pathology of the hematopoietic systempeople.upei.ca/eaburto/hemat-l2/hemat-l2-14.pdfmyelophthisis...
TRANSCRIPT
![Page 1: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/1.jpg)
Enrique Aburto, March 2014
Pathology of the Hematopoietic
System
Lecture 2: Lympho/Myelo-proliferative
diseases and Lymph nodes
![Page 2: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/2.jpg)
Hematopoietic Neoplasia
Lymphoproliferative Disease
Lymphoma
Lymphoid leukemia
Plasma cell tumours
Myeloproliferative
Disease
Histiocytic Neoplasia
Myeloid leukemia
Myelodysplastic Syndrome
Mast cell tumour
Primary Hematopoietic Neoplasia
![Page 3: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/3.jpg)
Plasma cell tumours
1. Cutaneous Plasmacytoma
• Common skin masses in dogs • Surgical excision is usually curative
2. Extramedullary Plasmacytoma
• Arising at sites other than BM / skin
• Often affect the GI tract
• More aggressive, may metastasize to the lymph nodes
![Page 4: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/4.jpg)
Normal Cat Serum
Monoclonal gammopathy
Plasma cell tumours
3. Multiple Myeloma
• Uncommon in domestic animals: dogs > cats
• Malignant tumour of plasma cell origin arising in the bone marrow
• Neoplastic (clonal) plasma cells secrete immunoglobulin leading to hypergammaglobulinemia:
• Monoclonal gammopathy on serum electrophoresis
• Hyperviscosity syndrome
• Bence-Jones proteinuria
![Page 5: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/5.jpg)
Masses may occur in any bone, but most often occur in the vertebrae Can see hypercalcemia due to ↑ osteoclastic activity *
Plasma cell tumours
3. Multiple Myeloma
• Gross: Pale pink to dark red gelatinous masses replace bone marrow – typically multiple masses!
• Histologically: Sheets of round cells– with plasmacytoid morphology
![Page 6: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/6.jpg)
Clinical diagnosis of multiple myeloma is based on finding 2 - 3 + of the
following features:
• Increased plasma cells in bone marrow
• Punched out lesions on radiographs
• Monoclonal gammopathy
• Hypercalcemia
• Light chain (Bence-Jones) proteinuria
3. Multiple myeloma
Affected bones often
have “punched” out
appearance on
radiographs
Courtesy of Dr. A Matthews, AVC
• Clinical signs: lameness, pain, lethargy, paraplegia
• Slowly progressive
Plasma cell tumours
![Page 7: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/7.jpg)
Hematopoietic Neoplasia
Lymphoproliferative Disease
Lymphoma
Lymphoid leukemia
Plasma cell tumours
Myeloproliferative
Disease
Histiocytic Neoplasia
Myeloid leukemia
Myelodysplastic Syndrome
Mast cell tumour
Myeloproliferative Disease
![Page 8: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/8.jpg)
Histiocytic Proliferative Disorders
1. Cutaneous histiocytoma
• Common benign skin mass • Young dogs • Spontaneously regress
2. Reactive histiocytosis
• Immunoregulatory disease • Waxing and waning, progressive
• Cutaneous histiocytosis • Skin; dermal dendritic cells
• Systemic histiocytosis • Skin and viscera; interstitial dendritic cells
http://vetmedicine.about.com/od/diseasesandconditions/tp/Lumps-Bumps.htm
![Page 9: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/9.jpg)
Histiocytic Proliferative Disorders
3. Histiocytic Sarcoma
• Malignant neoplasia of macrophages or dendritic cells
• Breed predispositions • Bernese Mountain dog, Rottweiler,
Flat-coated Retriever
• Can be solitary of multiple:
• Solitary lesions • Subsynovium (joints), subcutis
• Lymph nodes, spleen or liver
• Multiple lesions
• Disseminated histiocytic sarcoma = Malignant histiocytosis
![Page 10: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/10.jpg)
• Aggressive multisystemic disease
• Tumour masses in several organs: spleen*, bone marrow*, lymph nodes*, lung, skin
• Splenomegaly, hepatomegaly
3. Disseminated histiocytic sarcoma (= malignant histiocytosis)
Histiocytic sarcoma, hilar and mesenteric lymph nodes
Histiocytic Proliferative Disorders
Courtesy of Dr A Lopez, AVC
![Page 11: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/11.jpg)
• Histology: Masses / diffuse infiltrates composed of atypical histiocytes
• May be avidly hemophagocytic causing a non-regenerative anemia
Hemophagocytic histiocytic sarcoma
Histiocytic Proliferative Disorders
3. Disseminated histiocytic sarcoma (= malignant histiocytosis)
![Page 12: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/12.jpg)
Mast cell neoplasia
Mast cells are widely distributed in the connective tissues - however they originate in bone marrow
1. Cutaneous mast cell tumour
• Common skin tumours of dogs
2. Systemic mastocytosis
• Involves primarily the hematopoietic system
![Page 13: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/13.jpg)
3. Systemic mastocytosis = Visceral mast cell tumours
Mast cell neoplasia
• Spleen, bone marrow
• Liver, intestine, kidney
• Rare in animals: cats
• Splenomegaly ; hepatomegaly +/- nodular surface
![Page 14: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/14.jpg)
Histology: Cords and sheets of mast cells efface the parenchyma
Toluidine Blue
3. Systemic mastocytosis = Visceral mast cell tumours
Mast cell neoplasia
![Page 15: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/15.jpg)
Secondary Bone Marrow Neoplasia
• Results of metastasis of a tumour from a distant site to the bone marrow
• Can be a carcinoma or a sarcoma
Image Courtesy of Dr A Lopez
Metastasis of a malignant pheochromocytoma to the rib, dog
![Page 16: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/16.jpg)
Myelophthisis
• Fibrosis → Myelofibrosis
• Neoplastic cells → leukemia, lymphoma, histiocytic sarcoma etc.
