The cytopathology of mycobacterial infection

Utility of Rapid On-Site Evaluation during Bronchoscopy in the Diagnosis of Pulmonary Tuberculosis

INTRODUCTION

The diagnostic value of rapid on-site evaluation (ROSE) in bronchoscopy for lung tumors has been widely researched. However, the diagnostic efficacy of ROSE for pulmonary tuberculosis (TB) has not been extensively assessed yet. This study aimed to examine the value of ROSE in diagnosing pulmonary TB during bronchoscopy, and the relationship between ROSE cytology patterns and acid-fast bacilli (AFB) smears and mycobacterial cultures.

METHODS

A retrospective study was conducted at a single respiratory endoscopy center, including 418 patients under clinical or radiological suspicion of having pulmonary TB who underwent bronchoscopy. In addition to the use of ROSE and definitive cytology, material obtained by aspiration/lavage or brushing was sent for AFB smear and mycobacterial culture. If histopathological examination was required, endobronchial biopsy, transbronchial lung biopsy, and transbronchial needle aspiration were performed at the discretion of the clinician. A composite reference standard (CRS) was used as the diagnostic gold standard for this study. The diagnosis obtained by ROSE was compared with the final diagnosis.

RESULTS

Of the 418 patients studied, 282 (67.5%) were diagnosed on the basis of bronchoscopic findings, as follows: pulmonary TB, in 238 (84.4%); non-TB, in 44 (15.6%). In 238 pulmonary TB patients, ROSE cytology showed granulomas without necrosis were observed in 107 cases, granulomas and necrosis in 51 cases, caseous necrosis only in 25 cases, and nonspecific inflammation in 55 cases. For the diagnosis of TB according to CRS, ROSE showed the sensitivity, specificity, positive predictive value, and negative predictive value were 76.9%, 68.2%, 92.9%, and 35.3%, respectively. The positivity rate for bacterial detection through acid-fast staining and culture during bronchoscopy was 51.7%. The cytological pattern showed a higher detection rate for bacteria in cases of necrosis.

DISCUSSION

The application of ROSE during bronchoscopy is a straightforward procedure that delivers an immediate and precise assessment regarding the adequacy of collected samples, enabling a preliminary diagnosis of pulmonary TB. ROSE has exhibited a higher sensitivity in detecting pulmonary TB compared to microbiological examinations. In addition, the cytological presentation of ROSE tends to show a higher positivity rate for microbiological testing in caseous necrosis. Therefore, samples with these characteristics should be prioritized for microbiological examination after on-site evaluation.

Transbronchial brushing cytology and paired biopsy in endobronchial tuberculosis: A report of 72 cases focusing on the morphological features

Objectives

The objectives of this study were to review the transbronchial brushing cytology and histological specimens of endobronchial tuberculosis (EBTB) and to explore the morphological features, diagnostic pitfalls, and dilemmas.

Material and Methods

Transbronchial brushing cytology and concurrent biopsy specimens obtained between July 2017 and June 2020 were reviewed. EBTB was confirmed based on the clinical response to the anti-TB treatment in addition to the positive findings of at least one of the following methods: Acid-fast bacilli stain (AFB), auramine-rhodamine stain (A-R), detection of TB bacterial DNA (TB-DNA) by polymerase chain reaction, T-cell spot test (T-spot), and typical pathologic changes of TB on cytology or bronchoscopy biopsy. A total of 72 confirmed cases were studied.

Results

Of the 72 patients, 42/72 (58.3%) and 30/72 (41.7%) were female and male patients, respectively. Bronchoscopic findings revealed five subtypes of EBTB, including inflammation infiltration, ulceration necrosis, granulation hyperplasia, cicatrices stricture, and tracheobronchial malacia. AFB, A-R, TB-DNA, and T-spot were positive in 39, 26, 33, and 46 cases, respectively. The detection rate of necrosis in the cytological specimens (90.3%) was significantly higher than that in the biopsy specimens (77.8%; P < 0.01). The percentage of Langhans giant cells detected by cytology (13.9%) was significantly lower than that detected by the pathological examinations of the tissues (38.9%) (P < 0.01). The detection rates of metaplastic squamous cells and epithelioid cells showed no significant difference with respect to the cytology and biopsy findings. In addition to the two patients who had concurrent carcinomas, atypical cells were reported in nine patients through cytopathological diagnosis, among them two were suspected to have carcinomas, two were with the impression that spindle cell neoplasms could not be excluded, and the other five were considered as reactive atypia. Moreover, one biopsy could not rule out the well-differentiated squamous cell carcinoma.

Conclusion

Some morphological variations may cause challenges in cytological evaluation. Moreover, diagnostic dilemmas can occur even in the assessments of tissue pathology.

