A Single-Center Retrospective Analysis of Kaposi's Sarcoma: Is There a Relationship Between Emmprin/CD147 Expression and Biological Behavior?

OBJECTIVES: Emmprin (CD147/BSG) protein is estimated to play a key role in cell migration and chemoresistance in viral carcinogenesis. However, there are very limited studies investigating the CD147 in the oncogenesis of Kaposi's sarcoma-associated herpesvirus. This study aims to reveal the relationship between CD147 expression with histopathological parameters, disease pattern, and recurrence in Kaposi's sarcoma (KS). METHODS: The study included 67 patients diagnosed with KS between January 1982 and September 2023. Clinical and histopathological features were analyzed retrospectively. HHV-8, CD31, and CD147 expressions were evaluated by immunohistochemistry. RESULTS: Sixteen (24%) female and 51 (76%) male patients with median age of 64 (10-86) were included in the study. CD147 was positive in 57 (85%) cases and associated with nodular pattern (P = .001), presence of solid/fibrosarcomatous area (P = .005), and high mitotic activity (P = .035). The disease relapsed in 17 (27%) of the 63 patients with median 2 (0-12) years follow-up. While a 5-year relapse-free survival was 48.5% in the CD147 diffuse positive group, it was 83.4% in focal positive and 100% in negative cases (P = .029). CONCLUSION: Our study exhibited the relationship between CD147 overexpression and recurrence in KS, but the inhomogeneity of the treatment groups and the small number of patients should also be considered. These findings may provide insight into the pathogenesis of KS and the development of targeted therapies in the future.

Epstein-Barr Virus-Positive Leiomyosarcoma in Immunocompetent Patients.

OBJECTIVE: Epstein-Barr Virus-Associated Smooth Muscle Tumor (EBV-SMT) is a rare tumor with a higher rate of occurrence in unusual locations in the setting of immunodeficiency. In this study, we evaluated a cohort of ordinary leiomyosarcomas (LMS) for the presence of EBV and described the clinicopathological features deviating from routinely diagnosed cases of EBV-SMT. MATERIAL AND METHOD: The sections of tissue microarrays including 93 classical LMS occurring in various locations were hybridized with EBER and stained for LMP1 antibody using the Leica Bond Autostainer. EBV real-time PCR assay was performed in 2 EBER-positive cases. RESULTS: Among the 93 LMS cases, 2 non-uterine cases (2.2%) were positive for EBER and negative for LMP1, and were referred to as `EBV-positive LMS`. Both were females in their 6th decade without immunosuppression. EBV real-time PCR assay revealed the presence of EBV in one of the cases. Tumors were located in the pancreas and chest wall. Morphologically, tumors were rather myxoid, multinodular, and composed of long fascicles of spindle cells with intermediate- to high-grade features. High mitotic activity and focal necrosis were present, whereas no accompanying lymphocytes were detected. One of the patients developed metastatic disease after 3 years. CONCLUSION: EBV-positive LMS occurring in immunocompetent patients has features distinct from classical EBV-SMT seen in immunosuppressed patients.

Giant cell tumor arising from the anterior arc of the rib: an extremely rare site in an adolescent girl.

BACKGROUND: Giant cell tumor is a rare and locally aggressive neoplasm of the long bones in children. Rib is the least frequently affected site, seen in less than 1% of all cases and most of them occur at the posterior arc. CASE: A 12-year-old girl presented with swelling and slight pain on the left inferior-anterior chest wall for two years. Physical examination revealed a giant, hard and fixed mass on the left chest wall. Hematological and biochemical test results were in normal limits but slight elevation of alkaline phosphatase level. Computed tomography of the chest showed a large expansive mass and lytic lesion with internal calcification arising from the anterior part of the 7th rib. En-bloc resection was performed including the 6th-8th ribs and a small part of the diaphragm. The pathological evaluation revealed giant cell tumor of bone. CONCLUSIONS: Herein, we aim to emphasize that giant cell tumor should be considered in the differential diagnosis of chest wall tumors in childhood whereby en-bloc resection and close follow up would be paramount.

