Histiocytes


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Histiocytes

 

(wandering cells at rest; polyblasts; clasmatocytes), cells of reticular connective tissue in vertebrate animals and humans. Histiocytes are sharply contoured, with basophilic cytoplasm, in which there are often vacuoles and inclusions. The shape of the cell varies owing to its capacity for amoeboid movement. Histiocytes perform a protective function by trapping and digesting various foreign particles, including bacteria. In various types of irritations—for example, in inflammatory reactions—the histiocytes are activated and transformed into typical macrophages. Sometimes the cytoplasm of histiocytes forms short, rounded projections that break away from the body of the cell (clasmatosis). In embryos, histiocytes develop from the mesenchyme, and in the adult body they develop from undifferentiated cells of reticular connective tissue, reticular tissue, and certain kinds of blood cells—lymphocytes and monocytes.

E. S. KIRPICHNIKOVA

References in periodicals archive ?
Patients may present with systemic symptoms including fever, night sweats, malaise, and weight loss which may be related to enhanced production of monokines by the activated histiocytes.1 RDD mostly presents with massive non-tender cervical lymphadenopathy.
Rosai-Dorfman disease bears at least superficial resemblance to histiocytic sarcoma because of the presence of large histiocytes with abundant cytoplasm and emperipolesis.
In early lesions, scalloped macrophages dominate the histology, but most well-developed lesions have a mixture of the above.14 Immunohistochemical studies show negative staining for S-100, CD1a, and Birbeck granules, and positive staining for the surface markers CD68 and factor XIIIa.15 Our patient had typical lesion involving typical sites and histopathology of skin lesions showed foamy histiocytes and occasional multinucleated giant cell in dermis.
CD163 has recently been recognized as a marker of histiocytes that is positive in SHML and may prove useful in diagnosing RDD [2, 5, 6].
The two classical histological features include scattered histiocytes with emperipolesis, which represent histiocytic phagocytosis of intact plasma cells, lymphocytes, and cellular debris as well as expression of S100 protein, CD14, CD68, and CD1c and absence of staining for CD1a and MHC-2 (which are both positive for Langerhans-type dendritic cells).
Harris et al., "Tumours of histiocytes and accessory dendritic cells: an immunohistochemical approach to classification from the international lymphoma study group based on 61 cases," Histopathology, vol.
Histologically, SIGBIC is formed by extracellular and/ or intracellular silicone, numerous histiocytes, chronic granulomatous inflammatory infiltrate with multinucleated giant cells, and infiltrate of mixed lymphocytes--T and B without atypia.
Skin biopsies of the neck, chin, and forearm showed patchy or diffuse granulomatous dermal inflammation, with foamy and epithelioid histiocytes. We found numerous acid-fast bacilli within histiocytes and invading nerves (Figure 2), highlighted by Fite, Gomori methenamine silver, and Gram stains; Ziehl-Neelsen stain highlighted only a few organisms.
Microscopically, the lesion is characterized by dense aggregates of large mononuclear histiocytes (the 'von Hansemann' cells) admixed with intracellular and extracellular calcied granular inclusions known as Michaelis-Gutmann bodies and lymphoplasmacytic inltrate.
The pathological analysis of the nephrectomy specimen revealed an inflammatory infiltrate formed by foamy histiocytes that were positively stained for CD68 and neutrophilic aggregates which confirmed the preoperative diagnosis (Figures 4 and 5).
The Haematoxylin and Eosin stained sections from the appendicectomy specimen showed patchy neutrophilic infiltration of mucosa and clusters of foamy histiocytes (Figure 1) along with foreign body type multinucleated giant cells, lymphocytes and plasma cells in the muscular and serosal layers (Figure 2).
Histological examination showed paracortical necrotic foci with the presence of small to large CD3+, CD5+/-, CD4-/+, CD8+/- T lymphocytes, in addition to numerous histiocytes expressing CD68PGM1/MPO and abundant apoptotic nuclear debris.