Endometrial
metastasis from the lung primary remains is rare. Moreover, the literature only contains case reports of endometrial
metastasis from the primary
lung cancer. An 83-year-old female patient presented with postmenopausal
uterine bleeding and
anemia. Endometrial thickening was detected using transvaginal ultrasound and endometrial
curettage was performed. Histopathology revealed
adenocarcinoma infiltration on an endometrial
polyp surface. On histologic examination, high-grade serous
carcinoma and clear cell
carcinoma diagnoses were initially considered. The
tumor cells were immunohistochemically negative for
Wilms' tumor 1 and wild-type for p53 expression; however, it was positive for Napsin A. Primary
lung adenocarcinoma (LUAD)
metastasis was also included in the differential diagnosis.
Thyroid transcription factor 1 was positive, whereas paired box gene 8 (Pax8) was negative in
tumor cells. Primary LUAD
metastasis was diagnosed since a lung mass was radiologically confirmed. Furthermore,
epidermal growth factor receptor-exon 19 mutation was detected by molecular analysis. In addition to the clinical and morphological features, this case report emphasizes the importance of multiple immunohistochemical panel applications for the correct diagnosis.