School of Medicine, University of Sarajevo, Sarajevo, Bosnia and Herzegovina Department of Pathology, Clinical Center, University of Sarajevo, Sarajevo, Bosnia and Herzegovina Department of Radiology, Clinical Center, University of Sarajevo, Sarajevo, Bosnia and Herzegovina Department of Oncology, Clinical Center, University of Sarajevo, Sarajevo, Bosnia and Herzegovina College of Medicine, Qatar University, Doha, Qatar

SUMMARY – Epithelioid hemangioendothelioma is a rare vascular brain tumor. It develops from endothelial cells, usually in the liver, lung, bone and soft tissue. Primary localization of this tumor in the intracranial space is very uncommon; only 47 cases have been described in the literature. This tumor was initially classified as grade I (benign) in the World Health Organization (WHO) 2007 classification. In 2016, this tumor was re-classified as grade III (malignant). Herein, the first case report of epithelioid hemangioendothelioma in the cerebellum of a male patient is presented. Complete surgical excision was done. No adjuvant therapy was administered. Magnetic resonance imaging performed 2 years after the surgery continued to show no recurrence of the tumor. To our knowledge, this is the first report of cerebellar location of this rare tumor. In addition, the authors report drastic re-classification of the epithelioid hemangioendothelioma from the benign tumor (WHO 2007) to a malignant one (2016), which significantly changes postoperative management and follow up of this brain neoplasm.

Incidence of breast cancer ranges from 27 per 100,000 in Middle Africa and Eastern Asia to 92 per 100,000 in Northern America. It is the fifth most common cause of death from cancer in women, with an estimated 522,000 deaths per year (6.4% of the total). Autosomal dominant inheritance of these cancers is characterized by transmission of cancer predisposition from generation to generation, with around 5-10% of all breast cancers being associated with inherited mutations in BRCA1, BRCA2 and other genes.  Breast and ovarian cancers are strongly associated with BRCA1 and BRCA2 mutations. In this study, we genotyped BRCA1 gene for large genomic rearrangements in breast and ovarian cancer patients from Bosnia and Herzegovina, with aim to assess frequency of large BRCA1 mutations (exon deletions/duplications) in this group. We collected 59 breast cancer samples, as well as other data concerning patients’ histopathological parameters of tumor, like age at diagnosis, cancer type, TNM class, cancer grade, as well as estrogen, progesterone and Her2/neu expression. Following DNA extraction from breast cancer samples (tissue after biopsy), BRCA1 mutations were identified by Multiplex Ligase - Dependent Probe Amplification (MLPA) analysis. Biostatistical analyses were conducted using MedCalc v.9.2.0.0 software. In all statistical tests p<0.05 was considered significant. Mean age at diagnosis was 54±1.75 (range 17 – 80). BRCA1 genomic rearrangements were found in 22% of breast and ovarian cancer patients. Statistically significant associations and correlations were found between BRCA1 genomic rearrangements and cancer type, estrogen, progesterone and Her2/neu expression, but not cancer grade, size, invasiveness or patients’ age

Targeted immunotherapy based on PD-1/PD-L1 suppression has revolutionized the treatment of various solid tumors. A remarkable improvement has also been observed in the treatment of patients with refractory/relapsing classical Hodgkin lymphoma (cHL). We investigated PD-L1 status in a variety of treatment resistant lymphomas. Tumor samples from 78 patients with therapy resistant lymphomas were immunohistochemically (IHC) investigated for the expression of PD-L1 using two antibody clones (SP142 and SP263, Ventana). Thirteen PD-L1+ cases were further analyzed for gene copy number variations (CNV) by NGS and for PD-L1/JAK2/PD-L2 co-amplification using fluorescent in-situ hybridization assay (FISH). PD-L1 positivity (≥5% positive cancer cells, IHC) was present in 32/77 (42%) and 33/71 cases (46%) using SP142 and SP263 antibodies, respectively. Concordance between the two anti-PD-L1 clones was high with only three (4%) discrepant cases. The strongest and consistent (10/11 cases) expression was observed in cHL and primary mediastinal B-cell lymphomas (3/3). Diffuse large B-cell lymphomas (DLBCL) were frequently positive (13/26) irrespective of subtype. Follicular (1/8), peripheral T-cell (3/11) and mantle cell (1/8) lymphomas were rarely positive, while small lymphocytic lymphoma/CLL and marginal zone lymphomas were consistently negative (3/3). Co-amplification/CNVs of PD-L1/JAK2/PD-L2 were observed in 3 cases of DLBCL and cHL, respectively. Of note, all three cHL-amplified cases were positive by FISH, but not by NGS. Since only a fraction of the IHC positive lymphoma cases were positive by FISH and NGS assays, other mechanisms are involved in PD-L1 upregulation, especially in DLBCL. FISH assay may be more suitable than NGS assay for determination of PD-L1 alterations in cHL.

Lung cancer is usually presented with cough, dyspnea, pain and weight loss, which is overlapping with symptoms of other lung diseases such as pulmonary fibrosis. Pulmonary fibrosis shows characteristic reticular and nodular pattern, while lung cancers are mostly presented with infiltrative mass, thick-walled cavitations or a solitary nodule with spiculated borders. If the diagnosis is established based on clinical symptoms and CT findings, it would be a misapprehension. We report a case of lung adenocarcinoma whose symptoms as well as clinical images overlapped strongly with pulmonary fibrosis. The patient’s non-productive cough, progressive dyspnea, restrictive pattern of pulmonary function test and CT scans (showing reticular interstitial opacities) were all indicative of pulmonary fibrosis. The patient underwent a treatment consisting of corticosteroids and antibiotics, to no avail. Histopathology of the lung showed that the patient suffered from mucinous adenocarcinoma. Albeit the immunohistochemical staining was not consistent with lung adenocarcinoma, tumor’s morphological characteristics were consistent, and were used to make the definitive diagnosis. Given the fact that radiography cannot always make a clear-cut difference between pulmonary fibrosis and lung adenocarcinomas, and that clinical symptoms often overlap, histological examination should be considered as gold standard for diagnosis of lung adenocarcinoma.

The histiocytoses are rare tumors characterized by the primary accumulation and tissue infiltration of histiocytes and dendritic cells. Identification of the activating BRAFV600E mutation in Erdheim-Chester disease (ECD) and Langerhans cell histiocytosis (LCH) cases provided the basis for the treatment with BRAF and/or MEK inhibitors, but additional treatment options are needed. Twenty-four cases of neoplastic histiocytic diseases [11 extrapulmonary LCH, 4 ECD, 4 extranodal Rosai-Dorfman disease (RDD), 3 follicular dendritic cell sarcoma (FDCS), 1 histiocytic sarcoma (HS) and 1 blastic plasmacytoid dendritic cell neoplasm (BPDCN)] were analyzed using immunohistochemical and mutational analysis in search of biomarkers for targeted therapy. BRAF V600E mutations were detected in 4/11 LCH and 4/4 ECD cases. A pathogenic PTEN gene mutation and loss of PTEN protein expression were identified in the case of HS. Increased expression of PD-L1 (≥2+/≥5%) was seen in 3/4 ECD, 7/8 LCH, 3/3 FDCS and 1/1 HS, with overall 81% concordance between 2 antibodies used in the study (SP142 vs. MAB1561 clone). These results show for the first time significant expression of the PD-L1 immune checkpoint protein in these disorders, which may provide rationale for addition of immune check-point inhibitors in treatment of disseminated and/or refractory histiocytoses.