Epithelial Membrane Antigen Research Articles

Solitary nodule of cutaneous reticulohistiocytosis: A case report

Introduction: Solitary cutaneous reticulohistiocytosis represents a rare form of benign monocyte/macrophage proliferation. On routine histology, these lesions are typically described as large cells with cytoplasm showing ground glass appearance and giant cells. They grow up to 1 cm in size with rare cases exceeding this size. Case Report: This case report of a 28-year-old male demonstrated a nodule of reticulohistiocytosis measuring 2.2 cm in size. Microscopic features showed a well-demarcated nodule in the dermis with large histiocytes with ground-glass eosinophilic cytoplasm, giant cells, and foamy macrophages in a background of mixed inflammatory cells. Immunohistochemical staining showed positive staining for vimentin, CD68, CD31, with focal and patchy positivity for S100, CD43, and CD45 and negative staining for CD1a, langerin, CD21, CD23, CD30, CD34, ERG, D2-40, AE1/AE3, epithelial membrane antigen (EMA), smooth muscle actin (SMA), myogenin, desmin, SOX10, HMB-45, tyrosinase, and MelanA. Conclusion: The microscopic and immunohistochemical findings are characteristic of this entity but it is important to recognize for proper management and differentiation from other malignant lesions.

Extranodal Mesenteric Follicular Dendritic Cell Sarcoma Expressing Keratin Antigens: What Pitfalls Initiate Diagnostic Clues.

Extranodal follicular dendritic cell sarcomas are infrequent diagnostically challenging tumors. Because of their rarity, heterogeneous histomorphologic features and variable histologic grades a significant number of extranodal lesions are prone to be misdiagnosed. Even though they have a characteristic immunoprofile, expression of a range of nonspecific markers is well documented. Even though they are typically negative for keratins, few authors have reported lesions expressing keratin. Keratin expressing tumors are more likely to be misinterpreted by pathologists further deterring their inclusion in the differential diagnosis. We report an intraabdominal mesenteric follicular dendritic cell sarcoma in a 44-year-old male that immunophenotypically expressed keratin antigens. The lesion showed a high-grade pleomorphic epithelioid appearance and the initial differential diagnosis included lymphoma, sarcomas, melanoma, and carcinomas. Follicular dendritic cell sarcoma was not considered. Expression of epithelial membrane antigen and keratin further deterred the diagnosis which was reached only after extensive use of immunomarkers. The tumor cells expressed CD21, CD23, and D2-40. Morphologically, the tumor showed some thymoma-like features with occasional TDT-expressing background T-lymphocytes. These features were hints to reconsider our differential diagnosis to include follicular dendritic cell tumors. Awareness of this aberrant staining of epithelial immunomarkers and attention to certain clues should encourage pathologists to consider this entity. Speculative assumptions may explain this unusual keratin expression in some lesions. The histomorphologic and immunohistochemical heterogeneity may suggest different variants and grades of follicular dendritic cell sarcomas. The prevalence, importance, and histogenesis of keratin expression in follicular dendritic cell sarcomas warrant further studies.

Anaplastic Large-cell Lymphoma Involving Gastrointestinal Tract: A Clinicopathologic Study of 25 Cases of a Rare Tumor at a Rare Site.

Background. Anaplastic large-cell lymphoma (ALCL) is an uncommon lymphoma divided into anaplastic lymphoma kinase (ALK) positive, ALK negative, and breast implant-associated (BIA) ALCL. Gastrointestinal tract involvement is very rare and may be difficult to diagnose. Its recognition is crucial as prognostic ramifications are different. Objectives. To describe clinicopathological features of ALCL involving the gastrointestinal tract. Materials and Methods. Slides were reviewed. Diagnosis was confirmed. Histological and immunohistochemical features were described. Results.Twenty-five tumors were diagnosed during the study period. Ages ranged from 14 to 65 years (mean 41 years). Mean age for ALK-negative and ALK-positive patients were 49 and 17 years, respectively. Twenty-one were males and 4 were females. Eighteen involved small intestine. Mean tumor size was 4.2 cm. All showed diffuse sheets of large anaplastic cells with pleomorphic nuclei, abundant pink cytoplasm, and strong positivity for CD30. Epithelial membrane antigen was positive in 17 tumors and keratin was negative in all. Eighteen tumors were ALK negative. Out of 14 patients with follow-up, 12 died within a few months of diagnosis. Seven had stage IE, 5 had stage IIE, and 2 had stage IV disease. Two patients were alive at 35 and 60 months. Twelve received chemotherapy. Conclusion. A marked male predominance was noted. Small intestine was the commonest site of involvement. Majority were ALK negative. ALK-negative tumors occurred in older patients and ALK positive in younger patients. Prognosis was poor. ALCL should be included in the differential diagnosis of anaplastic epithelioid cell neoplasms in the gastrointestinal tract.

