Rapidly growing small peripheral lung cancers detected by screening CT: correlation between radiological appearance and pathological features.

Abstract

12 peripheral small lung cancers (< 20 mm) of rapid growth (volume doubling time < 150 days), detected by repeated low dose CT screening, were evaluated to examine their CT features and to correlate such features with histopathological findings. Each patient's CT images, including follow-up and thin section CT images, were studied retrospectively to determine tumour growth rate and CT morphological features. Nine of the tumours exhibited a solid tumour growth pattern: seven of these showed a well defined, homogeneous, soft tissue density with spicular or lobulated margin. These seven tumours included small cell lung cancer (n = 3), moderately differentiated adenocarcinoma (n = 2), poorly differentiated adenocarcinoma (n = 1) and squamous cell carcinoma (n = 1). The other two tumours, a moderately differentiated adenocarcinoma and a well differentiated adenocarcinoma, appeared as irregular, soft tissue density nodules with poorly defined margins. The latter exhibited an air bronchogram pattern and a small cavity. The remaining three tumours exhibited a lepidic tumour growth pattern. They showed ground glass opacity or ground glass opacity with a higher density central zone on CT images and were well differentiated adenocarcinomas. In conclusion, most peripheral small lung cancers of rapid growth were adenocarcinomas. They also included small cell lung cancer and squamous cell carcinoma. The majority showed solid tumour growth pattern and lacked an air bronchogram and/or small air spaces in the nodule. Some well differentiated adenocarcinomas with lepidic tumour growth pattern also showed rapid growth.

Limited value of shape, margin and CT density in the discrimination between benign and malignant screen detected solid pulmonary nodules of the NELSON trial

“…This was consistent with the results of studies performed in usually larger SPN's [11,23,26,27]. Despite these findings, we do not recommend the use of nodule density in the differentiation between malignant and benign nodules because of the large overlap and the wide range of densities observed among the malignant nodules.…”

Accurate Diagnosis of Peripheral Small Cell Lung Cancer with Computed Tomography

“…However, these internal and marginal characteristics were not specific to peripheral SCLCs. Poorly differentiated adenocarcinomas and squamous cell carcinomas appear on CT images as a well-defined solid mass showing lobulation or spiculation (Sone et al 1997;Wang et al 2000). Large cell neuroendocrine carcinoma appears on CT images as a solid mass with marginal characteristics similar to those observed in SCLCs (Oshiro et al 2004).…”

Smooth or Attached Solid Indeterminate Nodules Detected at Baseline CT Screening in the NELSON Study: Cancer Risk during 1 Year of Follow-up

“…During the past few years, a lot of new information has become available on the value of size, shape, and margin in the discrimination of benign from malignant CT-detected pulmonary nodules (3,5,(14)(15)(16)(17)(18)(19). Nodules less than 3 mm in diameter have only a 0.2% chance of being malignant; this chance is 0.9% for nodules between 4 and 7 mm, 18% for nodules between 8 and 20 mm, and 50% for those larger than 20 mm (6).…”