Placental site nodule

Placental site nodule
	Diagnosis in short
	; Placental site nodule. H&E stain.
LM	paucicellular hyaline material scattered cells (variable cell population: small to large cells with clear to eosinophilic cytoplasm), +/-multinucleation, no mitotic activity
LM DDx	invasive cervical squamous cell carcinoma, exaggerated placental site, fibrin +/-inflammatory cells
Site	endometrium
Clinical history	previously pregnant
Symptoms	none
Prevalence	common
Prognosis	benign
Treatment	none

Placental site nodule, abbreviated PSN, is a benign remnant of a placenta. It is seen on endometrial biopsies and hysterectomy specimens.

Implantation site redirects here.

General

Benign.
Intermediate trophoblast remnants from a previous gestation.^[1]
Usually an incidental finding.

Clinical:

Usually asymptomatic.
Vaginal bleeding. (?)
Infertility. (?)

Microscopic

Features:^[1]

Paucicellular with hyaline material scattered cells.
Variable cell population:
- Small-large cells.
- Clear to eosinophilic cytoplasm.
- +/-Multinucleation.

Notes:

No mitotic activity.

DDx:

Invasive (cervical) squamous cell carcinoma.
- Can be sorted-out with IHC (SCC will typically be: p16 +ve, MIB1 +ve).
Exaggerated placental site.
- Different histomorphology than PSN; EPS:^[1] syncytiotrophoblastic tissue, in cords/nests, no hyaline nodules.
Fibrin +/-inflammatory cells.

Images

Case 1

PSN - intermed. mag. (WC)
PSN - high mag. (WC)

Case 2

PSN - low mag.
PSN - intermed. mag.
PSN - high mag.
PSN - very high mag.

www

PSN (ijpmonline.org).^[1]
PSN (gfmer.ch) - includes images from Jacob and Mohapatra.^[1]

IHC

Features:^[1]

Inhibin alpha +ve.
CK18 +ve.
MIB1 low.

Other:

p16 -ve.

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- CONSISTENT WITH MENSTRUAL ENDOMETRIUM (FRAGMENTED ENDOMETRIUM WITH SIMPLE
  GLANDS WITH APOPTOTIC CELLS, ABUNDANT NEUTROPHILS, CONDENSED ENDOMETRIAL STROMA
  (FOCAL) AND BLOOD).
- PLACENTAL SITE NODULE AND DECIDUA.
- NEGATIVE FOR HYPERPLASIA AND NEGATIVE FOR MALIGNANCY.

ENDOMETRIUM, BIOPSY:
- PROLIFERATIVE PHASE ENDOMETRIUM.
- BENIGN PLACENTAL SITE NODULE, SMALL.
- NEGATIVE FOR HYPERPLASIA.

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 Jacob, S.; Mohapatra, D.. "Placental site nodule: a tumor-like trophoblastic lesion.". Indian J Pathol Microbiol 52 (2): 240-1. PMID 19332926. http://www.ijpmonline.org/text.asp?2009/52/2/240/48931.

[pmid19332926-1] 1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 Jacob, S.; Mohapatra, D.. "Placental site nodule: a tumor-like trophoblastic lesion.". Indian J Pathol Microbiol 52 (2): 240-1. PMID 19332926. http://www.ijpmonline.org/text.asp?2009/52/2/240/48931.

[1]

Placental site nodule

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