The classification of neuroendocrine neoplasms of the lung and digestive system according to WHO, 5th edition: similarities, differences, challenges, and unmet needs.

Neuroendocrine neoplasms (NENs) are a group of disease entities sharing common morphological, ultrastructural and immunophenotypical features, yet with distinct biological behavior and clinical outcome, ranging from benign to frankly malignant. Accordingly, a spectrum of therapeutic options for each single entity is available, including somatostatin analogues (SSA), mTOR-inhibitors, peptide receptor radionuclide therapy (PRRT), non-platinum and platinum chemotherapy. In the last few decades, several attempts have been made to better stratify these lesions refining the pathological classifications, so as to obtain an optimal correspondence between the scientific terminology and, the predictive and prognostic features of each disease subtype, and achieve a global Classification encompassing NENs arising at different anatomical sites. The aim of this review was to analyze, compare and discuss the main features and issues of the latest WHO Classifications of NENs of the lung and the digestive system, in order to point out the strengths and limitations of our current understanding of these complex diseases.

EBV-Driven Lymphoproliferative Disorders and Lymphomas of the Gastrointestinal Tract: A Spectrum of Entities with a Common Denominator (Part 3).

EBV is the first known oncogenic virus involved in the development of several tumors. The majority of the global population are infected with the virus early in life and the virus persists throughout life, in a latent stage, and usually within B lymphocytes. Despite the worldwide diffusion of EBV infection, EBV-associated diseases develop in only in a small subset of individuals often when conditions of immunosuppression disrupt the balance between the infection and host immune system. EBV-driven lymphoid proliferations are either of B-cell or T/NK-cell origin, and range from disorders with an indolent behavior to aggressive lymphomas. In this review, which is divided in three parts, we provide an update of EBV-associated lymphoid disorders developing in the gastrointestinal tract, often representing a challenging diagnostic and therapeutic issue. Our aim is to provide a practical diagnostic approach to clinicians and pathologists who face this complex spectrum of disorders in their daily practice. In this part of the review, the chronic active EBV infection of T-cell and NK-cell type, its systemic form; extranodal NK/T-cell lymphoma, nasal type and post-transplant lymphoproliferative disorders are discussed.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 2: Clinic-Pathologic Correlations.

Many studies have investigated the potential prognostic and predictive role of PD-L1 in prostatic carcinoma (PC). We performed a systematic literature review (PRISMA guidelines) to critically evaluate human tissue-based studies (immunohistochemistry, molecular analysis, etc.), experimental research (cell lines, mouse models), and clinical trials. Despite some controversial results and study limitations, PD-L1 expression by tumor cells may be related to clinic-pathologic features of adverse outcome, including advanced tumor stage (high pT, presence of lymph node, and distant metastases), positivity of surgical margins, high Grade Group, and castration resistance. Different PD-L1 positivity rates may be observed in matched primary PCs and various metastatic sites of the same patients. Over-fixation, type/duration of decalcification, and PD-L1 antibody clone may influence the immunohistochemical analysis of PD-L1 on bone metastases. PD-L1 seemed expressed more frequently by castration-resistant PCs (49%) as compared to hormone-sensitive PCs (17%). Some series found that PD-L1 positivity was associated with decreased time to castration resistance. Treatment with ipilimumab, cyclophosphamide/GVAX/degarelix, or degarelix alone may increase PD-L1 expression. Correlation of PD-L1 positivity with overall survival and outcomes related to tumor recurrence were rarely investigated; the few analyzed series produced conflicting results and sometimes showed limitations. Further studies are required. The testing and scoring of PD-L1 should be standardized.

Persistent Response and Prolonged Survival Following Pembrolizumab Discontinuation Due to Long-Lasting Autoimmune Colitis in Advanced NSCLC: A Case Report.

Pembrolizumab is a programmed death receptor-1 (PD-1) inhibitor that has been approved for treatment of a wide variety of malignancies including non-small-cell lung cancer (NSCLC). Immune-mediated colitis is a known adverse effect of pembrolizumab which can lead to the treatment interruption, although not compromising the control of the oncological disease. Herein, we report the case of a 59-year-old woman on pembrolizumab for advanced NSCLC which developed a severe and persistent colitis treated with infliximab for several months following anti-PD-1 antibody discontinuation. This strategy resulted in an improvement but not complete recovery of the gastrointestinal toxicity despite revealed sustained response and control of the oncological disease with prolonged survival over 24 months.

