adnexal tumors

PO

Definition: Cutaneous adnexal tumours encompass a wide group of lesions with apocrine, eccrine, follicular, sebaceous and mixed differentiation.

The large majority are benign and represent sporadic lesions, though malignant forms are occasionally encountered.

Some cases develop in the setting of inherited tumor predisposition syndromes.

Classification

 cutaneous follicular tumors
 cutaneous sebaceous tumors
 cutaneous apocrine tumors
 cutaneous eccrine tumors

See also : diagnosis of adnexal tumors

Main appearance

  cystic adnexal tumors
 basaloid adnexal tumors
 squamoid adnexal tumors
 glandular adnexal tumors
 biphasic adnexal tumors

Main types

 sebaceous tumors
 sweat gland tumors
 cutaneous follicular tumors / hair follicle tumors

Types

 sebaceaous tumors

• sebaceous hyperplasia
• sebaceous adenoma
• sebaceoma
• sebaceous carcinoma
• nevus sebaceus
• sebaceous neoplasms in Mui-Torre syndrome

 sweat gland tumors

• cystadenoma
• hidroacanthoma simplex
• poroma
• dermal duct tumor
• hidradenoma
  • papilary hidradenoma
  • nodular hidroadenoma

• malignant acrospiroma
• porocarcinoma
• hidradenocarcinoma
• spiradenoma
• cylindroma
• spiradenocarcinoma / malignant cylindroma
• microcystic adnexal carcinoma
• syringocystadenoma papilliferum
• hidradenoma papilliferum
• digital papillary adenocarcinoma
• chondroid syringoma
• myoepithelial carcinoma / malignant mixed tumor

 cutaneous follicular tumors / hair follicle tumors

• trichofolliculoma
• fibrofolliculoma / trichodiscoma
• trichoepithelioma / desmoplastic trichoepithelioma
• trichoblastoma
• malignant trichoblastoma
• trichilemmoma and Cowden disease / Cowden syndrome
• desmplastic trichilemmoma
• pilomatricoma
• malignant pilomatricoma

Main appearance

 cystic adnexal tumors
 basaloid adnexal tumors
 squamoid adnexal tumors

Predominant differentiation

 predominant apocrine and eccrine differentiation
 predominant follicular differentiation
 predominant sebaceous differentiation
 predominant myoepithelial differentiation
 predominant multilineage differentiation

Site-specific adnexal neoplasms

 nipple and areola
 anogenital mammary-like glands
 major and minor vestibular glands
 adnexal lesions of the vulva

• cystic lesions in the vulva
• non-cystic lesions in the vulva

 adnexal lesions of the penis

Patterns in sweat gland tumors

 cystic adnexal tumors

• dermal cyst with double cuboidal lining or columnar lining : hidrocystoma
• cystic space and papillary projections : syringocystadenoma papilliferum

 basaloid adnexal tumors

• - blue basaloid proliferation in dermis : spiradenoma and cylindroma

 squamoid adnexal tumors

• solid pink or clear or squamoid proliferation in epidermis and/or dermis +/- cystic change : acrospiroma

 glandular adnexal tumors

 tadpoles / Paisley tie syringoma

 dermal nodule with variable mixture of cords / chains / tubules and chondromyxoid stroma mixed tumor : chondroid syringoma

See also

 cutaneous tumors
 cutaneous nodules

• dermal nodules

Open references

 Skin Adnexal Tumors in Plain Language: A Practical Approach for the General Surgical Pathologist. 2018
https://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2018-0189-RA