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Background Immune checkpoint proteins, especially PD-L1 and PD-1, play a crucial role in controlling the intensity and duration of the immune response, thus preventing the development of autoimmunity. These proteins play a vital role in enabling cancer cells to escape immunity, proliferate and progress. Methods This brief review highlights essential points related to testing for immune checkpoint therapy that histopathologists need to know. Results In recent years, several inhibitors of these proteins have been used to reactivate the immune system to fight cancer. Selection of patients for such therapy requires demonstration of PD-L1 activation on the tumor cells, best done by immunohistochemical staining of the tumor and immune cells using various antibodies with predetermined thresholds. Conclusions Immune checkpoint therapy appears to be promising and is rapidly expanding to include a large variety of cancers.

Background Spinal metastasis of cerebral glioblastoma (GBM) is rare, with some reports suggesting a prevalence of 1%−2%. Case Description Herein, we present 2 unique cases of spinal metastasis of cerebral GBM, 1 of which was histologically proven to be a drop spinal GBM metastasis. The first case was a 25-year-old female who presented with a spinal intradural intramedullary spinal lesion a few months after resection of a left temporal lobe GBM (isocitrate dehydrogenase wild type). The patient underwent surgical resection of the new lesion, and subsequent histopathologic examination proved that the intramedullary spinal lesion was GBM. The patient experienced full recovery postoperatively, and then a few months later, she presented again with widespread drop metastasis of the spinal cord. The second case is a middle-aged male with right temporal GBM who developed spinal metastasis 10 months after his diagnosis. Conclusions We are reporting these 2 cases due to the rarity of spinal metastasis in GBM. We reviewed the current literature and included genetic and molecular profiles in the discussion. Currently, there are no established treatment guidelines for GBM spinal metastasis. The Stupp protocol after initial brain surgery for GBM did not appear to have beneficial effects on prolonging survival in these patients with spinal metastasis. The goal of treatment was primarily to alleviate pain and neurologic deficits with no effect on overall outcome. Prognosis following the diagnosis of spinal metastasis is poor.

Testicular stromal tumors are uncommon, although mostly benign. The purpose of this study is to assess the role of multi-parametric MRI in differentiating benign testicular stromal tumors from malignant testicular neoplasms (non-stromal and stromal). A single-center retrospective study comparing benign stromal tumors (STs) to malignant testicular neoplasms (MTNs) was conducted. MR imaging assessment included tumor size, T2- and T1-weighted signal intensity, T2- and T1-weighted texture pattern, diffusion restriction, presence of hemorrhage and/or necrosis, and measurement of apparent diffusion coefficient and dynamic contrast enhancement (DCE). Inter-observer agreement was assessed using Cohen’s kappa and Bland–Altman and data were compared using independent t-tests or χ2. Receiver operating characteristic curve analysis was used to test models incorporating various imaging features. Radical orchiectomy and histopathology revealed 20 testicular neoplasms: seven STs (35%) and thirteen MTNs (65%). MTNs were significantly larger in size than STs (5.1 ± 2.36 cm vs. 1.27 ± 0.56 cm; p-value

Amyloidosis is related to the extracellular deposition of abnormal protein fibrils in various tissues. It can be either localized to an organ or generalized, affecting multiple systems. Amyloidosis of the urinary bladder is a rare histopathological finding. It is clinically interesting that such cases' clinical, radiological, and even endoscopic presentation mimic urothelial carcinoma to a great extent. Here, we discuss a case of a 49‐year‐old gentleman who presented with frank painless hematuria. The patient was diagnosed with a bladder mass suspicious of malignancy depending on the clinical presentation aided by the cystoscopic and radiological evaluation. Histopathologic samples of the transurethral resection of the mass proved to be primary bladder amyloidosis. This case is of unique clinical interest in that it is the first case reported of bladder amyloidosis that is complicated by extraperitoneal bladder rupture post‐operatively. However, no immediate intraoperative perforation to the bladder wall during resection was evidenced., Primary urinary bladder amyloidosis is a rare histopathological finding. Interestingly, it presents clinically and radiologically similar to urothelial carcinoma of the bladder. The only differentiation can be reached by histopathologic examination. Resection of such bladder lesions requires special care as such flat pathological lesions can be complicated by bladder perforation.

