Rapidly vanishing lung pseudotumor in a patient with acute bilateral bronchopneumonia

Introduction. Rapidly vanishing lung pseudotumor (phantom tumor) refers to the transient well-demarcated accumulation of pleural fluid in the interlobar pulmonary fissures. Most frequently their appearance is associated with congestive heart failure, but also other disorders like hypoalbuminemia, renal insufficiency or pleuritis. Its rapid disappearance in response to the treatment of the underlying disorder is a classical feature of this clinical entity. Case report. A 47-yearold woman, chronic smoker with symptoms of shortness of breath, orthopnea, chills, cough, weakness and the temperature of 39.2°C was admitted to our hospital. A posteroanterior chest X-ray revealed cardiomegaly with the cardiothoracic ratio of > 0.5, blunting of both costophrenic angles and an adjacent 6 5 cm well-defined, rounded opacity in the right interlobar fissure. Transthoracic 2-dimensional echocardiography demonstrated left ventricular hyperthrophy with a systolic ejection fraction of 25% and moderate mitral regurgitation. The patient’s symptoms resolved rapidly after diuresis, and repeated chest X-ray four days later showed that the right lung opacity and pleural effusions had vanished. Conclusion. The presented case underlines the importance of the possibility of vanishing lung tumor in patients with left ventricular failure and a sharp oval lung mass on the chest X-ray. This is the way to avoid incorrect interpretation of this finding causing additional, unnecessary, costly or invasive imaging, interventions and drugs.


Introduction
Vanishing lung pseudotumor refers to the transient well demarcated accumulation of pleural fluid in the interlobar pulmonary fissures 1 .Most frequently their appearance is associated with congestive heart failure, but also other disorders like hypoalbuminemia, renal insufficiency and pleuritis 2 .Awareness of this form of pleural effusion is important for the differential diagnosis of pulmonary mass on radiography.Making the correct diagnosis is crucial in order to prevent further inappropriate and possibly harmful investigations and treatment (e.g.lung biopsy and/or surgery).Its rapid disappearance in response to underlying disorder treatment is a classical feature of this clinical entity 3 .

Case report
A 47-year-old woman, chronic smoker with symptoms of shortness of breath, orthopnea, chills, cough, weakness and the temperature of 39.2 °C was referred to our pulmology ward by her physician.The symptoms started five days before admission to our hospital, and she had been treated ambulatory with penicillin and paracetamol for two days before the referral.Physical examination revealed extreme obesity (body mass index 35.4kg/m 2 ), high blood pressure (170/100 mmHg), sinus tachycardia with systolic murmur on the apex, tachypnea and extensive bilateral crackles over both lung fields.There was no pedal oedema or elevated jugular venous pulse.Laboratory analyses revealed leucocytosis (18.3 10 9 /L) with neuthrophilia and highly elevated markers of acute inflammation [erytrocyte sedimentation rate (ESR) 90, C-reactive protein (CRP) 257mg/L, fibrinogen > 10g/L)].Other biochemical analyses including serum creatinine and albumin gave normal result.Three series of sputum culture were aseptic, as well as blood cultures.
On admission, posteroanterior chest X-ray revealed cardiomegaly with cardiothoracic ratio of > 0.5, blunting of both costophrenic angles and an adjacent 6 5 cm welldefined, rounded opacity in the right interlobar fissure (Figure 1).Transthoracic 2-dimensional echocardiography dem-onstrated left ventricular hyperthrophy with a systolic ejection fraction of 25% and a moderate mitral regurgitation.These findings were consistent with the diagnosis of acute bilateral bronchopneumonia and left ventricular failure.The treatment with two antibiotics (ceftriaxone, ciprofloxacin), diuretics (furosemide, spironolactone) and angiotensinconverting enzyme inhibitor (ramipril) was promptly instituted.The patient's symptoms resolved rapidly after extensive diuresis, and repeated chest X-ray four days later showed that the right lung opacity and pleural effusions had vanished (Figure 2).The patient was discharged 8 days after admission.

Fig. 2 -Posteroanterior chest X-ray 4 days after institution of heart failure and antibiotics therapy -right lung opacity
and pleural effusions had vanished.

Discussion
We reported an extremely rare case of vanishing lung pseudotumor in a patient with acute bilateral bronchopneumonia and previously unknown heart failure.In fact, the vanishing lung pseudotumor was the first clinical manifestation of heart failure in our patient and probably the associated bilateral bronchopneumonia promoted its outbreak.
The descriptors "vanishing", "pseudotumor" or "phantom tumor" (most frequently in Serbian literature) are used interchangeably and they refer to the transient localized collection of pleural fluid in the interlobar fissures which is typically transudative 1 .The most frequent cause of lung pseudotumor is congestive heart failure from various causes [4][5][6] , but it may also be caused by hypoalbuminamia, renal insufficiency and pleural infections 2 .Noteworthy, the presence of an interlobar pleural effusion does not necessarily correspond to the severity of the left heart failure.In fact, it may be the first or even the only sign of the left ventricular failure 5,6 .
Although the congestive heart failure with pleural effusion is very often encountered in clinical practice, vanishing lung pseudotumors as its complication can be seen extremely rare so as the exact incidence of this entity is difficult to assess due to the small number of reported cases.
Vanishing pseudotumor is a phenomenon predominantly occurring in the right lung, especially along the right horizontal fissure.Infrequently, it can occur in the horizontal and oblique fissures simultaneously 7 .
Regarding pathogenesis of vanishing lung pseudotumors several authors 3,6 attempted to explain it, and all of them presumed that pleuritis with subsequent adhesions resulting in symphysis is responsible for the localization of the fluid in the pleural space.Thereafter several predisposing factors contribute for accumulation of fluid in the interlobar space such as the anatomy of the pleural venous system, the right recumbent position assumed by many cardiac patients and finally the pulmonary lymphatic drainage.
Vanishing lung pseudotumors rapidly disappear with underlying cause treatment.In fact, it is the landmark of this phenomenon.

Conclusion
The presented case underlines the importance of the possibility of vanishing lung pseudotumor in patients with left ventricular failure and a sharp oval lung mass on chest X-ray.This may help to avoid incorrect interpretation of this finding causing additional, unnecessary, costly or invasive imaging, interventions and drugs.Treatment of this condition involves underlying disorder managing, like congestive heart failure in the presented case, leading to the rapid disappearance of the lung mass on control chest radiography.