• May result in pancytopenia due to competition for space/nutrients
Dog: Replacement of bone marrow by lymphoma
• Replacement of hematopoietic tissue within the bone marrow by abnormal tissue Myelophthisis
![Page 17: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/17.jpg)
Lymphoid Tissue: Lymph nodes
![Page 18: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/18.jpg)
Lymph nodes
Function:
• Filtration of lymph
• Immune response
Structure: • Outer cortex follicles
(mostly B cells)
• Inner cortex paracortex (mostly T cells)
• Medulla mostly B cells and macrophages
Lymph circulation: • Afferent lymphatics subcapsular sinuses trabecular
sinuses medullary sinuses efferent lymphatics thoracic duct
Modified from Pathologic Basis of Veterinary Disease
![Page 19: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/19.jpg)
Lymph node: General response to injury
Small lymph nodes Lymphoid atrophy
Lymph node degeneration
Lymph node hypoplasia
Two basic responses: Decrease in size or increase in size
Enlarged lymph nodes
Lymphadenitis
Lymphoid hyperplasia
Hyperplasia of the monocyte/macrophage system
Primary neoplasia
Secondary neoplasia
![Page 20: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/20.jpg)
Lymph node: General response to injury
Enlarged lymph nodes
Lymphadenitis
Lymphoid hyperplasia
Hyperplasia of the monocyte/macrophage system
Primary neoplasia
Secondary neoplasia
• Enlargement of the lymph node(s) of unknown cause
• Can be localized or generalized Lymphadenopathy
Enlargement of the right retropharyngeal LN sheep
![Page 21: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/21.jpg)
• As opposed to reactive hyperplasia which is an antigen
driven immunologic response
Lymph node: Inflammation
• An inflammatory response to an infectious agent within the node Lymphadenitis
Cervical and sternal lymphadenitis with sepsis
Acute Lymphadenitis
• Usually the result of a
regional lymph node
draining a site of
inflammation and
becoming infected
![Page 22: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/22.jpg)
Lymph node: Chronic lymphadenitis
• With chronicity the lymph nodes become large, irregular, and firm due to fibrosis
• Chronic suppurative lymphadenitis
• Chronic granulomatous lymphadenitis
Rhodococcus equi in a foal
![Page 23: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/23.jpg)
Lymph node: Chronic suppurative lymphadenitis
• Gross lesions:
• Swollen lymph node with pus-filled center = Lymph node abscess
• Can fistulate to the skin surface
• Response to pyogenic bacteria
From Pathologic Basis of Veterinary Disease
![Page 24: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/24.jpg)
• Streptococcus equi subsp equi
• Inflammation of the URT → abscesses in the mandibular, retropharyngeal and parotid LN
• May fistulate to the surface
• Can spread to the viscera → “Bastard Strangles”
Equine Strangles
Lymph node: Chronic suppurative lymphadenitis From Noah’s arkive
![Page 25: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/25.jpg)
Pathogenesis:
• Usually enters via contamination of shear wounds; rarely by inhalation
• Drains to regional lymph nodes
–Superficial nodes more often affected than internal nodes
• Prescapular LN • Prefemoral LN
Caseous lymphadenitis: Corynebacterium pseudotuberculosis
• Chronic suppurative lymphadenitis in sheep & goats • Ulcerative lymphangitis in horses and cattle • Pectoral abscesses in horses
Lymph node: Chronic suppurative lymphadenitis
Image source unknown
![Page 26: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/26.jpg)
Goat, caudal mediastinal
lymph nodes: lymph
node abcesses
Lymph node: Chronic suppurative lymphadenitis
Caseous lymphadenitis: Corynebacterium pseudotuberculosis
![Page 27: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/27.jpg)
• Chronic suppurative inflammation, caseous necrosis & fibrosis
• As lesion progresses → characteristic concentric laminations**
Lymph node: Chronic suppurative lymphadenitis
Caseous lymphadenitis: Corynebacterium pseudotuberculosis
With time, there may be systemic
involvement with abscesses in the
internal organs
![Page 28: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/28.jpg)
