(Chest. 2003;123:277-279.)
© 2003
American College of Chest Physicians
Necrotic Mass-like Upper Lobe Opacity*
Craig E. Stewart, BA;
Helen T. Winer-Muram, MD;
S. Gregory Jennings, MD;
Ian Dowdeswell, MD and
Cristopher A. Meyer, MD
* From the Department of Radiology (Mr. Stewart, and Drs. Winer-Muram, Jennings, and Meyer), Indiana University School of Medicine, Indianapolis; and Division of Pulmonary and Critical Care Medicine (Dr. Dowdeswell), Department of Medicine, Indiana University School of Medicine, Indianapolis, IN.
Correspondence to: Helen T. Winer-Muram, MD, Richard L. Roudebush VA Medical Center, Department of Radiology, 1481 West 10th St, Indianapolis IN 46202; e-mail: hwinermu{at}iupui.edu
 |
Introduction
|
|---|
A 48-year-old woman presented with a 1-month history of left anterior chest wall pain, dyspnea, productive cough, and night sweats. She denied having fever but admitted weight loss of approximately 15 lb over the past 2 months.
Her medical history was unremarkable except for alcohol abuse and a 74-pack-year smoking history. Her vital signs and physical examination were also unremarkable, except for bilateral wheezing and dullness to percussion over the right upper lobe. She had no known exposure history for tuberculosis. The chest radiograph showed an ill-defined opacity at the right upper lobe (Fig 1
).
She was admitted to the hospital and placed in respiratory isolation. A purified protein derivative was administered, and sputum was sent for cultures, cytology, and acid-fast bacilli test, all of which were negative for tuberculosis and/or malignancy. A chest CT without contrast was obtained that revealed a necrotic mass-like opacity in the right upper lobe, measuring 4.7 cm in diameter (volume, 31,871 mm3), as well as patchy ground-glass opacities. A 1.9-cm pretracheal lymph node was also present (Fig 2
).
Fine-needle aspiration of the mass was performed, and specimens were sent for stains/culture and cytology. The patient was treated empirically with levofloxacin, 500 mg qd, for 3 weeks, during which time she had symptomatic improvement. A follow-up CT scan 4 weeks later demonstrated clearing of the ground-glass opacities and pretracheal lymphadenopathy, with reduction in diameter of the mass-like opacity to 3.1 cm (volume, 24,646 mm3).
|
What is the diagnosis?
|
|---|
|
Diagnosis: Squamous cell carcinoma of the lung, infected with Streptococcus pneumoniae
|
|---|
|
Discussion
|
|---|
Fine-needle aspiration smears demonstrated squamous cell carcinoma, and cultures from the aspirate grew S pneumoniae. The patient’s cough and night sweats resolved after antibiotic therapy, as did her lymphadenopathy. The mass also decreased significantly in size, probably because the antibiotic therapy cleared the infection associated with the tumor. Despite counseling regarding treatment options for lung cancer, the patient refused both surgical and palliative treatment.
Lung cancers, particularly squamous cell carcinomas, may necrose and form central cavitations. The cavity may then become infected, producing an abscess. This process is referred to as in situ infection of a lung tumor or a carcinomatous abscess.1
Sputum or fine-needle aspiration smears and cultures may show the infection. Cytology may be difficult to interpret as positive for malignancy during active infection.2
The association of lung abscesses and underlying lung cancer has long been recognized.1
In patients with known cavitary lung tumors, the incidence of in situ infection has been reported to be as high as 27% in one study3
of 22 patients. In our experience, in situ infection does not appear to occur this frequently. Some patients may have colonization, but never develop symptoms consistent with an actual abscess. Patients presenting with a symptomatic abscess have an associated malignancy in 7 to 18% of cases, but more recent reports indicate that the incidence may be as high as 36%.4
Often, patients presenting with lung abscess secondary to an undiagnosed lung cancer may have repeated bouts of pneumonia and require a diagnostic workup before their lung cancer is discovered. The clinical and radiographic improvement following medical management in these patients with infected lung tumor often mimics that of patients with benign lung abscesses. The symptomatic improvement in these patients frequently leads to the delay in diagnosis and treatment; when the cancer is diagnosed, the percentage of patients with resectable tumor is relatively low.1
In patients at risk for lung cancer, it is vital to recognize that a lung abscess may be carcinomatous. Patients with a known lung cancer who develop symptoms consistent with lung infection also require urgent investigation to rule out infection, as failure to recognize lung abscesses is associated with poor clinical outcome.
