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Updated: Sep 11, 2025
Optimization of a Multiplex RNA-based Expression Assay Using Breast Cancer Archival Material
Published on: August 1, 2018
Clinicopathological Features of HER2 Expressing Lobular Carcinoma of Breast
Majd Khader1, Bayan Maraqa1, Hikmat Abdel-Razeq2
1Department of Pathology and Laboratory Medicine, King Hussein Cancer Center, Amman, Jordan.
Background:
Invasive lobular carcinoma (ILC) accounts for approximately 10% of invasive breast carcinomas and is the most common special subtype. Most ILCs express estrogen receptors (ERs) and progesterone receptors (PRs) but typically lack ERBB2 (human epidermal growth factor receptor 2 (HER2)) overexpression. HER2-positive ILC is rare, understudied, and often linked to aggressive clinical and histopathologic features. This study aimed to examine the clinicopathologic characteristics of HER2-positive ILC to ensure proper classification and management.
Methods:
A retrospective review was conducted on 48 cases, including 28 HER2-positive ILC and 20 pleomorphic invasive lobular carcinoma (p-ILC) cases without HER2 overexpression. Histological features assessed included nuclear pleomorphism, signet ring cell morphology, and apocrine features. Hormone receptor status and clinical outcomes were also analyzed.
Results:
All HER2-positive ILC cases exhibited at least one pleomorphic histological feature. Hormone receptor positivity was lower in HER2-positive ILC compared to p-ILC without HER2 overexpression. However, overall survival did not significantly differ between the two groups.
Conclusion:
HER2 overexpression in ILC is frequently associated with pleomorphic features. p-ILC, regardless of HER2 status, portends a worse prognosis. Identifying these features in HER2-positive ILC and classifying them as pleomorphic lobular carcinoma, a more aggressive ILC variant, is crucial for closer patient follow-up.
