Emperipolesis in pleural fluid mesothelial cells. A phenomenon not associated with Rosai-Dorfman disease, report of a case.

Emperipolesis is a cell-within-cell phenomenon distinct from phagocytosis more often described in Rosai-Dorfman disease, where usually lymphocytes or other bone marrow cells (plasma cells, erythroblasts or neutrophils) are entirely surrounded but not engulfed by macrophages as the host cell, but occasionally megakaryocytes and neoplastic could be. Mesothelial cell has been described in a couple of cases of lymphomas affecting serous membranes, but never described in pleuritis. In the present work, the first case of emperipolesis by mesothelial cells in a patient with self-limited pleural effusion was demonstrated by immunohistochemistry and Electron Microscopy studies.

Lymphocytic emperipolesis in breast carcinoma on cytology smears-A curious finding!

In this article, we discuss an intimidating finding of lymphocytic emperipolesis which was observed in breast carcinoma cells on cytology smears.

Fumarate hydratase-deficient renal cell carcinoma: A tumor with diverse morphology including cannibalism, lymphocytic emperipolesis, and defective autophagy.

We report the clinicopathological findings of the first series of 3 patients from Brazil with fumarate hydratase-deficient renal cell carcinoma. The clinicopathological findings disclosed a very aggressive tumor. All 3 patients had solitary tumor at the left side, metastasis and advanced stage at the time of diagnosis; were females with a median age of 40 years; had a history of uterine leiomyomas; and, at follow-up two patients are deceased and one patient alive. The microscopic findings of these 3 patients are in accordance with the literature disclosing a variety of morphologic features being papillary arrangement, eosinophilic cytoplasm, and prominent nucleoli surrounded by clear halo the constant and most frequent findings. Previously not reported in this tumor, we describe presence of cannibalism, lymphocytic emperipolesis, and cytoplasmic vacuoles with eosinophilic inclusions associated with overexpression of p62 in immunohistochemistry which is considered to be evidence of defective autophagy. Lymphocytic emperipolesis was a more frequent finding than cannibalism and immunohistochemistry for p62 was overexpressed only in the 2 patients disclosing cytoplasmic vacuoles with eosinophilic inclusions. The presence, frequency and significance of these novel findings should be checked in large series of this rare and aggressive tumor aiming to associate with clinical behavior and eventually influence the strategy of treatment.

Emperipolesis mediated by CD8+ T cells correlates with biliary epithelia cell injury in primary biliary cholangitis.

Primary biliary cholangitis (PBC) is an autoimmune disease characterized by chronic destruction of the bile ducts. A major unanswered question regarding the pathogenesis of PBC is the precise mechanisms of small bile duct injury. Emperipolesis is one of cell-in-cell structures that is a potential histological hallmark associated with chronic hepatitis B. This study aimed to clarify the pathogenesis and characteristics of emperipolesis in PBC liver injury. Sixty-six PBC patients, diagnosed by liver biopsy combined with laboratory test, were divided into early-stage PBC (stages I and II, n = 39) and late-stage PBC (stages III and IV, n = 27). Emperipolesis was measured in liver sections stained with haematoxylin-eosin. The expressions of CK19, CD3, CD4, CD8, CD20, Ki67 and apoptosis of BECs were evaluated by immunohistochemistry or immunofluorescence double labelling. Emperipolesis was observed in 62.1% of patients with PBC, and BECs were predominantly host cells. The number of infiltrating CD3+ and CD8+ T cells correlated with the advancement of emperipolesis (R2  = 0.318, P < .001; R2  = 0.060, P < .05). The cell numbers of TUNEL-positive BECs and double staining for CK19 and Ki67 showed a significant positive correlation with emperipolesis degree (R2  = 0.236, P < .001; R2  = 0.267, P < .001). We conclude that emperipolesis mediated by CD8+ T cells appears to be relevant to apoptosis of BEC and thus may aggravate the further injury of interlobular bile ducts.

Intralymphatic Rosai-Dorfman Disease Associated With Vulvar Lymphedema: A Case Report of an Extremely Rare Phenomenon.

