Non-Lymphoma Lymph Nodes, Spleen & Thymus Flashcards
What is the name for swelling of the lymph nodes for any cause?
lymphadenopathy
What is the term for infection of the lymph nodes (acute or chronic)?
lymphadenitis
What is the term for reactive increase in lymphocytes from any cause?
lymphoid hyperplasias
What is the clinical picture of acute lymphadenitis?
- affected region- redness, swelling, tenderness
- may be abscessed & drain to skin surface
Wha is the clinical picture of chronic lymphadenitis?
- nontender lymph node
- enlarge over time
- common in inguinal & axillary lymph nodes
- drain to extremities
What are the 3 non-neoplastic lymph reactive changes?
Follicular pattern
Paracortical pattern
Sinus pattern
What is the most common reactive lymphoid hyperplasia in children?
follicular (most common in all but especially children)
What is the morphology seen in follicular pattern reactive lymphoid hyperplasia?
- variably sized follicles
- large, oblong germinal centers
- dark zone: centroblasts
- lighter zone: centrocytes
- scattered antigen-presenting dendritic cells & tingible body macrophages
-
mantle (around germinal center)
- small B-lymphocytes with scant cytoplasm
- asymmetric
- large, oblong germinal centers
What lymph node pathology is shown in the provided image?
GOTCHA! (or hopefully I didn’t)
Normal lymph node
Identify the types of lymph node pathology shown in the provided diagram
- Follicular
- usually seen with humoral response (autoimmune & bacterial infections)
- Diffuse Hyperplasia
- usually viral
What pattern of reactive lymphoid hyperplasia is shown in the provided image?
Follicular
- variably sized follicles
- large, oblong germinal centers
- dark zone: centroblasts
- lighter zone: centrocytes
- scattered antigen-presenting dendritic cells & tingible body macrophages
-
mantle (around germinal center)
- small B-lymphocytes with scant cytoplasm
- asymmetric
- large, oblong germinal centers
What is the cause of follicular patter reactive lymphoid hyperplasia?
activated humoral immune response
(bacterial infections, RA, some viral infections, etc)
What pattern of reactive lymphoid hyperplasia is shown in the provided image?
common in cancer patients - because draining an organ that has tumor in it, so you get these antigens & get reactive sinus hyperplasia/histiocytosis
What pattern of reactive lymphoid hyperplasia is shown in the provided image?
What is the cause of paracortical pattern reactive lymphoid hyperplasia?
activated T-cell-mediated immune response
(acute viral infections & some medications)
What is the morphology seen in follicular pattern reactive lymphoid hyperplasia?
- diffuse expansion T-lymphocytes in interfollicular region
- scattered immunoblasts (3-4x size resting lymphocytes)
- round nuclei, open chromatin, prominent nucleoli, moderate amount pale cytoplasm
- scattered immunoblasts (3-4x size resting lymphocytes)
What are centroblasts?
proliferating blast-like B lymphocytes (large nucleus so cause a darker appearance)
(seen in Follicular pattern reactive lymphoid hyperplasia)
What are centrocytes?
zone with mainly B cells with irregular or cleaved nuclear contours
(seen in follicular pattern reactive lymphoid hyperplasia)
What is the cause of sinus pattern reactive lymphoid hyperplasia?
increase in number & size of cells lining the lymphatic sinusoids with numerous histiocytes
(lymph nodes draining tumors, Whipple disease, etc)
Rosai-Dorfman Disease displays what pattern of reactive lymphoid hyperplasia?
It most commonly affects what demographic?
Clinical presentation?
-
Sinus pattern
- massive dilation of sinuses
- numerous, large, intrasinusoidal histiocytes with intracytoplasmic lymphocytes
- plasma cells, neutrophils & RBC
- children/young adults
- Clinical picture
-
massive lymphadenopathy
- bilateral cervical lymphadenopathy (& others)
- fever, night sweats, weight loss, anemia, etc
-
massive lymphadenopathy
What lymph node pathology is shown in the provided slides?
Rosai-Dorfman Disease
-
Sinus pattern
- massive dilation of sinuses
- numerous, large, intrasinusoidal histiocytes with intracytoplasmic lymphocytes
- plasma cells, neutrophils & RBC
Granulomatous lymphadenopathy is due to what 3 main inciting factors?
- Infection
- Foreign bodies
- Malignancy
What are the 2 main morphologic types of granulomas?