Intramedullary spinal cord arachnoid cysts are rare. So, we present an interesting case of adult male presented with myelopathic symptoms and signs. Further investigations revealed a finding of thoracic intramedullary cystic lesion, found postoperatively to be an arachnoid cyst. Patient improved remarkably postoperative and during follow up period.

Objectives: Customer satisfaction surveys are a routine device used to assess performance. Surveys are used in hospitals to check physician and patient satisfaction. Hamad Medical corporation’s (HMC) histopathology laboratory is College of American pathologists (CAP) accredited with highly trained pathologists and technical staff that routinely undertake various educational courses and are involved in research related activities. The lab has state of the art staining and immunohistochemistry service as well. However, it was felt that not all clinicians are very comfortable approaching pathologists and some many times experience problems either contacting lab staff or updating histopathology orders. Hence to narrow down the problems encountered by the clinicians and improve the specimen flow through the lab along with the communication between clinician and pathologist, that we deem vital, we designed this pilot survey. Methods: The survey questionnaire was made online with 15 questions in total and the link was electronically mailed to all Consultant and Specialist physicians in Hamad medical corporation (HMC). Around 3500 emails were sent out but only 105 surveys were filled in two months’ time. The survey included questions pertaining to multiple facets of quality of histopathology services and information regarding the participant. Results: The overall satisfaction was highest for Multidisciplinary presentations (96%) and lowest (77%) for timeliness of reporting. The satisfaction was above 90% for clarity and format, Diagnostic accuracy and pathologists’ responsiveness to problems. Thirty six percent of the people rated MDT presentations as excellent while 46% of the people thought overall quality of professional interaction was good. The areas of improvement, as per this survey, was timeliness of reporting and notifications of significant abnormal results (overall satisfaction 79%). Majority of the people who took the survey (36%) were from internal medicine and half were members of multidisciplinary meetings (49%). Seventy-one of percent of the participants were from Hamad General hospital (HGH), while rest were from the other hospitals under HMC. Conclusion: The response rate for the survey was low, hence another survey with a wider reach, preferably by paper, is required to get more representative data. In general, the clinicians at HGH are satisfied with the services provided by the histopathology laboratory. Areas of improvement include Turnaround time (TAT), avoidance of descriptive reports and better communication with the ordering clinician. Keywords: Quality control, quality improvement, survey, histopathology, Laboratory

Background Appendicular neuroendocrine tumors (NET, Carcinoid tumors) of the appendix are rare and mostly diagnosed incidentally on the post-operative histopathological examination. NET are usually associated with good 5-year survival rates. We aimed to assess our experience for the diagnosis and management of NET over 11 years. Method It is a retrospective chart review of all clinically suspected patients with acute appendicitis who underwent emergent appendectomy with intention to treat between January 2004–December 2014, and were clinically followed up until 2016. Results During the study period, a total of 13641 patients underwent emergency appendectomy, of which 32 were histologically confirmed NET. The mean age of the NET cases was 25.3 ± 7.9 years; 78% were males and all were clinically presented with acute appendicitis. The mean leucocyte was 15 ± 14 × 109 per Liter, and mean tumor size was 4.86 ± 3.18 (ranged 1.5–13) mm. The median length of hospital stay was 4 (2–15) days. One patient had right hemicolectomy; diagnosed with right colonic cancer with NET being an incidental finding as part of histopathological assessment. Another patient required a second stage procedure; he was diagnosed as goblet cell carcinoid with positive margin. None of the patients died 30-day postoperatively and all of them survived on clinical follow-up that ranged between 2 and 13 years. Conclusion Carcinoid tumors of the appendix are rare and typically diagnosed incidentally. Detailed examination of routine appendectomy specimens is the key for diagnosis. Simple appendectomy suffices for tumors

