Fine-needle aspiration cytology of bronchocentric granulomatosis: a potential diagnostic pitfall

Granulomatous inflammation-an underestimated cause of false-positive diagnoses in lung fine-needle aspirates: observations from the college of american pathologists nongynecologic cytopathology interlaboratory comparison program

CONTEXT

The false-positive rate for fine-needle aspirates of the lung has been cited as less than 1% for granulomatous inflammation, comprising one of the known causes of false-positive diagnoses.

OBJECTIVE

To determine the rate of false-positive diagnoses of granulomatous inflammation for lung fine-needle aspirates by assessing the false-positive response rate in the context of the College of American Pathologists Nongynecologic Cytopathology Interlaboratory Comparison Program.

DESIGN

We performed a retrospective review of 1092 participant responses for lung fine-needle aspirate challenges with the reference diagnosis of specific infections/granulomatous inflammation from 1998 to 2008 from the College of American Pathologists Nongynecologic Cytopathology Interlaboratory Comparison Program. False-positive rates by participant type (pathologist versus cytotechnologist), general diagnosis category, reference diagnosis, and preparation type were analyzed for the pathologists' responses.

RESULTS

Of the 502 general category responses for pathologists, 428 (85.3%) were benign, 55 (11%) were malignant, and 19 (3.8%) were suspicious. There was no difference in the false-positive rate between preparations (P  =  .76) or participants (P  =  .39). Of those responses by pathologists that were benign, only 68.7% (292 of 425) were an exact match to granulomatous inflammation. Non-small cell carcinoma, adenocarcinoma, and squamous carcinoma represented 64% of false-positive/suspicious responses, while small cell carcinoma and carcinoid comprised 13%.

CONCLUSION

In an interlaboratory comparison program, granulomatous inflammation represents an important cause of false-positive/suspicious responses in lung fine-needle aspirates (14.8%) and is much higher than false-positive rates reported historically in clinical studies. These results highlight the importance of granulomatous inflammation as a mimic of carcinoma.

Bronchocentric granulomatosis associated with influenza-A virus infection

Bronchocentric granulomatosis is an unusual pathologic entity that is characterized by a necrotizing granulomatous inflammation surrounding the airways. The diagnosis is usually made retrospectively, after histopathologic examination of an open-lung biopsy or resection of a pulmonary lesion. Although the aetiology has not been fully elucidated, the current pathogenetic mechanism is considered to be an immunologic reaction against endobronchial antigens, since most patients exhibit signs of bronchial asthma, eosinophilia and allergic bronchopulmonary aspergillosis. However, non-asthmatic patients may develop bronchocentric granulomatosis without signs for endobronchial fungal infections, but probably as a consequence of other pulmonary infections. An 80-year-old female patient presented with high fever and bilateral pulmonary infiltrates and nodules. After extensive investigations and open-lung biopsy, the diagnosis bronchocentric granulomatosis was established that was possibly associated with an influenza-A virus infection. Treatment consisted of immunosuppressive drugs (prednisone and cyclophosphamide), which led to complete clinical and radiological recovery.

Bronchocentric granulomatosis with mucus impaction due to bronchogenic carcinoma. An association with clinical relevance

OBJECTIVE

To describe an unexpected inflammatory process associated with malignancy in the lung and to postulate a new mode of pathogenesis.

DESIGN

Retrospective review of surgical pathologic findings.

SETTING

Academic hospital pathology department.

PATIENTS

Four patients, 2 men and 2 women, ranging in age from 45 to 74 years, each of whom had a solitary mass on chest radiographs.

INTERVENTIONS

Pulmonary lobectomy.

MAIN OUTCOME MEASURE

Histopathologic identification of bronchocentric granulomatosis.

RESULTS

Accompanying a bronchogenic carcinoma in each case was a necrotizing chronic granulomatous reaction centered around bronchioles that were plugged with mucus, necrotic detritus from the tumor, lipid, or a combination of these substances. Eosinophils were present in small numbers in one case. The pathologic findings characterize bronchocentric granulomatosis.

CONCLUSIONS

The presence of bronchocentric granulomatosis in the biopsy of a mass does not exclude the presence of an accompanying bronchogenic carcinoma associated with obstruction of bronchioles. Bronchocentric granulomatosis in some cases may represent an immunologic response to tumor detritus or lipid, as well as to mucus impaction.

Intraoperative cytologic diagnosis of granulomas: a retrospective study of 156 cases

To avoid contamination of equipment and reduce risks of infection, intraoperative cytology (IOC) is a useful substitute to conventional frozen section in the diagnosis of infectious diseases. One of the various histomorphologic patterns of infections is the granuloma, which sometimes may be difficult to diagnose cytologically. In an attempt to assess accuracy and pitfalls of IOC in the diagnosis of granuloma, cases diagnosed as granuloma on IOC or on permanent sections (PS) at George Washington University Medical Center were collected for the period of September 1990 to March 1996. Cyto-histologic correlation was performed. During that time, a diagnosis of granuloma in either the IOC or PS was rendered in 156 of 5,901 IOC cases. IOC showed definite granuloma (87), suspicious for granuloma (23), and neither definite nor suspicious for granuloma in 46 cases. The latter group corresponded to neoplasms (5) and benign conditions (41). Eighty-five cases were accurately diagnosed as definite granuloma by both IOC and PS. Fifty-seven cases diagnosed as granuloma by PS corresponded on IOC to suspicious for granuloma (11), benign smear (41), and neoplasms (5). Only two cases were incorrectly diagnosed as granuloma on IOC: a neoplasm and a case of fibrosis. Overall, four cases of neoplasms were interpreted as suspicious for granuloma (3) or definite granuloma (1) on IOC, and five cases of granulomas were misdiagnosed as neoplasms on IOC. Four of these nine case were deferred for a PS diagnosis. IOC is a useful tool in the diagnosis of granulomas with a sensitivity of 60% and specificity of 99% and positive and negative predictive values of 98% and 99%, respectively. Rarely, neoplasms may be misdiagnosed as granulomas and vice versa.