Three young osteosarcoma patients with small adenocarcinoma or atypical adenomatous hyperplasia of the lung.

Three young osteosarcoma patients with adenocarcinoma (AD) or atypical adenomatous hyperplasia (AAH) of the lung are reported. A 14-year-old male patient with femoral osteosarcoma had solitary AD (case 1); a 23-year-old female patient with femoral osteosarcoma had AAH and lung metastasis (case 2); and a 17-year-old male patient with humeral osteosarcoma had AD and lung metastasis of osteosarcoma (case 3). They have been the youngest patients with lung cancer or AAH in our hospital. The maximum diameter of each lung tumor on computed tomography (CT) was 0.5, 0.6, and 0.5 cm, respectively. On immunohistochemical analyses, the p53 was positive in both AD and osteosarcoma and negative in both AAH and osteosarcoma. On genomic analyses, p53 mutation was detected in only one osteosarcoma (case 3). Epidermal growth factor receptor (EGFR) mutations, short in-frame deletion in exon 19, and insertion in exon 20 were found in AD, but not in AAH or osteosarcoma. There was no apparent genomic relationship between AD/AAH and osteosarcoma in the young patients in this study. Advances in CT and its applications to osteosarcoma patients as a method of assessing lung metastasis might contribute in large part to the detection of AD/AAH in patients younger than 30.