Patient: Female, 45 Final Diagnosis: Primary pituitary tuberculosis Symptoms: Headache • vomiting • vomiting Medication: — Clinical Procedure: Pituitary biospy Specialty: Endocrinology and Metabolic Objective: Rare disease Background: Primary pituitary tuberculosis (in absence of other organ involvement and constitutional symptoms) is an extremely rare disease with total reported cases in the literature fewer than a hundred. Misdiagnosis as pituitary adenoma is common and late diagnosis can result in a permanent endocrine dysfunction and/or long-term neurologic sequelae. Case Report: We report on the case of a middle-aged woman who presented with severe headache and left third cranial nerve palsy. Magnetic resonance imaging (MRI) revealed a large pituitary tumor invading the left cavernous sinus. The case was initially misdiagnosed as pituitary adenoma. A pituitary biopsy was performed and was suggestive of pituitary tuberculosis. Extensive radiologic investigations did not reveal any evidence of other organ involvement by tuberculosis. She was successfully treated with anti-tuberculous medications. Conclusions: In areas with a high pre-test probability of tuberculosis, pituitary tuberculosis should be included in the differential diagnosis of pituitary tumors in order to avoid unnecessary surgical interventions. Besides being the first histologically-proven primary pituitary tuberculosis case reported from Qatar, the current case is unique in that extensive radiologic investigations did not reveal any evidence of other systemic or pulmonary tuberculosis.

Cytokeratins belong to the family of intermediate filaments. They are expressed in a highly specific manner in epithelial cells where they play a crucial role in the integrity and mechanical stability of the cells. Several types of cytokeratins have been described in normal as well as neoplastic urothelium. In the case of urothelial neoplasms expression of CK20 and CK5/6 has been shown in several studies to have diagnostic and prognostic implications. Thus, low-grade urothelial carcinoma manifests CK expression limited to the umbrella cells, while high-grade tumors usually have an expression in the entire thickness of the urothelium except for the basal layer. CK5/6 expression on the other hand is expressed in the basal cells in all low-grade and some high-grade urothelial carcinomas. Diffuse CK20 staining accompanied by loss of CK5/6-positive basal layer is usually associated with aggressive clinical behavior. Double staining of the slides for these cytokeratins may facilitate proper interpretation and correlation.

The terminology “Intradural Extramedullary” is often associated with Nerve sheath tumors (schwannoma, Neurofibroma) and Meningioma, while dermoid cyst, epidermoid, neurenteric cyst are other benign entities. Hemangioblastomas are rare, accounting for 1-5% of all spinal cord tumours.1 75% of the Spinal hemangiblastoma are Intramedullary, and another 10-15% have combined intramedullary and extramedullary-intradural component, while isolated extramedullary hemangioblastoma are rare1. Our case had an isolated intradural extramedullary hemangioblastoma without any associated manifestations of VHL syndrome. Surgery is a preferred option where total resection is possible, where as SRS is also an option in case of residual or incomplete resection.

We present a rare case of epithelioid hemangioendothelioma arising from the wall of ulnar artery in distal forearm. The presentation was interesting in a 34-year-old man, with progressively worsening symptoms of ulnar neuropathy. A mass was seen arising from the ulnar artery on imaging with ultrasound and magnetic resonance imaging. Soft tissue epithelioid hemangioendothelioma in extremities almost always arise from the veins. Existing literature do not have elaborated imaging findings of epithelioid hemangioendothelioma arising from the arterial wall. The aim of this paper is to briefly review the interesting presentation and imaging features of this rare entity. Knowledge of such vascular tumor would avoid the mishap during surgery. Our case will add an interesting presentation of such rare pathology to the existing literature.

Bladder cancer is a highly prevalent disease throughout the world usually encountered in older patients, and associated with substantial morbidity, mortality, and cost. The treatment of bladder cancer has remained unchanged for the last several decades. However, in recent years the availability of comprehensive genomic data from The Cancer Genome Atlas and other large projects have considerably improved our understanding of the pathogenesis of these tumors. These studies demonstrated that bladder cancers can be grouped into 2 broad categories namely basal and luminal molecular subtypes with recognizable subgroups in each of these categories. Clinical data suggest that invasive basal cancers are more sensitive to neoadjuvant chemotherapy (NAC), such that most patients with basal cancers who are aggressively managed with NAC have excellent outcomes. Patients with luminal cancers do not appear to derive much clinical benefit from NAC, but some may appear to be sensitive to anti-programmed death-ligand 1 (PDL1) antibodies and possibly other immune checkpoint inhibitors. It is hoped that future studies will also identify biomarkers such as immunohistochemical markers which may be used to predict therapeutic response of these tumors. This will contribute substantially toward efficient and cost-effective diagnosis and management of these neoplasms.