Adamantinoma with a Prominent Spindle Cell Component Mimicking Intraosseous Synovial Sarcoma: Clinicopathological Features of Six Tumors.

Introduction. Adamantinoma is sub-classified into classic/biphasic, osteofibrous dysplasia-like, and de-differentiated type. We present six adamantinomas with a prominent spindle cell component mimicking intraosseous synovial sarcomas. Methods. Six patients were either referred with a diagnosis of intraosseous synovial sarcoma or wherein synovial sarcoma was a differential diagnosis. Three tumors were tested for SS18 gene rearrangement by FISH and two for SS18::SSX fusion by RT-PCR technique. Results. There were three males and three females with an average age of 20.6 years. Radiologically, the lesions were expansile and showed lytic and/or sclerotic components, involving the cortex and/or medulla. Five lesions occurred in the tibia and two in the fibula. Two tumors displayed soft tissue extension and two occurred as multifocal lesions. Two patients were diagnosed with synovial sarcoma and a single patient with sarcomatoid carcinoma, elsewhere. Two "in-house" patients were initially diagnosed with synovial sarcomas. On review, all tumors were cellular comprising monomorphic spindle-shaped cells arranged in sheets and fascicles (n = 6), including a "herringbone-like" pattern (n = 3), focal tubules (n = 1), cohesive nests (n = 5), cords (n = 2), including pseudocystic component (n = 2). Immunohistochemically, tumor cells were positive for p63 (6/6), p40 (4/4), EMA (2/3), AE1/AE3 (5/6), various keratins (2/2), and TLE1 (2/4). Three tumors tested for SS18 rearrangement were negative, while two tumors tested for SS18::SSX fusion were negative. Conclusions. Adamantinomas with spindle cell morphology display overlapping features with synovial sarcoma. A clinico-radiological index of suspicion immunostains (p63 and p40) and molecular test for t(X; 18) translocation are useful in an exact diagnosis, which has treatment-related implications.

Aneurysmal Bone Cyst of Pisiform Bone: Diagnosis and Treatment of a Rare Entity: Case Report and a Review of the Literature.

Aneurysmal bone cyst (ABC) is a benign expansile bone tumor without metastasis capability. Only 3-4% of ABCs occur in the hand and they mainly take place in metaphysis' of long bones like metacarpals or phalanges. Carpal ABCs have been reported as individual case reports in the literature due to rarity. A patient presented with pain in her right wrist. Magnetic resonance imaging revealed a well circumscribed one cm sized mass in the pisiform bone that resembled an aneurysmal bone cyst. Total pisiformectomy was performed. Treatment options are total excision or curettaging in ABCs. But rarity of these lesions may delay the diagnosis process for the inexperienced surgeon.

Comprehensive clinicopathologic characteristics of intraabdominal neurogenic tumors: Single institution experience.

BACKGROUND: Neurogenic tumors are rare but represent an important consideration in the differential diagnosis of abdominal mesenchymal tumors. Reports on their incidence, pathological features and clinical characteristics are scarce. AIM: To advance the overall knowledge on the histologic, immunohistochemical, clinical and radiologic characteristics of neurogenic tumors through this case series. METHODS: An established database of a nationwide tertiary referral center, covering a 15-year period (2005 and 2020), was retrospectively re-evaluated. Diagnoses of neurogenic tumor cases were confirmed by two experts following review of the macroscopic, histological and immunohistochemical records along with findings from analysis of archived tissue sections for each included patient. Tissue microarrays were constructed for cases lacking necessary immunohistochemical studies. Clinical data and follow-up information were collected from the hospital records and the patients themselves, when available. RESULTS: The study included 19 cases of intraabdominal neurogenic tumors, representing 12 women and 7 men, between 18 and 86 years of age (median: 51 years). Final confirmed diagnoses were 12 schwannomas, 2 diffuse submucosal neuro-fibromatoses, 2 ganglioneuromas, 2 malignant peripheral sheath nerve tumors, and 1 mucosal Schwann cell hamartoma. Sizes of the tumors were variable, with a median diameter of 4 cm; the two largest (> 10 cm) were schwannomas. The majority of cases were asymptomatic at presentation, but the most frequent symptom was abdominal pain. Gastrointestinal tract lesions were detected with endoscopy and extra-luminal lesions were detected with cross-sectional imaging. All cases were S100-positive and CD117-negative; most cases were negative for desmin, epithelial membrane antigen, smooth muscle actin and CD34. In all but 5 cases, the Ki67 proliferation index was ≤ 1%. CONCLUSION: Re-evaluation of 19 cases of abdominal neurogenic tumors demonstrated con-siderable variability in clinicopathologic characteristics depending on location, dimension and histological features.