Sinus histiocytosis with massive lymphadenopathy, also known as Rosai-Dorfman disease (RDD), is a self-limited histiocytic disorder of unclear etiology which most commonly presents with cervical lymphadenopathy. Purely extranodal presentation of RDD is uncommon, and isolated intralymphatic/intravascular confinement of this entity has not previously been described. We report a 16-yr-old female who presented with vaginal swelling and mass-like enlargement of the right labia. The mass had been present for nearly a year without pain or tenderness. Clinically, the lesion was thought to be a Bartholin gland cyst. Following surgical resection, histologic examination demonstrated a hypocellular myxedematous stroma with a mixture of ectatic thin and thick-walled vessels within which there were numerous collections of histiocytes, lymphocytes, and plasma cells. The histopathologic differential diagnosis included localized vulvar lymphedema, a specialized genital tract neoplasm, and childhood asymmetric labium majus enlargement. The histiocytes showed occasional plasma cells and lymphocytes within their cytoplasm, consistent with emperipolesis. Immunohistochemical studies showed that the histiocytes expressed CD163 and S100, while ERG and D2-40 highlighted their intralymphatic confinement, ultimately leading to the diagnosis of intralymphatic RDD. Intralymphatic RDD may present as vulvar lymphedema and can potentially mimic other myxedematous neoplasms of the vulvovaginal region.

Megakaryocyte emperipolesis: a new frontier in cell-in-cell interaction.

Histology of bone marrow routinely identifies megakaryocytes that enclose neutrophils and other hematopoietic cells, a phenomenon termed emperipolesis. Preserved across mammalian species and enhanced with systemic inflammation and platelet demand, the nature and significance of emperipolesis remain largely unexplored. Recent advances demonstrate that emperipolesis is in fact a distinct form of cell-in-cell interaction. Following integrin-mediated attachment, megakaryocytes and neutrophils both actively drive entry via cytoskeletal rearrangement. Neutrophils enter a vacuole termed the emperisome which then releases them directly into the megakaryocyte cytoplasm. From this surprising location, neutrophils fuse with the demarcation membrane system to pass membrane to circulating platelets, enhancing the efficiency of thrombocytogenesis. Neutrophils then egress intact, carrying megakaryocyte membrane and potentially other cell components along with them. In this review, we summarize what is known about this intriguing cell-in-cell interaction and discuss potential roles for emperipolesis in megakaryocyte, platelet and neutrophil biology.

Primary cutaneous Rosai-Dorfman disease; a case-based review of a diagnostically and therapeutically challenging rare variant.

Primary cutaneous Rosai-Dorfman disease is a rare form of Rosai-Dorfman disease limited to the skin. The diagnosis of primary cutaneous disease is based on a combination of clinical presentation, histopathology, and the detection of S100+, CD68+, and CD1a- histiocytic immunophenotyping. However, the diagnosis of primary cutaneous disease is often difficult and significantly delayed due to the non-specific nature of its histologic and clinical features. In this review, we describe four cases in order to familiarize pathologists and dermatopathologists with the clinicopathologic correlation of primary cutaneous Rosai-Dorfman disease and to help facilitate early diagnosis. In addition, we discuss the proposed pathophysiology and molecular etiology of this tumor, and its relationship with IgG4 sclerosing disease.

Syncytial Variant Nodular Sclerosis Classical Hodgkin Lymphoma in an Adolescent and Review of the Literature: A Unique Entity.

Syncytial variant of nodular sclerosis (SV-NS) classical Hodgkin lymphoma (cHL) with its histologic features and clinical presentation is uncommon in adults and extremely rare in children. Here, we report a female teenager presenting with long-standing B symptoms, prominent soft tissue and bone involvement mimicking sarcoma and significant nodal disease who is diagnosed with advanced SV-NS cHL. Rare Reed-Sternberg-like cells displaying neutrophil and erythrocyte emperipolesis were seen on bone marrow aspiration slides. Despite initial complete response to chemotherapy and radiotherapy, the patient experienced early relapse suggestive of high-risk biology. This variant may constitute a unique entity.

Acrolein-induced oxidative stress and genotoxicity in rats: protective effects of whey protein and conjugated linoleic acid.

Acrolein (AC), a highly reactive hazardous pollutant, poses serious threats to human health. Whey protein (WP) and conjugated linoleic acid (CLA) have beneficial health implications. We investigated the protective effects of WP and CLA against AC-induced toxicity in rats. The animals were orally gavaged with CLA (200 mg/kg/day), WP (200 mg/kg/day), AC (5 mg/kg/day), CLA + AC (200 + 5 mg/kg/day), and WP + AC (200 + 5 mg/kg/day) six days per week for 30 days. The oral administration of AC significantly induced oxidative stress by increasing thiobarbituric acid reactive substances (TBARS) and protein carbonyls (PCOs) levels and decreasing glutathione (GSH) level in the spleen, thymus, and polymorphonuclear leukocytes (PMNs). It also increased the frequencies of micronucleus (MN) and megakaryocytic emperipolesis (ME) and decreased the ratio of polychromatic erythrocytes (PCEs) in bone marrow. Slight alterations in urinary 8-hydroxydeoxyguanosine (8-OHdG) levels were not significant. Co-treatment with CLA + AC or WP + AC ameliorated the values of oxidative stress, MN, PCE, and ME. These data suggest that CLA and WP can improve the antioxidant defenses and preclude the formation of genetic damage and ME.