Urothelial carcinoma in situ (CIS) is a high-grade noninvasive malignancy with a high tendency of progression. Although it is typically grouped with other nonmuscle invasive bladder cancers, its higher grade and aggressiveness make it a unique clinical entity. Urothelial CIS is histologically characterized by replacement of the urothelium by cells which fulfill the morphologic criteria of malignancy including nuclear pleomorphism, hyperchromasia, prominent nucleoli, and increased numbers of normal and abnormal mitoses. Urothelial CIS may be categorized as primary when it is not associated with any past or present urothelial carcinoma. It is termed as secondary when there is concomitant or previous urothelial carcinoma in the patient. In recent years detailed molecular studies have provided valuable data for intrinsic molecular subclassification of urothelial carcinoma into 2 broad categories namely luminal and basal types with significant implications for prognosis and therapy. Similar studies on urothelial CIS are limited but have provided crucial insight into the molecular basis of CIS. These studies have revealed that urothelial CIS may also be divided into luminal and basal subtypes, but luminal subtype is much more common. It has also been shown that in many cases, luminal type of urothelial CIS may undergo a class switch to basal type during progression to an invasive carcinoma. Additional studies may be required to confirm and further elaborate these findings.

Schistosomiasis is the third most widespread devastating parasitic disease worldwide and has a high mortality burden. Neuroschistosomiasis is one of the rare and most severe clinical presentations of the disease. It is caused by granuloma formation around eggs that lodge in the central nervous system, with Schistosoma japonicum usually causing most reported cerebral disease. Three unusual presentations of schistosomiasis in Qatar are described herein. The three patients were young males who presented with seizures and tumor-like lesions on brain imaging. The diagnosis was confirmed by biopsy, which showed necrotizing granulomas containing Schistosoma eggs. These cases raise awareness of neuroschistosomiasis as a potential cause of tumor-like brain lesions in migrants and returning travelers from endemic areas. Keywords: Neuroschistosomiasis, Schistosoma, Seizure, Granuloma, Tumor-like brain lesion

Granulosa cell tumours (GCTs) can be either juvenile or adult type, and more commonly occur in the ovaries. Adult-type GCTs of the testis (AGCTT) are very rare and only 46 cases have previously been reported. We report here on a 48-year-old Filipino man with a left testicular AGCTT, which measured 1.2 × 1.2 × 1.0 cm. He underwent radical orchidectomy with postoperative surveillance for 1 year, which included computed tomography with oral intravenous contrast and clinical examinations, which have been unremarkable. The previously reported AGCTTs were briefly reviewed.

Background: Rosai-Dorfman disease (RDD) is an idiopathic nonneoplastic lymphadenopathy disorder which is characterized by lymph node enlargement, but it may also presents primarily involving a variety of extranodal sites, including central nerves system and craniospinal axis. This study reports five cases of craniospinal RDD, with review of epidemiology, clinical presentation, imaging, and histopathological features with current management strategies. Case Description: Five cases of RDD are diagnosed at Hamad General Hospital, Qatar, during 2013–2018. Two cases had dural-based cranial lesions with overlying cranial involvement while three cases were having extradural thoracic spine lesions. All cases underwent surgical intervention and confirmed by histopathology. Conclusion: Craniospinal RDD is a rare clinical presentation and poses significant diagnostic challenges preoperatively due to its similarity with other neoplastic or inflammatory diseases. Surgical option to remove compressive neural pathology provides a good clinical outcome with no recurrence in long-term follow-up.

Patient: Male, 43-year-old Final Diagnosis: Rifampicin-induced pneumonitis Symptoms: Dyspnea • fatigue • fever Medication: — Clinical Procedure: Bronchoalveolar lavage • bronchoscopy • CT scan • lung biopsy Specialty: Pulmonology Objective: Rare disease Background: Rifampicin-induced pneumonitis is an infrequent occurrence, with only a few cases reported in the literature. Furthermore, this condition constitutes a diagnostic challenge, particularly in the era of COVID-19 infection. Here, we report a case of rifampicin-induced pneumonitis with clinical, imaging, and histological features of acute respiratory distress syndrome (ARDS), which required severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing to exclude a diagnosis of coronavirus disease 2019 (COVID-19) pneumonia. Case Report: A 43-year-old man on anti-TB treatment for TB meningitis developed new-onset fever, fatigue, hypoxemic respiratory failure, and bilateral pulmonary opacities. His clinical, chest X-ray, and CT thorax findings of ARDS were similar to both rifampicin-induced pneumonitis and severe COVID-19 pneumonia. However, reverse transcription polymerase chain reaction (RT-PCR) testing from a nasopharyngeal swab and bronchoalveolar lavage (BAL) via the GeneXpert system was negative for SARS-CoV-2. A detailed workup, including lung biopsy, revealed drug-induced pneumonitis as the cause of his presentation. His pneumonitis improved after discontinuation of rifampicin and recurred following the rifampicin challenge. Conclusions: This case highlights the importance of early, rapid, and accurate testing for SARS-CoV-2 during the COVID-19 pandemic for patients presenting with acute respiratory symptoms, so that accurate diagnosis and early patient management are not delayed for patients with treatable causes of acute and severe lung diseases. Timely identification of rifampicin-induced pneumonitis via a high clinical suspicion, detailed workup, and histopathological analysis is required to avoid permanent damage to the lungs.

