Inflammation / parasites
Trichomonas vaginalis

Topic Completed: 1 August 2015

Minor changes: 19 March 2020

Copyright: 2003-2020, PathologyOutlines.com, Inc.

PubMed Search: Trichomonas vaginalis [title] cervix

John K.S.S. Philip, M.D.
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Cite this page: Philip J, Salih Z. Trichomonas vaginalis. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cervixtrichomonasvaginalis.html. Accessed May 28th, 2020.
Definition / general
  • Trichomonas vaginalis is a parasitic protozoan that causes trichomoniasis, a sexually transmitted disease
  • Trichomoniasis is the most prevalent nonviral sexually transmitted infection in the United States, affecting an estimated 3.7 million persons (CDC - Trichomoniasis)
  • Having multiple sexual partners is the primary risk factor
  • Mainly affects women from ages 16 - 35 years, but can occur in postmenopausal women
  • Female: vagina, cervix, urethra and occasionally Bartholin's gland
  • Male: urethra, epididymis and prostate
Clinical features
  • Most infected persons (70% - 85%) have minimal or no symptoms, and untreated infections might last for months to years (CDC - Trichomoniasis)
  • Copious yellow, green or gray, white vaginal discharge with a strong odor
  • Itching and irritation are frequent
  • Discomfort during sexual intercourse or urination
  • In pregnancy, can cause premature rupture of membranes and preterm delivery
  • Largely asymptomatic in men, act as a carrier; may cause urethritis
  • Nucleic acid amplification test (NAAT)
  • OSOM trichomonas rapid test: Immunochromatographic test that detects pathogen antigens from vaginal swab
  • DNA hybridization probe test
  • Direct microscopic examination of secretions - wet mount
  • Culture: Was considered as a gold standard before the availability of molecular tests
Prognostic factors
  • Treatment reduces the signs and symptoms of infection and might reduce transmission (CDC - Trichomoniasis)
Case reports
  • Metronidazole or tinidazole
  • Sexual partners must also be treated
Clinical images

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Strawberry cervix

Cytology description
  • Pear shaped, oval or round cyanophilic organisms, 15 - 30 microns
  • Eosinophilic cytoplasmic granules are often evident
  • Nucleus is pale, vesicular and eccentrically located
  • Flagella are sometimes observed
  • Leptothrix may be seen in association with Trichomonas vaginalis
  • Mature squamous cells with slightly enlarged, dark nuclei and small perinuclear halos ("trich change") are common that may mimic a low grade squamous dysplasia
  • 3 dimensional clusters of neutrophils ("polyballs") may be seen in the background
  • Numerous lymphocytes and many mast cells may be seen
  • Organisms tend to be smaller and rounder with better visualized nuclei, cytoplasmic eosinophilic granules and flagella in liquid based preparations
  • Neutrophils and "polyballs" are reduced in liquid based preparations compared to the conventional smears
  • Occasional kite shaped forms may be seen, especially on SurePath preparations (Nayar: The Bethesda System for Reporting Cervical Cytology, 3rd Edition, 2015)
Cytology images


in wet mount

Trichomonas in conventional
pap smear

Trichomonas vaginalis
with leptothrix



Various images

Contributed by
Dr. Marilin Rosa

Electron microscopy images

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T. vaginalis parasite

Differential diagnosis
  • Cell fragments, cytoplasmic debris, bare epithelial nuclei, small mucus aggregates and leukocytes:
    • Identification of a definite elliptical nucleus helps avoid misinterpretation
    • Presence of eosinophilic cytoplasmic granules will be helpful
    • In most cases, trichomonad organisms are plentiful ("trich party")
      • Therefore, a rare fragment of cyanophilic debris is not likely to be a true trichomonad
Additional references
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