Calcification in large cell neuroendocrine carcinoma of the lung

Background: The aim was to investigate the prevalence of intratumoral calcification in large cell neuroendocrine carcinoma (LCNEC) and to review computed tomography (CT) and histological findings. Patients and methods: From August 1992 through March 2000, 35 out of 1183 surgically resected lung cancer patients were histologically diagnosed as having LCNEC at our institute. We reviewed the plain radiographs and CT scans of these 35 LCNEC patients. In LCNEC cases with intratumoral calcification, we examined the size, number, distribution and pattern of intratumoral calcifications visible on the CT scans and the histological features. Results: Three cases (9%) exhibited calcification. The calcifications were recognized by CT scans alone. The CT scans showed punctate or eccentric intratumoral calcifications, which are considered to be a malignant feature, in all three cases. In two cases, the calcifications were histologically confirmed to be located within the necrotic areas of a tumor nest. Conclusion: We found three LCNEC cases with intratumoral calcification. The prevalence of LCNEC calcification was similar to that in previous reports on lung cancer. The mechanism of the intratumoral calcification in our LCNEC cases is speculated to be dystrophic calcification.