Adnexal tumour
Cutaneous adnexal tumours are numerous types of benign and malignant tumours that arise from:
- Hair follicles
- Sebaceous glands
- Eccrine and apocrine sweat glands
Adnexal tumours may be sporadic but are sometimes due to syndromes, such as:
- Birt-Hogg-Dube
- Brooke-Spiegler syndrome
- Cowden disease
- Torre-Muir syndrome (Lynch syndrome).
They are usually diagnosed by biopsy findings, rather than clinically. Their histological features are combined with special immunohistochemistry stains for a pathological diagnosis.
Benign eccrine and apocrine tumours include:
- Syringoma
- Poroma
- Cylindroma and spiradenoma
- Cutaneous mixed tumor
- Syringofibroadenoma
- Syringocystadenoma papilliferum
- Hidradenoma papilliferum
- Hidradenoma
- Tubular/papillary adenoma, including papillary cystadenoma.
Malignant eccrine and apocrine tumours include:
- Porocarcinoma
- Adenoid cystic carcinoma
- Mucinous carcinoma
- Microcystic adnexal carcinoma
- Digital papillary adenocarcinoma
- Extramammary Paget disease.
Benign follicular tumours include:
- Trichoblastoma and trichoepithelioma
- Trichoadenoma
- Trichofolliculoma
- Trichilemmoma
- Trichodiscoma and fibrofolliculoma
- Tumour of the follicular infundibulum
- Panfolliculoma
- Pilomatricoma
- Proliferating trichilemmal tumour.
Malignant follicular tumours include:
- Trichoblastic carcinoma
- Trichilemmal carcinoma
- Pilomatrix (matrical) carcinoma.
Sebaceous tumours include:
- Sebaceous hyperplasia
- Sebaceous adenoma and sebaceoma
- Sebaceous carcinoma.