Evaluation of prognostic inflammatory and systemic inflammatory response indices in auxiliary diagnosis of bacteria-negative pulmonary tuberculosis: A diagnostic accuracy study

Although molecular biology has made great progress in recent years, the detection rate of mycobacterium tuberculosis (MTB) is still not ideal. This study aimed to evaluate the role of prognostic inflammatory index (PII) and systemic inflammatory response index (SIRI) in the auxiliary diagnosis of bacteria-negative pulmonary tuberculosis (TB). Sixty patients diagnosed with bacteria-negative pulmonary TB at the Affiliated Hospital of Qinghai University between October 2019 and September 2022 were randomly selected as the case group, and seventy patients with nontuberculous pulmonary infection in the same department of the same hospital during the same period were randomly selected as the control group. Baseline data and values of erythrocyte sedimentation rate (ESR), lymphocyte count (LY), neutrophil count (NE), monocyte count (MO), albumin (ALB), prealbumin (PA), C-reactive protein (CRP), fibrinogen (FIB), neutrophil-to-lymphocyte ratio (NLR), PII, and SIRI were compared between the 2 groups. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic efficacy of PII and SIRI in the diagnosis of bacteria-negative pulmonary TB. No significant differences were found between the 2 groups in terms of sex and age (P > .05); however significant differences were observed in relation to body mass index (BMI), ESR, LY, NE, MO, ALB, PA, CRP, FIB, NLR, PII, and SIRI (P < .05). ROC curve analysis showed that area under curve (AUC) value {0.84 [95% CI (0.77, 0.90)]} and specificity {82.86% [95% CI (72.0, 90.8)]} of PII were the highest, while the sensitivity {86.67 [95% CI (75.4, 94.1)]} of NLR + PII was the highest. Pairwise comparison of the 7 indicators of ROC curve was performed, and only the diagnostic efficiency of NLR and NLR + PII was statistically significant (Z = 2.36, P = .02 < .05). NLR, PII, SIRI, pairwise combinations, and NLR + PII + SIRI showed auxiliary diagnostic values for bacteria-negative pulmonary TB, among which PII had the highest diagnostic value and specificity, while NLR + PII had the highest sensitivity.

Importance of Cytopathologic Diagnosis in Early Cancer Diagnosis in Resource-Constrained Countries

PURPOSE

The rising cancer burden in low- and middle-income countries (LMICs) stresses already weak health care systems and poses unique challenges. In resource-constrained LMICs and in circumstances where most patients must pay out of pocket for diagnostic tests, these may not be available or affordable for many. Cytopathology provides a simple, inexpensive, standardized, and low-technology diagnostic procedure that is increasingly used as an effective tool to address the hurdles faced in cancer control programs in LMICs. This review explores the potential role of cytopathology in LMICs in reducing the cancer burden.

METHODS

This review studied the existing literature across the globe regarding the utilization of cytopathology as a diagnostic or screening tool for various types of malignancies as well as its advantages and disadvantages, depending on the local situation.

RESULTS

Apart from the usefulness of cytopathology, this review also sheds light on the barriers to using cytopathology in LMICs. Most recently, SARS-CoV-2 has produced several unique challenges for cytopathology. These are being met with innovative measures to combat the effects of the pandemic and ensure the safe delivery of essential cytopathology services.

CONCLUSION

The usefulness of cytopathologic techniques has been demonstrated via various studies, even during the recent pandemic. If cytology is to be used appropriately, the focus needs to be on integrating it into the national cancer screening and diagnostic programs as well as providing well-trained human resources.

Spectrum of HIV-associated infectious diseases: A case series through the eyes of the histopathologist

Background

Human immunodeficiency virus (HIV) infection increases the risk of infection by a host of other opportunistic pathogens. The clinical presentations of these co-infections in immunocompromised patients are often atypical; therefore diagnosis is delayed in the absence of investigations such as tissue biopsy. Infection may involve sites that are difficult to access for biopsy and, as a consequence, there is limited diagnostic tissue available for analysis. The histopathologist, aided by ancillary tests, is relied upon to make a timeous and accurate diagnosis.

Objectives

To illustrate key histological features of HIV-associated infectious diseases encountered in a histopathology laboratory and to highlight, with the aid of literature, the relevance of histopathology in diagnosis.

Method

A retrospective descriptive case series of biopsies histologically diagnosed with HIV-associated infectious diseases over four years (2015–2019) was performed at the Chris Hani Baragwanath Academic Hospital National Health Laboratory Services Histopathology department. These cases have been photographed to illustrate microscopic aspects and will be accompanied by a literature review of opportunistic infections in the context of HIV infection.

