How to hypoplastic states vs. hyperplastic/neoplastic states affect the ratio of fat cells:hematopoietic cells in the bone marrow when biopsied?
- Hypoplastic = proportion of fat cells is >>> increased
- Hyperplastic = the fat cells often dissapear
Where do the definitive hematopoietic stem cells (HSCs) arise from during development?
Mesoderm of the intraembryonic aorta / gonads/ mesonephros region
Where do HSCs migrate to during the 3rd month of embryogenesis, which becomes the chief site of blood cell formation until shortly before birth?
Where is the hematopoietically-active tissue found in adults?
Bone marrow of axial skeleton
In adults, where are BM biopsies typically collected from?
Which cells lie next to bone marrow sinusoids and extend cytoplasmic processes that bud off into the bloodstream to produce platelets?
What is the most common cause of clinically significant neutropenia (agranulocytosis)?
What are characteristics findings of the damage due to infections seen in agranulocytosis?
Ulcerating necrotizing lesions of the gingiva, floor of mouth, buccal mucosa, and pharynx
Neutropenic patients are at high risk for deep fungal infection caused by which 2 organisms?
Candida and Aspergillus
What is the most distinctive symptom of Franklin Disease (aka γ-heavy chain disease)?
Characteristic findings of the LN's associated w/ acute nonspecific lymphadenitis?
- Enlarged and painful
- Large, reactive, germinal centers containing numerous mitotic figures
What are 3 morphological features which favor a reactive (non-neoplastic) follicular hyperplasia?
- Preservation of LN architecture
- Marked variation in the shape and size of follicles
- Presence of frequent mitotic figures, phagocytic macrophages (tingible body), and recognizable dark and light zones
Infection caused by what bacteria is associated with lymphocytosis?
What is the pathogenesis of hemophagocytic lymphohistiocytosis (aka macrophage activating syndrome)?
Systemic activation of macrophages and CD8+ cytotoxic T cells
What is the most common trigger for hemophagocytic lymphohistiocytosis (HLH)?
Infection, particularly EBV
What is the typical presenation of patient with hemophagocytic lymphohistiocytosis; what are lab values will be seen?
- Pt presents w/ acute febrile illness assoc. w/ splenomegaly and hepatomegaly
- Labs show anemia + thrombocytopenia + VERY high levels of plasma ferritin and soluble IL-2 receptor + ↑ LFT's
What are 2 major causes of neutrophilic leukocytosis?
- Acute bacterial infections, especially pyogenic
- Tissue necrosis (MI, burns)
Basophilic leukocytosis is usually indicative of what?