Intrasinusoidal Hodgkin Lymphoma; A Mimic of Anaplastic Large Cell Lymphoma

The distinction between classical Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL) is not problematic in most instances. In rare situations, HL may present with a sinusoidal infiltrative pattern that may mimic ALCL. It is important to use a battery of immunohistochemical stains to differentiate between these two entities as therapy and clinical behavior are different. We present a case of a young woman who presents with the very unusual intrasinusoidal infiltrative pattern.

Postmortem Findings in Patients with COVID19 Using Multiple Organ Core Needle Biopsies

Introduction/Objective The coronavirus disease 2019 (COVID19) pandemic had caused more than 500,000 deaths in the United States. Although it mainly manifests with respiratory symptoms, postmortem examination reveals that it is more of a systemic disease affecting mutliple body organs. Methods/Case Report Postmortem needle core biopsies from multiple organs were obtained from 9 patients who died at our institution in the months of April and May of 2020 due to a confirmed SARS-CoV-2 infection by RT-PCR testing of nasopharyngeal swabs. The core biopsies from body organs included lungs (8), liver (7), kidneys (5), heart (2), spleen (2), and brain (2). Histopathological examination was performed in conjunction with a set of special and immunohistochemical stains. Electron microscopy examination was also done in 4 cases. Results (if a Case Study enter NA) The cohort consisted of 6 males and 3 females with a mean age of 70.4 years (range: 68–79). The majority had comorbidities (8/9) and presented with respiratory symptoms (9/9). The most significant postmortem findings were mainly in the lungs, including alveolar hemorrhage, hyaline membranes, fibrin thrombi, intraalveolar macrophages, type-2 pneumocyte hyperplasia, and interstitial myofibroblast reaction and collagen deposition. Immunohistochemical stains showed predominance of T-lymphocytes with a mixture of CD4 and CD8 positive cells. Examination of liver showed minimal to marked microvesicular and macrovesicular steatosis and centrilobular congestion and necrosis. Tissue from kidneys revealed mild to severe acute tubular injury. Microglial activation and Alzheimer type-II astrocytosis were noted in brain, and mild white pulp depletion was seen in the spleen. Electron microscopy showed the presence of foreign bodies suspicious for viral particles ranging in size from 52.6 to 97.9 nm in 2/4 cases. Conclusion Our findings based on postmortem core needle biopsies confirm the observation that most severely affected patients have significant pulmonary pathology. However, other organs show findings that may lead to a better understanding of this disease. Postmortem examination will continue to be an invaluable tool for studying the pathologic manifestations of COVID-19.

Aberrant Expression of Immunohistochemical Markers in Malignant Melanoma: A Review

Immunohistochemical stains are increasingly used to aid in the diagnosis of malignant melanoma, especially when the differentiation of the tumor is unclear based on examination with hematoxylin and eosin. However, aberrant expression of non-melanocytic markers has been reported in melanomas, which can sometimes be further complicated by the loss of conventional melanocytic markers. This review aims to summarize available data regarding unusual staining patterns in primary and metastatic malignant melanoma. It also raises awareness of the potential pitfalls and highlights the importance of appropriate use and interpretation of broad immunohistochemical markers in the context of clinical and histopathologic findings to facilitate the diagnosis of atypical cases of malignant melanoma.

Update on Diagnosing and Reporting Malignant Pleural Mesothelioma

<p>In this review, we summarize current approaches to diagnosis of malignant pleural mesothelioma, focusing on the distinction from benign mesothelial proliferations and other malignant tumors. Current recommendations for reporting histological sub-type and tumor grade are also reviewed. Particular emphasis is placed on immunohistochemical and molecular tools that may help in establishing the diagnosis of mesothelioma with greater confidence. Immunohistochemical stains for BRCA1-associated protein (BAP1) and methylthioadenosine phosphorylase (MTAP) and homozygous deletion of p16 using fluorescence in situ hybridization (FISH) are emphasized as important methods for distinguishing benign from malignant mesothelial prolifera- tions.</p><p><strong>Conclusions</strong>. Diffuse malignant pleural mesothelioma is a heterogeneous group of aggressive pleural tumors for which histological classification plays an increasingly important role in patient management. Stage and resectability remain key drivers of therapeutic strategies and outcomes. There is an increasingly robust suite of diagnostic tools, including immunohistochemical stains for BAP1 and MTAP and p16 FISH, for differentiating benign from malignant mesothelial proliferations in cytology and tissue specimens.</p>

Histopathology of Human Donor Spleen Utilized as a Desensitization Tool Before Intestinal Transplantation

