Triple-negative pleomorphic lobular carcinoma and expression of androgen receptor: Personal case series and review of the literature

Abstract

Pleomorphic lobular carcinoma (PLC) is a histological variant of invasive lobular carcinoma (ILC) and is associated with worse prognosis than classical ILC. It exhibits a greater degree of cellular atypia and pleomorphism and is occasionally accompanied with apocrine morphology. We investigated the immunohistochemical characteristics of samples from 31 Japanese patients with PLC to elucidate the clinicopathological characteristics of PLC including androgen receptor (AR) immunoreactivity. The surrogate molecular subtypes were luminal Alike , luminal B-like, luminal B-like/HER2, HER2-type, and triple-negative in 5, 4, 3, 5, and 14 cases, respectively. AR was positive in 92.8% (13/14) of the triple-negative PLC cases and 100% (10/10) of the non-triple-negative PLC cases. Disease-specific survival was worse in patients with histological grade 3 PLCs than in those with histological grade 2 PLCs (p = 0.007). However, there was no significant difference in the progression-free survival between the two groups (p = 0.152). No other clinicopathological characteristics were associated with prognosis. These results reveal that PLC exhibits various surrogate molecular subtypes and that the triple-negative subtype frequently expresses AR. The observed molecular apocrine differentiation implicates that triple-negative PLC can be categorized into the luminal AR subtype. Furthermore, AR-targeted therapy might be useful for patients with triple-negative PLC.

Current and future diagnostic and treatment strategies for patients with invasive lobular breast cancer

“…66,[199][200][201][202] Finally, since AR is often enriched in ILC, this pathway may also be of interest, especially in triple-negative ILC. 44,203,204…”

A Case Report on Apocrine Encapsulated Papillary Carcinoma of the Breast with Frank Invasion: A Diagnostic Quandary

“…2 Some rare types of breast cancer including pleomorphic lobular carcinoma, demonstrate the same receptor statuses and are categorized in luminal androgen receptor subtype. 3,4 Previous reports have described 10 cases of apocrine encapsulated papillary carcinoma, and only one had invasive component (Table 1). [5][6][7][8] Herein, we report a case of apocrine encapsulated papillary carcinoma with frank invasion, making this the second case report of apocrine encapsulated papillary carcinoma with invasion.…”

“…2 Some rare types of breast cancer including pleomorphic lobular carcinoma, demonstrate the same receptor statuses and are categorized in luminal androgen receptor subtype. 3,4…”