Fallopian tubes
Benign or nonneoplastic conditions
Placental site nodule

Author: Nicole Riddle, M.D. (see Authors page)
Editor: Jamie Shutter, M.D.

Revised: 11 August 2017, last major update July 2013

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Placental site nodule

Cite this page: Placental site nodule. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/fallopiantubesplacentalsitenodule.html. Accessed November 12th, 2018.
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 (lower)

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

Differential diagnosis