Stains & molecular markers
Treponema pallidum IHC


Topic Completed: 20 August 2020

Minor changes: 20 August 2020

Copyright: 2020, PathologyOutlines.com, Inc.

PubMed Search: Treponema[TIAB] immunohistochemistry[TIAB]

Maryam Aghighi, M.D.
Silvija P. Gottesman, M.D.
Page views in 2020 to date: 177
Cite this page: Aghighi M, Gottesman SP. Treponema pallidum IHC. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/stainstreponemaihc.html. Accessed September 23rd, 2020.
Definition / general
  • Syphilis is a sexually transmitted disease caused by Treponema pallidum, a bacterium discovered in 1905 by Schaudinn and Hoffman who initially named it Spirochaeta pallida (J Med Life 2014;7:4)
  • T. pallidum can be localized on formalin fixed paraffin embedded tissue; the antibody has a rabbit purified IgG fraction (J Cutan Pathol 2004;31:595)
Essential features
  • Immunohistochemical stain for T. pallidum is more sensitive (71% sensitive) than silver stains - Warthin-Starry or Steiner (41% sensitive) (J Cutan Pathol 2004;31:595)
  • Diaminobenzidine chromogen can be problematic (melanin pigment on dendritic melanocytes can be confused for spirochetes)
  • Thus, some labs use fast red chromogen, in which the spirochetes stain red
Terminology
  • Anti-Treponema pallidum immunohistochemical stain
Pathophysiology
  • In patients with syphilis, T. pallidum spirochetes show an epitheliotropic and vasculotropic pattern (Hum Pathol 2009;40:624)
Clinical features
  • Primary syphilis: painless chancre with nontender lymphadenopathy 1 - 3 weeks after exposure
  • Secondary syphilis:
    • Papulosquamous thin papules on the trunk and extremities, palms and soles, fever and adenopathy
    • Rash may resemble a drug eruption, pityriasis rosea and psoriasis
    • May present as moth eaten alopecia on the scalp, mucous patches on tongue
  • Tertiary syphilis: may present with gummatous lesions, neurologic or cardiovascular symptoms (Infect Dis Clin North Am 2013;27:705)
Interpretation
  • Coiled spirochetes are highlighted in the lower half of epidermis or mucosa and in dermal vessel walls and perivascular space
Uses by pathologists
  • Although serologic studies remain the gold standard, for histologic evaluation, T. pallidum IHC is preferred in evaluating mucocutaneous biopsies suspicious for syphilis (J Cutan Pathol 2004;31:595)
Prognostic factors
Microscopic (histologic) images

Contributed by Silvija P. Gottesman, M.D.
Lymphoplasmacytic infiltrate

Lymphoplasmacytic infiltrate

Spirochetes in epidermis

Spirochetes in epidermis

Spirochetes in dermal vessel walls

Spirochetes in dermal vessel walls

Spirochetes in epidermis

Spirochetes in epidermis

Virtual slides

Images hosted on other servers:

Spirochetes highlighted with IHC (brown)

Subtle spirochetes with IHC (red)

Spirochetes highlighted with IHC (brown)

Positive staining - normal
  • None
Positive staining - disease
Molecular / cytogenetics description
  • Polymerase chain reaction (PCR) may be used to detect T. pallidum in mucocutaneous lesions and is more sensitive and specific than T. pallidum immunohistochemistry (Br J Dermatol 2011;165:50)
Board review style question #1

A 35 year old pregnant woman presented to clinic with fever, fatigue and a papulosquamous eruption on the trunk and extremities that includes the palms and soles. Which one of the following stains is the most sensitive for diagnosis of syphilis in biopsy specimens?

  1. Giemsa stain
  2. Gram stain
  3. Steiner stain
  4. T. pallidum IHC stain
  5. Warthin-Starry stain
Board review answer #1
D. T. pallidum IHC stain

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Reference: Treponema pallidum IHC
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