Patients with a central tumor may present with a peripheral suppurative abscess due to tumor obstructing the bronchus. While these patients typically respond rapidly to medical therapy, they often present with more advanced disease and have a poorer prognosis than those with other types of carcinomatous lung abscesses.1
5
The preferred method for diagnosis of a central tumor is sputum cytology or bronchoscopy,6
as fine-needle aspiration may show only infection. Moreover, the central mass lesion may be difficult to distinguish from postobstructive infection with CT. Patients may also present with a "spill-over" abscess, when pus or sloughed tumor fragments are spread bronchially, producing distant segmental or subsegmental pneumonitis and abscess.5
Unfortunately, imaging cannot be used to reliably differentiate between a cavitary tumor, carcinomatous abscess, and a benign abscess. While cavities with thickened and irregular walls are more likely to be associated with malignancy, this is not always the case.4
7
The presence of a mural nodule (a solid mass attached to the wall of a cavitary lesion) was once considered highly suggestive of malignancy, but has been found in 26% of patients with benign abscesses.6
8
Cavitary lesions with a maximum wall thickness of < 1 mm generally suggest a benign process, while those with cavity wall > 15 mm are more frequently malignant.7
Another problem in diagnosing carcinomatous lung abscesses is that they most frequently occur in the bronchopulmonary segments most associated with lung abscesses resulting from aspiration. Fifty to 60% of carcinomatous lung abscesses occur in the posterior segments of the upper lobes and superior segments of the lower lobes, making differentiation from aspiration lung abscess difficult. Conversely, abscesses located elsewhere are particularly suspicious for malignancy, especially in the anterior segments of the upper lobes.6
Ipsilateral hilar/mediastinal lymphadenopathy may be due to malignancy but may also represent reactive hyperplastic lymph nodes. Definitive diagnosis can be made with fine-needle aspiration biopsy or mediastinoscopy, but resolution with antibiotic treatment or progression despite antibiotic treatment suggests the correct diagnosis.9
The use of fluoroscopic, ultrasound, or CT-guided fine needle aspiration has also been effective in the diagnosis of peripheral lung cancer. Transthoracic needle aspiration is the most reliable way to obtain uncontaminated specimens for culture when one suspects infection.10
It is important to obtain samples for microbiology and cytology; the aspirate from the center of the lesion may show the infection while aspirate from the wall of the lesion may reveal tumor.
Patients with infected bronchogenic carcinoma typically respond clinically and radiographically to proper antibiotic treatment based on cultures and sensitivities. In a series of nine patients with infected, undiagnosed lung cancer, "roentgenographic improvement" was noted in all patients.1
Specific radiographic changes in such patients, however, have not been evaluated. In this case, CT showed decreasing size of the infected tumor (> 1 cm decrease in diameter) and resolution of mediastinal lymphadenopathy following administration of antibiotics (Fig 3
). In patients with benign lung abscess, radiologic improvement with antibiotic treatment occurs in nearly all patients, with the majority having complete resolution of cavities within 3 months of presentation.11
It is interesting to note that lung cancers may require restaging following antibiotic therapy if the tumor shrinks in size and/or the lymphadenopathy resolves. Prior to treatment with antibiotics, this patient’s cancer would have been staged as IIIA (T2N2M0); after antibiotics, the patient’s cancer was stage IB (T2N0M0).
In summary, this case demonstrates the importance of both microbiologic and cytologic examination of fine-needle aspirates of cavitary masses, since infection and tumor may coexist in some of these lesions. Antibiotic treatment can significantly alter the apparent size and stage of these lung cancers.
Received for publication October 9, 2001.
Accepted for publication November 27, 2001.
|
References
|
|---|
- Bernhard, WF, Malcolm, JA, Wylie, RH (1962) The carcinomatous abscess: a clinical paradox. N Engl J Med 266,914-919
- Aisner, J, Satterfield, JR, Aisner, SC Inflammatory changes related to active tuberculosis: confusion with oat cell carcinoma of the lung on cytology specimen. Chest 1978;73,670-672[Abstract/Free Full Text]
- Liao, WY, Liaw, YS, Wang, HC, et al Bacteriology of infected cavitating lung tumor. Am J Respir Crit Care Med 2000;161,1750-1753[Abstract/Free Full Text]
- Sosenko, A, Glassroth, J Fiberoptic bronchoscopy in the evaluation of lung abscess. Chest 1985;87,489-494[Abstract/Free Full Text]
- Flavell, G Lung abscess. BMJ 1966;5494,1032-1036[ISI][Medline]
- Wallace, RJ, Cohen, A, Awe, RJ, et al Carcinomatous lung abscess: diagnosis by bronchoscopy and cytopathology. JAMA 1979;242,521-522[Abstract]
- Woodring, JH, Fried, AM, Chuang, VP Solitary cavities of the lung: diagnostic implications of cavity wall thickness. AJR Am J Roentgenol 1980;135,1269-1271[Abstract]
- Good, CA, Holman, CB Cavitary carcinoma of the lung: roentgenologic features in 19 cases. Dis Chest 1960;37,289-293
- Rohlfing, BM, White, EA, Webb, WR, et al Hilar and mediastinal adenopathy caused by bacterial abscess of the lung. Radiology 1978;128,289-293[Abstract]
- Yang, PC, Luh, KT, Lee, YC, et al Lung abscess: US examination and US-guided transthoracic aspiration. Radiology 1990;180,171-175[Abstract/Free Full Text]
- Weiss, W Cavitary behavior in acute, primary, nonspecific lung abscess. Am Rev Respir Dis 1973;108,1273-1275[ISI][Medline]
TOP
Introduction
What is the diagnosis?
