hidradenoma

{{Infobox medical condition (new)

| name = Hidradenoma

| synonyms = Acrospiroma, cystadenoma, hydrocystadenomas

| image = Nodular hidradenoma - intermed mag.jpg

| caption = Micrograph showing an acrospiroma. H&E stain.

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| field = Dermatology

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Hidradenoma refers to a benign adnexal tumor of the apical sweat gland.{{cite journal | vauthors = Laws RA, English JC, Elston DM | title = Acrospiroma: a case report and review | journal = Cutis | volume = 58 | issue = 5 | pages = 349–51 | date = November 1996 | pmid = 8934076 }}

{{cite journal | vauthors = Obaidat NA, Alsaad KO, Ghazarian D | title = Skin adnexal neoplasms--part 2: an approach to tumours of cutaneous sweat glands | journal = Journal of Clinical Pathology | volume = 60 | issue = 2 | pages = 145–59 | date = February 2007 | pmid = 16882695 | pmc = 1860616 | doi = 10.1136/jcp.2006.041608 }} These are 1–3 cm translucent blue cystic nodules. It usually presents as a single, small skin-colored lesion, and may be considered closely related to or a variant of poromas.{{cite journal | vauthors = Lim JS, Kwon ES, Myung KB, Cheong SH | title = Poroid Hidradenoma: A Two-Case Report and Literature Review | journal = Annals of Dermatology | volume = 33 | issue = 3 | pages = 289–292 | date = June 2021 | pmid = 34079192 | pmc = 8137338 | doi = 10.5021/ad.2021.33.3.289 | url = }} Hidradenomas are often sub-classified based on subtle histologic differences, for example:{{cite journal | vauthors = Al-Adawi SS, Al-Qasabi B, Al-Bahri M, Aljarrah A, Al-Aghbari S | title = Clear Cell Hidradenoma of the Breast Diagnosed on a Core Needle Biopsy: A case report and review of the literature | journal = Sultan Qaboos University Medical Journal | volume = 20 | issue = 3 | pages = e357–e361 | date = August 2020 | pmid = 33110653 | pmc = 7574794 | doi = 10.18295/squmj.2020.20.03.017 | url = }}

• Eccrine acrospiroma
• Clear-cell hidradenoma or acrospiroma
• Nodular hidradenoma or acrospiroma
• Solid-cystic hidradenoma

Discussion of sweat gland tumors can be difficult and confusing due to the complex classification and redundant terminology used to describe the same tumors. For example, acrospiroma and hidradenoma are synonymous, and sometimes the term acrospiroma is used to generally describe benign sweat gland tumors. In addition, a single lesion may contain a mixture of cell-types. There has also been a change in understanding about how tumors that were previously believed to strictly derive from specific sweat gland types may, in fact, derive from both eccrine or apocrine glands.{{Cite book|title = Rook's Textbook of Dermatology|edition = 8th|publisher = John Wiley & Sons Ltd.|year = 2010|isbn = 978-1-4051-6169-5|location = Chichester, West Sussex|editor-last = Griffiths|editor-first = C|editor2-last = Cox|editor2-first = N|editor3-last = Breathnach|editor3-first = S|display-editors = 3 |editor4-last = Burns|editor4-first = T | name-list-style = vanc |chapter = 53. Tumours of the Skin Appendages: Eccrine or aprocrine/follicular tumours}}{{Cite book|title = Rook's Textbook of Dermatology|edition = 8th|publisher = John Wiley & Sons Ltd.|year = 2010|isbn = 978-1-4051-6169-5|location = Chichester, West Sussex|editor-last = Griffiths|editor-first = C|editor2-last = Cox|editor2-first = N|editor3-last = Breathnach|editor3-first = S|display-editors = 3 |editor4-last = Burns|editor4-first = T | name-list-style = vanc |chapter = 53. Tumours of the Skin Appendages: Eccrine gland tumours}}

Hidradenomas are by definition benign, with malignant transformation very rare. When tumors show malignant characteristics, they are known as hidradenocarcinoma.{{cite journal | vauthors = Hernández-Pérez E, Cestoni-Parducci R | title = Nodular hidradenoma and hidradenocarcinoma. A 10-year review | journal = Journal of the American Academy of Dermatology | volume = 12 | issue = 1 Pt 1 | pages = 15–20 | year = 1985 | pmid = 2984259 | doi = 10.1016/s0190-9622(85)70002-3 }} Surgical excision is usually curative and local recurrences are rare, although malignant tumors may metastasize.

File:Gross pathology of cystic nodular hidradenoma.jpg|Gross pathology of a cystic nodular hidradenoma

File:SkinTumors-P7150488.JPG|Dermal duct tumor

File:SkinTumors-P7240522.JPG|Acrospiroma, solid type

File:SkinTumors-P8080553.JPG|Acrospiroma, clear cell type