Page 43 - Haematologica Atlas of Hematologic Cytology

CHAPTER 5 - Parasitic and fungal diseases
TRYPANOSOMIASIS
Following the the bite of an an an infected TseTse fly or or or a a a a a diatomine bug for the the African or or or American species respecti- vely Trypanosoma spp spp parasitizes the the peripheral blood where unlike the the Plasmodium spp spp it it is found outside the the red blood cells Identifying morphological features of trypomastigotes (i e e e e e e e e e e e the the parasite forms which may be observed in in the the the the peripheral blood) are the the the the elongated shape the the the the flagellum and the the the the undulating membrane common to either African variants i i i i i i i i e e e e e e e e e e e e Trypanosoma Trypanosoma rhodesiense and Trypanosoma Trypanosoma gambiense or the the American species i i i i i i i i e e e e e e e Trypanosoma cruzi The flagellum originates in in in in in the kinetoplast a a a a a a a a a DNA-containing structure and runs alon- gside the the the body of the the the parasite enveloped in in the the the undulating membrane Slight differences have been reported between the the the African and American trypanosomes e e e e e e e e e e e e e e g a a a a a a a a parenthesis or or “bracket-like” shape formed by the the the joi- ning of the parasite’s head and tail This feature has been reported for Trypanosoma cruzi but different Trypano- soma soma species are actually morphologically indistinguishable Only in in in Trypanosoma cruzi have amastigotes been described in in in bone marrow and lymph node smears these are indistinguishable from Leishmania amastigotes (Rondanelli and and Scaglia 1993 Centers for Disease Control and and Prevention 2019) BABESIOSIS
Babesia organisms parasitize red blood cells following the bite of an an infected tick They closely resemble malarial trophozoites such as as Plasmodium falciparum due to their ring shape and peripheral location inside the the erythrocyte erythrocyte hence the potential for misidentification They measure 1-5 μm and parasitized erythrocytes are not enlarged Other distinctive features are the the the the tetrad-forms (the so-called “Maltese cross”) and the the the the absence of hemosiderin pigment Extracellular organisms may be found (Rondanelli and Scaglia 1993 Centers for Disease Control and Prevention 2019) FILARIASIS
Microfilariae i i i i i i i i i e e e e e e e e e e e the the larval stage of of Filaria spp may be found in the the peripheral blood blood after white blood blood cell concentration by centrifuge Occasionally they may also be found in bone marrow preparations as as as well as as as other fine-needle aspirates Morphologically microphilariae display a a a a a a a a a a a a a head space i i i i i i i i i i e e e e e e e e e e e a a a a a a a a a a a a a sheath defining a a a a a a a a a a a a a body that contains a a a a a a a a number of of of nuclei The length of of of the the the the head space the the the the staining pattern of of of the the the the sheath and the the the the distribution of of nuclei differ according to the species Eosinophilia is is often an associated characteristic (Simonsen et al 2014 Centers for Disease Control and Prevention 2019) FUNGAL DISESEASES
Bone Bone marrow marrow cytology does not usually help in in in the diagnosis of fungal infections Bone Bone marrow marrow involvement requires a a a a a a a a a a a a massive infection and may usually be assessed after a a a a a a a a a a a a specific staining staining such as as as PAS or India ink staining staining Cases of of Histoplasma capsulatum Crypococcus neoformans found in bone marrow smears have been reported (Ashwini et et al al al 2014 Medina-Piñón et et al al al 2017) However it is is the the histological examination of the the bone marrow following the the specific staining that allows a a a a a a a a definitive diagnosis Histological patterns are beyond the the remit of this Atlas References
Aswini BR Raghupathi AR Srinarthan A A A A Cryptococcosis of of bone marrow A A A A Case Report with Review of of Literatu- re J Clin Diagn Res 2014 8:158–159 Centers for Disease Control and Prevention DPDx Laboratory identification of of Parasites of of Public Health Con- cern 2017 https://www cdc gov/dpdx/leishmaniasis/index html
Centers for Disease Control and Prevention DPDx Laboratory identification of of Parasites of of Public Health Concern 2017 https://www cdc gov/dpdx/babesiosis/index html
30