Tubular/papillary apocrine adenoma

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Papillary eccrine adenoma & tubular apocrine adenoma are very similar and some authors combine the two entities under the umbrella term “tubular adenoma”. While this has merit, there are clinical differences. Papillary eccrine adenoma arises most often on the extremities and shows a marked predilection for black females (9F:1M). Tubular apocrine adenoma most commonly arises on the scalp & very rarely affects the extremities. Tubular apocrine adenoma is characterized by decapitation secretion, papillary eccrine adenoma is not. Tubular apocrine adenoma shows GCDFP-15 expression, papillary eccrine adenoma does not. However, supporting the hypophysis that they are very closely related is the report that both tumors share BRAF & KRAS mutations (Liau et al 2018)

Clinical features

•Rare tumor showing a predilection for the scalp but may arise in the eyelid, on the face, axilla and elsewhere

•Dermal nodule (1-2 cm)

•Genital lesions are best regarded as tumors of the anogenital mammary-like glands

•A relatively common tumor arising in nevus sebaceus

•2F:1M

.Wide age distribution

Histological features

•Dermal nodule

•May communicate with epidermis/follicle- also arise below a syringocystadenoma papilliferum

•Some tumors may overlap syringocystadenoma papilliferum/hidradenoma papilliferum

•Double-layered glands with outer myoepithelial cells and inner layer of cuboidal/columnar cells showing decapitation secretion

•Intraluminal pseudopapillae/papillae

•Stromal lymphocytic/plasma cell infiltrate

•Rarely sebaceous differentiation

•Luminal cells EMA, CEA, GCDFP-15, HMFG-1 +ve

•Myoepithelial cells S100, SMA, p63 +ve

An interesting case. The top piece of tissue shows tubular apocrine adenoma. The lower is reminiscent of hidradenoma papilliferum.
These first two photographs are textbook papillary eccrine adenoma
The two photographs above are again typical papillary eccrine adenoma but in the subsequent photographs, the appearances are mixed. Focal decapitation secretion is present. Nothing is clear cut in pathology! If this arose on the extremity, I would favor papillary eccrine adenoma but if it presented on the scalp, I might favor tubular apocrine adenoma!.

Thank you Viktoryia for sharing this fascinating case.

2 responses to “Tubular/papillary apocrine adenoma”

  1. Goran avatar
    Goran

    What features would you use to distinguish PEA from aggressive digital papillary adenocarcinoma in a superficial biopsy? Someone reported HPV42 immuno positive in the latter, but are there reliable distinguishing features on HnE? Thank you

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    1. Phillip McKee avatar
      Phillip McKee

      I think that the clinical history is of great importance. Lesions on the digits should be considered digital papillary adenocarcinoma unless there is really very, very good reason to think otherwise. I haven’t encountered a papillary eccrine adenoma at this site. In a partial biopsy, an infiltrating growth pattern, pleomorphism, marked mitotic activity and abnormal mitoses would be definite features to make the correct diagnosis. I think that the two tumors are very distinctive and it is unlikely that they should be confused.

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