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The “tennis racket” sign on a chest radiograph

Rajendra Takhar, Moti Lal Bunkar

From the Department of Respiratory Medicine, Government. Medical College, Kota, Rajasthan, India 

How to cite this article:

Takhar R, Bunkar ML. The “tennis racket” sign on a chest radiograph. Ann Saudi Med 2016; 36(2): 152.



A 20-year-old male presented with complaints of cough with expectoration, weight loss, decreased appetite, and fever of 1 month duration. He denied for hemoptysis and chest pain. He was a non-smoker and did not drink alcohol. He had no history of having tuberculosis or contact with a tuberculosis patient in the recent past. All routine blood investigations were within normal limits including human immunodeficiency virus serology except raised erythrocyte sedimentation rate (80 mm in the first hour). A chest x-ray showed a thick-walled cavity in the left upper zone, a feature known as “tennis racket” sign (Figure 1).


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Diagnosis: Reactivation of pulmonary TB


Formation of single or multiple, thin- or thick- walled cavities on either side of the lung fields, especially in the apical or posterior segment and superior segment of the lower lobe, is considered an important hallmark of reactivation pulmonary tuberculosis.1 Differential diagnosis of a cavitory lesion on chest x-ray includes infectious diseases like common bacterial infections (Staphylococcus, Klebsiella, anaerobes), necrotizing pneumonias and lung abscesses, septic pulmonary emboli, fungal infections, parasitic infections, and, most importantly, mycobacterial infections in a country like India where tuberculosis is rampant. However, non-infectious causes include malignancies (squamous cell carcinoma of the lung), rheumatologic diseases, pulmo- nary infarcts, and Wegener granulomatosis.2



How does “tennis racket” form?

Involvement of bronchus in the tuberculous process, causing its narrowing or occlusion with the dilatation of its distal part beyond this narrowing, due to the local wall destruction with weakening, appears as a ring shadow (tuberculous cavity) while the proximal part of the draining bronchus (toward hilum) is also either narrowed, thickened, or dilated by the tuberculous process, giving it the appearance of a “tennis racket” shadow.3 Histological features of the wall of such a “cavity” are similar to those of the bronchial wall with or without tuberculosis foci in it.4



Clinical significance

The ring shadows or tubercular cavity has abundantsignificance in the definitive diagnosis of active tuberculosis infection as a solid nodule of 2 cm in diameter devoid of communication with the bronchi. The number of tubercle bacilli ranges from 102 to 104, while a cavitory lesion of the same size contains approximately 107 to 109 bacilli. Thus, cavitory disease having bronchial communication has a good association with a sputum smear positivity, as a large number of bacilli are excreted with the sputum and such patients are highly infectious.Therefore, the “tennis racket” sign can beconsidered one of the radiological hallmarks of active pulmonary tuberculosis.3



Learning points:

1. No radiological pattern or sign is specific for tuberculosis; however, the presence of “tennis racket” sign endorses higher grades of bacteriological presence.

2. The presence of “tennis racket” sign on chest radiograph should ignite a search for underlying active pulmonary tuberculosis.






1. Hansell DM, Bankier AA, MacMahon H, McLoud TC, Müller nL and Remy J. Imaging of diseases of the chest. 5th ed. 2008; p 232-3.

2. Gadkowski LB and Stout Je. Cavitary Pulmonary Disease. Clinical microbiology reviews, Apr. 2008, Vol. 21, no. 2. p. 305-33

3. Shital, Patil, and Laxman Kasture. “‘Tennis Racket cavity’ on Chest Radiograph: Strong Predictor of Active Pulmonary Tuberculosis! – A Case Report.” American Journal of Medical Case Reports 2.9 (2014): 167-9.

4. George Simon. Principles of chest x raydiagnosis: Butterworth- Heinemann, fourth edition, 1978, p 134-5.

5. Toman’s tuberculosis case detection, treatment, and monitoring: questions and answers edited by T. Frieden. -2nd ed. World Health Organization, Geneva 2004, p 51-6.



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