Case Number : Case 1322 - 17 July Posted By: Guest

Thinking of cutaneous apocrine carcinoma, favouring primary but will first exclude metastasis.

Malignant cylindroma vs apocrine carcinoma. Of course metastasis should be ruled out.

cylindroma with apocrine tubular adenoma

Cylindroma with extensive ductal differentiation.

Cylindroma.

[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/Case%201322_RAC7182x20_CK7_4pm.jpg[/img]

[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/Case%201322_RAC7182x20_DPAS_AB_4pm.jpg[/img]

[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/Case%201322_RAC7182x20_Ki67_4pm.jpg[/img]

[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/Case%201322_RAC7182x20_p53_4pm.jpg[/img]

[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/Case%201322_RAC7182x20_p63_4pm.jpg[/img]

So with the striking PAS positivity, this is cylindoma as Romualdo said with extensive ductal differentiation. I was wrong. Actually, the extensive ductal and tubular formations confused me.

Cylindroma, although I admit I first thought of apocrine carcinoma.

Agree, Cylindroma with prominent glandular/ductal structures. Described in Kazakov's textbook as adenomatous /adenomyoepitheliomatous component.

My report:
A relatively circumscribed adnexal tumour comprising tubules and more solid aggregates of basaloid cells that are closely packed and in areas have a distinct basement membrane. Mitotic activity is low (~1/mm2), nuclear proliferation wiht Ki67~10% and there is minimal cellular pleomorphism. No alcian blue positive mucin. p63 highlights well form peripheral myoepithelial layer around all cellular aggregates.
In my opinion appearances fit best wtih a cylindroma (benign sweat gland lesion) with unusually well form tubules. These lesions can grow to large size but malignant transformation is rare. In this case mitotic activity is moderate. The lesion is incompletely removed.

Discussion: Thanks all for excellent responses. I too had not seen such a tubular variation on cylindroma but, like Arti, think I had seen it described in Kazakov's book. I think the immunos and PAS were quite helpful in excluding a tubular variant of adenoid cystic or other low grade adenocarcinoma. Incidentally no one mentioned the couple of mature sebaceous cells in the bottom left image (not that uncommon in cylindromas).