Susceptibility and Pathology in Juvenile Atlantic Cod Gadus morhua to a Marine Viral Haemorrhagic Septicaemia Virus Isolated from Diseased Rainbow Trout Oncorhynchus mykiss

The first known outbreak caused by a viral haemorrhagic septicaemia virus (VHSV) strain of genotype III in rainbow trout occurred in 2007 at a marine farm in Storfjorden, Norway. The source of the virus is unknown, and cod and other marine fish around the farms are suspected as a possible reservoir. The main objective of this study was to test the susceptibility of juvenile Atlantic cod to the VHSV isolate from Storfjorden. As the pathology of VHS in cod is sparsely described, an additional aim of the study was to give a histopathological description of the disease. Two separate challenge experiments were carried out, using both intra peritoneal (ip) injection and cohabitation as challenge methods. Mortality in the ip injection experiment leveled at approximately 50% three weeks post challenge. Both immunohistochemical and rRT-PCR analysis of organs sampled from diseased and surviving fish confirmed VHSV infection. No VHSV was detected in the cohabitants. The results indicate that Atlantic cod has a low natural susceptibility to this VHSV genotype III strain. One of the most extensive pathological changes was degeneration of cardiac myocytes. Immunohistochemistry confirmed that the lesions were related to VHSV. In some fish, the hematopoietic tissue of spleen and kidney showed degeneration and immunostaining, classical signs of VHS, as described in rainbow trout. Positive immunostaining of the capillaries of the gills, suggests this organ as a useful alternative when screening for VHSV.

Florid Mesothelial Hyperplasia Associated with Abdominal Wall Endometriosis Mimicking Invasive Carcinoma

Florid mesothelial hyperplasia typically occurs in the pelvis, abdomen, or chest associated with an underlying neoplastic or inflammatory process. These lesions are of clinical significance because they can mimic a neoplasm. Early reports were published in the 1970s, but only a few case series of such lesions have been published in the gynecologic pathology literature. Here, we report a case of florid mesothelial hyperplasia with an infiltrative growth pattern, mimicking an invasive carcinoma. The lesion was associated with endometriosis forming a mass lesion in the abdominal wall. Histologically, tubular arrangements and nests of mesothelial cells, some with artifactual slit-like spaces, formed a stellate lesion adjacent to endometrial glands and stroma. Cytologic atypia was mild and reactive, and positive immunostaining for calretinin, WT-1, and cytokeratin 5 identified the lesion as mesothelial and benign. We describe in detail the histologic findings in this case and review the pertinent literature. We discuss the clinically importance of this diagnostic pitfall and the path to arriving at the correct diagnosis.

Case Report: The Carotid Body in COVID-19: Histopathological and Virological Analyses of an Autopsy Case Series

Various authors have hypothesized carotid body (CB) involvement in Coronavirus Disease 2019 (COVID-19), through direct invasion or indirect effects by systemic stimuli (‘cytokine storm’, angiotensin-converting enzyme [ACE]1/ACE2 imbalance). However, empirical evidence is limited or partial. Here, we present an integrated histopathological and virological analysis of CBs sampled at autopsy from four subjects (2 males and 2 females; age: >70 years old) who died of COVID-19. Histopathological, immunohistochemical and molecular investigation techniques were employed to characterize Severe Acute Respiratory Syndrome – Coronavirus 2 (SARS-CoV2) viral invasion and inflammatory reaction. SARS-CoV2 RNA was detected in the CBs of three cases through Real-Time Reverse Transcription Polymerase Chain Reaction (RT-PCR). In these cases, positive immunostaining for Nucleocapsid and Spike protein were also demonstrated, mainly at the level of large roundish cells consistent with type I cells, confirming direct CB invasion. In these cases, T lymphocytes showed focal aggregations in the CBs, suggestive of local inflammatory reaction. Blood congestion and microthrombosis were also found in one of the positive cases. Intriguingly, microthrombosis, blood congestion and microhaemorrages were also bilaterally detected in the CBs of the negative case, supporting the possibility of COVID-19 effects on the CB even in the absence of its direct invasion. SARS-CoV-2 direct invasion of the CB is confirmed through both immunohistochemistry and RT-PCR, with likely involvement of different cell types. We also reported histopathological findings which could be ascribed to local and/or systemic actions of SARS-CoV-2 and which could potentially affect chemoreception.

