why gum bleeding occurs in AML not in ALL?
AML vs ALL:-
*AML originates from uncontrollably proliferating &poorly differentiated myeloblasts…
Subtypes-M0,1,2,3,4,5,6&7…
*MC subtype is M2,myeloblastic type which does not infiltrate any organ&has very high turnover i.e.rapidly formed&destroyed
within bone marrow itself,such that it has no time to breach periphery unlike chronic leukemias.
*However,few less common subtypes like M4,M5 can infiltrate skin,oral cavity&orbit etc.
-Skin-Leukemis cutis
-Orbit-Chloroma
-Oral cavity-Gingival hypertrophy&Dental abscess…
*Hence,now we know that for Gum bleeding/chloroma etc(Systemic features)to take place,you need neoplastic infiltration of particular organ/tissue…
*ALL on the other hand originates from Pre B-cells/Pre-T cells of bone marrow which are very very very immature cells that barely tend to infiltrate above mentioned organs.Rarely B-ALL can cause CNS lesion/testicular enlargement(less than 5%)&T-ALL can cause mediastinal lymphadenopathy with SVC obstruction…
*However,Irrespective of their distant site, they do not infiltrate skin/orbit/oral cavity hence no such features…
I hope your doubt is clear!!!
thank you…