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An Elderly Man With Pancreatic Neuroendocrine Tumor and a Cavitary Right Upper Lobe Lung Mass FREE TO VIEW

Palla DeSilva, MD; Adarsha Selvachandra, MD; Jennifer Kanaan, MD; Debapriya Datta, MD, FCCP
Author and Funding Information

Department of Pulmonary and Critical Care Medicine, University of Connecticut Health Center, Farmington, CT

CORRESPONDENCE TO: Debapriya Datta, MD, FCCP, Division of Pulmonary and Critical Care Medicine, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT 06030


Copyright 2016, American College of Chest Physicians. All Rights Reserved.


Chest. 2017;151(6):e135-e139. doi:10.1016/j.chest.2016.11.058
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Published online

Case presentation  An elderly man presented to the ED from a nursing care facility after transient loss of consciousness. Three weeks previously, the patient had been diagnosed with a high-grade pancreatic neuroendocrine tumor (NET) with metastases to the liver after being hospitalized for weakness. A chest radiograph at that time had revealed a right upper lobe mass that was presumed to represent a metastatic lesion (Fig 1); CT of the chest demonstrated similar findings (Fig 2). The patient had recovered consciousness on arrival to the ED and was diagnosed clinically as having had a syncopal episode from dehydration due to poor intake. On review of systems, the patient reported shortness of breath and a cough productive of scant mucoid sputum of 1 week's duration. He had no complaints of fever but complained of weakness and poor appetite. In addition, his medical history was significant for hypertension, diabetes mellitus, and congestive heart failure with systolic dysfunction. He was a former smoker. Prior to his recent illness and hospitalization, he lived at home with his family and was independent in his activities of daily living.

Figures in this Article

On physical examination, the patient was awake, alert, and appropriately responsive. His vital signs were within normal limits. There was no cervical lymphadenopathy. Cardiac examination was normal. Lungs were clear to auscultation. The lower extremities revealed trace edema. The remainder of the examination was normal.

Figure 1
Figure Jump LinkFigure 1 Chest radiograph revealing right upper lobe mass.Grahic Jump Location
Figure 2
Figure Jump LinkFigure 2 Initial CT scan of chest showing right upper lobe mass with surrounding area of ground glass opacity (halo sign).Grahic Jump Location

CBC findings were notable for normal WBC and platelet counts but a hemoglobin value of 11 g/dL, which was chronic. Serum chemistry values were normal except for a mildly reduced serum sodium concentration of 134 mEq/L. CT of the head was normal. A second chest radiograph revealed enlargement of the right upper lobe mass from 3 weeks before (Fig 3). A second chest CT scan (Fig 4) showed a cavitating right upper lobe mass; in addition, another small cavitating mass was present in the right lower lobe (Fig 5). Sputum cultures were obtained, and Gram staining of sputum is shown in Figure 6.

Figure 3
Figure Jump LinkFigure 3 Second chest radiograph, 3 weeks later, revealing progression of the mass with cavitation.Grahic Jump Location
Figure 4
Figure Jump LinkFigure 4 Subsequent chest CT (3 weeks after initial scan) showing enlarged right upper lobe mass with cavitation. Patchy opacities are present in the adjoining areas.Grahic Jump Location
Figure 5
Figure Jump LinkFigure 5 Additional section of subsequent chest CT showing new right lower lobe mass.Grahic Jump Location
Figure 6
Figure Jump LinkFigure 6 Gram stain of sputum culture revealing beaded branching filamentous Gram-positive bacilli.Grahic Jump Location

What is the diagnosis?

Diagnosis: Pulmonary nocardiosis

Pulmonary nocardiosis (PN) is an opportunistic infection typically encountered in immunocompromised individuals, more commonly in those with defects in cell-mediated immunity. PN has also been reported in immunocompetent persons. The responsible microorganisms are gram-positive, variably acid-fast, strictly aerobic bacteria that form filamentous branched cells that fragment into pleomorphic, rod-shaped, or coccoid elements. Approximately 25 species are associated with human infections, including Nocardia asteroides complex. Inadequacy of samples and difficulty in culturing the organism render diagnosis of PN difficult. Therefore, diagnosis is often delayed or missed, as cultures are sometimes discarded by the laboratories prior to the visible growth of the organism. A presumptive diagnosis can be made if this organism is visualized as partially acid-fast filamentous rods in specimens in the appropriate clinical setting. Radiographic findings of PN are variable and include lobar consolidation, alveolar or interstitial infiltrates, necrotizing pneumonias with cavitation, pulmonary nodules, or pleural effusions. Disease progression and cavitation in PN can occur rapidly, as in this patient. Although relatively rare, infection with Nocardia should be included in the differential diagnosis in patients with rapidly developing cavitating lung lesions, particularly in the setting of immunosuppression.