Primary Pulmonary Hyalinizing Clear Cell Carcinoma: Case Series With Review of Literature.

Background: Hyalinizing clear cell carcinomas of tracheobronchial origin are very rare salivary gland type tumors accounting for less than 1% of lung tumors with only 13 cases reported to date. Their radiological features, morphological spectrum, and molecular features are not well described. Aim: To perform a clinicopathological analysis of primary pulmonary hyalinizing clear cell carcinomas. Method: A retrospective search of primary pulmonary hyalinizing clear cell carcinomas was conducted from authors' institutions and the clinicopathological features including details of molecular testing were analyzed. Results: Five primary pulmonary hyalinizing clear cell carcinomas were identified. The mean patient age at diagnosis was 48.2 years (range: 33-64 years). Three patients were women. All patients were nonsmokers and 3 were symptomatic; 2 were detected incidentally during health screening. The tumors were located in the main lobar bronchi ranging from 1.3 to 4.9 cm in maximum dimension. Microscopy showed cords and nests of at least, focally clear tumor cells. Mucin cysts lacking goblet cells were seen. All tumors were uniformly positive for p40, p63, AE1/AE3, keratin 7, and epithelial membrane antigen but negative for TTF1, KIT, neuroendocrine markers, and other myoepithelial markers. All cases showed Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement. Perineural invasion and lymph node metastases were detected in patient 5. Two patients with available follow-up data were recurrence-free until 4 years (patient 1) and 9 months (patient 5) after resection. Conclusion: The present series adds to the scant available literature on primary pulmonary hyalinizing clear cell carcinomas highlighting the characteristic histomorphology, immunoprofiles, and benign outcomes of these rare tumors.

Primary cutaneous adenoid cystic carcinoma of the scalp: dermatosurgical approach with favourable outcome.

Although described as early as 1975 as a distinct, rare form of cancer with diverse localization, primary cutaneous adenoid cystic carcinoma (PCACC) remains a mystery and challenge for both clinicians and pathologists. The clinical presentation cannot be clearly distinguished from amelanotic melanoma or intradermal nevus, Merkel cell carcinoma, trichofolliculoma, trichoepithelioma or other rare tumors of the adnexa, or dermatofibrosarcoma protuberans. The histopathological diagnosis requires not only careful evaluation of standard hematoxylin/eosin preparations, but also immunohistochemical staining with a number of markers such as epithelial membrane antigen (EMA), S-100, SOX-10, Ki- 67, CD-117 (c-kit), Vimentin, carcinoembryonic antigen (CEA), Ber-EP4 and many others. The surgical approach should consist of excision with margins between 1 and 2 cm, with the choice of margins depending upon the histopathological findings in the primary excisional specimen. We present a 31-year-old patient with an enlarging, amelanotic, plaque-like tumor of the scalp with a duration of no more than 18-24 months. Surgical treatment was performed within two surgical sessions with a total resection field of 1.3 cm. A good cosmetic result was achieved.

Sekretuar Meningiom: Radyolojik ve Patolojik Olarak Malign Tümörlerle Karıştırılabilen Nadir Bir Antite