Introduction: Scleromyxedema (rare cutaneous mucinosis), is characterized by the formation of lichenoid papules and presence of Serum monoclonal IgG in most cases, or all; after repeated testing. Patient concerns : The patient is a 51-year-old male presented with thick, disfiguring elephant-like erythematous skin folds over the forehead, papular shiny eruptions over ears and trunk and waxy erythematous papules over arms and hands without dysphagia or respiratory or neurologic symptoms Diagnosis : Skin biopsy from right arm was consistent with scleromyxedema. Serum cryoglobulin was reported negative. Complete blood count and routine blood biochemistry were normal. Thyroid function tests were normal. Serum protein electrophoresis and immunofixation showed monoclonal band of 14.5 g/L typed as IgG lambda. Interventions : Our patient was refractory to lenalidomide however improved clinically on immunoglobulins infusions on monthly basis without change in the MGUS level. Outcomes : NGF analysis revealed approximately 0.25% Lambda monotypic plasma cells in the bone marrow expressing CD38, CD138, and CD27 with aberrant expression of CD56 and were negative for CD45, CD19, CD117, and CD81. We also detected 0.002% circulating plasma cells (PCs) in peripheral blood. Conclusion : The immunophenotype of circulating tumor cells (CTCs) remain close to the malignant PCs phenotype in the BM. Hence, we report NGF approach as a novel diagnostic tool for highly sensitive MRD detection in plasma cell dyscrasias including scleromyxedema.

Papillary renal cell carcinoma (PRCC) is the second most common type of renal carcinoma following clear cell renal cell carcinoma. Papillary renal cell carcinoma is usually divided histologically into 2 types namely, type 1 and type 2. This classification, however, is unsatisfactory as many of papillary carcinoma are unclassifiable by the existing criteria. In recent years there has been a remarkable progress in our understanding of the molecular basis of PRCC. These studies have revealed that type 2 PRCCs represent a heterogenous group which may be subdivided into additional subtypes based on the genetic and molecular make up of these tumors and reflecting different clinical course and prognosis. Some of the molecular features such a hypermethylation of CPG islands in the promotor regions of genes and over expression of the antioxidant pathways within tumor cells have been recognized as markers of poor prognosis. Targeted therapies for papillary carcinoma in the past have been unsuccessful because of lack of clear understanding of the molecular basis of these tumors. It is hoped that recent progress in our understanding of the pathogenesis of various subtypes of PRCC, effective targeted therapies will eventually emerge in due course.

Background Primary central nervous system lymphoma is a rare malignant tumor of the central nervous system. It is associated with poor prognosis and accounts for 0.7%–0.9% of all lymphomas and only 0.3%–1.5% of intracranial tumors. Typically, these lesions are in the cerebral white matter near the corpus callosum, the central gray matter, the basal ganglia-thalamus-hypothalamic region, the posterior fossa and the periventricular region. Only 2 cases with pure third ventricular lymphoma have been reported in the literature. Case Description A 72-year-old female patient known to have type II diabetes mellitus treated with insulin, hypertension, chronic kidney disease, dyslipidemia, and obesity presented with a history of acute confusion and urinary incontinence. No headache was reported on admission, but previously she had intermittent mild headaches and generalized body aches. She had no history of visual symptoms. Her family said she was mildly confused and had memory difficulties that started acutely 2 days before presentation to the hospital. The patient had urgent computed tomography of the brain, which showed a hyperdense lesion in the region of the foramen of Monro. Pre-operative images diagnosed the case as colloid cyst, but post-operative histopathology proved the lesion to be primary CNS lymphoma. Conclusions Eleven months after surgery, the patient is fully consciousness and oriented, with no memory issues or neurologic deficit. She is back to her baseline activities. We are reporting this case for the rarity of the disease and the unusual location of it.

