Benign Lymphocyte Disorders Flashcards
How do you identify a NK cell?
Large granular lymphocyte
-> only lymphocyte which will have granules to kill target cell
How is lymphocytosis (not leukocytosis) defined in adults and infants / young children?
Adults - >4,000 / microliter
Infants and young children - >9,000 / microliter
How is lymphopenia defined and what is relative lymphocytosis?
Lymphopenia - <1,500 / microliter
Relative lymphocytosis - absolute lymphocyte count is normal / near normal despite low WBC count -> makes up a relatively larger percentage
How is leukocytosis vs leukopenia defined?
Leukopenia - <5k / ul
Leukocytosis - >10k / ul
A patient has lymphadenopathy AND lymphocytosis. What findings suggest the cause is more likely malignant than benign?
> 5 cm lymph node. (very large, anything over 1 cm is abnormal)
SEVERE anemia or thrombocytopenia (viral may be mild)
Older patient or constitutional symptoms
What are the benign acute causes of lymphocytosis / lymphadenopathy (L/L)?
Bordetella Pertussis (think of the popcorn spilling in sketchy)
Infectious mononucleosis (reactive lymphocytosis in infectious process)
Infectious Hepatitis
What are the benign chronic causes of lymphocytosis / lymphadenopathy (L/L)?
Brucellosis
Tuberculosis
Toxoplasmosis
Secondary and congenital syphilis
What are the malignant disorders which are associated with L/L?
- Chronic Lymphoid Leukemias
- ALL
- Leukemic phase of lymphomas
What are the peripheral blood smear features of infectious mononucleosis?
Reactive lymphocytes with atypical macrophage-like morphology (can look like blasts)
Red cell hugging - cytoplasm of CD8 reactive T cells will hug RBCs
What establishes diagnosis of IM in a patient? How can you generally tell if an increase in antibodies is benign or malignant?
Heterophile IgM antibody
Can tell by running flow cytometry for B cell light chain. If both light chain types are present equally, it’s benign (polyclonal). If one is greatly favored, it’s malignant (monoclonal).
What usually causes IM, who gets it, and what are the clinical symptoms?
IM usually caused by EBV, less commonly CMV. Virus infects B cells, and T cells react
Affects young people (kissing disease)
Constitutional symptoms + stiff neck
- Splenomegaly - T cell hyperplasia in PALS
- Lymphadenopathy - often generalized, usually in neck (where infection started)
What are the atypical lymphocytes of IM called?
Downey cells
What is the risk of treating IM as a bacterial infection and what is the general care we advise?
If patient is given ampicillin, they will develop a rash
Only give steroids in very severe symptoms, otherwise just supportive
What are the complications of IM?
Splenic rupture
AIHA - due to cold agglutinins
What is definition of localized vs generalized lymphadenopathy?
Localized - <3 contiguous lymph node affected
Generalized - >=3 noncontiguous lymph nodes affected
What are the general causes of local lymphadenopathy?
Local infection - i.e. pyogenic infection, cat scratch, TB
Lymphomas - HL and NHL
Metastatic carcinomas
What are the general causes of generalized lymphadenopathy?
Infections
Non-infectious inflammatory processes (sarcoidosis, SLE, RA)
Malignant processes which have spread more
Miscellanous (drug reactions, hyperthyroidism, sinus histiocytosis with massive lymphadenopathy)
What are the superficial vs axial lymph nodes?
Superficial - accessible by physical exam
Axial - located in chest, abdomen, and pelvis, better seen by imaging. I.e. hilar nodes, para-aortic nodes.
How do you know something is abdominal lymphadeopathy on CT and not just a blood vessel or a loop of bowel?
You give them both oral and IV contrast with their CT
What features of lymphadenopathy lead you to believe its more likely a benign than a malignant process?
Rapid onset (days) - except for very aggressive lymphomas
Associated with pain / tenderness (lymphadenitis draining an area of infection)
Soft consistency
What would a firm vs a woody / hard lymph node give you suspicion for?
Firm - Non-Hodgkin’s lymphoma
Woody hard - metastatic carcinoma
What diagnostic workup should be done with isolated lymphadenopathy?
CBC with differential
Serology and cultures (for viruses and bacteria)
Flow cytometry if lymphocytes are increased
Lymph node biopsy as a last resort
What are the four types of lymph node hyperplasia which can be detected by biopsy?
Follicular - stimulation of B cells
Paracortical - T cell hyperplasia
Sinus - expansion of sinus histiocytes
Angiofollicular hyperplasia - “onion skinning appearance”
What are the causes of follicular and paracortical hyperplasia of LN?
Follicular - bacterial and viral infections, autoimmune diseases like RA (which overproduce Abs)
Paracortical - T cell processes, i.e. drug reaction and infectious mononucleosis
What are the causes of sinus and angiofollicular hyperplasia?
Sinus:
Sinus histiocytosis with massive lymphadenopathy - Rosai-Dorfman disease
Angiofollicular hyperplasia - Castleman’s disease
What are the two types of Castleman’s disease? What is usually associated with second type, and their overall clinical course?
- Unicentric - localized angiofollicular hyperplasia - indolent, benign course
- Multicentric - multicenter angiofollicular hyperplasia -HHV-8-associated, aggressive, lymphoma-like course
What pathological subtype of Castleman’s disease is most associated with unifocal castleman’s disease (UCD)? What are its features
Hyaline vascular type
- > onion peel mantle zone
- > Lollipop appearance - radially penetrating sclerotic vessels
- > lots of pink, acellular material
What pathological subtype of Castleman’s disease is most associated with multifocal castleman’s disease (MCD)? What are its features, and how is it treated?
Plasma cell / plasmablastic type - IL-6 driven (cytokine)
- > Sheets of plasma cells
- > more aggressive course, treated like myeloma
What are the events in the pathogenesis of Castleman’s disease?
Viral homologue of IL-6 drives B cell proliferation
Infected B cells localize to mantle zone of LN follicles, and cytokine release contributes to constitutional symptoms
What are the treatments for UCD and MCD?
UCD - surgical resection
MCD - Rituximab, corticosteroids, antiviral agents
What is the definition of splenomegaly?
> 14cm span in the mid-clavicular line
What are the criteria for hypersplenism and its underlying pathophysiology?
- Splenomegaly
- Reduction of at least one cell line in the blood
- Normal bone marrow function
-> spleen is enlarging due to sequestering more WBCs/RBCs
What are the indications for splenectomy?
Splenic rupture
Chronic immune thrombocytopenia
Hemolytic anemias - hereditary spherocytosis, AIHA, thalassemia major or intermedia
Hypersplenism (in symptomatic patients)
What must be done prior to splenectomy?
Pneumococcal vaccination at least two weeks before, annual flu shots, and meningococcal vaccine
