Programmed Death Ligand 1 (PD-L1) Expression in Lymphomas: State of the Art.

The interaction of programmed death-1 (PD-1) on T lymphocytes with its ligands Programmed Death Ligand 1 (PD-L1) and Programmed Death Ligand 2 (PD-L2) on tumor cells and/or tumor-associated macrophages results in inhibitory signals to the T-cell receptor pathway, consequently causing tumor immune escape. PD-L1/PD-L2 are currently used as predictive tissue biomarkers in clinical practice. Virtually PD-L1 levels expressed by tumor cells are associated with a good response to immune checkpoint blockade therapies targeting the PD-1/PD-L1 axis. These therapies restore T-cell antitumor immune response by releasing T-lymphocytes from the inhibitory effects of tumor cells. Immune checkpoint therapies have completely changed the management of patients with solid cancers. This therapeutic strategy is less used in hematological malignancies, although good results have been achieved in some settings, such as refractory/relapsed classic Hodgkin lymphoma and primary mediastinal large B-cell lymphoma. Variable results have been obtained in diffuse large B-cell lymphoma and T-cell lymphomas. Immunohistochemistry represents the main technique for assessing PD-L1 expression on tumor cells. This review aims to describe the current knowledge of PD-L1 expression in various types of lymphomas, focusing on the principal mechanisms underlying PD-L1 overexpression, its prognostic significance and practical issues concerning the evaluation of PD-L1 immunohistochemical results in lymphomas.

Biomarkers Changes after Neoadjuvant Chemotherapy in Breast Cancer: A Seven-Year Single Institution Experience.

The adoption of neoadjuvant chemotherapy (NACT) for breast cancer (BC) is increasing. The need to repeat the biomarkers on a residual tumor after NACT is still a matter of debate. We verified estrogen receptors (ER), progesterone receptors (PR), Ki67 and human epidermal growth factor receptor 2 (HER2) status changes impact in a retrospective monocentric series of 265 BCs undergoing NACT. All biomarkers changed with an overall tendency toward a reduced expression. Changes in PR and Ki67 were statistically significant (p = 0.001). Ki67 changed in 114/265 (43.0%) cases, PR in 44/265 (16.6%), ER in 31/265 (11.7%) and HER2 in 26/265 (9.8%). Overall, intrinsic subtype changed in 72/265 (27.2%) cases after NACT, and 10/265 (3.8%) cases switched to a different adjuvant therapy accordingly. Luminal subtypes changed most frequently (66/175; 31.7%) but with less impact on therapy (5/175; 2.8%). Only 3 of 58 triple-negative BCs (5.2%) changed their intrinsic subtype, but all of them switched treatment. No correlation was found between intrinsic subtype changes and clinicopathological features. To conclude, biomarkers changes with prognostic implications occurred in all BC intrinsic subtypes, albeit they impacted therapy mostly in HER2 negative and/or hormone receptors negative BCs. Biomarkers retesting after NACT is important to improve both tailored adjuvant therapies and prognostication of patients.

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.

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.

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.

An Italian case of intestinal anisakiasis with a presurgical diagnosis: Could this parasite represent an emerging disease?

Anisakiasis is a parasitic infection caused by the consumption of raw fish containing larvae of the Anisakis species. Since the first description in 1960 of a patient suffering from this pathogen, in the Netherlands, most of the cases have been reported in Japan, where consumption of raw fish is common, but the number of cases is increasing worldwide. The first case identified in Italy dates back to 1996 and a few cases have been reported since then. In Italy the intestinal form occurs almost as frequently as the gastric form, which is far more frequent in Japan. Intestinal Anisakiasis represents a diagnostic challenge as it is clinically misdiagnosed and most of the patients require surgery due to the occurrence of complications such as bowel occlusion or perforation. Practically no cases of the intestinal form are diagnosed preoperatively. We report the first case, to our knowledge, of intestinal Anisakiasis in which surgery was avoided, due to a prompt diagnosis suspected on intestinal biopsies. A literature review of Anisakiasis cases reported in Italy is also carried out.

Oncocytic adenocarcinoma of the rectum arising on a villous adenoma with oncocytic features.

Rectal adenocarcinoma with diffuse oncocytic features is a very rare lesion, having been reported only once in the English literature. We describe a case of oncocytic adenocarcinoma of the rectum, associated with a villous adenoma, arising on a 66-year-old man. On histological examination, the adenocarcinoma was composed of neoplastic glands lined by a strongly eosinophilic, granular epithelium that deeply infiltrated the rectal wall. Some basophilic calcifications were present in the gland lumina. Superficially, a villous adenoma with high-grade dysplasia was evident; adenomatous cells showed focal eosinophilic changes, consisting of a large granular cytoplasm, an oval atypical nucleus, and a prominent nucleolus. Immunohistochemically, neoplastic glands reacted strongly with antimitochondria antibody, carcinoembryonic antigen, cytokeratin 20, p53, and CDX2. Molecular alterations observed in oncocytic changes and their significance with regards to neoplastic transformation are briefly discussed.

Spitz nevus is relatively frequent in adults: a clinico-pathologic study of 247 cases related to patient's age.

