Clinicopathological analysis of four cases of localized endometrial proliferations of pregnancy and literature review

doi:10.16150/j.1671-2870.2025.05.008

Abstract

Abstract:

Objective To investigate the clinicopathological features of localized endometrial proliferations of pregnancy (LEPP). Methods Clinicopathological data of 4 LEPP patients treated at the International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine from 2014 to 2024 were collected. Their hematoxylin and eosin (HE)-stained pathological sections were reviewed, immunohistochemical (IHC) testing was performed, and literature was reviewed to summarize clinicopathological characteristics. Results The average age of the 4 patients was 34.5 years (range: 29-40). LEPP was identified in first-trimester abortion specimens in all cases. Microscopically, low-power examination revealed dilated glands arranged in cribriform or papillary patterns, with epithelial hyperplasia and cell stratification. High-power examination showed mild nuclear atypia, with rare mitotic figures (0-1/2 mm²). Calcification was observed in one case. IHC staining demonstrated that all 4 patients were positive for estrogen receptor (ER), progesterone receptor (PR), and paired box gene 2 (PAX2), with stronger expression than in surrounding endometrium. Tumor protein 53 (P53) showed wild-type expression. Mismatch repair proteins were positive. Phosphatase and tensin homolog (PTEN) expression was absent. Literature review indicated that LEPP was characterized by marked glandular epithelial hyperplasia, minimal cytological atypia, and benign biological behavior. Seven cases diagnosed as atypical endometrial hyperplasia or early endometrial carcinoma exhibited morphological features more consistent with LEPP, and no recurrence of endometrial-related diseases was observed during follow-up. Conclusion LEPP is a type of lesion occurring during pregnancy characterized by marked glandular epithelial hyperplasia, minimal cytological atypia, PTEN loss, and PAX2 positivity. It is currently considered biologically benign.

Key words: Localized endometrial proliferations of pregnancy, Atypical endometrial hyperplasia, Phosphatase and tensin homolog

CLC Number:

HUANG Suming, ZHANG Huijuan, ZHOU Feng. Clinicopathological analysis of four cases of localized endometrial proliferations of pregnancy and literature review[J]. Journal of Diagnostics Concepts & Practice, 2025, 24(05): 529-533.

Figures/Tables 3

Table 1

Figure 1

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Indice	Case
Indice	1	2	3	4
Clinical features
Age (years)	39	30	40	29
Gestational period (weeks)	7	7	7	8
Gravidity and parity	G2P1	G1P0	G2P1	G2P1
Pathological features	15	5	10	15
Maximum diameter (mm)
Microscopic structure	Papillary, cribriform	cribriform	cribriform	cribriform
Mitosis (/2mm²)	1	1	0	0
Nuclear atypia	mild-mode-rate	mild	mild	mild-moderate
Calcification	yes	no	no	no
Arias-Stella	focal	focal	focal	focal
IHC
ER	70%+	90%+	50%+	70%+
PR	20%+	70%+	10%+	10%+
P53	wild	wild	wild	wild
Ki-67	5%	5%	3%	3%
MSH2	+	+	+	+
MSH6	+	+	+	+
MLH1	+	+	+	+
PMS2	+	+	+	+
PAX2	80%+	80%+	95%+	80%+
PTEN	-	-	-	-
ARID1A	+	+	+	+
β-catenin	membrane+	membrane+	membrane+	membrane+
P40	-	-	-	-

Reference	Age	Gestational age (wk)	Diagnosis	FIGO stage	Follow-up(mo)	Status
Bayoglu, et al^[5]	36	<13	EC, grade 1	Ⅰ	12	NED
Carinelli, et al^[6]	40	Unknown	AH	Ⅰ	6	NED
Hannuna, et al^[7]	39	<13	EC, grade 2	Ⅰ	18	NED
Sandstrom, et al^[8]	37	10	EC, grade 1	ⅠA	30	NED
Shiomi, et al^[9]	35	35	EC, grade 1	ⅠA	48	NED
Terada^[10]	29	8	EC, grade 2	Ⅰ	Unknown	Unknown
Zhou, et al^[11]	33	9	EC, grade 1	Ⅰ	4	NED