Gastrointestinal Manifestations in Systemic Mastocytosis: The Need of a Multidisciplinary Approach.

Mastocytosis represents a heterogeneous group of neoplastic mast cell disorders. The basic classification into a skin-limited disease and a systemic form with multi-organ involvement remains valid. Systemic mastocytosis is a disease often hard to diagnose, characterized by different symptoms originating from either the release of mast cell mediators or organ damage due to mast cell infiltration. Gastrointestinal symptoms represent one of the major causes of morbidity, being present in 60-80% of patients. A high index of suspicion by clinicians and pathologists is required to reach the diagnosis. Gastrointestinal mastocytosis can be a challenging diagnosis, as symptoms simulate other more common gastrointestinal diseases. The endoscopic appearance is generally unremarkable or nonspecific and gastrointestinal mast cell infiltration can be focal and subtle, requiring an adequate sampling with multiple biopsies by the endoscopists. Special stains, such as CD117, tryptase, and CD25, should be performed in order not to miss the gastrointestinal mast cell infiltrate. A proper patient's workup requires a multidisciplinary approach including gastroenterologists, endoscopists, hematologists, oncologists, and pathologists. The aim of this review is to analyze the clinicopathological features of gastrointestinal involvement in systemic mastocytosis, focusing on the relevance of a multidisciplinary approach.

How Can We Treat Vulvar Carcinoma in Pregnancy? A Systematic Review of the Literature.

According to our systematic literature review (PRISMA guidelines), only 37 vulvar squamous cell carcinomas (VSCCs) were diagnosed during pregnancy (age range: 17-41 years). The tumor size range was 0.3-15 cm. The treatment was performed after (14/37, 38%), before (10/37, 27%), or before-and-after delivery (11/37, 30%). We found that 21/37 (57%) cases were stage I, 2 II (5%), 11 III (30%), and 3 IVB (8%). HPV-related features (condylomas/warts; HPV infection; high-grade squamous intraepithelial lesion) were reported in 11/37 (30%) cases. We also found that 9/37 (24%) patients had inflammatory conditions (lichen sclerosus/planus, psoriasis, chronic dermatitis). The time-to-recurrence/progression (12/37, 32%) ranged from 0 to 36 (mean 9) months. Eight women died of disease (22%) 2.5-48 months after diagnosis, 2 (5%) were alive with disease, and 23 (62%) were disease-free at the end of follow-up. Pregnant patients must be followed-up. Even if they are small, newly arising vulvar lesions should be biopsied, especially in women with risk factors (HPV, dermatosis, etc.). The treatment of VSCCs diagnosed in late third trimester might be delayed until postpartum. Elective cesarean section may prevent vulvar wound dehiscence. In the few reported cases, pregnancy/fetal outcomes seemed to not be affected by invasive treatments during pregnancy. However, clinicians must be careful; larger cohorts should define the best treatment. Definite guidelines are lacking, so a multidisciplinary approach and discussion with patients are mandatory.

Acute Radiation Colitis after Preoperative Short-Course Radiotherapy for Rectal Cancer: A Morphological, Immunohistochemical and Genetic Study.

Preoperative radiotherapy is a widely accepted treatment procedure in rectal cancer. Radiation-induced changes in the tumor are well described, whereas less attention has been given to the non-neoplastic mucosa. Our aim is to provide a detailed analysis of the morphological features present in non-neoplastic mucosa that pathologists need to be familiar with, in order to avoid misdiagnosis, when evaluating rectal cancer specimens of patients preoperatively treated with radiotherapy, especially with short-course regimen. We compared 2 groups of 95 rectal cancer patients treated preoperatively with either short-course (45 patients) or long-course radiotherapy (50 patients). Depending on the type of protocol, different histopathological features, in terms of inflammation, glandular abnormalities and endocrine differentiation were seen in the non-neoplastic mucosa within the irradiated volume. Of note, features mimicking dysplasia, such as crypt distortion, nuclear and cytoplasmic atypia of glandular epithelium, were identified only in the short-course group. DNA mutation analysis, using a panel of 56 genes frequently mutated in cancer, and p53 immunostaining were performed on both tumor and radiation-damaged mucosa in a subset of short course cases. Somatic mutations were identified only in tumors, supporting the concept that tissues with radiation-induced "dysplastic-like" features are not genetically transformed. Pathologists should be aware of the characteristic morphological changes induced by radiation. The presence of features simulating dysplasia in the group treated with short-course radiotherapy may lead to serious diagnostic mistakes, if erroneously interpreted. Next generation sequencing (NGS) analysis further validated the morphological concept that radiation-induced abnormalities do not represent pre-neoplastic lesions.

