Page 478 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

434 SectIon III Hematology and oncology ` hematology and oncology—Pathology Hematology and oncology ` hematology and oncology—PhaRmacology

Polycythemia
PlaSma VolUme RBc maSS o SatURatIon ePo leVelS aSSocIatIonS
2
Relative  – – – Dehydration, burns.
Appropriate absolute –    Lung disease, congenital heart
disease, high altitude.
Inappropriate absolute –  –  Exogenous EPO: athlete abuse
(“blood doping”).
Inappropriate EPO secretion:
malignancy (eg, renal cell
carcinoma, hepatocellular
carcinoma).
Polycythemia vera   –  EPO  in PCV due to negative
feedback suppressing renal
EPO production.
 = 1º disturbance

Chromosomal translocations
tRanSlocatIon aSSocIated dISoRdeR noteS
t(8;14) Burkitt (Burk-8) lymphoma (c-myc activation) The Ig heavy chain genes on chromosome 14
t(11;14) Mantle cell lymphoma (cyclin D1 activation) are constitutively expressed. When other
genes (eg, c-myc and BCL-2) are translocated
t(11;18) Marginal zone lymphoma
next to this heavy chain gene region, they are
t(14;18) Follicular lymphoma (BCL-2 activation) overexpressed.
t(15;17) APL (M3 type of AML; responds to all-trans
retinoic acid)
t(9;22) (Philadelphia CML (BCR-ABL hybrid), ALL (less common,
chromosome) poor prognostic factor); Philadelphia CreaML
cheese

Langerhans cell Collective group of proliferative disorders of A B
histiocytosis Langerhans cells. Presents in a child as lytic Birbeck granules
bone lesions A and skin rash or as recurrent
otitis media with a mass involving the mastoid
bone. Cells are functionally immature and
do not effectively stimulate primary T cells
via antigen presentation. Cells express S-100
(mesodermal origin) and CD1a. Birbeck
granules (“tennis rackets” or rod shaped on
EM) are characteristic B .

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