Objectives To describe the histopathologic and immunophenotypic features of a temporary splenic allograft exposed to massive donor-specific antibody (DSA) insult. Methods A human cadaveric donor splenic allograft was temporarily transplanted in a highly sensitized patient with the intention of removing DSA before intestinal transplantation from the same donor. Before splenic transplant, the patient had several preformed cytotoxic DSAs that resulted in positive flow cytometric and complement-dependent cytotoxicity crossmatch. The splenic allograft was removed before intestinal transplantation and evaluated by H&E and immunohistochemical stains. Results Explanted donor splenic allograft showed several histopathologic changes: expanded red pulp secondary to congestion and marked neutrophilic and macrophage infiltration in the sinusoids, numerous neutrophilic microabscesses, and focal capillaritis. The C4d and IgG immunohistochemical stains were diffusely positive in the endothelial lining of the capillaries and sinusoidal lining, indicating diffuse IgG deposition and complement activation. Conclusions We propose that the noted changes are features of splenic acute antibody-mediated rejection (AMR). Additional cases are required to determine all the features of splenic AMR. To our knowledge, this is the first report of histopathologic changes in donor spleen after exposure to DSA for a short duration.

Clinicopathologic characteristics and surgical outcome of synthetic fiber conjunctival granuloma

Background Until recently, synthetic fiber conjunctival granuloma (SFCG) is rarely reported and has been poorly understood. Our study was to explore the clinical features, histopathologic characteristics, surgical outcomes, and prognosis of SFCG after surgical excision. Methods Retrospective review of clinical findings, histopathological and immunohistochemical studies identified 18 cases of SFCG. Specimens were routinely processed and stained with H&E. Immunohistochemical stains for GMS, PAS, CD68 and CK-pan were also performed. Results Eighteen patients with an average age of 9.3 ± 6.6 years had a tender white to red mass on the conjunctiva. All the lesions were completely removed, and none of the patients relapsed. Histologically, all of the specimens revealed inflammatory granulation tissues with a large number of inflammatory cells infiltration and the presence of synthetic fibers. Immunohistochemical stains were positive for CD68, CK, GMS and PAS. Conclusions Synthetic fiber conjunctival granuloma is an uncommon lesion with foreign body sensation caused by inoculation of synthetic exogenous materials. These lesions are mostly unilateral and occur in the inferior conjunctival fornix. SFCGs are characterized by a large number of inflammatory cells infiltration and the presence of synthetic fibers. Surgical excision followed by topical corticosteroids has been clinically proven to be effective.

Clinicopathologic Characteristics and Surgical Outcome of Synthetic Fiber Conjunctival Granuloma

Background: Until recently, synthetic fiber conjunctival granuloma (SFCG) is rarely reported and has been poorly understood. Our study was to explore the clinical features, histopathologic characteristics, surgical outcomes, and prognosis of SFCG after surgical excision. Methods: Retrospective review of clinical findings, histopathological and immunohistochemical studies identified 18 cases of SFCG. Specimens were routinely processed and stained with H&E. Immunohistochemical stains for GMS, PAS, CD68 and CK-pan were also performed.Results: Eighteen patients with an average age of 9.3±6.6 years had a tender white to red mass on the conjunctiva. All the lesions were completely removed, and none of the patients relapsed. Histologically, all of the specimens revealed inflammatory granulation tissues with a large number of inflammatory cells infiltration and the presence of synthetic fibers. Immunohistochemical stains were positive for CD68, CK, GMS and PAS. Conclusions: Synthetic fiber conjunctival granuloma is an uncommon lesion with foreign body sensation caused by inoculation of synthetic exogenous materials. These lesions are mostly unilateral and occur in the inferior conjunctival fornix. SFCGs are characterized by a large number of inflammatory cells infiltration and the presence of synthetic fibers. Surgical excision followed by topical corticosteroids has been clinically proven to be effective.

Clinicopathologic Characteristics and Surgical Outcome of Synthetic Fiber Conjunctival Granuloma

Background: Until recently, synthetic fiber conjunctival granuloma (SFCG) is rarely reported and has been poorly understood. Our study was to explore the clinical features, histopathologic characteristics, surgical outcomes, and prognosis of SFCG after surgical excision. Methods: Retrospective review of clinical findings, histopathological and immunohistochemical studies identified 18 cases of SFCG. Specimens were routinely processed and stained with H&E. Immunohistochemical stains for GMS, PAS, CD68 and CK-pan were also performed.Results: Eighteen patients with an average age of 9.3±6.6 years had a tender white to red mass on the conjunctiva. All the lesions were completely removed, and none of the patients relapsed. Histologically, all of the specimens revealed inflammatory granulation tissues with a large number of inflammatory cells infiltration and the presence of synthetic fibers. Immunohistochemical stains were positive for CD68, CK, GMS and PAS. Conclusions: Synthetic fiber conjunctival granuloma is an uncommon lesion with foreign body sensation caused by inoculation of synthetic exogenous materials. These lesions are mostly unilateral and occur in the inferior conjunctival fornix. SFCGs are characterized by a large number of inflammatory cells infiltration and the presence of synthetic fibers. Surgical excision followed by topical corticosteroids has been clinically proven to be effective.