Oral plasmablastic lymphoma: A case report.

INTRODUCTION: Plasmablastic lymphoma (PBL) is an uncommon and aggressive large B-cell lymphoma commonly diagnosed in human immunodeficiency viruses -positive patients. Oral cavity is the most commonly PBL affected site. Most oral PBLs presented as asymptomatic swellings, frequently associated with ulcerations and bleeding. Most cases lacked B-symptoms, suggesting a more local involvement of the disease. No standard treatment is yet for oral PBL. Five-year survival rate recorded no more than 33.5%. PATIENT CONCERNS: A 39-year-old male presented to Dental Clinic with 1 month swelling of the oral cavity, in absence of any other symptoms or signs. He followed antibiotic therapy just on suspicion of an oral abscess and later oral surgical treatment on suspicion of bone neoplasm. DIAGNOSIS: Surgical specimen analysis highlighted a diffuse infiltrate of large-sized atypical cells with plasmablastic appearance and plasma cell phenotype. Oral cavity PBL was diagnosed. Blood tests recorded mild lymphopenia and positive human immunodeficiency viruses serology. INTERVENTIONS: Patient underwent chemotherapy including intrathecal methotrexate prophylaxis, in addition to a highly active antiretroviral therapy. OUTCOMES: At 12 months from diagnosis, patient recorded complete hematological remission. CONCLUSIONS: Oral PBL diagnosis requires a high level of suspicion and awareness both by physicians and pathologists. They should be aware of the extent of such disease which is often mistaken as oral abscess or infected tooth, thus leading to delay the most appropriate diagnostic evaluation. As PBL is an aggressive non-Hodgkin lymphoma, a delayed diagnosis might negatively impact on both treatment and survival.

Germinotropic lymphoproliferative disorder: a systematic review.

Germinotropic lymphoproliferative disorder is a rare and rather enigmatic novel entity with distinctive clinicopathological features, one of which is the typical co-infection by Human herpesvirus 8 and Epstein-Barr virus. Human herpesvirus 8 is a lymphotropic virus detected in Kaposi sarcoma, multicentric Castleman disease, primary effusion lymphoma, Human herpesvirus 8-positive diffuse large B cell lymphoma not otherwise specified, and germinotropic lymphoproliferative disorder. Co-infection by Human herpesvirus 8 and Epstein-Barr virus is identified only in two lymphoproliferative diseases: germinotropic lymphoproliferative disorder and primary effusion lymphoma, which are otherwise diseases with totally different clinical presentations and outcomes. Unlike primary effusion lymphoma mostly occurring in immunocompromised individuals and following an aggressive course, germinotropic lymphoproliferative disorder usually presents with single or multiple lymphadenopathy affecting mainly immunocompetent individuals and mostly follows an indolent course. Based on the PRISMA guidelines, we carried out a systematic search on PubMed/MEDLINE, Web of Science, Scopus, EMBASE, and Cochrane Library using the search terms "germinotropic" and "lymphoproliferative disorder." Current scientific literature reports just 19 cases of germinotropic lymphoproliferative disorder. The purpose of our systematic review is to improve our understanding of the disease, focusing on epidemiology, clinical presentation, pathological features, treatment, and outcome. In addition, we discuss the differential diagnosis with the other Human herpesvirus 8-related lymphoproliferative diseases as currently recognized in the World Health Organization classification, adding a focus on lymphoproliferative disorders showing overlapping features.

A tricky and rare cause of pulmonary eosinophilia: myeloid/lymphoid neoplasm with eosinophilia and rearrangement of PDGFRA.

