中心巢状硬化性乳腺放射状病变（RSL）中已知存在腺鳞状增生（ASP）。然而，它们的意义受到争议，仍然大部分未知。此外，ASP和低度腺鳞状癌（LGASC）之间存在组织学的重叠。我们对247个RSL进行了大规模的回顾性研究，以评估ASP的患病率，并定量分析RSL的组织学特征，包括大小、基质细胞密度和慢性炎症的存在。RSL的中心巢状部分被分为硬化性的121例（49%），细胞性的37例（15%）和混合硬化和细胞性相等的89例（36%）。247个RSL中有92个出现了ASP（37.2%）。具有ASP的病例与细胞质基质明显相关；细胞质基质中有78.4%的RSL发生了ASP，而只有11.6%的硬化性RSL发生了ASP。在我们的大样本中，发现ASP的RSL中常见慢性炎症（p= <0.001）。综上所述，我们确认ASP在细胞质基质的RSL中有较高的统计概率。此外，ASP常与慢性炎症相关。这一发现挑战了在有限的活检材料中显著淋巴细胞是LGASC的诊断线索的观念。版权所有© 2023 作者，由Elsevier Ltd.出版。保留所有权利。

Adenosquamous proliferation (ASP) is known to occur in the central nidus of radial sclerosing lesions (RSL) of the breast. However, their significance is debated and remains largely unknown. In addition, there is a histologic overlap between ASP and low-grade adenosquamous carcinomas (LGASC). We conducted a large retrospective review of 247 RSLs to evaluate the prevalence of ASP and quantitatively analyze associated histologic features of RSLs including size, stromal cellularity, and presence of chronic inflammation. The central nidus of RSLs were classified as hyalinized in 121 cases (49%), cellular in 37 cases (15%), and equally mixed hyalinized and cellular in 89 (36%). ASP occurred in 92 of 247 RSLs (37.2%). Cases with ASP were significantly associated with a cellular stroma; 78.4% of RSLS with cellular stroma had ASP versus just 11.6% of hyalinized RSLs. In our large cohort, inflammation is commonly found in RSLs with ASP (p= <0.001). In conclusion, we confirm that ASP is statistically more likely to be found in RSLs with a cellular stroma. In addition, ASP is commonly associated with chronic inflammation. The finding challenges the notion that prominent lymphocytes are a diagnostic clue to LGASC on limited biopsy material.Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.