PLAG1-rearranged pulmonary metastases from pleomorphic adenoma-spectrum salivary gland neoplasms: A clinicopathologic study of metastasizing pleomorphic adenoma and carcinoma ex pleomorphic adenoma.
Min Zhang, Chengfeng Xu, Xianzheng Gao et al.
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From the abstract
Pulmonary metastases from pleomorphic adenoma (PA)-spectrum salivary gland neoplasms are rare and may be difficult to diagnose, particularly in limited pulmonary specimens. We aimed to characterize their clinicopathologic and molecular features and highlight practical diagnostic pitfalls.
Reported results
Two pulmonary lesions were classified as histologically bland MPA, whereas the third was classified as metastatic carcinoma ex pleomorphic adenoma (CXPA) with a myoepithelial carcinoma component. In one MPA, apparent focal TTF-1 and Napsin A immunoreactivity in a core biopsy was attributable predominantly to entrapped pneumocytes rather than convincing expression in the neoplastic component, creating a potential…
Authors' conclusions
Pulmonary PA-lineage metastases may be histologically bland or overtly malignant. Entrapped pneumocytes may cause misleading TTF-1 and Napsin A immunoreactivity in limited pulmonary specimens. PLAG1 FISH provides useful support for PA-lineage origin but does not independently distinguish MPA from metastatic CXPA.