Spherical pneumonia caused by Ralstonia mannitolilytica: a case report and literature review

Abstract

Background Spherical pneumonia is an extremely rare condition that is difficult to diagnose. It is a specific type of lung infection that often manifests as a round or round-like mass on chest imaging. Spherical pneumonia is easily misdiagnosed as a pulmonary tumor; therefore, awareness of this disease must be strengthened. Case presentation The patient was a 29-year-old female who had persistent cough and sputum for approximately 1 month and fever for 5 days. Chest computed tomography (CT) at our hospital revealed a mass in the lower lobe of the right lung near the hilar region, with obstructive pulmonary atelectasis and obstructive pneumonia. Although lung cancer was suspected, Ralstonia mannitolilytica was detected by metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid, and no cancer cells or Mycobacterium tuberculosis were detected. Finally, the patient was diagnosed with spherical pneumonia caused by R. mannitolilytica. Anti-infective treatment, symptomatic treatment, and administration of a traditional Chinese medicine decoction were performed based on the syndrome differentiation. After 10 days of treatment, chest CT revealed few lesions in the lower lobe of the right lung, which were significantly reduced compared with those in the past. Conclusions Spherical pneumonia caused by R. mannitolilytica has not yet been reported and differential diagnosis is key in clinical diagnosis. When spherical pneumonia is difficult to diagnose, mNGS may be a better alternative.

Commonly misdiagnosed round pneumonia in a child: a case report

“…Young infants are more likely to develop round pneumonia due to their underdeveloped pores of Kohn and Lambert's channels, which may result in the centrifugal spread of fluid or bacteria. 1,4,5 Round pneumonia typically affects children under 5 years of age and rarely occurs in children older than 8 years of age, as the lateral airways are usually welldeveloped by that age. 6,7 The upper lobe of the right lung is most commonly affected; round pneumonia occurs in the upper lobe of the right lung 8 times more often than in the left upper lobe and twice as often as in the right middle or lower lobes.…”

“…This is one of the most important features distinguishing round pneumonia from pulmonary neoplasms. 5,10 Round pneumonia may appear as a halo sign on chest non-contrast CT. 5 However, the halo sign may also be seen in fungal infections, lung abscesses, pulmonary TB, and lung malformations. 7 Therefore, a non-contrast chest CT scan cannot definitively conclude whether a lesion is a tumor or another pathology.…”