Testis & paratestis
Other tumors
Metastases
Author: Gang Wang, M.D., Ph.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Last author update: 28 January 2020
Last staff update: 3 August 2023
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Metastases testes
Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Clinical features | Diagnosis | Radiology images | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Wang G. Metastases. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testismetastases.html. Accessed April 25th, 2024.
Definition / general
- Tumors secondarily involving testis and paratesticular structures from distant sites
- Excludes hematopoietic tumors
Essential features
- Most have known history of primary but rarely the initial presentation
- Histologic features recapitulate their site of origin
- Should be differentiated from germ cell tumor, sex cord stromal tumor, malignant mesothelioma and adenocarcinoma of the rete testis or epididymis
Terminology
- Also called secondary tumors of the testis
Epidemiology
- Occur in 0.7% of patients with solid organ malignancies in autopsy studies (Ann Diagn Pathol 2000;4:59)
- Majority are > 50 years old (Am J Surg Pathol 2008;32:1683)
Sites
- Most common primary sites include the prostate, lung, skin, colon and kidney (Am J Surg Pathol 2008;32:1683)
Clinical features
- Most nonsymptomatic or incidental finding
- Most unilateral and solitary
- Rarely present as carcinoma of unknown primary
Diagnosis
- Clinical information and ancillary investigations can be more helpful than special histological techniques in the differential diagnosis
Radiology images
Images hosted on other servers:
Renal cell carcinoma metastasis to testis
Lung adenocarcinoma metastasis to testis
Colorectal adenocarcinoma metastasis to testis
Case reports
- 15 year old boy with colorectal carcinoma metastasis to his right testis (J Med Case Rep 2018;12:304)
- 29 year old man with mucinous lung adenocarcinoma metastasis to testis (Urology 2018;118:3)
- 35 year old man with testicular metastasis of colorectal carcinoma (BMJ Case Rep 2013; 2013)
- 53 year old man with uncommon testicular metastasis of a primary neuroendocrine tumour of the lung (Can Urol Assoc J 2013;7:E614)
- 58 year old man with stage IV squamous cell carcinoma of the lung with metastases to the brain and right testis (Case Rep Oncol 2015;8:133)
- 65 year old man with simultaneous bilateral testicular metastases from renal clear cell carcinoma (Oncol Lett 2014;7:1273)
- 69 year old man with metastatic renal cell carcinoma to his left testis (Rare Tumors 2016;8:6471)
- 78 year old man with metachronous ipsilateral testicular metastasis from renal cell carcinoma 6 years after nephrectomy (Case Rep Oncol 2017;10:388)
Gross description
- Localized mass, multiple nodules
Gross images
Contributed by Debra L. Zynger, M.D.
Metastatic prostatic adenocarcinoma
Images hosted on other servers:
Metastatic colorectal adenocarcinoma
Metastatic renal cell carcinoma
Microscopic (histologic) description
- Histologic features recapitulate their site of origin
- Metastatic prostatic adenocarcinoma tends to involve the tubular system
- Other metastatic carcinomas tend to infiltrate the testicular interstitium while sparing the seminiferous tubules
- Prominent lymphovascular invasion
Microscopic (histologic) images
Contributed by Gang Wang, M.D., Ph.D.
Metastatic prostatic adenocarcinoma
Involvement of the tubular system
Cribriform pattern
most frequent,
epididymis
involvement
Solid growth pattern
Metastatic ductal adenocarcinoma
Positive for PSA
Positive for ERG
Metastatic renal cell carcinoma, clear cell type
Broad pushing borders
Mixed patterns
Positive for PAX8
Positive for CAIX
Metastatic colorectal
adenocarcinoma
adenocarcinoma
Cystic spaces containing mucin
Metastatic cutaneous squamous
cell carcinoma
cell carcinoma
Infiltrating and anastomosing nests
Positive for p40
Molecular / cytogenetics description
- Detection of isochromosome 12 by fluorescence in situ hybridization would suggest a primary germ cell tumor rather than a metastases
Sample pathology report
- Right testis and spermatic cord, radical orchiectomy:
- Metastatic renal cell carcinoma, clear cell type, 2 cm, confined to the testicular parenchyma
- Margins of resection, negative for malignancy
Differential diagnosis
- Germ cell tumor:
- Relatively younger age (typically 30s and 40s)
- Background of germ cell neoplasm in situ
- Positive for SALL4 (all germ cell tumors), OCT 3/4 and PLAP (seminoma and embryonal carcinoma), CD30 (embryonal carcinoma), AFP and glypican 3 (yolk sac tumor)
- Presence of isochromosome 12p (Am J Surg Pathol 2009;33:1529, Arch Pathol Lab Med 2012;136:435, Am J Surg Pathol 2014;38:689)
- Sex cord stromal tumor:
- Positive for inhibin and calretinin, negative for CK (Mod Pathol 1998;11:77, Am J Surg Pathol 1998;22:615)
- Malignant mesothelioma:
- Usually extensively and diffusely involves tunica
- Typically positive for mesothelial markers such as calretinin, CK5/6, D2-40 and WT1 (Mod Pathol 2005;18:S131, Am J Surg Pathol 2006;30:1, Arch Pathol Lab Med 2012;136:113)
- Adenocarcinoma of the rete testis or epididymis:
- Has a morphologic transition from nonneoplastic rete or epididymis to adenocarcinoma (including in situ changes)
- Positive for PAX8 (Mod Pathol 2005;18:S131, Am J Surg Pathol 2011;35:1473)
Board review style question #1
Which of the following is the most common primary site of metastatic carcinoma in the testis?
- Bladder
- Kidney
- Prostate
- Lung
- Colon
Board review style answer #1
C. The most common primary site of metastatic carcinoma in the testis is the prostate
Comment Here
Reference: Metastases to testes
Comment Here
Reference: Metastases to testes
Board review style question #2
- As shown in the figure, there is an adenocarcinoma in the testis. Which of the following markers is the best for differentiation between this metastatic adenocarcinoma in the testis and primary adenocarcinoma of the rete testis or epididymis?
- Calretinin
- CDX2
- CK7
- CK20
- PAX8
Board review style answer #2
E. Primary adenocarcinomas of the rete testis or epididymis are positive for PAX8 while metastatic adenocarcinomas from other sites are usually negative for PAX8 (except kidney and thyroid)
Comment Here
Reference: Metastases to testes
Comment Here
Reference: Metastases to testes