PN has been reported in patients with NET. In these patients, immunosuppression may occur due to hypercortisolism resulting from ectopic adrenocorticotropic hormone (ACTH) production by these tumors. Hypercortisolism causes immunosuppression through three different mechanisms: inhibition of phospholipid A2 synthesis, inhibition of interleukin 2, and inhibition of release of histamine from mast cells. The resulting environment is hospitable for opportunistic infections such as PN.

Only 5% to 7% of NETs originate in the pancreas, and only 1.2% of pancreatic NETs secrete ACTH. Although the prevalence of pancreatic NET-based ACTH production and immunosuppression is small, manifestations of ectopic ACTH production should increase concern for opportunistic infection. Secondary to the hypercortisolism, typical signs of infection (leukocytosis or fever) may not be as apparent, and as such, a pulmonary lesion in the setting of a pancreatic tumor may lend itself to a premature diagnosis of pulmonary metastasis. As disease progression of PN in the immunosuppressed person occurs rapidly, it is important to identify signs of ectopic ACTH production. Easy bruising, facial plethora, skin striae, a dorsocervical fat pad, weight gain, peripheral edema, newly diagnosed hypertension, vertebral osteoporosis, type 2 diabetes, hypokalemia, menstrual abnormalities, decreased libido, and depression are all signs and symptoms that are suspicious for ectopic ACTH production.

Initial testing for hypercortisolism involves a urinary free cortisol measurement (usually at two separate times), a late-night salivary cortisol measurement, or a dexamethasone suppression test. Once a hypercortisol state has been confirmed, the cause of hypercortisolism should be explored. In the setting of a known pancreatic NET, ectopic ACTH production resulting in Cushing syndrome is most probable. This can be corroborated by formal testing that would include the following: (1) ACTH level, which would be high in the case of ectopic ACTH production; (2) a high-dose dexamethasone suppression test, which would result in < 50% suppression in ectopic production; or (3) a corticotropin-releasing hormone stimulation test, which would show no response with ectopic ACTH production. Effective antimicrobial treatment for PN includes trimethoprim-sulfamethoxazole (TMP-SMX), third-generation cephalosporins, carbapenems, and amikacin. Most species of Nocardia are susceptible to sulfonamides, but drug-resistant strains have been increasingly identified. TMP-SMX is considered the drug of choice in PN. In patients with severe infection, combination therapy with either TMP-SMX plus amikacin or imipenem plus amikacin is recommended by experts. PN in immunocompetent patients usually requires 6 months of treatment, but in immunocompromised patients, at least 1 year of treatment is recommended. Despite effective treatment, invasive disease in the immunocompromised host carries high mortality.

Clinical Course

Treatment with TMP-SMX and meropenem was initiated, based on the results of the Gram stain. Cultures subsequently grew Nocardia. Antibiotics were discontinued when the patient opted for hospice care given the poor prognosis of his pancreatic malignancy. Consequently, further evaluation of the patient’s ACTH and serum cortisol levels was not pursued.

  • 1.

    Nocardiosis should be considered in immunocompromised patients with rapidly progressive pulmonary opacities, particularly those with cavitation.

  • 2.

    A minority of NETs produce ectopic ACTH, leading to immunosuppression and the potential for opportunistic infections.

  • 3.

    In patients with NET with presumed metastases to the lung, possibility of an infectious cause of the pulmonary lesion should be considered.

  • 4.

    TMP/SMX is the treatment of choice for mild cases of nocardiosis. However, for more severe cases, combination therapy with TMP-SMX plus amikacin or imipenem plus amikacin is recommended.

Financial/nonfinancial disclosures: None declared.

Other contributions:CHEST worked with the authors to ensure that the Journal policies on patient consent to report information were met.


Figures

Figure Jump LinkFigure 1 Chest radiograph revealing right upper lobe mass.Grahic Jump Location
Figure Jump LinkFigure 2 Initial CT scan of chest showing right upper lobe mass with surrounding area of ground glass opacity (halo sign).Grahic Jump Location
Figure Jump LinkFigure 3 Second chest radiograph, 3 weeks later, revealing progression of the mass with cavitation.Grahic Jump Location
Figure Jump LinkFigure 4 Subsequent chest CT (3 weeks after initial scan) showing enlarged right upper lobe mass with cavitation. Patchy opacities are present in the adjoining areas.Grahic Jump Location
Figure Jump LinkFigure 5 Additional section of subsequent chest CT showing new right lower lobe mass.Grahic Jump Location
Figure Jump LinkFigure 6 Gram stain of sputum culture revealing beaded branching filamentous Gram-positive bacilli.Grahic Jump Location

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