Differentiation and histogenesis of syringomatous tumour of the nipple and low‐grade adenosquamous carcinoma: evidence for a common origin

Abstract

Our data provide evidence that syringomatous tumour of the nipple and LGAdSC are identical or nearly identical lesions. They contain p63+/K5/14+ cells as the key cells from which the K10+ squamous lineage and the K8/18+ glandular lineage arise. On the basis of our findings in normal breast tissue and associated benign lesions, we suggest that p63+/K5/14+ cells of the normal breast duct epithelium or early related cells might play a key role in the neoplastic transformation of both syringomatous tumour and LGAdSC. We propose that the differentiation patterns found in both lesions reflect the early ontogenetic stages of the normal breast epithelium.

High rate of PIK3CA mutations but no TP53 mutations in low‐grade adenosquamous carcinoma of the breast

“…Although several case reports and relatively small cohorts have been reported over the years, LGASC remains poorly defined in terms of phenotype; in addition, its genetic profile is yet to be established . The immunohistochemical studies published to date have described LGASC as part of the triple‐negative breast cancer (TNBC) spectrum …”

“…6 Although several case reports and relatively small cohorts have been reported over the years, LGASC remains poorly defined in terms of phenotype; in addition, its genetic profile is yet to be established. 3,[6][7][8][9][10][11][12][13][14][15][16] The immunohistochemical studies published to date have described LGASC as part of the triple-negative breast cancer (TNBC) spectrum. 1,6,17,18 A genome-wide characterisation of copy number alterations has been performed on two cases, one of which showed a complex profile of copy number changes encompassing focal amplifications.…”

Low‐grade adenosquamous carcinoma arising in association with a nipple adenoma

“…Histologically, it closely resembles LGASC of the breast, which typically occurs in breast parenchyma and rarely occurs in the nipple, but has previously been reported in associated with NA It rarely metastasises, except when over 30 mm in size and after multiple recurrences . Both lesions characteristically may arise in association with benign breast lesions . They are characterised by the common element of ASP and share a virtually identical histological and immunohistochemical profile, as described above, a profile initially described in LGASC but, in fact, common to ASP in multiple contexts .…”

Mesenchymal tumours of the breast and their mimics: a review with approach to diagnosis

“…[17][18][19] Often they have a tear-drop morphology resembling syringomatous tumours of the nipple, and some have proposed a relationship to syringoma. 20 There is commonly a prominent lymphoid cuff surrounding the tumour. The spindle cell stroma is variably cellular and merges with the epithelial component in areas.…”