complicated by sebaceous hyperplasia: a case report

A 67-year-old male patient presented with a plaque on the top of the head for more than 1 year. Physical examination showed an annular pale red plaque sized about 1.5 cm × 1 cm on the top of the head. It had a depressed center and papule-like elevated faint yellow boundaries, and there was no hair on the surface of the lesion. Histopathologic examination revealed milder epidermal hyperplasia, a small area of epidermal depression, confluence and hyperplasia of multiple sebaceous glands in the dermis, many keratinous cysts and funicular basophilic epithelial cells surrounded by hyperplastic collagen fibers in the superficial dermis. Immunohistochemical study showed positive staining for CD34 (hair mesenchymal cells) , epithelial membrane antigen (EMA) , cytokeratin 20 (CK20) , but negative staining for bcl-2, P53, CD56 and collagen Ⅳ, with the proliferation index Ki-67 of 2% - 5%. Based on the pathological results, the patient was diagnosed with desmoplastic trichoepithelioma complicated by sebaceous hyperplasia. Key words: Sebaceous gland diseases; Desmoplastic trichoepithelioma

Colonic perineurioma (benign fibroblastic polyp): case report and review of the literature

BackgroundColorectal perineuriomas are uncommon benign mucosal-based proliferations of mesenchymal cells that express perineurial markers, often associated with colonic crypts displaying a serrated/hyperplastic architecture. The vast majority of cases arise distal to the splenic flexure and have been described as sessile polyps. Using molecular analysis, BRAF mutations have been demonstrated in the serrated crypt epithelium. We report a new case of perineurioma presenting as a pedunculated polyp in the transverse colon, with prominent hemosiderin deposits in the uninvolved lamina propria that separated the perineurial proliferation from the surface epithelium, a previously unreported histological finding. By using immunohistochemistry, we demonstrated the presence of BRAF V600E mutated protein in the serrated crypt epithelium. In addition, a review of the literature on colorectal perineurioma is provided.Case presentationA 5 mm pedunculated polyp was removed from the transverse colon of a 42 year old man who presented with epigastric pain, weight loss and rectal bleeding. A proliferation of uniform plump spindled cells expanded the lamina propria and separated serrated colonic crypts. The epithelial component closely resembled microvesicular hyperplastic polyp. Immunohistochemical stains for epithelial membrane antigen (EMA), glucose transporter 1 (GLUT1) and collagen IV were positive in the stromal proliferation. A mutation-specific monoclonal antibody directed against BRAF V600E showed positive cytoplasmic staining in the serrated crypt epithelium but not in the perineurial proliferation. Conspicuous hemosiderin deposition was seen in the inflamed lamina propria between the perineurial proliferation and the surface epithelium.ConclusionAlthough the majority of colorectal perineuriomas occur in the sigmoid colon and rectum and are described as sessile polyps, colorectal perineurioma can present as a pedunculated polyp proximal to the splenic flexure as described in this case. Conspicuous hemosiderin deposition can be seen in the superficial lamina propria. BRAF mutations are limited to the serrated crypt epithelium.

Cell Polarity Reversal Distinguishes True Micropapillary Growth From Retraction Artifact in Invasive Urothelial Carcinoma.

Focal micropapillary features in invasive urothelial carcinoma is sometimes difficult to distinguish from retraction artifact morphologically. Cell polarity reversal has been demonstrated in micropapillary tumors by epithelial membrane antigen (EMA) immunostaining. We have previously described the use of E-cadherin as a cell polarity marker in ovarian micropapillary serous borderline tumors. The aim of this study was to evaluate the utility of immunohistochemistry for EMA and E-cadherin in differentiating micropapillary urothelial carcinoma from retraction artifact. We identified 29 invasive urothelial carcinomas with micropapillary features and 30 invasive urothelial carcinomas without reported micropapillary features but with areas of retraction artifact. Cell polarity reversal was considered present if E-cadherin showed membranous apical cup-like staining or if EMA demonstrated a well-defined basal staining towards the stroma. Twenty-seven of 29 cases (93%) of urothelial carcinoma with micropapillary features demonstrated EMA or E-cadherin staining patterns consistent with cell polarity reversal. Staining consistent with micropapillary architecture was identified with both markers in 20 of these 27 cases (74%). Six cases showed reversal of polarity by E-cadherin alone, whereas 1 case showed polarity reversal by EMA alone. Retraction artifacts showed circumferential staining by E-cadherin and lacked well-defined basal staining by EMA. Three cases originally classified as with retraction artifact showed reversal of cell polarity by both EMA and E-cadherin and were reclassified as micropapillary. Our data show that pathologists can reliably make this distinction in most cases. However, in some cases with ambiguous features, EMA and E-cadherin immunostaining may aid in resolving this diagnostic dilemma.

