[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Skin](https://durgical.com/en/general-pathology/areas/skin/) › Adnexal tumours of the skin

# Adnexal tumours of the skin

- Lesion

Tumours of hair follicles and sweat or oil glands are usually benign. A few point to inherited syndromes that also cause internal cancers.

Updated Nov 12, 2026

## Key points

- Cylindroma: forehead and scalp, islands of basaloid cells fitted like a jigsaw puzzle, with hyaline membranes; many tumours on the scalp form a «turban tumour»; CYLD.
- Trichoepithelioma: follicular differentiation, basaloid nests with horn cysts; can mimic basal cell carcinoma; CYLD when multiple.
- Syringoma: eccrine ducts, small papules under the eyes, comma- or tadpole-shaped ducts.
- Sebaceous adenoma and carcinoma: Muir-Torre syndrome (mismatch repair defect, Lynch) with colon and other cancers.
- Trichilemmomas (multiple, on the face): Cowden syndrome (PTEN) with breast, thyroid and endometrial cancers.
- Pilomatricoma: children, CTNNB1 mutation, ghost (shadow) cells and calcification.

## What it is

Adnexal tumours differentiate toward hair follicle, sebaceous gland, or apocrine and eccrine sweat glands. Most are benign, slow-growing papules or nodules on the head and neck, and malignant versions are rare. Their importance lies in the syndromes they mark: multiple cylindromas and trichoepitheliomas in CYLD cutaneous syndrome, sebaceous tumours in Muir-Torre (a Lynch variant), trichilemmomas in Cowden syndrome.

## Structure

- Cylindroma: dermal islands of small basaloid cells with peripheral palisading, surrounded and penetrated by hyaline basement membrane material.
- Sebaceous adenoma: lobules with more than half mature vacuolated sebocytes.
- Pilomatricoma: basaloid cells turning into eosinophilic anucleate ghost cells, calcification, giant cells.

## Adnexal tumours and the syndromes they flag

| Tumour | Differentiation | Syndrome | Gene |
| --- | --- | --- | --- |
| Cylindroma, spiradenoma | Apocrine | CYLD cutaneous syndrome (Brooke-Spiegler) | CYLD |
| Trichoepithelioma (multiple) | Hair follicle | CYLD cutaneous syndrome | CYLD |
| [Sebaceous adenoma or carcinoma](https://durgical.com/en/conditions/lynch-syndrome/) | Sebaceous | Muir-Torre syndrome | Mismatch repair genes |
| Trichilemmoma (multiple) | Outer root sheath | Cowden syndrome | PTEN |
| Fibrofolliculoma | Hair follicle mantle | Birt-Hogg-Dubé syndrome | FLCN |
| Pilomatricoma | Hair matrix | Sporadic; myotonic dystrophy when multiple | CTNNB1 |

## Clinical notes

- A sebaceous neoplasm prompts mismatch-repair immunostaining and a search for Lynch syndrome.
- Malignant adnexal tumours (sebaceous carcinoma of the eyelid, porocarcinoma) are rare but can metastasise.

## Memory aid

Follow the skin clue inward: CYLD makes a turban, a sebaceous tumour points to the colon, and trichilemmomas point to PTEN.

## Test yourself

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

## Which syndrome links sebaceous tumours of the skin with colon cancer?

Muir-Torre syndrome, a variant of Lynch syndrome caused by mismatch repair gene defects.

## What is a turban tumour?

Many confluent cylindromas covering the scalp, typical of CYLD cutaneous syndrome.

## What are ghost cells?

Anucleate eosinophilic keratinised cells characteristic of pilomatricoma.

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## Elsewhere in DurgiPedia

- [Hair follicles, sebaceous and sweat glands, nails](https://durgical.com/en/histology/hair-follicles-sebaceous-and-sweat-glands-nails/)
- [Hereditary cancer syndromes: the table to know](https://durgical.com/en/general-pathology/hereditary-cancer-syndromes-the-table-to-know/)

## Connections

## Related 3

- [Benign epidermal growths](https://durgical.com/en/general-pathology/benign-epidermal-growths/)
- [Basal cell carcinoma](https://durgical.com/en/general-pathology/basal-cell-carcinoma/)
- [Hereditary cancer syndromes: the table to know](https://durgical.com/en/general-pathology/hereditary-cancer-syndromes-the-table-to-know/)

## Related conditions 1

- [Lynch syndrome (hereditary non-polyposis colorectal cancer)](https://durgical.com/en/conditions/lynch-syndrome/)

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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: [CYLD cutaneous syndrome](https://medlineplus.gov/genetics/condition/cyld-cutaneous-syndrome/) (MedlinePlus, US National Library of Medicine, 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/adnexal-tumours-of-the-skin/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/adnexal-tumours-of-the-skin/