Necrotizing granulomas
Non-nectorizing granulomas
TB, histoplasmosis, cat scratch disease & tularemia cause what type of granulomas?
necrotizing granulomas
Non-necrotizing granulomas can be cause by what conditions?
numerous infections
sarcoidosis (diagnosis of exclusion)
How do metastatic tumors infiltrate the lymph nodes?
First: marginal sinus
Then: medullary sinus, medulla, & cortex
- pink = capsule
- dark purple = non-neoplastic lymph node (no germinal centers)
- tube = afferent lymphatics - notice clusters of tumor cells migrating into the lymph node
What type of granuloma seen in the provided image?
Necrotizing
What type of granuloma is seen in the provided image?
Non-necrotizing
What is the most common congenital abnormality of the spleen?
accessory spleen
20-35% normal persons
histology & function are normal
What is the major significance of having an accessory spleen?
may be found anywhere in the abdomen
if there is a hematologic disorder where a splenectomy is indicated & the accessory spleen is overlooked, the benefit of the splenectomy may be reduced/lost
What are the 4 major functions of the spleen?
- phagocytosis of blood cell & particulate matter
- antibody production
- hematopoiesis
- sequestration of formed blood elements
What organ is seen in the provide image?
Spleen
Why do we we see nonspecific acute splenitis in situation of blood-borne infections? What is the major histology feature seen in this condition?
reaction caused by organisms themselves & cytokines released by immune system
congestion of red pulp, neutrophils & plasma cells seen throughout, white pulp follicles may be necrotic
What splenic condition is seen in the provided slide? What is it commonly caused by?
granulomas
certain infections (esp fungal)
sarcoidosis
hodgkin lymphoma
some non-hodgkin lymphomas
What is perisplenitis? What is it caused by?
inflammation of the peritoneal covering of the spleen
due to multiple rounds of inflammation of the splenic capsule & peritoneal covering
What condition is seen in the provided image?
Perisplenitis
thick white fibrous nodules & plaques coat the spleen surface
What are the causes of splenic insufficiency?
surgical splenectomy
auto-spenectomy (repeated infarction ie. sickle cell)
Splenic insufficiency results in increased susceptibility to what 3 specific encapsulated organisms?
What precaution should individuals with splenic insufficiency take to protect against these organisms?
- Streptococcus pneumoniae*
- Haemophilus influenza*
- Neisseria meningitides*
vaccination for all of these organisms
What are the 8 causes of splenomegaly?
- Hematogenous disorder
- Autoimmune diseases
- Storage disorders
- Primary splenic neoplasms
- Metastatic tumor
- Infections
- Congestive states
- Hemophagocytic lymphohistiocytosis
What splenic condition is seen in the provided images?
Splenic Amyloid
- Top: Waxy pink appearance on H&E
- Bottom: Apple green birefrengence on Congo Red stain
Why does splenomegaly develop in the instance of congestive states?
direct consequence of venous outflow obstruction
-
intrahepatic: impede portal venous drainage
- cirrhosis
-
extrahepatic: directly impinge portal or splenic veins
- thrombosis of hepatic, portal or splenic veins
- congestive heart failure
What condition is shown in the provided image of the gross sample?
Congestive Splenomegaly
moderately enlarged
homogeneous, beefy red & focally hemorrhagic
capsule is thick & fibrous
How does the the red pulp or the spleen change through the course of congestive splenomegaly?
initially congested but becomes increasing fibrotic & cellular over time
Chronically enlarged spleen can result in what complications?
may removed excessive numbers of blood cells - anemia, leukocytopenia, or thrombocytopenia
What are the causes of hypersplenism?
- autoimmune diseases
- congestive splenomegaly
- gaucher disease
- hematolymphoid neoplasms
- hereditary spherocytosis & other hemolytic anemias
- many infections
What is the cause of hemophagocytic lymphohistiocytosis?
systemic activation of macrophages & CD8+ cytotoxic T cells
What is the clinical manifestation of hemophagocytic lymphohistiocytosis?
peripheral cytopenias & signs/symptoms of systemic inflammation due to macrophage activation
if untreated may progress to DIC, shock, multiorgan failure & death
What is the most common trigger of hemophagocytic lymphohistiocytosis?
infection - specifically EBV & HIV
also triggered by malignancy, autoimmune diseases, immunosuppression, medications & metabolic disorders
What condition is seen in the provided image?