AbstractMeningiomas are slow growing, extra axial brain tumors that originating from the meningothelial cells of the arachnoid. Meningiomas are the most common brain tumors, however secretory meningiomas are extremely rare variant and can be confused radiologically and pathologically with malignant tumors. A 48 years old male was presented with a complaint of headache and visual impairment in the left eye. Magnetic resonance imaging revealed an extra axial mass lesion in the left pontocerebellar region, 57x48x30 mm in size, and marked edema around the mass. Microscopically, a tumoral lesion consisting ofuniform meningothelial cells with oval-round nuclei, thin vesiculated chromatin, and moderately eosinophilic cytoplasm was observed. The presence of epithelial differentiation characterized by pseudopsammom structures formed by lumens containing eosinophilic secretion was appointed among the tumor cells. Eosinophilic secretion within the lumens were highlighted with histochemical periodic acid schiff (PAS) stain. Immunoreaction was observed in the pseudopsammom structures and the surrounding tumor cells with carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA) and pan cytokeratin (Pan-CK). Tumor cells were immunopositive with Vimentin and progesterone receptor (PR). Ki67 proliferation index was determined as <1%. No necrosis or mitosis were detected. The tumor was reported as ‘‘secretory meningioma’’. No additional treatment was applied to the case and no recurrence was detected in 32 month follow-up after surgical resection. Although secretory meningiomas are not clinically important due to their benign course, differantial diagnosis is critical, since they can be confused with malign tumors because of marked brain edema radiologically, elevated serum CEA levels and epithelial differentiation.

Undifferentiated Wing Sarcoma in a Peach-Faced Lovebird (Agapornis roseicollis)

A 10-year-old peach-faced lovebird (Agapornis roseicollis) was evaluated for an ulcerated and painful mass at the location of a fracture 2 years previously. Whole body radiographs showed a humeral fracture with a presumptive neoplastic proliferation in the distal diaphysis. Right wing amputation was elected but the animal died during recovery from surgery. Histopathological examination of the amputated wing revealed an infiltrative sarcomatous neoplastic proliferation. Immunohistochemistry (IHC) was carried out to characterize the tumour using antibodies against vimentin, desmin, smooth muscle actin (SMA), S-100, ionized calcium-binding adapter molecule-1 (IBA-1), CD18, cytokeratin and epithelial membrane antigen (EMA). The mesenchymal component of the mass was immunolabelled for vimentin and SMA and sparse epithelial cells were immunopositive for cytokeratin. Very few scattered cells were immunopositive for CD18 and IBA-1. The final diagnosis was consistent with an undifferentiated sarcoma with intralesional hyperplastic epithelium. According to the location, the history of a previous fracture and the histological pattern and IHC profile, the tumour was classified as an undifferentiated sarcoma with entrapped air sac epithelium.

JAK/STAT3 Signaling Activation Related to Distinct Clinicopathologic Features in Systemic ALK - Anaplastic Large Cell Lymphomas : New Insights into Their Heterogeneity.

Systemic anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is a group of heterogenous CD30 + T-cell non-Hodgkin lymphomas. Previous studies have highlighted the importance of JAK/STAT3 signaling activation in the molecular pathogenesis of ALK - ALCLs. In the present study, we aimed to establish a potential relationship between JAK/STAT3 signaling activation and clinicopathologic features in ALK - ALCLs, and further recognize the heterogenous nature of these neoplasms. Immunohistochemistry staining of the phosphorylated-STAT3 (p-STAT3) and dual-specificity protein phosphatase 22 ( DUSP22 ) gene rearrangement analysis were performed. Forty-five cases of ALK - ALCL were divided into 3 groups, including 9 DUSP22 -rearranged ALCLs, 21 p-STAT3 + double-negative (DN) ALCLs (both ALK and DUSP22 rearrangement negative), and 15 p-STAT3 - DN-ALCLs. Morphologically, p-STAT3 + DN-ALCLs exhibited sheet-like neoplastic cells and sometimes showed large pleomorphic cells scattered in a lymphocyte-rich background more frequently than those in other ALK - ALCLs subtypes. Phenotypically, the p-STAT3 + DN-ALCLs frequently expressed cytotoxic molecules, epithelial membrane antigen, and programmed death-ligand 1, whereas CD3 and CD5 expression was not observed. Clinically, patients with p-STAT3 + DN-ALCLs had a better prognosis than those with p-STAT3 - DN-ALCLs. These observations suggest that p-STAT3 + DN-ALCLs represent a distinct subtype of ALK - ALCLs. Identifying ALK - ALCL subtypes by using p-STAT3 staining and DUSP22 rearrangement is a promising approach that may contribute to risk stratification and better treatment decisions in the future clinical practice.

Diagnosis and Management of Porocarcinoma.