Loss of CTNNB1 exon 3 in sclerosing angiomatoid nodular transformation of the spleen.

Sclerosing angiomatoid nodular transformation (SANT) is a rare vascular lesion of the spleen. Although several hypotheses have been suggested, the etiopathogenesis of SANT remains unknown. It is also unclear whether SANT is a reactive or a neoplastic lesion. Since CTNNB1 (ß-catenin gene) exon 3 mutations were frequently detected in some rare fibrovascular lesions, we aimed to investigate the presence of oncogenic CTNNB1 mutations in SANT cases. For this purpose, 7 cases of SANT with typical histopathological features were retrieved. First, the presence of CTNNB1 exon 3 alterations was examined with a recently described immunohistochemistry-based method. Then, the findings were confirmed with polymerase chain reaction (PCR), reverse transcription PCR (RT-PCR), and Sanger sequencing. In all cases, immunochemistry of ß-catenin gave a staining pattern that was suggestive of exon 3 alteration; however, no missense mutations were found in any case at the CTNNB1 exon 3 hotspot region. Subsequently, we screened for large interstitial deletions of CTNNB1 exon 3 which revealed short PCR products in three cases. Sequencing confirmed that these cases had large interstitial deletions, resulting in loss of the entire exon 3 of CTNNB1. In the remaining four cases, loss of exon 3 was documented at the cDNA level, although genomic deletion was not identified. These results demonstrate that loss of CTNNB1 exon 3 and stabilization of ß-catenin with activation of Wnt signaling pathway might have a significant role in the pathogenesis of SANT. Through this study, we provided important evidence for the neoplastic nature and pathogenesis of this disorder.

High-grade neuroepithelial tumor with medulloepithelioma-like areas out of the central nervous system in an infant with hemihypertrophy: a unique association.

BACKGROUND: High-grade neuroepithelial tumor with areas resembling medulloepithelioma was diagnosed in an infant with coccygeal and inguinal masses. Hemihypertrophy is associated with Wilms tumor, hepatoblastoma and pancreatic tumors in children. CASE: The authors report on the first case of peripheral HNET associated with hemihypertrophy in an infant, with special discussion on histopathological differential diagnosis and management of this rare and highly malignant tumor. CONCLUSIONS: HNET should be included into the list of hemihypertrophy associated tumors. Complete surgical excision with free margins is essential for the successful treatment of such cases and should be tried in suitable cases at the time of diagnosis. Continued treatment should be decided individually on a case to case basis.

Stereotactic ablative radiotherapy for bone metastasis of gastrointestinal stromal tumor: Case report and review of the literature.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. These tumors are rare and only make bone metastases at a rate of 5%. CASE SUMMARY: A 31-year-old male with a GIST presented with solitary bone metastasis at the right iliac bone. We performed stereotactic ablative radiotherapy (SABR) and achieved excellent local control. Herein, our case is presented, and a short review of the literature is carried out. CONCLUSION: SABR should be considered as a treatment option in GIST with bone metastasis.

Synovial Non-langerhans Cell Histiocytosis of the Shoulder: A Case Report and Review of the Literature.