Spitz nevus is a clinico-pathologic entity that can cause diagnostic concern, particularly in adults. Many studies have been performed to establish reliable histologic criteria, in the attempt to differentiate this lesion from melanoma. A series of 247 Spitz nevi, 6 of which were formerly classified as melanomas, were reviewed for clinical and histopathological parameters. Patients older than 20 comprised 66% of cases, with a predominance of women. The lower extremity was more affected in females of any age, whereas the trunk was more frequently involved in men over 40. Histopathologic examination showed the following differences among Spitz nevi related to age: acanthosis, parakeratosis, pagetoid infiltration, and Kamino bodies were more frequent in young people, whereas multinucleated melanocytes were more frequent in adults. The latter also had lesions that were less pigmented, with less maturation and more desmoplasia. At a mean follow-up of 94 months (range 52-172), recurrence at the site of biopsy or metastases were absent. In our study, a greater proportion of Spitz nevi occurred in adults than in previous series. Moreover, the relative incidence of Spitz nevus compared with melanoma in our population was higher than in other studies. Histopathologic criteria elaborated to diagnose Spitz nevus, applied to our cases, appeared reliable, allowing a correct diagnosis, even in adults.

TTF-1, cytokeratin 7, 34betaE12, and CD56/NCAM immunostaining in the subclassification of large cell carcinomas of the lung.

We selected a 4-stain immunopanel including thyroid transcription factor (7ITF)-], cytokeratin (CK)7, 34betaE12, and CD56/neural cell adhesion molecule(NCAM) to subclassify a series of 45 pulmonary large cell carcinomas (LCCs) on bronchial biopsy. All cases consisted of a large tumor cell proliferation with abundant cytoplasm, vesicular nuclei, and prominent nucleoli. Immunohistochemically, 27 tumors (60%)were subclassified as adenocarcinoma (7TF-1 +/CK7+,24; CK7+ only, 3), 10 (22%) as squamous cell carcinoma (34betaE12+ only), and 4 (9%) as LCC with neuroendocrine differentiation (CD56+, variably stained with TTF-I and CK7, 34betaE12-). In 4 cases, the tumors coexpressed CK7 and 34betaE12 (3 cases) or were completely unstained (I case). Surgically resected tumors matched exactly with the corresponding original biopsy specimens in 21 of 23 cases; consistent CD56 expression was a reliable marker in confirming a diagnosis of large cell neuroendocrine carcinoma even on biopsy. Our results suggest that the proposed 4-stainset of commercially available markers might help subclassify LCC even in small biopsy material, validating expression-profiling studies aimed at lung cancer classification and permitting more consistent patient enrollment for trials with targeted treatments.

Primary mixed adenocarcinoma and small cell carcinoma of the appendix: a clinicopathologic, immunohistochemical, and molecular study of a hitherto unreported tumor.

Appendiceal carcinoids range from well-differentiated endocrine tumor to well-differentiated endocrine carcinoma, while poorly differentiated (small cell) carcinoma has not been described in this site. We report herein a case of mixed intestinal-type adenocarcinoma associated with a small cell carcinoma arisen in a 35-year-old woman and clinically presenting as an appendiceal abscess. The resected tumor histologically appeared as a biphasic lesion composed of a nonmucinous adenocarcinoma closely juxtaposed with a poorly differentiated (small cell) endocrine carcinoma. The subsequent right hemicolectomy was unremarkable, but one pericolic lymph node showed a metastatic deposit consisting of the adenocarcinoma only. The patient thus underwent a chemotherapeutic protocol for colorectal cancer, and she is alive and well at the 65-month follow-up. Immunohistochemically, the adenocarcinoma strongly stained for cytokeratin 20 and carcinoembryonic antigen, while the endocrine component displayed a dot-like positivity for pan-cytokeratins and chromogranin. Of note, both components did not stain with CDX2 and p53. At genotypic analysis by microsatellite instability, both components shared many microsatellite alterations as well as a normal p53 gene setup, although small cell carcinoma harbored additional alterations. Clinical and molecular findings led us to consider this lesion as a clonal tumor in which the endocrine component seems to derive from a progressive differentiation of the adenocarcinoma following a glandular-to-endocrine sequence.

Human cytomegalovirus infection of the gastrointestinal tract in apparently immunocompetent patients.

Human cytomegalovirus (HCMV) infection is usually reported in immunocompromised patients. This study reports 11 cases of HCMV infection of the gastrointestinal (GI) tract diagnosed in apparently immunocompetent hosts. The median age of the patients studied was 76 years, and the major presenting symptoms were diarrhea, epigastric pain, and abdominal discomfort. The large intestine was involved in 6 cases, the stomach in 4 cases, and the lower esophagus in 1 case. Endoscopy revealed ulcers or hypertrophic folds in the GI tract and single ulcers or erosions in the colon and rectum. Light microscopy showed chronic inflammatory infiltrate in the lamina propria in all cases. The diagnosis of HCMV infection was based on the histological and immunohistochemical identification of HCMV inclusion bodies in different cell types, including epithelial, endothelial, stromal, and smooth muscle cells. Both "classical" inclusions, characterized by an "owl's eye" appearance, and atypical inclusions were found. For all patients, no apparent causes of immunodeficiency were detected at the time of diagnosis of HCMV infection. At follow-up, however, 4 patients were found to harbor a malignant tumor (ie, pancreas, lung, Vater's papilla, and extrahepatic bile duct) at an interval of 2 to 5 months after the diagnosis of HCMV infection. Especially in elderly patients, HCMV infection of the GI tract might be an early clue to the presence of immunologic defects induced by an underlying neoplasia.