Evaluation of pure ground glass pulmonary nodule: a case report

Abstract

A pulmonary nodule is a single, nearly spherical, well-circumscribed pulmonary opacity up to 30 mm in diameter and surrounded by aerated lung tissue. In radiographs, pulmonary nodules may appear as solid, completely obscuring the lung parenchyma, or as subsolid, not completely obscuring adjacent tissues. A subsolid pulmonary nodule may be further subclassified as a pure ground glass nodule (pGGN) or a part solid nodule, a mixture of ground glass components and focal opacity obscuring the adjacent tissues. Guidelines for evaluation of solid pulmonary nodules are based on nodule size, recommending vigilance and non-operative management for small nodules (less than 8 mm in diameter) and diagnostic biopsy for nodules with a diameter of 8 mm or more. However, subsolid ground glass pulmonary nodules are an exception to this rule. Although small in size, persistent subsolid nodules are potentially premalignant or malignant. We present the case of a non-smoker who was found to have an incidental pulmonary pGGN. We then discuss the radiologic appearance, histology, clinical outcomes, and evaluation and management strategy of subsolid pulmonary nodules compared with solid nodules.

Keywords: papillary adenocarcinoma; pulmonary nodule; subsolid.

Fig. 1

Initial chest CT of the pulmonary nodule with lung (a) and mediastinal window (b). A 2.4×2.6 cm pure ground glass nodule (pGGN) was present in the left lower lobe of the lung.

Fig. 2

The pathology slide from resection tissue reveals well-differentiated papillary adenocarcinoma at the low power field (a). High-powered field slide demonstrates the typical acinar pattern of glandular differentiation (b). The tumor is strongly and diffusely TTF-1 positive (c), as is characteristic of primary adenocarcinoma of the lung.

Fig. 3

Classification of pulmonary nodule.