Adrenal gland & paraganglia
Other nonneoplastic
Adrenal rests
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Last author update: 12 July 2022
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PubMed Search: Ectopic adrenal tissue
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Pathophysiology | Etiology | Clinical features | Diagnosis | Laboratory | Radiology description | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Sample pathology report | Differential diagnosis | Additional references | Board review style question #1 | Board review style answer #1Cite this page: Yamazaki Y, Sasano H. Adrenal rests. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/adrenalaccessoryadrenaltissue.html. Accessed December 22nd, 2024.
Definition / general
- Nests or foci of adrenal tissue, detected in aberrant locations distant from the eutopic adrenal glands
Essential features
- Ectopic adrenal tissue, also termed heterotopic adrenal tissue or adrenal rests, represents nests or foci of adrenal tissue detected in various locations distant from the eutopic adrenal glands
- Adrenal rests are frequently detected in retroperitoneal, pelvic or groin areas, mainly composed of adrenocortical component
- Steroidogenic factor 1 (SF1) is a useful immunohistochemical marker to identify adrenal rests
Terminology
- Heterotopic adrenal tissue, adrenal rest, renal adrenal fusion
Epidemiology
- Detected in both pediatric and adult subjects
Sites
- Identified in retroperitoneal, pelvic or groin areas
- Prevalence of involvement by location (Endocr Pathol 2021;32:375):
- Paraovarian / ovarian / parasalpingeal / infundibulopelvic ligament, broad ligament (≈50%)
- Spermatic cord / paratesticular (≈30%)
- Inguinal hernia sac / inguinal fat (≈15%)
- Peritoneal / appendiceal mesentery and others (intrahepatic / intrarenal, etc.) (≈5%)
Pathophysiology
- Cortex originates from the intermediate mesoderm and medullary part from the neural crest
- During the sixth to seventh week of gestation, the primordial aggregation of cortical cells is derived from the mesenteric root, medial to the developing gonads and anterior to the mesonephros
- Compartment of chromaffin cells penetrates into the unencapsulated primordial adrenal cortex
- Reference: Endocrinol Metab Clin North Am 2015;44:243
Etiology
- Common sites considered to be due to the abnormality of fusion or persistent remnants of adrenal ridge
- Rare sites could be explained by abnormal migration of adrenal tissue during gestation or differentiation of adrenal progenitor stem cells (Mol Endocrinol 2009;23:1657)
Clinical features
- Usually single nodule and rarely multiple nodules, measuring less than 10 mm in greatest dimension (Endocr Pathol 2021;32:375)
- In general, endocrinologically inactive and in the great majority of cases, incidentally detected during surgery or laparoscopy (Hernia 2016;20:879)
- Hyperplastic ectopic adrenal glands are often detected in congenital adrenal hyperplasia (CAH) due to chronic ACTH stimulation (Endocr Rev 2019;40:973)
Diagnosis
- Because the lesion is hormonally silent, diagnosis can be made only by histopathological examination, usually as an incidental finding
- In rare cases, functional adrenocortical tumor (adenoma or carcinoma, even oncocytoma) could also arise from the adrenal nests
- Reference: Endocr Pathol 2021;32:375
Laboratory
- No characteristic findings
Radiology description
- Generally undetectable by radiological examination
- Rarely, the mass can be detected in cases of adrenocortical tumors arising from the ectopic adrenal tissues
- Reference: Endocr Pathol 2021;32:375, Hernia 2016;20:879
Case reports
- 29 year old woman with oncocytic adrenocortical neoplasm arising from an adrenal rest in the broad ligament of the uterus (Pathol Int 2014;64:183)
- 31 year old man with Williams syndrome, with suspected coexisting ectopic aldosterone producing tumor in the liver (Endocrinol Diabetes Metab Case Rep 2020;2020:20)
- 51 year old man with adrenocortical carcinoma arising in an adrenal rest (Endocr Pathol 2017;28:165)
Treatment
- No treatment is required unless a neoplasm has developed in the ectopic tissue
Gross description
- Golden yellow upon gross examination
- May be grossly mistaken for an additional nodule of renal cell carcinoma in a nephrectomy or a lymph node in a lymph node dissection
Gross images
Contributed by Debra L. Zynger, M.D.
Partial nephrectomy
Microscopic (histologic) description
- Composed of adrenal cortex, which is made of large polygonal cells, distinct cell membranes, vesicular eosinophilic to clear cytoplasm and bland nuclei
- Medulla component is rarely present; more likely to be identified near the celiac plexus
- Reference: Endocr Pathol 2021;32:375
Microscopic (histologic) images
Contributed by Yuto Yamazaki, M.D., Ph.D., Hironobu Sasano, M.D., Ph.D., Debra L. Zynger, M.D. and Sean R. Williamson, M.D.
Spermatic cord adrenal rest and SF1
Spermatic cord adrenal rests
Paratesticular adrenal cortical rest
Intrarenal adrenals
Positive stains
- SF1
- MelanA
- Inhibin A
- Reference: Endocr Pathol 2006;17:345
Negative stains
Sample pathology report
- Left testis, mass, orchiectomy:
- Mixed germ cell tumor (see synoptic report)
- Incidental adrenocortical rest of paratesticular soft tissue (0.5 cm)
Differential diagnosis
- Testicular or ovarian Sertoli-Leydig cell tumor:
- Reinke crystals
- Other ovarian tumors:
- Primary or metastatic clear cell renal cell carcinoma:
- Hilus cells
- Paraganglioma / ganglion with clear cell change
- Metastatic adrenal cortical carcinoma
Additional references
Board review style question #1
Ectopic adrenal tissue is shown in the image above, identified in the renal hilum area in a 40 year old man as an incidental finding in a nephrectomy specimen. Which is the most useful diagnostic immunohistochemical marker to confirm the diagnosis?
- CD20
- CDX2
- SF1
- Vimentin
Board review style answer #1
C. SF1. Adrenal rests are generally composed of both clear adrenocortical cells and compact ones. However, the zonation is frequently blurred and only composed of either clear or compact cells. Nests of adrenal cortical cells are, in general, immunohistochemically positive for SF1, MelanA and inhibin A at both eutopic and ectopic sites.
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Reference: Ectopic adrenal tissue
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Reference: Ectopic adrenal tissue