Eccrine porocarcinoma, also known as porocarcinoma (PC) and malignant eccrine poroma, is very rare and is known to arise from the cutaneous intraepidermal ducts of the sweat glands. Its etiology is not well understood; however, some studies suggest that PC tumors originate from benign eccrine poroma. Recently, several gene alterations have been reported in PC that can reveal mechanisms of the oncogenic process. Since the clinical and histopathological findings of PC are variable, PC is difficult to diagnose precisely, especially when the histology resembles that of cutaneous squamous cell carcinoma or poroma. Immunohistochemical staining with carcinoembryonic antigen and epithelial membrane antigen may help to distinguish PC from other tumors. The standard treatment for local PC is wide local excision. The prognosis of patients with metastatic PC is poor, with mortality rates of approximately 60-70%. The efficacy of radiation and chemotherapy for metastatic PC is limited; however, immunotherapy with pembrolizumab, a programmed cell death protein 1 inhibitor, could be a promising treatment. This review focuses on the history, pathogenesis, pathological features, diagnosis, and treatment of eccrine porocarcinoma.

Distinctive Nested Glomoid Neoplasm: Clinicopathologic Analysis of 20 Cases of a Mesenchymal Neoplasm With Frequent GLI1 Alterations and Indolent Behavior.

Recently, it has been recognized that a subset of primary soft tissue neoplasms with GLI1 gene alterations exhibit nested architecture and can mimic glomus tumors or well-differentiated neuroendocrine tumors. Here, we report a series of 20 such neoplasms, which we have provisionally termed "distinctive nested glomoid neoplasm." Eleven patients (55%) were female and 9 were male. The median age at presentation was 41.5 years (range: congenital to 74y). The anatomic distribution was wide, with body sites including the trunk (7 tumors), lower extremity (5), tongue (4), upper extremity (3), and neck (1). Excluding tumors of the tongue, 10 tumors (62%) arose in deep soft tissue and 6 (38%) arose primarily in the subcutis. Tumor size ranged from 0.9 to 11.1cm (median: 3cm). Distinctive nested glomoid neoplasms are composed of nests of round-to-ovoid cells with scant, palely eosinophilic cytoplasm and monomorphic nuclei with vesicular chromatin and small nucleoli. The nests are invested by prominent capillary networks, and they are situated within large lobules separated by irregular, thick fibrous septa. Among 18 tumors for which adjacent non-neoplastic tissue could be assessed, perivascular proliferation of tumor cells was identified in 16 tumors (89%). Microcystic architecture was present at least focally in 8 tumors (40%), and myxoid stroma was identified at least focally in 5 (25%). Seven tumors (35%) showed clear cell features. By immunohistochemistry, some tumors expressed MDM2 (7/15; 47%), S100 (5 of 19; 26%), STAT6 (2 of 5; 20%), and AE1/AE3 (1/5; 20%). Tumors rarely expressed pan-keratin (1/10; 10%) or CAM5.2 (1/10), and all tumors were negative for β-catenin (12 tumors), chromogranin (12), synaptophysin (11), epithelial membrane antigen (10), desmin (10), smooth muscle actin (9), INSM1 (7), and CD34 (6). GLI1 break-apart fluorescence in situ hybridization was performed on 7 tumors, and next-generation sequencing was performed on 15 tumors (10 DNA sequencing only, 1 RNA sequencing only, 4 both DNA and RNA sequencing). Sixteen tumors, including all 15 tested by next-generation sequencing and an additional case tested by fluorescence in situ hybridization only, were found to harbor GLI1 gene alterations: 10 harbored GLI1 gene rearrangements (3 ACTB :: GLI1 , 2 PTCH1 :: GLI1 , 1 HNRNPA1 :: GLI1 , 1 NEAT1 :: GLI1 , 1 TXNIP :: GLI1 , 2 undetermined fusion partners), and 6 harbored GLI1 amplification. Clinical follow-up was available for 10 patients (50%; range: 3mo to 10y; median: 6.4y), including 8 with >1 year of follow-up. Three patients (30%) experienced local recurrence (at intervals of 3mo to 10y). None developed distant metastases or died of disease as yet. Overall, our findings support the notion that a subset of GLI1 -altered soft tissue neoplasms are indolent, morphologically distinctive nested glomoid neoplasms that should not be classified as sarcomas.

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.

Structure and barrier functions of the perineurium and its relationship with associated sensory corpuscles: A review.