Results

This article highlights aspects of fungal, parasitic, viral and selected bacterial infections of people living with HIV for whom the histopathological examination of tissue was an essential component of the clinical diagnosis. Histological features are noted on routine slides and accompanied by diagnostic features revealed with histochemical and immunohistochemical stains.

Conclusion

Medical practitioners working in areas of high HIV endemicity should be familiar with the variety of infectious diseases that are encountered and with the diagnostic importance of the histopathologist in clinical management.

Infectious disease diagnosed by fine needle aspiration biopsy

INTRODUCTION

Fine needle aspiration biopsies (FNABs) have become increasingly important in the assessment of infectious diseases. We assess the ability of cytopathology to predict the presence of a pathogen and review how often neoplasia occurs concurrently with infection.

MATERIALS AND METHODS

A 3-year retrospective review of FNABs with concurrent culture results was performed at the Zuckerberg San Francisco General Hospital and Trauma Center. Rapid onsite evaluation was performed for all cases by a pathologist. The results of the special and immunohistochemical stains and polymerase chain reaction testing were correlated, when available.

RESULTS

A total of 231 samples from 11 different tissue sites were submitted for microbial culture, of which 49 (21%) were positive for pathogenic organisms. Only 2 false-negative cases by cytology were found in immunosuppressed patients. A total of 38 patients had a diagnosis of neoplasia, with 2 (5%) having concurrent infection. Overall, the sensitivity and specificity of cytology in predicting the presence of infection was 96% (95% confidence interval, 86%-100%) and 42% (95% confidence interval, 34%-50%), respectively. Molecular testing was performed in 11 cases, 2 of which were positive for Mycobacterium tuberculosis complex and had cytologic findings of necrosis. Polymerase chain reaction and other ancillary tests were unable to further characterize 2 cases with acid-fast bacilli.

CONCLUSIONS

Our study has shown that FNABs have high sensitivity in detecting infection and that negative cytology findings will correlate with a negative infectious workup. Although infection in the setting of neoplasia is uncommon, it should be considered if clinical data are available to suggest infection.

Mycobacterium tuberculosis diagnosed promptly by bronchial brushing cytology in an immunocompetent patient

Respiratory cytology plays an important role in the diagnosis of lower respiratory tract infection. The timely diagnosis of pulmonary tuberculosis (TB) can be very challenging due to the nonspecific cytomorphologic features and limited number of organisms, especially in the immunocompetent patients. Here, we reported a case of TB diagnosed promptly by bronchial brushing cytology in a 51-year-old immunocompetent patient. She presented with a 4 cm fungating lesion involving right lower lobe of the lung and mediastinal lymphadenopathy with an initial concern for malignancy. Bronchial brushing showed scattered acute inflammatory cells in the background of necrosis. A cell block was prepared and acid-fast bacilli (AFB)-positive organisms were identified. Subsequent polymerase chain reaction (PCR) performed on the sputum detected Mycobacterium tuberculosis. This case highlights the importance of recognizing the cytomorphology of TB from a bronchial brushing specimen; and also emphasizes the potential utility of the cell block from respiratory cytology in the diagnosis of TB.

Granulomatous inflammation diagnosed by fine-needle aspiration biopsy

INTRODUCTION

Fine-needle aspiration biopsy (FNAB) is a minimally invasive biopsy technique and an important tool for diagnosing infectious diseases. Rapid onsite evaluation allows for triage for ancillary testing, including microbiologic cultures. We aimed to determine the etiology of granulomatous inflammation diagnosed by FNAB by correlating with culture results and clinical history.

MATERIALS AND METHODS

A 16-year retrospective review of cases diagnosed as "granulomatous inflammation" or "granuloma" was performed at the Departments of Pathology at the Zuckerberg San Francisco General Hospital and Trauma Center and University of California, San Francisco.

RESULTS

A total of 339 FNABs diagnosed as granulomatous inflammation were identified. Necrotizing granulomatous inflammation was present in 117 of 339 cases (34.5%) and non-necrotizing granulomatous inflammation was present in 222 of 339 cases (65.5%). A pathogen was detected in 100 of 339 (29.5%) FNABs by either cytomorphology, special stains, or culture, or a combination of more than one test. Of the 100 pathogen-positive cases, necrotizing granulomatous inflammation was seen in 50 of 100 (50%) and non-necrotizing granulomatous inflammation was identified in 50 of 100 (50%) cases. Culture results were available in 239 cases and positive in 70 (29%). Positive culture results included 40 of 239 (17%) cases with Mycobacterium tuberculosis complex, 15 of 239 (6.3%) with atypical mycobacterial species, 6 of 239 (3%) with Coccidioides immitis, 2 of 239 (<1%) with Histoplasma capsulatum, and 2 of 239 with Talaromyces marneffei (<1%).

