{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,28]],"date-time":"2025-08-28T10:40:12Z","timestamp":1756377612623,"version":"3.44.0"},"reference-count":9,"publisher":"BMJ","issue":"11","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2024,10,26]]},"published-print":{"date-parts":[[2024,11]]},"abstract":"<jats:p>Gestational trophoblastic disease is a group of pregnancy-related trophoblastic tumours. Gestational trophoblastic neoplasia refers to its invasive and malignant forms: invasive mole, choriocarcinoma, placental site trophoblastic tumour and epithelioid trophoblastic tumour. Patients exhibit elevated beta human chorionic gonadotropin (\u03b2 hCG) levels, sometimes exceeding 100\u2009000 mIU\/mL. When the serum levels of hCG surpass 500 000 mIU\/mL, there is a possibility of encountering a phenomenon called \u2018hook effect\u2019 which causes erroneously low or negative value when using the immunometric hCG assays that are presently available in the commercial market. We present a rare case involving a female in mid-30s with an invasive molar pregnancy presenting with bleeding, an abdominal mass, hypertension and hyperthyroidism. Despite a negative urine \u03b2 hCG test, her serum hCG, after dilution, was recalculated to over 850 000 mIU\/mL. MRI confirmed invasive mole. Post-hysterectomy, she received methotrexate chemotherapy. Her \u03b2 hCG normalised after two cycles, and she remains disease-free for 14 months.<\/jats:p>","DOI":"10.1136\/bcr-2024-261848","type":"journal-article","created":{"date-parts":[[2024,11,12]],"date-time":"2024-11-12T13:05:32Z","timestamp":1731416732000},"page":"e261848","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Curious phenomenon of \u2018hook effect\u2019 in invasive mole"],"prefix":"10.1136","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-4139-5789","authenticated-orcid":false,"given":"Sakshi","family":"Heda","sequence":"first","affiliation":[{"name":"Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences-Rishikesh, Rishikesh, Uttarakhand, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rujuta","family":"Fuke","sequence":"additional","affiliation":[{"name":"Government Medical College and Hospital Nagpur, Nagpur, Maharashtra, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4205-7430","authenticated-orcid":false,"given":"Ayush","family":"Heda","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynaecology, All India Institute of Medical Sciences-Rishikesh, Rishikesh, Uttarakhand, India"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Preeti","family":"Gattani","sequence":"additional","affiliation":[{"name":"Shalinitai Meghe Hospital and Research Centre, Wanadongri, Nagpur, India"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2024,11,12]]},"reference":[{"key":"2025082803235616000_17.11.e261848.1","article-title":"First-line chemotherapy in low-risk gestational trophoblastic neoplasia","volume":"2016","author":"Lawrie","year":"2016","journal-title":"Cochrane Database Syst Rev"},{"key":"2025082803235616000_17.11.e261848.2","doi-asserted-by":"crossref","first-page":"6","DOI":"10.1016\/j.gynor.2011.10.003","article-title":"Abnormally low hCG in a complete hydatidiform molar pregnancy: The hook effect","volume":"1","author":"Nodler","year":"2011","journal-title":"Gynecol Oncol Case Rep"},{"key":"2025082803235616000_17.11.e261848.3","unstructured":"AlJulaih GH , Muzio MR . Gestational trophoblastic neoplasia. In: StatPearls. Treasure Island (FL): StatPearls Publishing, 2023. Available: http:\/\/www.ncbi.nlm.nih.gov\/books\/NBK562225\/"},{"key":"2025082803235616000_17.11.e261848.4","doi-asserted-by":"publisher","DOI":"10.1016\/j.jemermed.2011.05.032"},{"key":"2025082803235616000_17.11.e261848.5","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.gore.2017.06.008","article-title":"The 'hook effect' causing a negative pregnancy test in a patient with an advanced molar pregnancy","volume":"21","author":"Winder","year":"2017","journal-title":"Gynecol Oncol Rep"},{"key":"2025082803235616000_17.11.e261848.6","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1002\/ijgo.13877","article-title":"Diagnosis and management of gestational trophoblastic disease: 2021 update","volume":"155 Suppl 1","author":"Ngan","year":"2021","journal-title":"Int J Gynaecol Obstet"},{"key":"2025082803235616000_17.11.e261848.7","doi-asserted-by":"crossref","unstructured":"Ning F , Hou H , Morse AN , et al . Understanding and management of gestational trophoblastic disease. F1000Res 2019;8. doi:10.12688\/f1000research.14953.1","DOI":"10.12688\/f1000research.14953.1"},{"key":"2025082803235616000_17.11.e261848.8","unstructured":"Bruce S , Sorosky J . Gestational trophoblastic disease. In: StatPearls. Treasure Island (FL): StatPearls Publishing, 2024. Available: http:\/\/www.ncbi.nlm.nih.gov\/books\/NBK470267\/"},{"key":"2025082803235616000_17.11.e261848.9","doi-asserted-by":"publisher","DOI":"10.1038\/bjc.2011.139"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2024-261848","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,8,28]],"date-time":"2025-08-28T10:24:05Z","timestamp":1756376645000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2024-261848"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,11]]},"references-count":9,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2024,11,12]]},"published-print":{"date-parts":[[2024,11]]}},"alternative-id":["10.1136\/bcr-2024-261848"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2024-261848","relation":{},"ISSN":["1757-790X"],"issn-type":[{"type":"electronic","value":"1757-790X"}],"subject":[],"published":{"date-parts":[[2024,11]]}}}