Lymph nodes & spleen, nonlymphoma
Ectopic tissue / inclusions
Decidual reaction
Author: Jayalakshmi Balakrishna, M.D.
Last author update: 1 February 2014
Last staff update: 18 July 2022
Copyright: 2003-2024, PathologyOutlines.com, Inc.
PubMed Search: Decidual reaction [title]
Table of Contents
Definition / general | Epidemiology | Sites | Etiology | Clinical features | Diagnosis | Prognostic factors | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Negative stains | Differential diagnosis | Additional referencesCite this page: Balakrishna J. Decidual reaction. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/lymphnodesdecidualreaction.html. Accessed November 29th, 2024.
Definition / general
- Deposits of decidual tissue without accompanying glands in lymph nodes
- Rare, incidental microscopic finding in para-aortic and pelvic lymph nodes in pregnancy
- Decidual cell reaction in the absence of pregnancy is seen only with a corpus luteum present in the ovary
- Ectopic decidual reaction in lymph nodes was first reported by Geipel in 1913
- Ectopic decidual reaction can be located in the vagina, cervix, fallopian tubes, ovary, peritoneum; also appendix, diaphragm, liver (surface), lymph nodes, mesentery, small bowel, spleen
Epidemiology
- Rare, but exact incidence unknown since it is detected as an incidental finding at autopsy or pelvic lymphadenectomy for a genital tract malignancy
- A particular problem differentiating from squamous cell carcinoma during frozen section (Arch Pathol Lab Med 2005;129:e117)
Sites
- Limited to para-aortic and pelvic lymph nodes including obturator and internal iliac lymph nodes
Etiology
- Unclear
- Theories postulated are:
- Decidual change of endometriotic sites in pregnant women
- Entrapment of or failure of migration of coelomic remanants during embryologic development and during pregnancy, these rests are sensitized by estrogen, progesterone and further stimuli inducing a decidual reaction
- Benign metastasis or lymphatic spread
Clinical features
- May be enlargement of lymph nodes
- May have associated peritoneal decidual reaction
Diagnosis
- Biopsy of the involved lymph nodes
Prognostic factors
- Typically no treatment needed
- Although extremely rare, malignant change can occur in these inclusions
Case reports
- 33 year old woman with ectopic decidua suspicious of malignancy in pregnancy (The Internet Journal of Gynecology and Obstetrics 2004;5)
- Decidual change in pelvic lymph nodes in the presence of cervical squamous cell carcinoma during pregnancy (Am J Obstet Gynecol 1977;127:674)
- Decidua in pelvic lymph nodes (Obstet Gynecol 1967;29:824)
- Ectopic decidua and metastatic squamous carcinoma (J Surg Oncol 1988;38:126)
Gross description
- Rarely is grossly visible as tiny, gray, subcapsular nodules
- Typically occupies the subcapsular sinus and superficial cortex, and less commonly, the central parts of the lymph node
Microscopic (histologic) description
- Decidual cells arranged in well circumscribed round groups, solid nests and loosely cohesive aggregates in the subcapsular sinus, as well as deep within the lymphoid tissue
- The individual large polygonal cells show abundant granular esosinophilic cytoplasm, sharply defined cell borders, small, round to oval bland nuclei with dispersed chromatin and single conspicuous nucleoli
- Mitoses or atypical features are not present
- The cells may be separated by an intervening amorphous pale staining myxoid stroma
Microscopic (histologic) images
AFIP images
Deciduosis
Differential diagnosis
- Metastatic squamous cell carcinoma: small, irregular nests with well circumscribed borders of tightly cohesive, polygonal cells with small, dark staining nuclei and pleomorphism
Additional references