INTRODUCTION: Histiocytoses are rare disorders and most orthopedic surgeons are unfamiliar with this diagnosis. We report a case of synovial non-Langerhans cell histiocytosis (LCH) located in the shoulder, which has not been reported in the literature previously. CASE REPORT: A 24-year-old female patient presented to our clinic with shoulder pain and decreased range of motion. MRI results suggested pigmented villonodular synovitis. Arthroscopic synovial debridement and biopsy were performed. Histologic examination came back as non-LCH of the shoulder. Hematology/oncology evaluation indicated localized disease and no further treatment was necessary. At the 6th month follow-up, the patient gained full shoulder motion and is symptom free. CONCLUSION: This case represents a rare diagnosis of synovial non-LCH which should be considered in the differential diagnosis of synovial diseases. A misdiagnosis could result in inadequate treatment, and coordination with the hematology/oncology department is of utmost importance in the treatment of this neoplastic disease.

An immunohistochemical approach to detect oncogenic CTNNB1 mutations in primary neoplastic tissues.

The Wnt/ß-catenin signaling pathway is dysregulated in different types of neoplasms including colorectal cancer (CRC). Aberrant activation of this signaling pathway is a key early event in the development of colorectal neoplasms, and is mainly caused by loss of function mutations in Adenomatous Polyposis Coli (APC), and less frequently by ß-catenin stabilization mutations via missense or interstitial genomic deletions in CTNNB1. In this study, we have defined an immunohistochemical algorithm to dissect Wnt pathway alterations in formalin-fixed and paraffin-embedded neoplastic tissues. Basically, consecutive sections of tumor specimens were stained by immunohistochemistry with two different monoclonal antibodies against ß-catenin: one (anti-active ß-catenin antibody) recognizes hypo-phosphorylated ß-catenin and the other recognizes the total pool of ß-catenin. We validated the strategy in the HCT116 CRC cell line which has an in-frame deletion of ß-catenin serine 45, and then studied human tumor microarrays containing colon adenomas, CRCs, solid pseudopapillary neoplasms of the pancreas as well as the whole tissue sections of CRCs, desmoid fibromatosis, and pilomatrixoma of the skin. In some tumors, we found strong ß-catenin cytoplasmic and/or nuclear staining with the total ß-catenin antibody but no staining with the anti-active ß-catenin antibody. This was inferred to be an altered/mutant ß-catenin staining pattern. All six colon adenomas of the 126 total adenomas studied for the altered/mutant ß-catenin staining pattern had presumptively pathogenic point mutations or deletions in CTNNB1. Four of 10 CRCs with the alterated/mutant ß-catenin staining pattern studied in depth, from 181 total CRCs from tissue microarray, had pathogenic CTNNB1 mutations. The frequencies of CTNNB1 alterations in non-colonic tumors with altered/mutant ß-catenin staining ranged between 46 and 100%. Our results demonstrate that the immunohistochemical approach described here can detect oncogenic forms of ß-catenin in primary tissue samples and can also highlight other tumors with presumptive novel defects activating the Wnt/ß-catenin pathway.

Corneal Relapse of Peripheral T-Cell Lymphoma Under Systemic Chemotherapy.

PURPOSE: To report a patient who developed unilateral corneal stromal infiltration while undergoing systemic chemotherapy for multinodal peripheral T-cell lymphoma not otherwise specified. METHODS: Clinical, imaging, and immunohistopathological features of a 40-year-old woman who presented with a stromal haze in the right cornea were reviewed. RESULTS: At initial presentation, her visual acuity in the right eye was 20/40. Slit-lamp examination showed stromal infiltration located mainly in the inferotemporal peripheral cornea without epithelial or limbal involvement. Immunohistochemical examination of the incisional biopsy specimen revealed CD3, CD5, and CD8 neoplastic lymphocytes suggestive of T-cell lymphoma. The corneal lesion and disseminated lymphadenopathy did not respond to various combinations of several cycles of systemic chemotherapy. Remission was achieved only after allogeneic bone marrow transplantation. The corneal infiltrates almost totally regressed within 6 months, and she maintained 20/20 visual acuity thereafter. She did not have any systemic or ocular recurrence during 6 years of posttransplantation follow-up. CONCLUSIONS: In this rare case of systemic multinodal peripheral T-cell lymphoma, corneal stromal infiltration was the only ocular manifestation. Prompt corneal biopsy enabled the appropriate diagnosis. Development and persistence of corneal infiltration despite systemic chemotherapy may be a warning sign for resistance to treatment.

