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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

3/6

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.”

3/6 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 characterisedPresent

    2 HPO annotations (e.g. Amenorrhea; Metrorrhagia) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  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)

2

Associated phenotypes · MONDO:0020552

  • Amenorrhea
  • Metrorrhagia

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

Open Targets candidates

No drugs or clinical candidates returned for this Mondo ID on Open Targets.

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

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=3967) is 59.

891 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

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 11 September 2026

1 interventional trial — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 80.1th percentile).

low confidence · 80.1th 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.

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 1 · after dedupe 1 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 1 · dropped 0 · fetched 2026-07-30

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Uncertain / not reviewed (1)

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Placental site trophoblastic tumor — check Associations / patient organisations on that page.

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