Solitary pulmonary nodule from metastatic endometrioid endometrial carcinoma: case report and histopathologic review

Abstract

Endometrioid endometrial carcinoma is the most common subtype of endometrial cancer. Distant metastases are uncommon, and pulmonary involvement is rare, especially as a solitary pulmonary nodule. We report a case of pulmonary metastasis from endometrioid endometrial carcinoma, emphasizing the diagnostic value of histopathology, immunohistochemistry, and clinicopathological correlation. A 61-year-old woman with a history of FIGO grade 2 endometrioid endometrial carcinoma, treated with adjuvant radiotherapy and brachytherapy, underwent oncologic follow-up. One year later, computed tomography revealed a 35 x 22 mm lesion in the posterior basal segment of the right lower lobe. Right lower lobectomy was performed. Gross examination revealed a well-circumscribed cystic nodule containing yellow mucinous material. Microscopically, the lesion showed a malignant glandular proliferation composed of irregular glands with focal cystic dilatation and intraluminal mucin. These glands were lined by cuboidal to columnar cells exhibiting mild to moderate atypia, loss of polarity, and occasional mitotic figures. The adjacent lung parenchyma showed necrosis and mixed inflammatory infiltrates. Surgical margins were free of tumour. Immunohistochemically, the neoplastic cells were positive for CK7 and estrogen receptor and negative for CK20, CDX2, and SATB2, supporting the diagnosis of metastatic carcinoma without intestinal differentiation. In patients with a history of endometrioid endometrial carcinoma, a solitary pulmonary nodule should raise suspicion for metastasis. When immunohistochemical resources are limited, clinical, imaging, and pathologic correlation is essential for accurate diagnosis.