Germ cell tumors can occur in the mediastinum. They account for about 20% of tumors at this location. The majority are located in the anterior mediastinum and usually occur in young adult males. Extension of mediastinal germ cell tumors into the neck with mass formation is a very rare and unusual event. Herein, we report a case of a 34 year old male who presented with a progressively enlarging neck mass. Fine Needle Aspiration (FNA) was performed as initial evaluation and showed cellular smears comprising atypical large cells with prominent irregular nucleoli and moderate amount of cytoplasm with lymphocytic infiltrate and some epithelioid granulomas in the background. The mass was misdiagnosed initially on the cytology smears as anaplastic thyroid carcinoma. The subsequent tissue core biopsy showed sheets and nests of atypical cells admixed with ill-defined granulomatous inflammation. By immunohistochemistry, the tumor cells were immunoreactive with SALL4, PLAP and OCT3/4, compatible with malignant germ cell tumor, seminomatous type. It is very rare for patients with primary mediastinal seminoma to present initially with a neck mass. Fine Needle Aspiration (FNA) of this "neck mass" can lead to misinterpretation of findings due to similarities in cytological features between malignant germ cell tumors and other undifferentiated malignant neoplasms and the diagnosis, therefore, can be very challenging.

Intravascular large B-cell lymphoma (IVLBCL) is a subtype of extranodal B-cell lymphoma with growth limited to the lumina of small vessels. Intramural great vessel lymphoma (IMGVL), on the contrary, is extremely rare and there have been only two reported cases of primary B-cell lymphoma that occurred in the lumen of the superior vena cava and one case of primary B-cell lymphoma with intra-aortic growth, diagnosed at autopsy. We present the case of a 72-year-old man who presented with severe abdominal pain and was found to have thrombosed abdominal aortic aneurysm. The retrieved thrombus showed Epstein Barr virus-positive large B cell lymphoma (LBCL). Post-operative Echocardiography, Computerized tomography (CT) and Positron Emission Tomography (PET) scan did not show any residual tumor focus, abnormal mass or thickening, increased FDG uptake or hypermetabolism (Nodal or extranodal). This is the first case of large B cell lymphoma presenting as a thrombus within abdominal aortic aneurysm and third case of intramural great vessel lymphoma. Keywords: Lymphoma, Large B cell lymphoma, Aorta, Aneurysm, Intravascular large B cell lymphoma

Patient: Male, 48 Final Diagnosis: Pituitary apoplexy complicated by cerebral infarction Symptoms: Disturbed conscious level • loss of vision Medication: — Clinical Procedure: — Specialty: Radiology Objective: Unusual clinical course Background: Pituitary macroadenoma is a common benign tumor that usually presents with visual field defects or hormonal abnormalities. Cerebral infarction can be a complication of a large pituitary adenoma. We report a rare case of bilateral anterior cerebral arteries infarcts by a large pituitary macroadenoma with apoplexy. Case Report: A 48-year-old male patient presented with altered conscious level and sudden loss of vision for one-day duration. Magnetic resonance imaging of the brain showed a large seller and suprasellar hemorrhagic mass of pituitary origin, with associated bilateral areas of diffusion restriction in the frontal parasagittal regions, consistent with infarctions. Magnetic resonance angiography showed elevation and compression of A1 segment of both anterior cerebral arteries by the hemorrhagic pituitary macroadenoma. The patient underwent trans-sphenoidal resection of the pituitary adenoma, but unfortunately, ischemia was irreversible. Computed tomography (CT) done post-operatively showed hypodensity in the frontal and parietal parasagittal areas, which was also persistent in the follow up CT scans. The patient’s neurological function remained poor, with GCS of 8/15, in vegetative state. Conclusions: Vascular complications of the pituitary apoplexy, although uncommon, can be very severe and life threatening. Early detection of vascular compromise caused by hemorrhagic pituitary macroadenoma can prevent delay in intervention. Clinicians should also consider pituitary adenoma as a possible cause of stroke.