Predictive Role of the p16 Immunostaining Pattern in Atypical Cervical Biopsies with Less Common High Risk HPV Genotypes

P16 immunostaining is considered a useful surrogate of transcriptionally active high-risk (hr) HPV infection. Only strong and widespread “block-like” immunoreactivity is considered specific, whereas weak/focal p16 positive immunostaining is considered not specific, and follow-up and HPV molecular detection is not indicated. The aim of the study was to evaluate the presence of HPV DNA and Ki67 immunostaining in 40 cervical atypical biopsies (CALs) with mild and focal histological features suggestive of HPV infection—20 cases with weak/focal p16 positive immunoreactivity and 20 cases negative for p16 expression. In 16/20 weak/focal p16 positive CALs (80%), the INNO-LiPA HPV genotyping detected hrHPV genotypes (HPV 31, 51, 56, 59, 26, 53, 66, 73, and 82). Co-infection of two or more hrHPV genotypes was often evidenced. HPV16 and 18 genotypes were never detected. Ki67 immunostaining was increased in 10/20 cases (50%). In 19/20 p16 negative CALs, hrHPV infection was absent and Ki67 was not increased. These results suggest that weak/focal p16 immunostaining represents the early stage of transcriptionally active infection, strongly related to the presence of less common hrHPV genotypes, probably with a slower transforming power, but with a potential risk of progression if the infection persists. HPV DNA genotyping and follow-up could be useful in these cases to verify if they are able to evolve into overt dysplastic changes and to improve knowledge of less common hrHPV genotypes.

Primary Hemangioblastoma of Kidney with Molecular Analyses by Next Generation Sequencing: A Case Report and Review of the Literature

Background: Hemangioblastoma is an indolent mesenchymal tumor most frequently occurring in the central nervous system (CNS), but can also arise extraneuraxially, as part of von Hippel-Lindau (VHL) disease or in sporadic cases. Extraneuraxial hemangioblastomas (EH) occur outside the central nervous system. It includes tumors arising from the nervous paraneuraxial structures and visceral organs. Sporadic hemangioblastoma of the kidney, a rare subset of EH, is an under-recognized renal neoplasm. There have been only 25 cases described to date in the English language literature. We report herein one additional case in a patient without VHL disease.Case presentation: A 61 year old male presenting with gross hematuria was found to have a 3.5 cm renal mass at the lateral mid to lower pole of the left kidney on computed tomography urogram. Patient underwent a partial nephrectomy for the mass. The pathological examination showed a well-circumscribed non-encapsulated tumor composed of sheets of large polygonal cells traversed by a rich vascular network. The tumor cells showed clear to eosinophilic cytoplasm and overall bland nuclei. The diagnosis of hemangioblastoma was confirmed by positive immunostaining for alpha-inhibin, S100, neuron-specific enolase, PAX8, and negative staining for epithelial membrane antigen, HMB-45, and Melan-A. VHL gene mutation was not detected in this tumor. The diagnosis of sporadic renal hemangioblastoma was made.Conclusion: Sporadic renal hemangioblastoma (RH) is a rare subset of EH. We report herein one such case in a patient without clinical or molecular evidence of VHL disease. We reviewed the literature to better understand the clinical, radiological and pathologic features of this neoplasm. From our review cases and the present case, we have found that the majority of RHs showed a positive immunostaining for PAX8, which supports the idea that the immunoprofiles of EH can vary depending on sites of origin. Diagnosis of renal hemangioblastoma is challenging because of its rarity and overlapping microscopic and immunophenotypic features with renal cell tumor, especially with clear cell renal cell carcinoma. However, accurate diagnosis is necessary, since RH is clinically benign and correct recognition of this pathological entity is important to avoid unnecessary over treatment.

A study of histomorphology and immunohistochemistry of papillary squamotransitional cell carcinoma: A rare variant of squamous cell carcinoma of cervix.