BACKGROUND: Eosinophilic lung diseases represent a heterogeneous group of disorders with prominent infiltrate of eosinophils in lung interstitium and alveolar spaces. Peripheral blood eosinophilia is often present. Infections, drugs, allergens, toxic agents have to be evaluated as possible causes of eosinophilic lung infiltrates. The category of myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, FGFR1 and PCM1-JAK2 represents an uncommon cause of eosinophilic lung infiltrate. CASE PRESENTATION: We report the case of a 70-year old man complaining of dry cough and dyspnea. Ground glass-opacities were seen on imaging studies and peripheral blood eosinophilia was present. A thorough step-wise patient's evaluation led to identify the clonal nature of eosinophilia and the diagnosis of myeloid/lymphoid neoplasm with eosinophilia and rearrangement of PDGFRA was made. CONCLUSIONS: Correlation with clinical history, laboratory tests and imaging studies is essential to achieve the correct diagnosis when facing with eosinophilic lung infiltrates. A prolonged eosinophilia can cause life-threatening organ damage. Identification of PDGFRA rearrangement, as in the present case, is particularly critical given the sensitivity and excellent response to imatinib, which has completely changed the natural history of this neoplasm.

Correction to: Management of duodenal stump fistula after gastrectomy for malignant disease: a systematic review of the literature.

Following publication of the original article [1], the authors have notified us that due to administrative reasons they would like to modify the first affiliation from.

Fibrin-associated large B-cell lymphoma: first case report within a cerebral artery aneurysm and literature review.

BACKGROUND: Fibrin-associated diffuse large B-cell lymphoma (FA-DLBCL) is a rare Epstein-Barr virus (EBV) positive lymphoproliferative disorder included in the current World Health Organization (WHO) classification. It arises within fibrinous material in the context of hematomas, pseudocysts, cardiac myxoma or in relation with prosthetic devices. In these clinical settings the diagnosis requires an high index of suspicion, because it does not form a mass itself, being composed of small foci of neoplastic cells. Despite overlapping features with diffuse large B-cell lymphoma associated with chronic inflammation, it deserves a separate classification, being not mass-forming and often following an indolent course. CASE PRESENTATION: A 64-year-old immunocompetent woman required medical care for cerebral hemorrhage. Computed Tomography (CT) angiography identified an aneurysm in the left middle cerebral artery. A FA-DLBCL was incidentally identified within thrombotic material in the context of the arterial aneurysm. After surgical removal, it followed a benign course with no further treatment. CONCLUSIONS: The current case represents the first report of FA-DLBCL identified in a cerebral artery aneurysm, expanding the clinicopathologic spectrum of this rare entity. A complete literature review is additionally made.

Management of duodenal stump fistula after gastrectomy for malignant disease: a systematic review of the literature.

BACKGROUND: Duodenal stump fistula (DSF) remains one of the most serious complications following subtotal or total gastrectomy, as it endangers patient's life. DSF is related to high mortality (16-20%) and morbidity (75%) rates. DSF-related morbidity always leads to longer hospitalization times due to medical and surgical complications such as wound infections, intra-abdominal abscesses, intra-abdominal bleeding, acute pancreatitis, acute cholecystitis, severe malnutrition, fluids and electrolytes disorders, diffuse peritonitis, and pneumonia. Our systematic review aimed at improving our understanding of such surgical complication, focusing on nonsurgical and surgical DSF management in patients undergoing gastric resection for gastric cancer. METHODS: We performed a systematic literature review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) guidelines. PubMed/MEDLINE, EMBASE, Scopus, Cochrane Library and Web of Science databases were used to search all related literature. RESULTS: The 20 included articles covered an approximately 40 years-study period (1979-2017), with a total 294 patient population. DSF diagnosis occurred between the fifth and tenth postoperative day. Main DSF-related complications were sepsis, abdominal abscess, wound infection, pneumonia, and intra-abdominal bleeding. DSF treatment was divided into four categories: conservative (101 cases), endoscopic (4 cases), percutaneous (82 cases), and surgical (157 cases). Length of hospitalization was 21-39 days, ranging from 1 to 1035 days. Healing time was 19-63 days, ranging from 1 to 1035 days. DSF-related mortality rate recorded 18.7%. CONCLUSIONS: DSF is a rare but potentially lethal complication after gastrectomy for gastric cancer. Early DSF diagnosis is crucial in reducing DSF-related morbidity and mortality. Conservative and/or endoscopic/percutaneous treatments is/are the first choice. However, if the patient clinical condition worsens, surgery becomes mandatory and duodenostomy appears to be the most effective surgical procedure.