Morphologic and Immunohistochemical Appraisal of Primary Gastric Carcinomas.

Gastric carcinoma management requires adjustments answering their genetic and morphologic heterogeneity. We aim to assess the expression and significance of a myriad of biomarkers (p53, MLH1, MSH2, PMS2, MSH6, Epstein-Barr encoding region-RNA, c-erbB2, E-cadherin, CEA, chromogranin, Ki-67, CDX2, presenilin-1, cathepsin E, MUC5AC, cyclin-dependent kinase 1) in 117 gastric carcinomas, which we have morphologically subclassified with a simple algorithm. Immunohistochemical stains were applied to 3 tissue microarrays of primary gastric carcinomas (n=117) obtained from resection specimens of untreated patients. These cases represented the morphologic subgroups that emerged from a reclassification attempt carried out according to the predominant (>50%) morphologic component they contained (adenocarcinoma, diffuse infiltrative carcinoma, mucinous carcinoma) and "mixed" carcinoma if none predominated. Cases with unusual morphology were assigned to a "special subtypes" group ("rare" tumors). Correlation of overall survival and staining patterns was carried out. Adenocarcinomas comprised 43.6% (n=51), diffuse infiltrative carcinomas 28.2% (n=33), mucinous carcinomas 6% (n=7), mixed carcinomas 6%, and "rare/other" carcinomas 16.2% (n=19) of the 117 muscle-invasive carcinoma cases. High tumor stage was associated with worse overall survival at multivariate analysis (P=0.000, log-rank). Higher cathepsin E and cyclin-dependent kinase 1 expression was associated with worse overall survival on univariate analysis (log-rank; P=0.050 and 0.001, respectively). Mismatch repair defects were seen in adenocarcinomas and "rare" tumors with MLH1 silencing. These above-mentioned points can lead to the differentiation of metabolic and phenotypic features per gastric carcinoma subtype and may help design targeted approaches.

Mesenchymal Chondrosarcoma of the Lacrimal Gland.

A 23-year-old woman presented with right-sided painless proptosis that developed in 12 months. MRI studies demonstrated a well-delineated tumorous enlargement of the right lacrimal gland with homogenous signal intensity and compressing the globe. The tumor was removed totally and in 1 piece with the tentative diagnosis of a pleomorphic adenoma. Pathologic examination revealed biphasic neoplastic elements, which were composed of the cartilaginous matrix and small round cell component. Immunohistopathological examination showed positive CD99 staining and negative reaction to S100, panCK, and CD15. The patient then received a total of 64 Gy orbital radiotherapy in 32 fractionations. There has been no recurrence or metastasis during 14 months of follow up. This case showed that mesenchymal chondrosarcoma may arise from the lacrimal gland and must be considered in the differential diagnosis of lacrimal gland tumors in young adults.

Programmed Death Ligand 1 (PD-L1) Expression in Malignant Mesenchymal Tumors.

