Apocrine Tubular Adenoma

 Tumors in anogenital area may truly represent adenoma of anogenital mammary-like glands


image Tumors in eyelid should be distinguished from endocrine mucin-producing sweat gland carcinoma


• F > M (2:1)

• Adult patients

• Nodule measuring < 2 cm
image Sometimes pedunculated




Microscopic




• Circumscribed intradermal nodule
image Subcutis may be involved

• Sometimes arises in association with nevus sebaceous and syringocystadenoma papilliferum

• Tubules of different size and shape

• Some cystically dilated

• Papillary projections devoid of fibrovascular cores
image True papillae may be seen in cases associated with syringocystadenoma papilliferum

• Outer layer composed of myoepithelial cells

• Inner layer composed of apocrine cells

• Focal follicular or sebaceous differentiation may be rarely seen


Ancillary Tests




• Luminal cells are positive for EMA and CEA

• Myoepithelial cells are positive for S100 and SMA


Top Differential Diagnoses




• Syringocystadenoma papilliferum

• Papillary eccrine adenoma

• Apocrine hamartoma

• Apocrine carcinoma

• Endocrine mucin-producing sweat gland carcinoma

image
Intradermal Tumor Without Epidermal Connection
Apocrine tubular adenoma is usually a well-circumscribed intradermal nodule composed of variably sized and shaped tubules. Some tubular structures are cystically dilated.


image
Cystically Dilated Tubules
The tubules may contain eosinophilic secretion and debris image. The tubular structures are separated by a connective tissue stroma with few blood vessels image and scant chronic inflammation.

image
Tubules Are Lined by Apocrine Cells
The tubules are lined by at least 2 layers of cells. The outer layer is composed of small myoepithelial cells image, and the luminal layer is composed of columnar apocrine cells image with apical snouts.

image
Apical Snouts in Tubular Apocrine Adenoma
Papillary projections image are common and usually devoid of fibrovascular cores. Note the decapitation secretions on the surface of the apocrine cells image.


TERMINOLOGY


Synonyms




• Tubular apocrine adenoma, apocrine adenoma, tubulopapillary hidradenoma, papillary tubular adenoma


Definitions




• Rare benign adnexal neoplasm with apocrine differentiation

Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Apocrine Tubular Adenoma
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