Extensive calcification in adenocarcinoma of the lung: A case report

Calcification in lung nodules usually indicates a benign lesion. Here, we report the case of a 59-year-old male patient with a well defined 30 mm calcified nodule in his right upper lung lobe and calcified mediastinal lymph nodes. The mass was diagnosed as adenocarcinoma by transbronchial biopsy. He received systemic chemotherapy, followed by lobectomy and mediastinal lymph node dissection. During surgery, the lymph nodes were tightly adherent to the superior vena cava with invasion of the vascular wall. Pathological diagnosis confirmed acinar adenocarcinoma and psammoma bodies (PBs). Immunohistochemical analysis revealed tumor cells positive for parathyroid hormone-related proteins 1 and 2. Calcification of primary lung adenocarcinoma is rare. We report a calcified lesion where the secretion of parathyroid hormone by the tumor may have caused the accumulation of PBs. Calcification of metastatic lymph nodes may increase the risk of adhesion, requiring care during surgery. KEY POINTS: Significant findings of the study Lung adenocarcinoma with extensive calcification in primary and metastatic lymph node lesions is rare and the mechanism involved is poorly understood. Of significance, calcification in our case was related to parathyroid hormone-related proteins 1 and 2 secreted by the tumor. What this study adds This study suggests the potential role of parathyroid hormone-related proteins in lung tumor calcification. The implications for clinicians are that calcified metastatic lymph nodes and tumors might be tightly fused to tissues. Therefore, surgery should be conducted with care.