OBJECTIVE: Programmed death ligand 1 (PD-L1) found on tumor cells has recently been reported to have a key role in the development and dissemination of many tumors, such as lung and breast carcinomas. In this study, we retrospectively analyzed PD-L1 expression among different types of sarcomas. MATERIAL AND METHOD: Tissue microarrays of 3-4 mm diameter were composed from paraffin blocks of 222 various sarcomas. Slides prepared from microarrays were stained for PD-L1 antibody (Cell Signaling, E1L3N®) using Leica Bond Autostainer. Any membranous staining over 5% of the cells was regarded as positive. Quantitative real-time PCR with TaqMan gene expression assays for PDL1 was performed using whole sections from FFPE tissue of PD-L1 positive cases, by normalizing absolute values to ß-actin. Relative expression level of mRNA of PDL1 was calculated and scored using Log102(threshold cycle of b-actin - threshold cycle of PDL1). RESULTS: Immunohistochemically, PD-L1 expression was present in 34 of 222 (15%) sarcomas. 5/13 (39%) undifferentiated pleomorphic sarcomas, 6/18 (33%) malignant peripheral nerve sheath tumors, 5/16 (31%) dedifferentiated liposarcomas, 4/19 (21%) rhabdomyosarcomas, 2/16 (13%) epithelioid sarcomas, 2/15 (13%) leiomyosarcomas, 3/26 (12%) synovial sarcomas, 1/18 (6%) myxoid liposarcoma, 1/2 (50%) extraskeletal myxoid chondrosarcoma, 1/3 (33%) alveolar soft part sarcoma, 1/3 (33%) parachordoma/myoepithelioma, 1/5 (20%) pleomorphic liposarcoma, 1/7 (14%) angiosarcoma, 1/8 (13%) Ewing sarcoma showed PD-L1 expression. Cases of solitary fibrous tumor/hemangiopericytoma (18), desmoplastic round cell tumor (14), Ewing-like sarcoma (6), epithelioid hemangioendothelioma (5), clear cell sarcoma (4), myxofibrosarcoma (4), low grade fibromyxoid sarcoma (2) were all negative. Tumor-infiltrating hematopoietic cells were positive for PD-L1 in 32 cases (15%) with only 2 cases overlapping with PD-L1 staining in tumoral cells. Sixteen of 34 (47%) immunohistochemically PD-L1 positive cases showed significant but low-level PD-L1 mRNA overexpression. CONCLUSION: We have shown PD-L1 expression in a subset of sarcomas, both at the protein and mRNA level. High-grade pleomorphic sarcomas tend to show more frequent PD-L1 expression. Clinical trials are necessary to further assess the effect of anti PD-L1 drugs on sarcomas showing PD-L1 expression.

Cyanoacrylate Associated Foreign Body Granulomatous Gastritis: A Report of Three Cases.

Granulomas are rarely seen in gastric biopsies mostly as an involvement of granulomatous diseases like sarcoidosis, Crohn's disease, infections, neoplasms, and vasculitis. Here, we claim cyanoacrylate as a foreign body type granuloma-causing agent in the stomach after vascular embolisation. We present cyanoacrylate associated gastric changes of three cases: two endoscopic biopsies and one gastric resection. In two cases, cyanoacrylate associated ulcers and granulomatous inflammation were observed in gastric mucosal biopsies following endoscopic examination after 7 months and 6 years of the glue injections, respectively. In the third case, the cyanoacrylate injection was performed 2 months prior to the surgery. Then the patient underwent distal pancreatectomy for pancreatic adenocarcinoma and during the operation a gastric mass was resected with a suspicion of tumoral infiltration. These three cases demonstrated that glue exposure causes active chronic inflammation with foreign body type granulomas, mucosal ulceration, and bleeding in the gastric mucosa. Even further, it can induce mass formation in the injection sites.

Primary diffuse pleural rhabdomyosarcoma in an adult patient.

Rhabdomyosarcoma is an aggressive malignant tumor of childhood, originating from immature cells that are destinated to form striated skeletal muscle. It usually arises in the head and neck or the extremities. Primary diffuse pleural rhabdomyosarcoma is exceptionally rare. Herein we report a case of primary diffuse pleural rhabdomyosarcoma in a 48-year-old man. The diagnosis was confirmed by percutaneous pleural biopsy. Chemotherapy (cisplatin, ifosfamide, adriamycin, vincristine) was initiated due to the large volume of the tumor. After 3 months, computed tomography of the thorax showed stable radiological findings.