Peripheral Ameloblastoma: A Study of 18 Cases and Usage of Ber-EP4 Immunohistochemistry to Rule out a Diagnosis of Intraoral Basal Cell Carcinoma

Peripheral ameloblastoma (PA) is a rare odontogenic tumor arising in the mucosa of tooth-bearing areas of the jaws that typically shows no radiographic evidence of bone involvement. It bears close histologic resemblance to intraoral basal cell carcinoma (IOBCC), an extremely rare entity. In our experience from previous published data, 3 cases of IOBCC were initially misdiagnosed as PA and were later differentiated from PA on the basis of Ber-EP4 protein expression. This unusual but significant experience set the premise for us to rule out a diagnosis of IOBCC by evaluating Ber-EP4 expression in all previously diagnosed cases of PA from the University of Florida Oral Pathology (UFOP) biopsy service archives. With institutional review board approval, 18 cases of PA were retrieved from the UFOP biopsy service archives. We describe the clinicopathologic features of these cases and discuss the Ber-EP4 immunohistochemical staining performed to rule out a potential diagnosis of IOBCC. In addition, we conducted calretinin and epithelial membrane antigen staining for 1 case of PA. Most PAs presented in the lingual gingiva of the posterior mandible. Men were affected twice as often as women, and the average age at the diagnosis was 59±21.5years. Of the 18 lesions, 13 showed no reactivity to Ber-EP4, 4 displayed patchy membranous immunoreactivity, and 1 demonstrated nonspecific reactivity. We have concluded that all cases of PA that present with histologic overlap with basal cell carcinoma, especially those from incisional biopsies, those that appear significantly infiltrative, and those that appear ulcerated and/or demonstrate recurrence should be evaluated with Ber-EP4 to rule out IOBCC.

Small cholangiolocellular carcinoma that was difficult to distinguish from cholangiocellular carcinoma: a case report

BackgroundCholangiolocellular carcinoma (CoCC) is thought to be derived from hepatic progenitor cells. Because of its origin, CoCC has diverse clinicopathological and imaging findings. Here, we report a case of small CoCC that was difficult to diagnose preoperatively.Case presentationA 62-year-old woman was confirmed with a small liver nodule in the left lobe 2 years after a sustained virological response of hepatitis C virus. The size of the nodule was 11.9 × 6.1 mm, and 6 months later, the size increased to 12.5 × 7.8 mm. The doubling time of this tumor was 285 days. The tumor revealed peripheral early enhancement and delayed internal staining in dynamic computed tomography images and marked high intensity in diffusion-weighted magnetic resonance imaging scans. These imaging findings resembled those of cholangiocellular carcinoma (CCC). The tumor was removed by laparoscopic lateral sectionectomy. Pathological findings revealed that the tumor was composed of small cuboidal cells and showed irregular anastomosis small grand. Immunohistochemical findings showed that the tumor cells were negative for Hep-par 1 and positive for cytokeratin 19. Epithelial membrane antigen staining was positive for the membranous side of the lumen. According to these pathological findings, the tumor was diagnosed as CoCC.ConclusionAlthough some characteristic imaging findings are reported for CoCC, they are not specific because of the variety in pathological findings. Especially, small CoCCs might have poor characteristic imaging findings and may be difficult to distinguish from CCC in the images. However, slow tumor growth might be one of the characteristics to suspect the possibility of a CoCC.

An aggressive case of sclerosing mucoepidermoid carcinoma with eosinophilia of thyroid: a case report

Sclerosing mucoepidermoid thyroid carcinoma with eosinophilia (SMECE) of the thyroid is a rare disease with approximately 50 cases reported worldwide. We describe SMECE of the thyroid affecting a 44 year old female and the first reported case of SMECE of thyroid in New Zealand. This case is of interest as the disease course was particularly aggressive with uncommon immunohistology. Our patient presented with a 4 month history of a painless swelling in her right upper neck. CT revealed a diffusely enlarged thyroid with infiltration of the trachea. A total thyroidectomy, tracheal resection and bilateral neck dissection was performed. Histology showed nests and cords of moderately sized epithelioid cells with prominent nucleoli, with focal glands and tubules. Immunohistology was performed. CK14 and epithelial membrane antigen staining was focally positive. The patient went on to receive chemo-radiotherapy. A CT scan later revealed metastasis to her lungs. She died 7 months from her diagnosis. Our case provides an example of aggressive SMECE of thyroid.