Hematopoietic System
Pritam S. Sahota, James A. Popp, Jerry F. Hardisty, Chirukandath Gopinath, Page R. Bouchard in Toxicologic Pathology, 2018
Platelet production begins with the megakaryoblast, which is a large, single nucleated cell with deeply basophilic cytoplasm. The megakaryoblast undergoes endomitosis, resulting in a larger multinucleated cell with increased amounts of moderately basophilic cytoplasm. As maturation progresses, the megakaryocyte cytoplasm develops numerous eosinophilic granules. Emperipolesis, the movement of blood cells (neutrophils, erythrocytes, lymphocytes) within megakaryocytes, is fairly common with up to 5 percent of megakaryocytes containing blood cells in normal bone marrow from humans (Centurione et al. 2004; Harvey 2001). Emperipolesis differs from phagocytosis in that the blood cells exist temporarily within the megakaryocyte (Harvey 2001). Emperipolesis has been described as a random process, although other proposed explanations include facilitation of cell traffic across the marrow–blood barrier, particularly with a high demand for blood cells or as a sanctuary for normal granulocytes in an unfavorable marrow environment (reviewed in Tanaka et al. 1997). The cytologic appearance of erythroid, myeloid, and megakaryocytic cells, including examples of rodent ring forms, is found in Figures 15.3 and 15.4.
Histiocytosis and Lipid Storage Diseases
Harold R. Schumacher, William A. Rock, Sanford A. Stass in Handbook of Hematologic Pathology, 2019
b. Sinus Histiocytosis with Massive Lymphadenopathy (Rosai-Dorfman Disease). Rosai-Dorfman disease (RDD) was first recognized in 1969 as an uncommon proliferative histiocytic disorder (Fig. 3). It is a benign, self-limiting disorder of unknown etiology. Some cases are associated with Epstein-Barr virus, herpes virus 6 infection, and lymphoma. It usually occurs in the first two decades of life. There is a predilection for children, especially <10 years, with the clinical picture of inflammation, i.e., fever, leukocytosis, high ESR, lymphadenopathy, and systemic symptoms. Significant numbers of cases appear in children with immunologic disorders, e.g., Wiskott-Aldrich syndrome, autoimmune hemolytic disease, and glomerulonephritis. The entity was originally described in lymph nodes, but has been reported to involve almost every organ system. Almost half of patients with RDD have at least one site of extra-nodal disease. In this hemophagocytic syndrome the internalized lymphocytes are intact, suggesting that they entered the histiocytes by emperipolesis rather than phagocytosis. Usually the course is benign and requires no therapy, but steroids and chemotherapy are used in severe cases.
Granulomatous Diseases
Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang in Roxburgh's Common Skin Diseases, 2022
Laboratory studies: A complete blood count is essential. Biopsy of a skin lesion is a crucial part of the diagnosis, and it shows masses of lymphocytes in which collections of histiocytes are noted. The hallmark of the disease is emperipolesis or histiocytes with lymphocytes within their cytoplasm. The histiocytes stain positive for S-100 and CD68 and negative for CD1a and langerin.
Megakaryocyte emperipolesis: a new frontier in cell-in-cell interaction
Published in Platelets, 2020
Pierre Cunin, Peter A. Nigrovic
Emperipolesis is a new type of cell-in-cell interaction characterized by several distinct features, at least with respect to MKs. These include [1] active cytoskeletal engagement by host and guest cell [2]; the transit of the guest cell through the cytoplasm of the host, potentially enabling an exchange of membrane and other cell components; and [3] egress of the guest cell without impairing the viability of either participant. Whether all cell-in-cell events currently termed ‘emperipolesis’ conform to all three features is unknown, even for cells inside MKs. Aside from the DMS, none of the cellular “machinery” of emperipolesis is unique to the neutrophil-MK dyad, suggesting the possibility that the phenomenon could occur more broadly. While it has been generally assumed that the one mammalian cell within another must necessarily reside in a membrane-bound compartment, emperipolesis shows that this principle is not invariable, raising the broader question of when else it might give way.
An update on the pharmacological management of autoimmune hepatitis
Published in Expert Opinion on Pharmacotherapy, 2021
Yooyun Chung, Mussarat N Rahim, Jonathon J Graham, Yoh Zen, Michael A Heneghan
Liver histology is crucial for the diagnosis of AIH. Hallmark features include interface hepatitis with plasma cell infiltration of the portal tracts, emperipolesis and hepatic rosette formation (Figure 1) [5]. Interface hepatitis denotes inflammation at the portal and parenchymal interface. Emperipolesis refers to the engulfment of lymphocytes by hepatocytes. Rosette formation is not always seen but represents regeneration of hepatocytes. The presence of all three features is convincing of AIH, whereas interface hepatitis and plasma cell infiltration without the other features are still considered compatible with a diagnosis of AIH according to the simplified diagnostic criteria. One-third of patients will have established cirrhosis at time of diagnosis [5].
Nasal septum lesions causing diagnostic difficulty: Case report
Published in Acta Oto-Laryngologica Case Reports, 2023
Aiko Kishino, Syuji Yonekura, Ichiro Fukumoto, Tomoyuki Arai, Tomohisa Iinuma, Takeshi Suzuki, Kazuki Yamasaki, Yuichiro Otsuka, Manayu Shiina, Masayuki Ota, Jun-ichiro Ikeda, Toyoyuki Hanazawa
The histopathologic examination showed marked histiocytic infiltration accompanied by mononuclear cells, such as lymphocytes and plasma cells. Emperipolesis, a process by which one cell engulfs and temporarily retains another cell within its cytoplasm, has been observed in immune cells, particularly macrophages (Figure 4(A)). In the present study, a small number of histiocytes demonstrated emperipolesis. An immunohistochemical analysis revealed positive staining for S-100 protein and CD68 but negative staining for CD1a (Figure 4(B–D)). These pathological findings supported the diagnosis of extranodal Rosai-Dorfman disease (RDD). At 19 months after surgery, marked improvement in nasal congestion was observed. No postoperative treatment was administered.
Related Knowledge Centers
- Cytoplasm
- Megakaryocyte
- Leukemia
- Hodgkin Lymphoma
- Hematopoietic Stem Cell
- Lysosome
- Phagocytosis
- Peripolesis
- Macrophage
- Acute Myeloid Leukemia