Background: Papillary squamotransitional cell carcinoma is a histopathological subcategory of squamouscell carcinoma of the uterine cervix that often resembles transitional cell carcinoma of the urinary tract.Histologically, it can be misdiagnosed as transitional cell carcinoma or other papillary lesions of thecervix. Stromal invasion on biopsy is difficult to diagnose due to the exophytic papillary growth of thetumor. It also has a propensity for local recurrence and late metastasis. The study is performed to diagnoseand categorize this uncommon variant of carcinoma cervix.Materials and Methods: Eighteen cases of Papillary squamotransitional cell carcinoma were diagnosedon a punch biopsy specimen on routine hematoxylin and eosin-stained sections. The tumors werecategorized into three groups according to the percentage of squamous and transitional components.Further, immunohistochemical evaluation for cytokeratin7 and cytokeratin20 was done.Results: The mean age of the patients was 51.61 years (range 37-62 years). The most common clinicalpresentation was postmenopausal bleeding. All the cases showed papillary architecture with fibrovascularcores. The papillae were lined by three cell types: clear, intermediate, and basaloid. Stromal invasionwas seen in all the cases. All the cases showed positive immunostaining for cytokeratin7 and negativeimmunostaining for cytokeratin20.Conclusions: Papillary squamotransitional cell carcinoma deserves accurate pre-operative biopsydiagnosis due to the risk of misdiagnosis as benign papillary or malignant transitional lesions.Immunohistochemistry plays an important role in the diagnosis of these tumors and is recommended inevery case. Late recurrence and metastasis warrants a longer duration of follow up.

Causes of Hyperprolactinemia in Acromegalic Patients and Clinical Correlations

Hyperprolactinemia in acromegalic patients may result either from cosecretion of growth hormone and prolactin by the tumour or from pituitary stalk compression. The occurrence of both conditions is possible. This study was designed aiming 1) to estimate the prevalence of each cause of hyperprolactinemia and its respective clinical course; 2) to compare the outcomes of patients with tumours staining only for growth hormone against tumours staining for both growth hormone and prolactin. 75 acromegalic patients submitted to transsphenoidal surgery between 1989 and 2018 were included. Patients were divided based on preoperative prolactin levels and immunostaining pattern. Statistical analysis was performed with SPSS version 23. Hyperprolactinemia was documented in 22 out of 36 patients (61%). Stalk compression was the only underlying cause of hyperprolactinemia in 45% of cases. The levels of prolactin were not associated with the immunostaining pattern for prolactin. Clinical differences were not observed between hyperprolactinemic and normoprolactinemic patients, except for a higher frequency of cavernous sinus invasion (64% vs 29%, p=0,064), that reached the level of significance for the subgroup with macroadenomas staining exclusively for growth hormone (p=0,031). In the present series, no clinical differences were noticed between patients with tumours staining only for growth hormone or staining for both growth hormone and prolactin. Hyperprolactinemia resulting from stalk compression is likely to anticipate a less favourable course of disease, since it is associated with larger tumours and a higher frequency of cavernous sinus invasion. On the contrary, positive immunostaining for prolactin was not a marker of worse prognosis.

Anaplastic Lymphoma Kinase‐Positive Inflammatory Myofibroblastic Tumor Mimicking Meningioma: A Case Report

A 15-year-old girl presented with intermittent nausea and vomiting, headache, and vision changes. MR imaging of the brain revealed an avidly enhancing infratemporal dural-based mass arising from the tentorium, with hyperintensity on T2WI and transdural extension into the posterior cranial fossa. The well-encapsulated fibrous tumor was resected en bloc after cauterization of its rich tentorial arterial supply. Histologic examination demonstrated pleomorphic myofibroblastic cells admixed with an inflammatory infiltrate. Spindle cells showed strong, diffusely positive immunostaining for anaplastic lymphoma kinase, and genomic sequencing uncovered a tropomyosin 3 gene and anaplastic lymphoma kinase fusion and an activating mutation in the Kirsten rat sarcoma oncogene. A diagnosis of inflammatory myofibroblastic tumor was made. Primary intracranial involvement of inflammatory myofibroblastic tumor is exceptionally rare, and few cases that feature an anaplastic lymphoma kinase translocation have been described. Inflammatory myofibroblastic tumor‐CNS is an important differential diagnosis for dural-based lesions in children and young adults due to its propensity for recurrence and malignant degeneration.

