Fallopian tubes & broad ligament

Fallopian tube nonneoplastic

Placental site nodule

Minor changes: 30 December 2020

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PubMed Search: Placental site nodule

Nicole Riddle, M.D.
Jamie Shutter, M.D.
Page views in 2020: 1,373
Page views in 2021 to date: 1,295
Cite this page: Riddle N, Shutter J. Placental site nodule. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/fallopiantubesplacentalsitenodule.html. Accessed October 25th, 2021.
Definition / general
  • Benign lesion of intermediate trophoblasts; represents a remnant of previous placental implantation site that failed to completely involute
  • Typically an incidental finding in women of child bearing age; history of pregnancy may be remote (months to years) or unknown (missed abortion)
  • Patients rarely present with infertility
  • Trophoblastic tumors: two main risk factors:
    • Under 20 years of age or over 35 years of age
    • Previous gestational trophoblastic disease
  • Other risk factors are Asian decent, women with blood group A have greater risk of choriocarcinoma than those with blood group O
  • Typically uterus (endometrium), occasionally cervix
  • Rare in fallopian tube, very rarely seen anywhere in abdominal / perineal cavity
  • May secrete human placental lactogen (human chorionic somatomammotropin) and result in a false positive pregnancy test
Prognostic factors
  • Benign, good prognosis unless progresses to tumor
Case reports
  • None for benign nodule
  • Gestational tumors (moles, choriocarcinoma) are treated with chemotherapy (usually methotrexate)
  • Placental trophoblastic tumor treated with resection, nonresponsive to chemotherapy
Gross description
  • Usually not grossly evident
  • May appear as a small ( < 2 mm) tan nodule
Microscopic (histologic) description
  • Large pleomorphic cells with varying amounts of hyalization
Microscopic (histologic) images

Images hosted on other servers:

Small cells (left), large cells (right)

Fallopian tube (left), trophoblastic cells (right)

Fallopian tube
(upper) trophoblasts
with mild hyalization


Low power view of placental nodule
(upper) in benign endometrium (lower);
note conspicuous hyalinization with
large atypical cells (trophoblasts)

Differential diagnosis
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Image 01 Image 02