Immunohistochemical expression of TRPS1 in mammary Paget disease, extramammary Paget disease, and their close histopathologic mimics

Abstract

Background Trichorhinophalangeal syndrome type 1 (TPRS1) expression has been found to be highly sensitive and specific for breast carcinomas. The frequency of TRPS1 expression in cutaneous neoplasms such as mammary Paget disease (MPD) and extramammary PD (EMPD) is currently unknown. We assessed the utility of TRPS1 immunohistochemistry (IHC) in the evaluation of MPD, EMPD, and their histopathologic mimics, squamous cell carcinoma in situ (SCCIS) and melanoma in situ (MIS). Methods Twenty‐four MPDs, 19 EMPDs, 13 SCCISs, and 9 MISs were subjected to immunohistochemical analysis using anti‐TRPS1 antibody. The intensity (none, 0; weak, 1+; moderate, 2+; strong, 3+) and proportion (<1%, absent; 1%–25%, focal; 26%–75%, patchy; >75%, diffuse) of TRPS1 expression were recorded. Relevant clinical data were documented. Results TPRS1 expression was present in 100% (24/24) of MPDs, with 88% (21/24) of MPDs exhibiting strong, diffuse immunoreactivity. Sixty‐eight percent (13/19) of EMPDs showed TRPS1 expression. Intriguingly, EMPDs lacking TRPS1 expression were consistently of perianal origin. TRPS1 expression was seen in 92% (12/13) of SCCISs but was absent in all MISs. Conclusions TRPS1 may be useful to distinguish MPDs/EMPDs from MISs, but its utility is limited in distinguishing them from other pagetoid intraepidermal neoplasms such as SCCISs.

TRPS1 expression is sensitive and specific for primary extramammary Paget disease

“…The results in this study are similar to those found in another recent study which evaluated TRPS1 staining in primary mammary Paget disease, EMPD (involving inguinal/groin, peri‐anal, axilla and trunk), squamous cell carcinoma in situ and melanoma in situ 15 . In this study, all the mammary Paget disease cases were TRPS1 immunoreactive, whereas only 68% (13 of 19) of EMPD cases were reportedly positive.…”

“…In this study, all the mammary Paget disease cases were TRPS1 immunoreactive, whereas only 68% (13 of 19) of EMPD cases were reportedly positive. Although these results appear lower than are found in the current study, it should be noted that five of the EMPD cases involving the inguinal/groin areas were from patients with known histories of colorectal or prostatic adenocarcinoma and may represent secondary EMPD; 15 based on the current study, these cases would be expected to be TRPS1‐negative. This recently published study also reports TRPS1 expression in 92% (12 of 13) of squamous cell carcinoma in situ cases; however, squamous cell carcinoma in situ and EMPD of the vulva rarely have significant morphological overlap due to full‐thickness atypia in the former.…”

“…The results in this study are similar to those found in another recent study which evaluated TRPS1 staining in primary mammary Paget disease, EMPD (involving inguinal/groin, peri-anal, axilla and trunk), squamous cell carcinoma in situ and melanoma in situ. 15 In this study, all the mammary Paget disease cases were TRPS1 immunoreactive, whereas only 68% (13 of 19) of EMPD cases were reportedly positive. Although these results appear lower than are found in the current study, it should be noted that five of the EMPD cases involving the inguinal/ groin areas were from patients with known histories of colorectal or prostatic adenocarcinoma and may represent secondary EMPD; 15 based on the current study, these cases would be expected to be TRPS1negative.…”

Transcriptional repressor GATA binding 1 (TRPS1) immunoexpression in normal skin tissues and various cutaneous tumors

“…Regarding sweat gland tumors, primary EMPD was frequently TRPS1+, which is consistent with a previous report. 23 This may be because primary EMPD is thought to originate from anogenital mammary-like glands, which are TRPS1+. Studies have also shown that primary EMPD has similarities with breast cancer.…”

“…Although the normal epidermis was TRPS1À, some cases of Bowen disease and actinic keratosis were TRPS1+, which is consistent with a previous report. 23 Since epidermal keratinocytes in the embryonal stage were TRPS1+, neoplastic keratinocytes in Bowen disease and actinic keratosis may revert to the embryonic stage due to tumorigenesis. However, there remains a contradiction since one case of invasive squamous cell carcinoma was TRPS1+.…”