Atypical Spleen Hemophagocytic Histiocytic Sarcoma in a Dog

Background: The histiocytic sarcoma (HS) complex is a set of malignant neoplasms originating from interstitial dendritic cells or macrophages. When it involves macrophages of the splenic red pulp and bone marrow, it is referred to as hemophagocytic histiocytic sarcoma (HHS). HHS behaves more aggressively than HS and is usually fatal. HHS can be diagnosed by cytological and histopathological examination of neoplastic tissue. HHS is confirmed by immunohistochemistry using an anti-CD11d antibody. This neoplasm is often confused with immune-mediated hemolytic anemia or Evans syndrome due to erythrophagocytosis and platelet consumption. The clinical presentation of the animals progresses with evident anemia and thrombocytopenia, leading to signs such as prostration, inappetence, and pale mucosa, making diagnosis challenging and often late. This study aimed to report the clinic-pathological aspects of a canine with atypical hemophagocytic splenic HS.Case: A 4-year-old male Shih-Tzu canine was referred to the Veterinary Hospital with a history of prostration and anorexia. Pale mucous membranes were observed on physical examination. Blood tests revealed non-regenerative anemia, leukopenia, and thrombocytopenia. Serum protein levels were below the reference values for the species in biochemical examinations. Hemoparasitosis was suspected; however, the result of the polymerase chain reaction was negative. Abdominal ultrasound revealed a splenomegaly with heterogeneous parenchyma and a slightly irregular surface, but no visible mass in the spleen. Due to the difficulty of stabilizing the patient, even after successive transfusions, the animal underwent exploratory laparotomy with medial access and posterior splenectomy. Subsequently, the spleen was surgically removed, fixed in 10% buffered formalin, and processed routinely. Macroscopically, it had an irregular reddish-brown capsular surface. Histopathological examination of the spleen revealed a densely cellular neoplasm composed of round to spindle cells (histiocytes) arranged haphazardly in variably sized sheets separating the pre-existing spleen stroma. These histopathological findings were consistent with a histiocytic malignant neoplasm. Immunohistochemical analysis was performed to better define the origin of the histiocytic neoplasm. Neoplastic cells showed positive immunostaining of more than 80% of tumor cells for the CD11d antibody and weak immunostaining for CD11c and lysozyme. The patient survived for less than 30 days after the first hospital visit.Discussion: The diagnosis of HHS was based on the histological characteristics and positive immunostaining of more than 80% of the tumor cells for the CD11d antibody. HHS is an extremely aggressive and rare tumor that affects elderly dogs of any breed. In this study, HHS had atypical histologic characteristics, in which erythrophagocytosis and hemosiderin were not observed within macrophages. HHSs arise from macrophages of the red pulp of the spleen or bone marrow and express the b2 integrin, CD11d, and have low expression of CD1 and CD11c, which are predominantly expressed by non-hemophagocytic HS. The hematological and biochemical changes observed in this case were similar to those described in other dogs with HHS. Treatment of HHS is only palliative. Erlichia ewingii, E. canis, Anaplasma phagocytophilum, A. platys, Borrelia burgdorferi, Dirofilaria immitis, Leishmania infantum and immune-mediated hemolytic anemia are the main differential diagnoses because they cause anemia and thrombocytopenia accompanied by splenomegaly.Keywords: histiocytic sarcoma, spleen, immunohistochemistry, splenectomy, erythrophagocytosis.

Expression of Malic Enzyme 3 in Breast Cancer and Precancerous Lesions: a Promising Novel Biomarker for Carcinogenesis and Prognosis

Purpose: While malic enzymes 1 (ME1) was correlated with breast cancer progression and prognosis, the association of ME3 (a homologue of ME1) with breast cancer is not known. The aim of this study is to explore the potential of ME3 as a biomarker in breast cancer carcinogenesis and prognosis.Methods: A total of 107 patients confirmed with breast cancer were enrolled. The ME3 expression was evaluated by IHC and correlated with clinicopathological indicators.Results: The ME3 positive immunostaining rate was higher in normal breast tissues and decreased stepwise from normal (97.60%) to usual ductal hyperplasia (91.1%), atypical ductal hyperplasia (64.2%), carcinoma in situ (62.5%) and invasive carcinoma (45.5%). Similarly, the decreasing tendency was observed for ME3 positive immunostaining rate from Tis (75.0%) through T1 (62.5%) and T2 (37.5%) to T3 (33.3%) and from stag 0 (75.0%) through I (72.0%), II (44.4%) to III (24.1%). ME3 expression was related with negative lymph node metastasis. Patients with positive expression of ME3 had better outcome. By incorporating ME3 into tumor TNM staging, the area under receiver operating characteristic curve for the 5-year survival was increased from 84.0% to 87.5%. Conclusions: ME3 may be a promising biomarker for better prognosis for breast cancer patients.