Akio Miyake1, Koji Okudela2, Mai Matsumura1, Mitsui Hideaki2, Hiromasa Arai3, Shigeaki Umeda2, Shoji Yamanaka1, Yoshihiro Ishikawa4, Michihiko Tajiri3, Kenichi Ohashi1,2. 1. Division of Diagnostic Pathology, Yokohama City University Hospital, Yokohama, Japan. 2. Department of Pathology, Yokohama University Graduate School of Medicine, Yokohama, Japan. 3. Division of General Thoracic Surgery, Kanagawa Prefectural Cardiovascular and, Respiratory Centre Hospital, Yokohama, Japan. 4. Division of General Thoracic Surgery, Yokohama City University Hospital, Yokohama, Japan.
Abstract
AIMS: Psammoma bodies are concentrically lamellated microscopic structures made of calcium. They are commonly observed in papillary carcinomas of the thyroid gland and serous papillary adenocarcinomas of the ovary, but are also occasionally detected in lung adenocarcinomas. Only one study, published in 1972, has systematically described the significance of psammoma bodies in lung adenocarcinomas. The aim of this study was to update the significance of psammoma bodies in lung adenocarcinomas from a modern perspective. METHODS AND RESULTS: Psammoma bodies were detected in 7.2% (59/822) of the adenocarcinomas examined, among which the papillary (20.3%, 12/59) and acinar (44.1%, 26/59) histological subtypes, with the feature of a terminal respiratory unit (91.5%, 54/59), were dominant. Malignant potential (cell growth activity measured by Ki67 labelling, lymph node metastasis, and postoperative survival) did not significantly differ between adenocarcinomas with and without psammoma bodies. On the basis of cytogenetic features, adenocarcinomas with psammoma bodies were preferentially affected by tyrosine kinase inhibitor (TKI)-targetable driver mutations [EGFR (69.8%, 37/53), ALK (13.2%, 7/53), and ROS1 (1.9%, 1/53)]. Multivariate analyses confirmed that psammoma bodies may constitute an independent predictor for these mutations, particularly EGFR and ALK mutations. CONCLUSIONS: Psammoma bodies may predict a favourable response of lung adenocarcinomas to TKIs.
AIMS: Psammoma bodies are concentrically lamellated microscopic structures made of calcium. They are commonly observed in papillary carcinomas of the thyroid gland and serous papillary adenocarcinomas of the ovary, but are also occasionally detected in lung adenocarcinomas. Only one study, published in 1972, has systematically described the significance of psammoma bodies in lung adenocarcinomas. The aim of this study was to update the significance of psammoma bodies in lung adenocarcinomas from a modern perspective. METHODS AND RESULTS:Psammoma bodies were detected in 7.2% (59/822) of the adenocarcinomas examined, among which the papillary (20.3%, 12/59) and acinar (44.1%, 26/59) histological subtypes, with the feature of a terminal respiratory unit (91.5%, 54/59), were dominant. Malignant potential (cell growth activity measured by Ki67 labelling, lymph node metastasis, and postoperative survival) did not significantly differ between adenocarcinomas with and without psammoma bodies. On the basis of cytogenetic features, adenocarcinomas with psammoma bodies were preferentially affected by tyrosine kinase inhibitor (TKI)-targetable driver mutations [EGFR (69.8%, 37/53), ALK (13.2%, 7/53), and ROS1 (1.9%, 1/53)]. Multivariate analyses confirmed that psammoma bodies may constitute an independent predictor for these mutations, particularly EGFR and ALK mutations. CONCLUSIONS:Psammoma bodies may predict a favourable response of lung adenocarcinomas to TKIs.