Skip to main content

Infective Conditions of the Lymph Node (Lymphadenitis)

(This is another continuation of the Sabah Lymphoma talk -- first and second part)

I. Toxoplasma

  • Three features:
    • Follicular hyperplasia.
    • Epithelioid histiocytes.
    • Monocytoid B cells in sinusoids.
  • Enlarged germinal centre (still have mantle zone and tingible body macrophages)
II. Viral
  • Partial architectural effacement with expanded paracortex.
  • Polymorphous cellularity.
  • Mottled histological appearance with marked follicular hyperplasia.
  1. Infectious mononucleosis
    • Expanded paracortez with heterogenous population.
    • Increased blood vessels.
    • Presence of immunoblasts that mimic Reed-Sternberg cells.
    • Hyperplastic follicles.
  2. Herpes simplex virus
    • Mixed cell population.
    • Reed-Sternberg-;ole activated lymphocytes.
    • Apoptotic cells and neutrophils.
  3. HIV
    • Early: present with acute reactive lymphadenitis.
    • Late: present with marked CD4+ T-cell depletion, and involution of lymph nodes.
    • 3 phases:
      1. Acute
        • Non-specific, more to viral lymphadenitis, eg paracortical expansion.
      2. Transition
        • Disruption of normal architecture, germinal centre smaller, excessive pool of blood vessels.
      3. Burn-out
        • Atrophic.
III. Bacterial
  • Composed of sinus expansion.
  • May contain proteinaceous fluids or microabscesses
  • eg Cat-scratch disease, tuberculosis.
Below is not an infective condition but important anyway:

Epithelial cell inclusion in lymph node
  • May include squamous, thyroid, mammary glands
  • Must differentiate from metastasis.

Comments

Popular posts from this blog

8 L's and DRUGS

I am so happy that I found an educational gem by Sullivan Nicolaides Pathology , a private pathology lab in Australia.  There are some videos of live lectures that one can find here.  I am particularly excited (and maybe starstruck) to find Professor  David Weedon's lectures here -- as I am particularly fond for Dermatopathology. A particular thing I learned today from Professor David Weedon was a checklist mnemonic for perivascular infiltrate in the skin: 8L's and DRUGS Light reaction Lymphoma (and pseudo) Leprosy Lues Lichen striatus Lupus erythematosus Lipoidica (and incomplete granuloma annulare) Lepidoptera (arthropods etc) Dermatophyte Reticular erthymatous mucinosis Urticaria Gyrate erythema Scleroderma

Dermatopathology Pearls

Some pointers taken from the Dermatopathology RCPA Quality Assurance Programme: 1. Glomus tumour : It can occur in other places other than the nailbed. Other variants may be glomangioma, glomangiomyoma and symplastic glomus tumour. Malignant glomus tumour is a rare entity. A differential is spiradenoma. 2, Fixed drug eruption : Composed of a combination of erythema multiforme -like changes, mixed inflammatory infiltrate, and melanophages in the superficial dermis. Here is a nice explanation on the clinical features . 3. Chondrodermatitis nodularis helicis Painful nodule typically in the upper part of ear in older males. 4. Naevus cell rests in lymph nodes. Apparently it is not that uncommon (22% of lymphadenectomies in a large study). 5. Superficial acral fibromyxoma Circumscribed but non encapsulated lesions, typically at fingers and toes. Strongly CD34 positive. Differentials include:     1. Low grade fibromyxoid sarcoma: Deep soft tissue lesion, ...

Review of serrated lesions by JCP

Mention the term 'serrated lesions" (of the colorectum) and immediately I will get a brief panic attack.  Based on my limited knowledge, the lesions sound and look the same.  Even when a senior teacher made a nice diagram of how to differentiate all of these lesions, it still did not hit me how things work... until today. There is a nice review article in Journal of Clinical Pathology regarding pathological diagnosis of serrated lesions by Bateman and Shepherd ( J Clin Pathol   2015 ; 68 : 585 - 591).   I think it very helpful in terms of clearing up the terminologies involved. Basically, the recommended terminology of serrated lesions in the colorectum is as follows: 1. Hyperplastic polyp 2.  Sessile serrated lesion (SSL) 3.  SSL with dysplasia 4. Traditional serrated adenoma 5. Mixed polyp Hyperplastic polyp is easy enough, but what about sessile serrated lesions?  They have listed the key histological features as follows: ...