Pilomyxoid astrocytomas (PMAs) are low-grade (WHO Grade II) tumors for which the imaging features are similar to pilocytic astrocytomas (PAs), but for which histological features and the clinical course differ. They are classified as a variant of PA. They have only been recently recognized, and they behave more aggressively than PAs. Most cases occur in the hypothalamic-chiasmatic area, although they may be located in any part of the neuraxis. Posterior fossa PMAs are very rare. The authors report a case of a 2-year-old girl with cerebellar PMA.

We report a case of primary mediastinal seminoma, which presented initially with shortness of breath and a swelling in upper part of anterior chest wall. The diagnosis of primary mediastinal seminoma was established on the basis of histologic findings and was confirmed by immunohistochemical analysis. Abdominal, pelvis and cerebral CT scan, testicular ultrasound and TC-99 MDP bone scintigraphy were negative. Chemotherapy was initiated with B.E.P. protocol (Bleomycin, Etoposide, Cisplatinum); the patient received four cycles of chemotherapy. After 8 months, the patient was seen in the clinic; he was well.

Pelvic actinomycosis is a chronic granulomatous infection caused by the gram-positive anaerobic bacteria, Actinomyces Israelli. Vesical lesions, particularly without any obvious source of infection, are rare. We report a case of primary vesical actinomycosis which presented as a bladder mass, giving suspicion of malignancy. Repeated trans-urethral deep resections and histo-pathological examinations revealed the true nature of the mass, which was treated by medical means. A high index of suspicion of potentially benign bladder lesions, particularly in a younger age group of patients, is advocated, to prevent unnecessary major surgical procedures.

Background: Prostate cancer is the most common malignancy in many industrialized countries and the second cause of cancer-related death in Europe and the United States. The incidence of the disease has been increasing in Arab populations. Large databases focused on genetic susceptibility to prostate cancer have been accumulated from population studies of different ancestries, including Europeans and African-Americans. Arab populations, however, have been only rarely studied. Genetic susceptibility to prostate cancer differs significantly across ethnicities. It would be of interest to identify the common alleles associated with prostate cancer risk in Arab population. Methods: With Affymetrix Genome-Wide Human SNP Array 6.0, we conducted a genome-wide association study (GWAS) in which 534,781 single nucleotide polymorphisms (SNPs) were genotyped in a Tunisian cohort of 92 cases with prostate cancer and 131 age-matched controls. Then we extended the study to evaluate promising associations of 11 SNPs, identified by GWAS, in a cohort of individuals of Arab ancestry living in Qatar and Saudi Arabia (155 cases and 182 controls) using TaqMan® SNP Genotyping Assays. Results: We identified 3 consecutive regions significantly associated with prostate cancer risk on chromosome 9, 17 and 22, including 18 SNPs (P=8.52×10-5 to P=2.18×10-6) in the Tunisian population. Three previous reported common loci associated with prostate cancer at 17q21 containing STAT3 gene in the Caucasian population were confirmed. Two novel chromosomal regions associated with prostate cancer contain candidate susceptibility genes: SMARCA2, LOC646851and SUN2 were revealed. Conclusion: Our findings, identifying novel GWAS prostate cancer susceptibilty loci, indicate that prostate cancer genetic risk factors could be ethnic specific.

A case report and review of an extraskeletal neuroectodermal tumour of the vagina. Ewing’s sarcoma (ES) and primitive neuroectodermal tumours (PNETs) account for approximately 6–10% of primary malignant bone tumours and, following osteosarcoma, are the second most common group of bone sarcomas in children. Ewing’s sarcoma rarely affects the genitourinary tract. We report a rare case of extraskeletal Ewing’s sarcoma diagnosed in a 47-year-old Indian woman presenting with a simple cystic lesion in the posterior wall of the vagina. The histopathology revealed a rare presentation of a primitive malignant extraskeletal neuroectodermal tumour. As our PubMed review found only six previously reported cases of vaginal extraskeletal Ewing’s sarcoma. Presentation as vaginal masses helped in early disease detection.

