Hidradenoma

 Primarily solid


image Primarily cystic

image Solid and cystic


• Classically, does not connect to epidermis and is deep-seated

• Solid areas composed of varying proportion of
image Clear cells

image Poroid cells

image Squamoid cells

image Rarely mucinous cells

• Ducts with eosinophilic cuticles present in solid areas

• Cystic areas lined by cuboidal cells
image Sometimes with evidence of decapitation secretion

• Stroma between solid islands &/or cystic areas is prominently hyalinized

• Well circumscribed

• Necrosis usually absent

• Prominent cytologic atypia not present

• Mitoses not numerous




Top Differential Diagnoses




• Metastatic renal cell carcinoma
• Other clear cell tumors

image Basal cell carcinoma

image Squamous cell carcinoma

• Other adnexal tumors
image Lymphadenoma

image Sebaceous adenoma

image Cystadenoma

image Sebaceoma

• Hidradenocarcinoma

image
Hidradenoma at Low Magnification
Low-magnification view of a hidradenoma shows a dermal-based, nodular-appearing, solid image to cystic image tumor.


image
Hidradenoma: Characteristic Stroma, Cells, and Ducts
Hidradenoma often has a prominent hyalinized stroma image. Islands are composed of clear cells and poroid cells with some evidence of ductal image and glandular image differentiation.

image
Hidradenoma: Poroid and Clear Cells
This solid area of a hidradenoma is composed of small, bland-appearing clear cells image and poroid cells image. There is minimal cytologic atypia, an absence of necrosis, and mitoses are not prominent.

image
Hidradenoma: Poroid and Clear Cells
Higher magnification of hidradenoma shows an admixture of clear cells image and basaloid/poroid cells image. The basaloid cells have minimal cytoplasm, which is eosinophilic to basophilic staining and round/oval nuclei. Mitoses and cytologic atypia are not present.


TERMINOLOGY


Synonyms




• Clear cell hidradenoma, nodular hidradenoma, solid-cystic hidradenoma, cystic hidradenoma, eccrine acrospiroma, eccrine sweat gland adenoma, poroid hidradenoma, apocrine hidradenoma


Definitions




• Benign tumor showing apocrine or eccrine differentiation


CLINICAL ISSUES


Presentation




• Solitary dermal nodule


Treatment




• Excision is generally curative


Prognosis




• Benign with very low malignant potential; may rarely transform to hidradenocarcinoma


MICROSCOPIC


Histologic Features




• Well-circumscribed, dermal-based tumor (classically does not connect to epidermis and is deep-seated)

• May be primarily composed of solid areas, cystic areas, or both

• Solid areas composed of varying proportion of clear cells, poroid cells, squamoid cells, and, rarely, mucinous cells

• Ducts with eosinophilic cuticles present in solid areas

• Cystic areas lined by cuboidal cells, sometimes with evidence of decapitation secretion

• Stroma between solid islands &/or cystic areas is prominently hyalinized appearing

• Prominent cytologic atypia, numerous mitoses, necrosis not present

• Generally does not show infiltrative pattern

Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Hidradenoma
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