[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Lower urinary tract and male genital system](https://durgical.com/en/general-pathology/areas/urinary-male/) › Spermatic cord, paratesticular and tunica lesions

# Spermatic cord, paratesticular and tunica lesions

- Lesion

Masses beside the testis are mostly benign fluid collections or tumours, but paratesticular sarcomas also occur.

Updated Nov 12, 2026

## Key points

- Adenomatoid tumour: small, firm, well circumscribed; mesothelial cells forming gland-like spaces; benign.
- Paratesticular rhabdomyosarcoma (children) and liposarcoma (adults) are the main malignancies.
- Hydrocele: transilluminates; congenital with a patent processus vaginalis, or acquired with inflammation or tumour.
- Varicocele: left-sided because the left gonadal vein drains at a right angle into the left renal vein; a right-sided or sudden one suggests a mass.
- Varicocele is a common correctable cause of male infertility.

## What it is

The tissues around the testis give a range of lesions. Adenomatoid tumour, of mesothelial origin, is the commonest benign paratesticular tumour, usually near the epididymis. Lipomas of the cord are common; malignant tumours include rhabdomyosarcoma in children and liposarcoma in adults. Fluid collects in the tunica vaginalis as a hydrocele (serous fluid), hematocele (blood, after trauma or tumour) or chylocele (lymph, in filariasis). Spermatoceles are cysts of the efferent ducts with sperm. Varicoceles are dilated pampiniform veins, usually on the left. Malignant mesothelioma of the tunica vaginalis is rare.

## Structure

- Hydrocele sac: smooth fibrous wall lined by flattened mesothelium; chronic ones thicken and calcify.
- Spermatocele: cyst lined by cuboidal epithelium containing spermatozoa.
- Adenomatoid tumour: cords and tubules of flattened to cuboidal mesothelial cells (calretinin positive) in fibrous stroma.

## Scrotal fluid collections and vascular lesions

| Lesion | Content or cause | Clue |
| --- | --- | --- |
| [Hydrocele](https://durgical.com/en/conditions/hydrocele/) | Serous fluid in the tunica vaginalis | Transilluminates; can hide a testicular tumour |
| Hematocele | Blood in the tunica | Trauma, torsion, tumour; does not transilluminate |
| Spermatocele | Cyst of efferent ducts with sperm | Separate from the testis, above it |
| [Varicocele](https://durgical.com/en/conditions/varicocele/) | Dilated pampiniform plexus | Bag of worms, left side, worse standing |

## Clinical notes

- Any hydrocele that hides the testis should be imaged to exclude a tumour.
- A new right-sided varicocele can signal compression of the vena cava or a renal tumour.

## Memory aid

Light passes through water (hydrocele), not through blood (hematocele); worms on the left are the veins.

## Test yourself

Think of the answer, then tap the question to see it.

## What is the commonest benign paratesticular tumour?

Adenomatoid tumour.

## Why are varicoceles usually left-sided?

The left testicular vein drains at a right angle into the left renal vein, which favours higher pressure and reflux.

## What does a spermatocele contain?

Spermatozoa, in a cyst arising from the efferent ducts or epididymis.

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## Elsewhere in DurgiPedia

- [Processus vaginalis: hydrocele and indirect inguinal hernia](https://durgical.com/en/embryology/processus-vaginalis-hydrocele-and-indirect-inguinal-hernia/)

## Connections

## Related 3

- [Cryptorchidism, testicular atrophy and reduced fertility](https://durgical.com/en/general-pathology/cryptorchidism-testicular-atrophy-and-reduced-fertility/)
- [Testicular germ cell tumours: overview](https://durgical.com/en/general-pathology/testicular-germ-cell-tumours-overview/)
- [Pleural tumours: mesothelioma and solitary fibrous tumour](https://durgical.com/en/general-pathology/pleural-tumours-mesothelioma-and-solitary-fibrous-tumour/)

## Related conditions 4

- [Hydrocele](https://durgical.com/en/conditions/hydrocele/)
- [Varicocele](https://durgical.com/en/conditions/varicocele/)
- [Male infertility](https://durgical.com/en/conditions/male-infertility/)
- [Soft tissue sarcomas (liposarcoma, leiomyosarcoma, rhabdomyosarcoma)](https://durgical.com/en/conditions/soft-tissue-sarcomas/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Hydrocele](https://www.ncbi.nlm.nih.gov/books/NBK559125/) (StatPearls (NCBI Bookshelf), 2024); [Varicocele](https://www.ncbi.nlm.nih.gov/books/NBK448113/) (StatPearls (NCBI Bookshelf), 2024).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/spermatic-cord-paratesticular-and-tunica-lesions/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/spermatic-cord-paratesticular-and-tunica-lesions/