Related Experiment Video For apocrine-like morphology
Updated: Jan 11, 2026
Pathological Analysis of Lung Metastasis Following Lateral Tail-Vein Injection of Tumor Cells
Published on: May 20, 2020
Lung Carcinoma Metastatic to the Breast: A Comprehensive Analysis of Clinical Presentation, Morphologic, and
Atif Ali Hashmi1, Theodore Vougiouklakis1, Andrea Gazzo1
1Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York.
Abstract:
Lung carcinoma metastatic to the breast (bLM) or axillary lymph nodes (lnLM) may closely mimic primary triple-negative breast carcinoma (BC), leading to possible misdiagnosis. We characterized the clinical, morphologic, and molecular features of a series of lung carcinomas metastatic to breast and regional lymph nodes to identify diagnostic clues and pitfalls. The study cohort consisted of 30 patients (27 women, 3 men) with a median age of 72 years (range, 46-86); 21 patients (70%) reported a smoking history. At the time of the index biopsy, 4 patients (13.3%) had no history of lung carcinoma. Most tumors (n = 25, 83.3%) were bLM; 4 (13.3%) were lnLM, and 1 was a supraclavicular lymph node metastasis. In 7 of 23 cases (30.4%) with available paired imaging studies, the bLM was larger than the lung tumor. Of the 30 cases, 26 (86.7%) were adenocarcinomas, 2 (6.7%) were small cell carcinomas, and 2 (6.7%) were atypical carcinoids. Metastatic adenocarcinoma resembled BC with apocrine morphology in 16 of 30 cases (53.3%), 6 cases (20%) had vacuolated cytoplasm, and 6 (20%) had micropapillary features. One bLM closely mimicked ductal carcinoma in situ morphologically, and another case showed peripheral expression of CK5/14 and p63 mimicking myoepithelium around ductal carcinoma in situ. Initial diagnosis of BC had been rendered in 7 cases (6 adenocarcinomas and 1 small cell carcinoma). Molecular analysis of 18 cases showed that the most altered cancer genes were TP53 (44%), KRAS (44%), CDKN2A (33%), and MTAP (31%). Compared with a cohort of primary triple-negative BC, the bLM/lnLM exhibited a higher tumor mutation burden (P = .002), a lower rate of TP53 mutations, and more frequently harbored genetic alterations in KRAS, RBM10, CDKN2A, CDKN2B, SMARCA4, and STK11. In 10 of 18 cases, mutational signature analysis revealed a dominant smoking signature, providing evidence of lung origin. Our findings unveil diagnostic pitfalls that may warrant additional evaluation to avoid misdiagnosis of metastatic lung carcinoma as a primary BC.