Nodular granulomatous lymphadenitis
Mycobacterium bovis
Mycobacterium avium subsp. paratuberculosis
Actinobacillus lignieresii
Migrating parasitic larva
Diffuse granulomatous lymphadenitis
Porcine Circovirus type 2
Histoplasma capsulatum
Blastomyces dermatitidis
Cryptococcus neoformans
• Focal or multifocal
• Often white-yellow nodules
• +/- caseous necrosis/mineralization
• Enlarged, pale, dry, firm
lymph nodes
• Loss of architecture
Lymph node: Granulomatous lymphadenitis
![Page 29: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/29.jpg)
• Gross: Enlargement of the lymph node with single to multiple discrete yellow-tan gritty (caseated) nodules
• Can disseminate to the organs
Bovine Tuberculosis: Mycobacterium bovis
Lymph node: Nodular granulomatous lymphadenitis
![Page 30: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/30.jpg)
• Histology: Granulomas with central necrosis and mineralization surrounded by epithelioid macrophages and multinucleated giant cells
Lymph node: Nodular granulomatous lymphadenitis
Bovine Tuberculosis: Mycobacterium bovis
![Page 31: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/31.jpg)
Lymph node: Nodular granulomatous lymphadenitis
Bovine Tuberculosis: Mycobacterium bovis
• Histology: Granulomas with central necrosis and mineralization surrounded by epithelioid macrophages and multinucleated giant cells
![Page 32: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/32.jpg)
Lymph node: Nodular granulomatous lymphadenitis
Bovine Tuberculosis: Mycobacterium bovis
Acid fast bacilli within macrophages
• Histology: Granulomas with central necrosis and mineralization surrounded by epithelioid macrophages and multinucleated giant cells
![Page 33: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/33.jpg)
• Gross: Diffuse enlargement of the mesenteric lymph nodes
Postweaning multisystemic wasting syndrome (PMWS): Porcine Circovirus type 2
Lymph node: Diffuse granulomatous lymphadenitis
From Noah’s arkive
![Page 34: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/34.jpg)
• Histology: Granulomatous infiltration of the node with large botryoid intracytoplasmic viral inclusions
Postweaning multisystemic wasting syndrome (PMWS): Porcine Circovirus type 2
Lymph node: Diffuse granulomatous lymphadenitis
Images from Noah’s arkive
![Page 35: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/35.jpg)
Gross:
• Moderate enlargement of the node(s)
= Lymphadenopathy
• May bulge on cut section
Lymph node: Hyperplasia
Supramammary LN
Reactive lymphoid hyperplasia
Normal lymph node
Benign Reactive Hyperplasia
• Immunological reaction = response to antigen presentation or circulating interleukin levels
• Causes lymph node enlargement • Can be localized or generalized • Lymph nodes draining site of local infection or vaccination • Also occurs during early stages of lymphadenitis
![Page 36: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/36.jpg)
Histology: • Proliferation of lymphoid follicles with prominent germinal centers*
• Increased T cells in the paracortex
• +/- Increased plasma cells in the medullary cords
Lymph node: Hyperplasia
Antigenic stimulation
*
*
![Page 37: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/37.jpg)
Primary lymph node neoplasia = Lymphoma
Lymph node: Neoplasia
Covered in primary hematopoietic neoplasia*
![Page 38: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/38.jpg)
• Lymph node metastasis:
• Common with carcinomas, melanomas, mast cell tumors…
• May see lymph node enlargement
• Variable effacement of normal architecture
• One basis of staging tumor malignancy
• Stage 0: regional node normal
• Stage 1: regional node enlarged but still freely moveable
• Stage 2: regional node enlarged and fixed
Lymph node: Neoplasia
Secondary lymph node neoplasia
![Page 39: Pathology of the Hematopoietic Systempeople.upei.ca/eaburto/Hemat-L2/Hemat-L2-14.pdfMyelophthisis •Fibrosis → Myelofibrosis •Neoplastic cells → leukemia, lymphoma, histiocytic](https://reader034.vdocuments.us/reader034/viewer/2022042120/5e99c963aefba41d220cc913/html5/thumbnails/39.jpg)
Metastasis of mammary
carcinoma to a lymph node
Lymph node: Secondary neoplasia
Images: Courtesy of Dr Hanna, AVC