A Rare Case of Pulmonary Papillary Adenoma in Old Aged Woman: A Brief Case Report
A 68-year-old female, who was undergoing preoperative evaluation for known rectal cancer, received percutaneous needle biopsy for a pulmonary nodule () and endobronchial sono-guided biopsy for enlarged mediastinal lymph nodes, which showed no evidence of metastasis. However, the core of the pulmonary nodule was composed of bland papillae-like structures lined with a single layer of uniform cuboidal cells, suspicious for carcinoid or low-grade epithelial neoplasm. On consideration of double primary pulmonary neoplasm, she received combined laparoscopic low anterior resection of the rectum and wedge resection of the left lobe of the lung.\nThe resected specimen of lung contained a 2.5×1.5-cm-sized, peripherally located mass with a granular cut surface. At low power view, it is well demarcated without necrosis or hemorrhage (). Microscopically, it showed dominant papillary architecture and focal microcystic area (). The papillae contained prominent or delicate fibrovascular cores and were lined by monotonous cuboidal cells (). The epithelial cells had moderate or small amount of cytoplasm and round, centrally located nuclei with inconspicuous nucleoli, and no nuclear atypia or mitosis was found (). The chromatin was relatively uniformly distributed and finely granular, suspicious for neuroendocrine tumor. The microcystic area were lined with same epithelial cells and filled with amorphous eosinophilic material, similar to colloid or amyloid.\nFor the differential diagnoses with papillary adenoma of lung, metastatic follicular or medullary carcinoma of thyroid gland and less likely metastatic adenocarcinoma of rectum, immunohistochemical staining was performed. The tumor cells showed negativity for chromogranin (1:400, DAK-A3, Dako, Glostrup, Denmark), thyroglobulin (1:500, DAK-Tg6, Dako), calcitonin (1:4,000, Dako) and CDX-2 (1:50, AMT28, Novocastra, Newcastle upon Tyne, UK) and positivity for thyroid transcription factor-1 (1:100, 8G7G3/1, Dako) (, inset). The eosinophilic material was negative by Congo-red stain and polarizing microscopy.\nThe patient was confirmed to have primary papillary adenoma of the lung and adenocarcinoma of the rectum (pT3N0Mx), and was discharged without any complications.