Peripheral nerves are provided with a blood-nerve barrier which prevents the invasion of harmful substances and pathogens, and also regulates metabolic and ionic homeostasis within nerve fascicles. The barrier functions are attributed to both the concentric layer of flattened cells in the perineurium and blood vessels running in the endoneurium. The perineurial cells develop continuous tight junctions as a diffusion barrier. In order to take up a predominant nutrient, glucose, the perineurium as well as endoneurial capillaries expresses GLUT1, a glucose transporter. An axon-Schwann cell complex within peripheral nerves utilizes glucose as a major energy source via the GLUT1, as does the brain. Under conditions of a reduced utilization of glucose, only the perineurial cells can transfer other nutrients, namely monocarboxylates such as ketone bodies and lactate via MCT1. Thus, MCT1 colocalizes with GLUT1 in the perineurium but not in endoneurial capillaries. To identify the cellular origins of the nerve sheath, marker proteins such as glial specific S100 protein, GLUT1, endoneurial CD34, and EMA (epithelial membrane antigen) are useful. Immunohistochemical findings for these markers are reviewed in this paper, focusing on the perineurium and endoneurium and their derivatives, Pacinian and Meissner corpuscles. Growing evidence throws light on the critical involvement of the nerve sheaths in the development, maintenance, and diseases of peripheral nerves.

S2143 The Gang's All Here: A Rare Case of Polypoid Ganglioneuroma of the Colon

Introduction: Ganglioneuromas are rare benign growths characterized by proliferation of nerve ganglion cells, nerve fibers & supporting cells of the nervous system. These growths have mostly been described in children but occur in adults as well. They are usually found in the mediastinum, retroperitoneum and adrenal glands but rarely, they occur in the gastrointestinal tract. Clinical manifestations depend on the location and size but can include abdominal pain, constipation, bleeding or obstruction. There are no known modifiable risk factors, but in some cases, they are associated with rare genetic syndromes like Cowden, Juvenile Polyposis and Peutz-Jeghers. Herein, we report a rare case of an isolated cecal ganglioneuroma. Case Description/Methods: Our patient was a 63-year-old female with no pertinent past medical history who presented for a routine screening colonoscopy. She had normal vital signs and no abnormal laboratory findings. During the colonoscopy, cold forceps polypectomy was performed to retrieve 2 3-mm polyps in the ascending colon and one 2 mm polyp from the cecum. Hematoxylin and eosin staining of the cecal polyp revealed evidence of spindle cell proliferation accompanied by large cells with prominent nucleoli, consistent with ganglion cells. The immunostaining of the cecal polyp was reactive for the S100 protein but was negative for markers of stromal tissue (CD34, CD117, smooth muscle actin, desmin, epithelial membrane antigen). The concurrence of these findings was consistent with a diagnosis of polypoid ganglioneuroma (Table). Discussion: Colonic ganglioneuromas are divided into 3 major groups: polypoid ganglioneuromas, ganglioneuromatous polyposis & diffuse ganglioneuromatosis. Most of these tumors are found incidentally on screening colonoscopy. Though most of these tumors are benign, few reports have noted an associated incidence of colorectal cancer. Genetic testing is advised if there is existence of a genetic syndrome. There is a lack of guidelines regarding best practice management of these tumors as well as lack of consensus regarding screening measures & follow up surveillance colonoscopy for recurrence. However, similar to other cases reported in the literature that have been successfully treated with polypectomy, the tumor in our case was excised safely endoscopically. Thus endoscopic resection can be a curative method for solitary ganglioneuromas. We believe that awareness & proper counseling will translate into better care of patients with such tumors. Table 1. - Classification of colonic ganglioneuromas with identifying features 1. Polypoid ganglioneuroma - small (< 2cm) & solitary- sessile or pedunculated 2. Ganglioneuromatous polyposis - numerous (often 20-40)- sessile or pedunculated 3. Diffuse ganglioneuromatosis - can range from 1-17 cm in size- present as disseminated, nodular, intramural or transmural lesions

An uncommon case of primary synovial sarcoma of the lung with a rare intraoperative finding

We report a case of a 32-year-old male who was evaluated for right chest pain and cough with streaky hemoptysis. Chest X-ray and contrast-enhanced computerized tomography scan of the chest showed a large (20x16×16 cm), heterogeneously enhancing mass arising from the right lower lobe. Ultrasound-guided Tru-cut biopsy revealed spindle cell sarcoma. In immunohistochemistry, tumor cells expressed epithelial membrane antigen, CD99, and bcl-2. The final diagnosis of primary pulmonary synovial sarcoma was confirmed after positron emission tomography-computed tomography revealed that the lesion was confined to the right lung. The patient was managed by multimodal treatment. The patient underwent right anterolateral thoracotomy and lower lobectomy with staged systematic mediastinal lymphadenectomy. Intra-operatively, he was given 2 units of packed red blood cells (RBCs). The patient developed dark-colored urine near the end of the transfusion of the second unit of packed RBCs, but without any hemodynamic instability. All the tests for possible blood transfusion reactions were negative; thus, we concluded that this event was probably secondary to tumor lysis due to the handling of the large primary lesions during surgery.

