Lymph Node ( I and II) Flashcards
In a lymph node, what cells predominate in the dark zone and what types of cells predominate in the light zone?
Dark zone: Centroblasts
Light zone: Centrocytes
What cell type predominates in germinal centers and what stain can help demonstrate that?
A: B cells
CD20 will be positive in within germinal centers
Note: there should only be a few scattered reactive T cells within germinal centers. These are a normal component to the GC.
What lymphoma develops from the T cells that are normally found within the germinal centers (follicular T cells)?
A: Angioimmunoblastic T cell lymphoma
What are two good stains to identify a germinal center and how do we distinguish them?
BCL-6: nuclear stain
CD10: cytoplasmic stain
What do CD21 and BCL-2 stain?
CD21: Follicular dendritic cells of the GC
BCL-2: negative in reactive GC
What does IgD stain within a lymph node?
It stains the Mantle Zones
What cells and structures are found with the cortex of lymph nodes?
B-cells
Primary and secondary follicles
What cells and structures are seen in the paracortex?
T-cells
Blood vessels
Interfollicular zone
What cells are found in the medullary cords of lymph nodes?
Plasma cells
T-cells
What cells are found in the sinuses of lymph nodes?
Monocytes
What disease entities should you consider whenever you see Follicular Hyperplasia?
Non-specific
Castleman disease
Progressively transformed GC
HIV-related lymphadenopathy
Rheumatoid lymphadenopathy
Syphilitic lymphadenopathy
What disease entities should you think of when you have a Paracortical Infiltrate?
Viral infections, NOS
Post-vaccine lymphadenitis
Infectious mononucleosis (EBV)
Drug induced hypersensitivity
Dermatopathic lymphadenitis
Histiocytic necrotizing lymphadenitis
Systemic lupus erythematosus
What disease entities do you think of when you see an infiltrate in the sinuses of lymph nodes?
Sinus histiocytosis
Langerhans cell histiocytosis
Sinus histiocytosis with bilateral lymphadenopathy (Rosai Dorfmann Disease)
Hemophagocytic Syndrome
Vascularization of sinuses
What are features of Rheumatoid lymphadenopathy ?
Follicular hyperplasia
Polytypic plasma cells
Neutrophils in the sinuses
What are features of Syphilitic lymphadenopathy?
Follicular pattern
Thickened lymph node capsule
Plasma cells
**IMP: perform a Warthin Starry stain
Irregularly shaped and variably sized follicles that extend from the cortex all the way into the medulla of the lymph node are characteristic of?
Follicular hyperplasia
What features both morphologically and immunohistochemically favor a lymph node with Follicular Hyperplasia?
Polymoprhic cells
Increased mitosis ( inc. Ki-67)
Macrophages
BCL-2 negative GC
t(14;18) negative
Architecture preserved
Variation in size of GC
No back to back follicles
What features both morphologically and immunohistochemically favor a lymph node with Follicular Lymphoma?
Monotonous cells (loss of light and dark zone distinction)
Decreased mitosis
Decreased macrophages
BCL-2 positive GC
t(14;18) positive
Architecture is effaced
Little variation in the GC shape and size
Back to back follicles
What is the term for germinal centers that are decreased in size?
Atretic
What is the disease entity with the following description:
- Frequently presents within the mediastinum
- Characterized by atretic GC (sometimes have 2 GC in one follicle)
- Concentric layering of the Mantle Zone
- Radially penetrating arterioles into GC
- Interfollicular plasmacytoid monocytes (CD123 positive)
Castleman Lymphadenopathy
Notes Below:
- Multiple GC = Twinning
- Concentric layers = Onion skinning
- Radial arteries = Lollipop sign
- Also will see increased paracortical vascularity
How is Castleman disease classified ?
Unicentric and Multicentric
What are the features of Unicentric Castleman Disease?
- Hyaline deposits or plasma cells in the paracortex
- Plasma cells usually polytypic but can sometimes have monotypic
- Increased follicular dendritic cells in GC
- (+): CD21, CD23, and CD35
Treatment: surgical excision
What are the features of Multicentric Castleman disease?
- Frequent HHV8 infection
- generally more plasmablastic
- Increased serum IL-6
- HHV8 encodes for IL-6
- Patients have worse prognosis and are treated with steroids or chemotherapy
- Increased incidence of plasmablastic lymphoma, Kaposi sarcoma, and primary effusion lymphoma
What are some disease associations seen with Multicentric Castleman Disease?
- HIV
- Wiskott-Aldrich Syndrome
- Pemphigus
- Myasthenia gravis
-
POEMS syndrome
- Polyneuropathy
- Organomegaly
- Endocrinopathy
- Monoclonal gammopathy
- Skin lesions
What are the three patterns seen in HIV lymphadenopathy?
- Follicular Hyperplasia:
- usually early in the disease course
- Irregualr GCs (markedly enlarged), naked GCs
- Follicle lysis, monocytoid B-cells
- Follicular Involution (D/D: lymphoma)
- Regressed GCs
- Thin mantle zones
- Histiocytes and immunoblasts
- Lymphocyte Depletion
- Small lymph nodes
- No follicles
- Histiocytes
- Erythrophagocytosis
What disease entity is described by these features:
- Follicular hyperplasia
- Epithelioid histiocytes near the GC
- Monocytoid B-cell hyperplasia
Toxoplasmosis Lymphadenitis
What are key clinical features of Toxoplasma lymphadenitis ?
- T. gondii is a parasitic protozoan in which the cat is the definitive host and source of human infection
- People can be asymptomatic or have fever and enlarged cervical lymph nodes
- 50% of adults have antibodies to T. gondii