acquired hemophagocyic lymphiohistiocytosis
macrophages within sinuses with phagocytosis of lymphocytes & RBC
systemic inflammatory condition
What are the 3 most common causes of splenic infarct?
embolism to the splenic artery/branches (endocarditis or severe artherosclerosis)
massive splenomegaly
thrombosis of splenic vein
What condition is shown in the image of the provided gross sample?
splenic infarct
wedge-shaped, pale & subcapsular
What are the most common causes of splenic rupture?
trauma & surgical intervention
spontaneous rupture happens only in abnormal spleens
Splenic rupture can lead to what complications?
life-threatening intraperitoneal hemorrhage & requires prompt splenectomy
splenic implants
What condition is shown in the provided image of the gross sample?
Splenic rupture
What is the most common primary tumor of the spleen?
hemangioma
What type of splenic tumor is seen in the provided images?
Hemangioma
usually <2cm
may involve entire spleen
usually cavernous type
How is a lymphangioma different from a hemangioma?
channels contain lymph, not blood
otherwise very similar
What type of splenic tumor is shown in the provided image?
Lymphangioma
may be focal but may involved the entire organ
subcapsular, multicystic, lumina contains proteinaceous material (not red blood cells), endothelium may form small papillary projections
What demographic is most commonly affected by splenic lymphangiomas?
children
sometimes in association with lymphogiomas in other organs
What is the most common malignant primary nonlymphoid tumor of the spleen?
angiosarcoma
What type of splenic tumor is seen in the provided images?
Angiosarcoma
may present as a nodule or diffusely involves the spleen
Angiosarcoma of the spleen can lead to what complication?
spontaneous rupture
Metastasis to the spleen are most commonly originate from what sites?
melanoma
lung
breast
gastric
pancreas
liver
colon
What type of splenic tumor is seen in the provided image?
Metastasis
Which thymus sample is from and adult & which is from a child?
left child
right adult (much fattier)
What is acute Thymic Involution?
response to severe disease & metabolic stress associated with
pregnancy, lactation, infection, surgery, malnutrition, malignancy, etc.
characterized by lymphocyte death & is (prob) mediated by high levels corticosteroids
Thymic Involution most commonly affects what demographics?
premature infants or ill term infants exposed to chronic stress in utero
What condition is seen in the provided histological slide?
Thymic Involution
complete loss of the cortex
Hassall corpuscle (arrows) are prominent
What is the most common ectopic tissue to be found in the thymus?
parathyroid
Thymic hypoplasia is commonly seen in what condition?
DiGeorge syndrome
severe defects in cell-mediated immunity
Thymic Hyperplasia is seen in what conditions?
chronic inflammatory/immunologic states (particularly myasthenia gravis)
What is the definition of thymic hyperplasia?
presence of lymphoid follicles in the thymus regardless of thymic size (usually normal sized thymus)
What condition is seen in the provided histological slide?
Thymic hyperplasia
What is the most common primary anterior mediastinal neoplasm?
Benign thymoma
What is the origin of a benign thymoma?
primary tumor of thymic epithelial cells
NOT lymphoid cells
What demographics are most commonly affected by benign thymomas?
M v F?
age?
M = F
usually middle age
may be associated with paraneoplastic syndrome (MG)
What condition is seen in the provided image?
Benign Thymoma
lobulated, usually encapsulated mass
large, tan/gray with sharp lobulations due to fibrous bands with some nodules having pointed ends
cystic degeneration is common
What is the histology type of benign thymoma shown in the provided histological examples?
- Upper left: Spindle Type
- Upper Right: Epitheliod type
- Bottom: Mixed
background non-neoplastic small lymphocytes
usually no well-formed Hassall corpuscles
What are the two diagnostic patterns of malignant thymoma?
- Invasive Thymoma
- Thymic Carcinoma
What type of thymoma is shown in the provided histological slide?
Malignant thymoma - Invasive thymoma
- benign cytologic features
- locally aggressive architectural features
- invasion through capsule
- Pleural/pericardial implants
- distant metastases
What type of thymoma is shown in the provided histological slide?
Malignant thymoma- Thymic carcinoma
- cytologic & architectural features are malignant (this one resembles poorly differentiated SSC)
- often morphologically similar to squamous cell carcinoma
- typically NOT associated with myasthenia gravis
- ~5% all thymomas
What are the most common primary sites of tumors that metastasize to the thymus?
esophagus
lung/pleura
breast
thyroid
melanoma