Pseudomyxoma is a poorly understood condition which results from implantation of malignant tumors or irritation from ruptured benign cysts. Pseudomyxoma peritonei is a form of regional spread of gastrointestinal gynecological and other malignancies of mucinous nature. It is characterized by the accumulation of abundant mucinous material within the peritoneal cavity. The case presented here is unique in that extraperitoneal presentations of pseudomyxoma peritonei are exceedingly rare and presentation with scrotal mass is even rarer. To the best of my knowledge there is only one case in the English literature with similar scrotal mass presentation and 10 other cases with other types of extraperitoneal presentations. Literature review of extraperitoneal presentation of pseudomyxoma peritonei is also discussed. (excerpt)

Systemic dissemination of a rhabdomyosarcoma during pregnancy, including metastases to the placenta, illustrates both the rarity of the event and the usual sparing of the fetus. Of the rare cases of metastasis to products of conception from a maternal cancer, most commonly melanomas, leukemia or lymphoma, 54 cases have been reported since 1866. This is the sixth case of sarcoma, and the first rhabdomyosarcoma that has metastasized to the placenta.

Introduction Prostate cancer is the most common malignancy in many industrialized countries and the second cause of cancer-related death in Europe and the United States. The incidence of the disease has been increasing in Middle Eastern and North African (MENA) populations. Large databases focused on genetic susceptibility to prostate cancer have been accumulated from population studies of different ancestries, including Europeans and African-Americans. MENA populations, however, have been only rarely studied. Genetic susceptibility to prostate cancer differs significantly across ethnicities, e.g., the allele frequencies of the candidate prostate cancer susceptibility genes such as CYP3A4 and SRD5A2 differ substantially by ethnicity. It would be of interest to identify the common alleles associated with prostate cancer risk in MENA population. Material and Methods With Affymetrix SNP 6.0 chip, we conducted a genome-wide association study (GWAS) in which 534,781 single nucleotide polymorphisms (SNPs) were genotyped in a Tunisian cohort of 85 cases with prostate cancer and 131 age-matched controls. Then we extended the study to evaluate promising associations of 11 SNPs, identified by GWAS, in a cohort of individuals of Arab ancestry living in Qatar and Saudi Arabia (155 cases and 182 controls) using TaqMan® SNP Genotyping Assays.Results: We identified 3 consecutive regions significantly associated with prostate cancer risk on chromosome 9, 17 and 22, including 18 SNPs (P = 8.52 × 10 - 5 to P = 2.18 × 10 - 6) in the Tunisian population. 11 out of these 18 SNPs are not associated with prostate cancer risk in the population living in Qatar and Saudi Arabia. Conclusions We confirmed previous reports of common loci associated with prostate cancer at 17q11 and 17q21 containing STAT5A and STAT3 in the Caucasian population. Moreover, we found that 2 new consecutive regions associated with prostate cancer contain candidate susceptibility genes: SMARCA2, GNAQ, SEPT9, MYO18B and SUN2. Additionally, our findings further proved that prostate cancer risky genetic factors are ethnic specific.

Cancer coexisting with pregnancy is well reported; however, maternal malignancies that are metastatic to the products of conception are rare. We report a case of orbital rhabdomyosarcoma that metastasized to the placenta.

Prostate cancer rarely metastasis to the rectum. Findings in the patient reported here emphasize the importance of the relationship between urinary and gastrointestinal symptoms in detecting prostatic neoplasms in older male patients.

Background We considered the prediction of cancer classes (e.g. subtypes) using patient gene expression profiles that contain both systematic and condition-specific biases when compared with the training reference dataset. The conventional normalization-based approaches cannot guarantee that the gene signatures in the reference and prediction datasets always have the same distribution for all different conditions as the class-specific gene signatures change with the condition. Therefore, the trained classifier would work well under one condition but not under another. Methods To address the problem of current normalization approaches, we propose a novel algorithm called CrossLink (CL). CL recognizes that there is no universal, condition-independent normalization mapping of signatures. In contrast, it exploits the fact that the signature is unique to its associated class under any condition and thus employs an unsupervised clustering algorithm to discover this unique signature. Results We assessed the performance of CL for cross-condition predictions of PAM50 subtypes of breast cancer by using a simulated dataset modeled after TCGA BRCA tumor samples with a cross-validation scheme, and datasets with known and unknown PAM50 classification. CL achieved prediction accuracy >73 %, highest among other methods we evaluated. We also applied the algorithm to a set of breast cancer tumors derived from Arabic population to assign a PAM50 classification to each tumor based on their gene expression profiles. Conclusions A novel algorithm CrossLink for cross-condition prediction of cancer classes was proposed. In all test datasets, CL showed robust and consistent improvement in prediction performance over other state-of-the-art normalization and classification algorithms.