P-Selectin Sustains Extramedullary Hematopoiesis in the Gata1 low Model of Myelofibrosis.

Splenomegaly is a major manifestation of primary myelofibrosis (PMF) contributing to clinical symptoms and hematologic abnormalities. The spleen from PMF patients contains increased numbers of hematopoietic stem cells (HSC) and megakaryocytes (MK). These MK express high levels of P-selectin (P-sel) that, by triggering neutrophil emperipolesis, may cause TGF-ß release and disease progression. This hypothesis was tested by deleting the P-sel gene in the myelofibrosis mouse model carrying the hypomorphic Gata1(low) mutation that induces megakaryocyte abnormalities that recapitulate those observed in PMF. P-sel(null) Gata1(low) mice survived splenectomy and lived 3 months longer than P-sel(WT) Gata1(low) littermates and expressed limited fibrosis and osteosclerosis in the marrow or splenomegaly. Furthermore, deletion of P-sel disrupted megakaryocyte/neutrophil interactions in spleen, reduced TGF-ß content, and corrected the HSC distribution that in Gata1(low) mice, as in PMF patients, is abnormally expanded in spleen. Conversely, pharmacological inhibition of TGF-ß reduced P-sel expression in MK and corrected HSC distribution. Spleens, but not marrow, of Gata1(low) mice contained numerous cKIT(pos) activated fibrocytes, probably of dendritic cell origin, whose membrane protrusions interacted with MK establishing niches hosting immature cKIT(pos) hematopoietic cells. These activated fibrocytes were not detected in spleens from P-sel(null) Gata1(low) or TGF-ß-inhibited Gata1(low) littermates and were observed in spleen, but not in marrow, from PMF patients. Therefore, in Gata1(low) mice, and possibly in PMF, abnormal P-sel expression in MK may mediate the pathological cell interactions that increase TGF-ß content in MK and favor establishment of a microenvironment that supports myelofibrosis-related HSC in spleen.

Clinicopathological Study of Autoimmune Hepatitis Cases That Were Difficult to Differentiate from Drug-Induced Liver Injury.

AIM: Acute-onset autoimmune hepatitis (AIH) histopathologically presents with features of acute hepatitis and lacks a specific diagnostic method. Also, AIH is often difficult to differentiate from drug-induced liver injury (DILI). We aimed to investigate the final clinical diagnosis of these cases, and compare the clinical, biochemical, and histological characteristics of AIH vs. DILI. METHODS: We examined the Digestive Disease Week Japan 2004 (DDW-J) scale scores, AIH scores, clinical data, and pathological findings in 20 patients in whom it was difficult to differentiate autoimmune liver disease from DILI. RESULTS: In cases with a DDW-J scale score of ≥5, there was a good correlation between the final diagnosis and DDW-J scale assessments, but in cases with a DDW-J scale score of ≦4 they did not correlate well. The scores for pathological findings, such as cobblestone hepatocellular change (p = 0.015), interface hepatitis (p = 0.012), and prominent plasma cells in portal areas (p = 0.011), were higher in the AIH group than in the DILI group. CONCLUSION: This study showed that DDW-J scale was useful for differentiating AIH from DILI in cases with a DDW-J scale score of ≧5. The histologic features of AIH were characterized by cobblestone hepatocellular change, interface hepatitis, and plasma cell infiltration of the portal region.

Emperipolesis: An Unreported Novel Phenomenon in Oral Squamous Cell Carcinoma.