CONCLUSIONS

Granulomatous inflammation is a nonspecific finding and suggests a broad range of disease processes, ranging from infection to malignancy. FNAB is an excellent minimally invasive technique that allows for ancillary testing critical for definitive diagnosis.

Needle Biopsy Adequacy in the Era of Precision Medicine and Value-Based Health Care

CONTEXT.—

Needle biopsy of diseased tissue is an essential diagnostic tool that is becoming even more important as precision medicine develops. However, the capability of this modality to efficiently provide samples adequate for diagnostic and prognostic analysis remains quite limited relative to current diagnostic needs. For physicians and patients, inadequate biopsy frequently leads to diagnostic delay, procedure duplication, or insufficient information about tumor biology leading to delay in treatment; for health systems, this results in substantial incremental costs and inefficient use of scarce specialized diagnostic resources.

OBJECTIVE.—

To review current needle biopsy technology, devices, and practice with a perspective to identify current limitations and opportunities for improvement in the context of advancing precision medicine.

DATA SOURCES.—

PubMed searches of fine-needle aspiration and core needle biopsy devices and similar technologies were made generally, by tissue site, and by adequacy as well as by health economics of these technologies.

CONCLUSIONS.—

Needle biopsy adequacy can be improved by recognizing the importance of this diagnostic tool by promoting common criteria for needle biopsy adequacy; by optimizing needle biopsy procedural technique, technologies, clinical practice, professional education, and quality assurance; and by bundling biopsy procedure costs with downstream diagnostic modalities to provide better accountability and incentives to improve the diagnostic process.

The Role of Ancillary Techniques in Pulmonary Cytopathology

Ancillary techniques play an essential role in pulmonary cytopathology. Immunoperoxidase and special stains are by far the most common ancillary techniques used in cytopathology; however, the role of molecular diagnosis is growing, especially in the fields of pulmonary oncology and infectious disease. In this article, we review the uses of ancillary techniques in lung tumor diagnosis, lung tumor classification, predictive marker determination, primary versus metastasis differential diagnosis, and infectious organism detection.

The cytopathology of Actinomyces, Nocardia, and their mimickers

Nocardia species and Actinomyces species are 2 of the most commonly diagnosed filamentous bacteria in routine cytopathology practice. These genera share many overlapping cytomorphologic features, including their thin, beaded, branching, Gram-positive, GMS-positive filamentous structures that fragment at their peripheries into bacillary- and coccoid-appearing forms. Features that help distinguish between these 2 microorganisms include the width of their filamentous structures, the angles at which they branch, and their ability or lack thereof to retain a modified acid-fast stain. In addition to cytomorphologic overlap, overlap in clinical presentation is frequent with pulmonary and mucocutaneous presentations seen in both. Differentiating between Nocardia and Actinomyces is essential because patients with these infections require different approaches to medical management. Both antibiotic susceptibilities and the need for early surgical intervention as part of the treatment plan vary greatly among these 2 groups. This review focuses on the clinical presentation, cytomorphology and staining characteristics that can be useful in identifying and distinguishing between Nocardia and Actinomyces infections, as well as their mimickers.

Role of fine needle aspiration biopsy cytology in the diagnosis of infections

The role of fine needle aspiration biopsy (FNAB) cytology in diagnosing infections has expanded due to the increase in the number of immune compromised patients and the increasing role of FNAB in the developing world where infection is a major cause of illness. FNAB has become the first procedural test in cases where the clinical and imaging findings suggest an infectious lesion or where there is a differential diagnosis of infection or metastatic or primary tumor. This applies to FNAB of palpable or image directed or deep seated lesions accessed by EUS and EBUS. This article details a recommended approach and technique for FNAB of infectious lesions, and discusses the role of rapid on site evaluation and the application of ancillary testing including the rapidly expanding array of molecular tests based on FNAB material. The utility of recognizing suppurative and granulomatous infectious patterns in FNAB direct smears, and the specific cytomorphological features on routine Papanicolaou and Giemsa stains and on special stains of FNAB smears is described for a large number of bacterial, fungal, viral, parasitic, and protozoan infections. The role of cytopathologists is to now train cytopathologists in sufficient numbers to provide FNAB services, teach trainee cytopathologists and cytotechnologists, and to encourage our clinical colleagues to use FNAB in the diagnosis of infections and other lesions to the benefit of patients and the medical system. Diagn. Cytopathol. 2016;44:1024-1038. © 2016 Wiley Periodicals, Inc.