P11.39.B An unusual case of astroblastoma in adult: a case report and review of the literature

Abstract Background Astroblastoma is an uncommon glial neoplasm of controversial histogenesis, clinical behavior and response to treatment yet to be understood. It usually appears in the cerebral hemisphere of young patients, preferably in the frontal and parietal lobes. Histologically, its characteristics overlap with high-grade gliomas, making the differential diagnosis between these entities complex. Clinical, radiological, histopathological correlations and, if necessary, genetic tests (MN1 Rearrangement) are essential for an accurate diagnosis. Material and Methods We present a case report based on data collected retrospectively from electronic medical records. Results A 63-year-old male with a 3-month history of headache and one episode of mental confusion. In the neurological exam, language alteration was noted and the other systemic exams were normal. Magnetic resonance imaging of the brain revealed an intra-axial expansive formation involving the insula, superior and middle temporal gyrus, left portion of brainstem, with lobulated contours and heterogeneous, solid-cystic appearance with intermingled hematic foci. The solid portion had heterogeneous contrast enhancement and foci of gross calcification. The lesion was resected and the postoperative MRI showed no residual tumor lesion. Histopathological evaluation showed an extensive pattern of perivascular pseudorosettes of astrocytic cells with broad processes radiating to central vessels, in addition to frequent foci of hyalinization. Immunohistochemistry showed positive staining with antibodies to glial fibrillary acidic protein (GFAP), vimentin and S100 protein, in addition to membranous positivity for epithelial membrane antigen (EMA). The Ki-67 index was 20%. Based on these data, the diagnosis of NOS astroblastoma was established. Four months after resection, imaging follow-up displayed enhancement of the surgical cavity, suggestive of local recurrence. The patient underwent three-dimensional conformal radiotherapy with a total dose of 6000cGy in 30 sessions, followed by adjuvant chemotherapy with temozolomide.The patient did not have tumor recurrence until the last follow-up made 16 months after surgery. Conclusion This is an atypical case of an extremely rare glial tumor of the central nervous system, since most patients with astroblastoma range from 3 months to 40 years (median: 15 years), which makes the diagnosis challenging.

32748 A case series of pediatric cellular neurothekeomas and a review of the histologic spectrum

Neurothekeomas are rare, benign neoplasms of unknown histogenesis. These neoplasms are a frequent source of diagnostic challenge due to their incompletely defined clinical and morphologic spectrum. Clinically, they may present as a solitary, slow-growing papule or nodule on the head, neck, or extremities of younger individuals, with a slight female predominance. They have traditionally been classified into 3 histologic variants: classical (myxoid), cellular, and mixed, depending on immunohistochemical (IHC) staining and the amount of myxoid matrix. Although the classical variant is believed to be derived from neural sheath cells due to positive S-100 staining, the cellular variant is presumably derived from perineural or dermal lineage. IHC findings for cellular neurothekeomas are typically positive for NKI/C3, smooth muscle actin (SMA) and neuron-specific enolase (NSE), while negative for epithelial membrane antigen (EMA) and S-100. There have been few reports of a rare myxoid cellular neurothekeoma entity that presents with histologic features of the myxoid variant combined with IHC findings of the cellular variant. We herein report a case series of 3 pediatric patients diagnosed with cellular neurothekeoma, particularly highlighting 2 unusual case of a myxoid cellular neurothekeoma with atypical IHC that was negative for NKI/C3, SMA, and NSE as well as negative for S-100. In addition to reporting on our institutional experience with 3 clinical cases of cellular neurothekeomas in a pediatric population, we will explore the histologic spectrum and discuss the current understanding of cellular neurothekeomas.