Emperipolesis is a phenomenon characterized by engulfment of hematopoietic cells by megakaryocytes, monocytes, fibroblasts, and malignant cells within their cytoplasm. This phenomenon has been reported in various physiological and pathological conditions including malignancies. However, emperipolesis has never been reported in oral squamous cell carcinoma (OSCC) till date. We have analyzed histopathological slides of 56 cases of OSCC to see lymphocyte engulfment by tumor cells. Five cases showing features of this phenomenon were observed. Lymphocytes were typically identified as small round cells with oval nuclei and scanty cytoplasm. Both partial and complete engulfment of lymphocytes by tumor cells was appreciated. Nuclei of the host tumor cells were crescent shaped and illustrated small concave indentation, so as to accommodate the internalized lymphocyte. The intercellular bridges were not seen between the internalized cell and the host cell. There were no signs of degeneration appreciable in either cell, thus ruling out the possibility of cannibalism phenomenon. Although emperipolesis is a well-known phenomenon in pathology, this is the first report showing its evidence in OSCC.

Mass-forming primary angiitis of central nervous system with Rosai-Dorfmann disease-like massive histiocytosis with emperipolesis.

Primary angiitis of the central nervous system (PACNS) is a vasculitis restricted to the CNS without systemic involvement. We report a case of PACNS that was radiologically tumor-mimicking, and pathologically similar to the Rosai-Dorfmann disease. A 20-year-old woman presented with a focal facial motor seizure. Magnetic resonance image revealed heterogeneously enhanced well-demarcated solitary cerebral mass in the posterior frontal lobe. Histopathologically, the lesion showed lymphoplasmacytic vasculitis with massive parenchymal infiltration of large histiocytes with emperipolesis. Diffuse ischemic change, necrosis, hemorrhage of the brain parenchyma with neuronophagia, and extensive reactive gliosis by gemistocytic astrocytes were accompanying microscopic features. The patient was doing well for 3 years after complete resection of the lesion, except for occasional occurrence of alcohol- or sleep deprivation-associated seizure. We describe this unique case to provide evidence that mass formation can be developed in PACNS by accompanying parenchymal lymphohistiocytic infiltration, necrosis, and marked reactive gliosis.

Megakaryocytic emperipolesis and platelet function abnormalities in five patients with gray platelet syndrome.

The gray platelet syndrome (GPS) is a rare congenital platelet disorder characterized by mild to moderate bleeding diathesis, macrothrombocytopenia and lack of azurophilic α-granules in platelets. Some platelet and megakaryocyte (MK) abnormalities have been described, but confirmative studies of the defects in larger patient cohorts have not been undertaken. We studied platelet function and bone marrow (BM) features in five GPS patients with NBEAL2 autosomal recessive mutations from four unrelated families. In 3/3 patients, we observed a defect in platelet responses to protease-activated receptor (PAR)1-activating peptide as the most consistent finding, either isolated or combined to defective responses to other agonists. A reduction of PAR1 receptors with normal expression of major glycoproteins on the platelet surface was also found. Thrombin-induced fibrinogen binding to platelets was severely impaired in 2/2 patients. In 4/4 patients, the BM biopsy showed fibrosis (grade 2-3) and extensive emperipolesis, with many (36-65%) MKs containing 2-4 leukocytes engulfed within the cytoplasm. Reduced immunolabeling for platelet factor 4 together with normal immunolabeling for CD63 in MKs of two patients demonstrated that GPS MKs display an alpha granule-specific defect. Increased immunolabeling for P-selectin and decreased immunolabeling for PAR1, PAR4 and c-MPL were also observed in MKs of two patients. Marked emperipolesis, specific defect of MK alpha-granule content and defect of PAR1-mediated platelet responses are present in all GPS patients that we could study in detail. These results help to further characterize the disease.

A case report of meningeal Rosai-Dorfman disease associated with IgG4-related disease.

AIMS: Rosai-Dorfman disease is a rare entity that has been described as lymphadenopathy in young patients. Extranodal forms of this disease have been previously observed. The etiology of Rosai-Dorfman disease remains unknown, relationships with the IgG4-related sclerotic disease have been detected. Herein, a rare case of Rosai-Dorfman disease with meningeal involvement and IgG4-related sclerotic disease is reported. MATERIAL: A meningeal biopsy in a 35-year-old woman who had a 6-month history of intermittent headache was performed after MRI examination showing diffuse leptomeningeal enhancement without cerebral parenchymal involvement. RESULTS: A mixed infiltration of lymphocytes, plasma cells, and histiocytes exhibiting emperipolesis was identified. The stroma was fibrous. Immunohistochemical analysis revealed a high number of IgG4-positive plasma cells and a rate of IgG4/IgG-positive plasma cells higher than 50%. CONCLUSION: The pathological results in this patient with meningeal infiltration are suggestive of Rosai-Dorman disease associated with IgG4-related disease. This observation further confirms the link between these two entities.