WBC Disorders - LAD, Lymphomas

Question 1

Lymphadenopathy (LAD)

Answer 1

Enlarged lymph nodes.
Painful - draining a region of acute infection.
Painless - chronic inflammation, metastatic carcinoma, lymphoma.
In inflammation, due to hyperplasia.
Follicular hyperplasia (B-cell region) - rheumatoid arthritis and early HIV.
Paracortex hyperplasia (T-cell region) - viral.
Sinus histiocyte hyperplasie - draining a tissue w cancer.

Question 2

Lymphoma

Answer 2

Neoplastic proliferation of lymphoid cells that form a mass.
In lymph node or extra nodal tissue.
Hodgkin lymphoma 40%.
Non-hodgkin lymphoma (NHL) 60%.
NHL small B cells: follicular, mantle cell, marginal, and small lymphocytic lymphomas.
NHL medium B cells: Burkitt lymphoma.
NHL large B cells: diffuse large B-cell lymphoma.

Question 3

Follicular lymphoma

Answer 3

Small B cells (CD20+) –> follicle-like nodules.
Late adulthood. Painless LAD.
t(14;18) BCL2–> Ig heavy chain locus –> overexpression –> apoptosis inhibited.
Tx: just for symptomatic pts - chemo or rituximab (anti-CD20 Ab).
EnlargING lymph node = progression to diffuse large B-cell lymphoma.

Distinguish from reactive follicular hyperplasia…

• disruption of normal lymph node architecture.
• lack of tingible body macrophages in germinal centers.
• Bcl2 in follicles.
• Monoclonality.

Question 4

Mantle cell lymphoma

Answer 4

Small B cells (CD20+) –> expand mantle zone.
CD5+
Late adulthood. Painless LAD.
Very aggressive and usu present in late stage.
t(11;14) Cyclin D1 –> Ig heavy chain locus –> over expression –> promote G1/S transition –> neoplastic proliferation.

Question 5

Marginal zone lymphoma

Answer 5

Small B cells (CD20+) –> expand marginal zone (formed by post-germinal center B cells).
Assoc w chronic inflammatory states - Hashimoto thyroiditis, Sjogren’s, H pylori gastritis.
MALToma is when it’s in mucosal sites.
Gastric MALToma may regress if H pylori is treated.

Question 6

Burkitt lymphoma

Answer 6

Intermediate-sized B cells (CD20+).
Assoc w EBV.
Extranodal mass in child/young adult.
African form - jaw.
Sporadic form - abdomen.
t(8;14) c-myc –> Ig heavy chain locus –> over expression –> promotes cell growth.
High mitotic index. Starry-sky on microscopy.

Question 7

Diffuse large B cell lymphoma

Answer 7

Large B cells (CD20+) - grow diffusely in sheets.
Most common NHL.
Aggressive (high-grade).
Sporadic or from transformation of low-grade lymphoma.
Late adulthood - enlarging lymph node or extra nodal mass.

Question 8

Hodgkin lymphoma (HL)

Answer 8

Reed-Sternberg (RS) cells: large B cells w multilobed nuclei and prominent nucleoli (owl-eyes).
CD15, CD30.
RS secrete cytokines –> B symptoms (fevers, chills, night sweats), attract reactive inflammatory cells, maybe fibrosis.
Reactive inflammatory cells = bulk of tumor; classify tumor.

Nodular sclerosis (70% subtypes):
Enlarging cervical or mediastinal lymph node in young adult female.
Lymph node divided by bands of sclerosis.
RS cells in lake-like spaces (lacunar cells).

Other subtypes:
Lymphocyte-rich - best prognosis.
Mixed cellularity - abundant eosinophils (RS cells make IL-5).
Lymphocyte-depleted - most aggressive; elderly and HIV.