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ORPHA:99928

Placental site trophoblastic tumor

low confidenceDisorder

Also known as: PSST

Publications

891

Trials

1

Interventional, condition-specific

Researchers

954

Distinct authors in sample

Gene link

—

Readiness

2/6

Stages with a signal

Clinical definition (Orphanet)

A rare gestational trophoblastic neoplasm characterized histologically by invasion of myometrium by intermediate trophoblastic cells without chorionic villi and containing human placental lactogen hormone (hPL). Tissue necrosis is usually absent and hemorrhage is mild. The tumor develops from the placental implantation site and always occurs following pregnancy, voluntary termination of pregnancy (VTP) or miscarriage. Indicative signs are irregular metrorrhagia some time after spontaneous miscarriage or VTP, presence of metastasis or unexplained metrorrhagia in the weeks and months following normal childbirth or ectopic pregnancy.

How rare: <1 / 1 000 000 — fewer than one in a million. In a city the size of Kolkata, that might mean on the order of fifteen people.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (9)

placental site gestational trophoblastic tumor · placental site gestational trophoblastic tumour · placental site trophoblastic tumor · placental site trophoblastic tumor (morphologic abnormality) · placental site trophoblastic tumour (morphologic abnormality) · placental-site GTT · placental-site gestational trophoblastic neoplasm · placental-site gestational trophoblastic tumor · placental-site gestational trophoblastic tumour

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

2/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    891 matched papers (447 in last 10 years) Source

  3. Phenotype characterisedNot checked

    Not yet enriched from Monarch / HPO

  4. Animal modelNot checked

    Not yet enriched from Monarch / Alliance

  5. Orphan designationNot checked

    FDA/EMA orphan-drug designation not enriched yet

  6. Interventional trialPresent

    1 matched on ClinicalTrials.gov

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

Phenotypes (Monarch / HPO)

Not enriched in this build — Monarch phenotype joins were not run for this record.

Animal models (Monarch / Alliance)

Not enriched in this build.

Literature

Is anyone studying this?

891

891 papers have been published on this condition. That is a real research literature — still far smaller than common diseases (breast cancer: over 700,000 papers). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.

891 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).

447 in the last 10 years · low confidence

Phrase hits: 889 · MeSH hits: 3

Open Europe PMC search

Who's working on it?

954

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Xiang Y10 papers · 2026

    Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

    Papers in Europe PMC
  2. 02
    Wan X7 papers · 2026

    Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Peking Union Medical College, National Clinical Research Center for Obstetric and Gynecologic Diseases, Beijing, China.

    Papers in Europe PMC
  3. 03
    Yang J7 papers · 2026

    Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Peking Union Medical College, National Clinical Research Center for Obstetric and Gynecologic Diseases, Beijing, China.

    Papers in Europe PMC
  4. 04
    Berkowitz RS6 papers · 2025

    Department of Obstetrics and Gynecology, Division of Gynecologic Oncology, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA.

    Papers in Europe PMC
  5. 05
    Braga A6 papers · 2026

    Department of Obstetrics and Gynecology, Postgraduate Program in Perinatal Health, Maternity School of Rio de Janeiro Federal University, Rio de Janeiro, RJ, Brazil.

    Papers in Europe PMC
  6. 06
    Seckl MJ6 papers · 2026

    Department of Medical Oncology, Charing Cross Trophoblastic Disease Center, Charing Cross Campus of Imperial College London, London, UK.

    Papers in Europe PMC
  7. 07
    Zhao J6 papers · 2026

    Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Peking Union Medical College, National Clinical Research Center for Obstetric and Gynecologic Diseases, Beijing, China.

    Papers in Europe PMC
  8. 08
    Feng F5 papers · 2026

    Department of Obstetrics and Gynecology, Peking Union Medical College Hospital, Chinese Academy of Medical Science, Peking Union Medical College, National Clinical Research Center for Obstetric and Gynecologic Diseases, Beijing, China.

    Papers in Europe PMC
  9. 09
    Bolze PA4 papers · 2026

    Department of Gynecological Oncological, and Obstetrics Department, Lyon-Sud Hospital, Hospices Civils de Lyon, Lyon, France.

    Papers in Europe PMC
  10. 10
    Bonasoni MP4 papers · 2025

    Pathology Unit, Azienda USL-IRCCS di Reggio Emilia, 42123 Reggio Emilia, Italy.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

1

interventional trials for this specific condition

1 interventional trial matched this specific condition name; none in our sample are currently recruiting.

Data as of 27 July 2026

1 interventional trial — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 76.8th percentile).

low confidence · 76.8th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

1 interventional trials matched after quoted-phrase search and title/condition post-filter.

No currently recruiting studies in the matched set. Open the same search on ClinicalTrials.gov.

Where to find support

We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

"Placental site trophoblastic tumor" OR "placental site gestational trophoblastic tumor" OR "placental site gestational trophoblastic tumour" OR "placental site trophoblastic tumor (morphologic abnormality)" OR "placental site trophoblastic tumour (morphologic abnormality)" OR "placental-site GTT" OR "placental-site gestational trophoblastic neoplasm" OR "placental-site gestational trophoblastic tumor" OR "placental-site gestational trophoblastic tumour"

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Trophoblastic Tumor, Placental Site

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Placental site trophoblastic tumor" OR "placental site gestational trophoblastic tumor" OR "placental site gestational trophoblastic tumour" OR "placental site trophoblastic tumor (morphologic abnormality)" OR "placental site trophoblastic tumour (morphologic abnormality)" OR "placental-site GTT" OR "placental-site gestational trophoblastic neoplasm" OR "placental-site gestational trophoblastic tumor" OR "placental-site gestational trophoblastic tumour" OR "Trophoblastic Tumor, Placental Site"

Interventional trials matched via: phrase (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 1 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.

Query health: ok — strategies attempted: phrase, mesh; with hits: phrase, mesh

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: PSST

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • 1 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (891) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T06:40:52.504Z