Ominous lung cavity “Tambourine sign”

Abstract

Mucinous adenocarcinoma represents a rare subtype of adenocarcinoma of the lung, which is frequently invasive and has a poorer prognosis. Of its wide range of imaging appearances, air-space consolidation is the most frequent pattern while cavitary form has only rarely been reported. Despite imaging advancements, the differentiation of benign and malignant cavitary lung lesions sometimes remains imperfect. We propose “Tambourine” sign on computed tomography to raise the suspicion of mucinous adenocarcinoma in a lung cavity, under appropriate clinical settings. The sign indicates an irregular cavity with undistorted prominent thick walled bronchioles within the wall and draping along thereby resembling the musical instrument “tambourine”. Adjacent ground glass and internal septations may also be seen.

Keywords: Lung cavity; Tambourine; Adenocarcinoma mucinous; Tomography; X-ray

Core tip: Lung cavities are commonly encountered in routine chest imaging and diagnosis may become a challenge in certain cases despite advances in imaging techniques. Imaging points have been described in literature to differentiate benign from malignant cavities that help in diagnosing most of the cases, however some lesions are still difficult to interpret and accurately diagnose. Tambourine sign has been introduced by us for a relative thin walled lung cavity where undistorted smaller bronchi with thickened and prominent walls are seen to be entering and draping along the cavity walls. This imaging sign resembles the musical instrument tambourine, and this is ominous and point towards a more sinister lesion as in our case and in similar cases reported in literature. Hence in appropriate clinical and imaging background this sign should be carefully looked at and appropriate workup should be done for timely diagnosis.