ONCOCYTIC LIPOADENOMA: REPORT OF THREE RARE CASES INVOLVING THE PAROTID GLAND

Oncocytic lipoadenoma (OL) is a rare salivary gland tumor characterized by the presence of oncocytic cells and mature adipose tissue. To date, only 30 cases of OL have been reported in the English-language literature. We present 3 additional OL cases involving the parotid. Microscopically, the tumors were composed of a mixed population of oncocytes and adipocytes in varying proportions surrounded by a thin, connective tissue fibrous capsule. Oncocytes were positive for pan-cytokeratins AE1/AE3, epithelial membrane antigen, CK-5, CK-7, CK-14, CK-18, and CK-19. Calponin, p63, smooth muscle actin, and carcinoembryonic antigen were negative. Vimentin and S-100 protein were positive only in adipose cells. Despite distinctive morphologic features, OL is often misdiagnosed, given its rarity. Pathologists and surgeons must recognize OLs to avoid misdiagnoses and provide adequate management through conservative surgical excision.

INTRAORAL SEBACEOUS CARCINOMA: REPORT A RARE CASE ON THE TONGUE

Intraoral sebaceous carcinoma (SC) is extremely rare on the tongue. The clinical-pathologic and immunohistochemical characteristics of a rare case of SC in a 59-year-old man is presented. The patient had painful ulcers in the posterior region of the tongue. Microscopically, the tumor was composed of atypical basaloid cells with rounded to oval nuclei and prominent nucleoli arranged in lobes, with prominent sebaceous differentiation and areas of holocrine secretion. Staining with periodic acid-Schiff and staining with mucicarmine were negative in neoplastic cells. By immunohistochemistry, tumor cells were positive for pan-cytokeratin AE1/AE3 and epithelial membrane antigen. The sebaceous cells were positive for adipophilin and perforin. The diagnosis was SC. Ample surgical excision was performed followed by adjuvant chemotherapy and radiotherapy. Careful histopathologic analysis of these lesions is essential to ensure a correct diagnosis and increase the patient's survival time.

SEBACEOUS CARCINOMA IN RETROMOLAR REGION: CASE REPORT

Sebaceous carcinoma is a rare malignant tumor derived from the adnexal epithelium of the sebaceous glands. A 58-year-old White male patient attended the stomatology service complaining about a "lump near the third molar." In the history of the current disease, the patient reported a lesion that appeared approximately 6 months ago and with painful symptoms. Intraoral examination showed a single erythematous tumor in the retromolar region with a smooth surface and ulcerated areas, diffuse borders, irregular, firm, fixed with an infiltrative characteristic, tender, and measuring 2.5 × 2.0 × 1.0 cm. An incisional biopsy was performed with clinical suspicion of squamous cell carcinoma. The histologic sections stained in hematoxylin-eosin and the immunohistochemical reaction showed positivity for epithelial membrane antigen, highlighting the vesicular pattern of the tumor cell cytoplasm. The final result was compatible with sebaceous carcinoma. The patient was referred to the oncology sector and is waiting for cancer treatment.

Artículo traducido] Perfil de expresión de CD10, BCL-2, p63 y EMA en los carcinomas normales de piel y de células basales: Revaloración inmunohistoquímica

BackgroundBasal cell carcinoma (BCC) is common cutaneous malignancy. AimsTo examine the expression patterns of CD10, p63, BCL-2, and epithelial membrane antigen (EMA) proteins in BCC. Materials and methodsWe used immunohistochemistry to evaluate the expression pattern of these proteins in 45 BCC specimens and their adjacent normal skin. ResultsWe found variations in the expression pattern of these proteins among normal skins and BCC. In normal skins, we found strong EMA cytoplasmic expression (adnexal structures). A strong nuclear p63 protein expression was found in basal and some suprabasal keratinocytes, external root sheath cells of the hair follicles, basal cells of the sebaceous glands, and in sweat glands.CD10 protein expression was seen in peri-adnexal mesenchymal spindle cells and myoepithelial cells of sweat glands.BCL-2 protein expression was confined to the basal cell keratinocytes, epidermal melanocytes, outer root sheath, and infundibulum of the hair follicle. In BCC, we found p63 (diffuse, strong nuclear staining), CD10 (focal, moderate cytoplasmic reactivity), and BCL-2 (focal, moderate cytoplasmic reactivity) protein expression in the neoplastic cells. BCC was consistently negative for EMA (except in areas of squamous differentiation). ConclusionsThere is an altered expression of these proteins in BCC. The underlying molecular mechanisms are open to further investigations.