Fine-needle aspiration of histoplasmosis in the era of endoscopic ultrasound and endobronchial ultrasound

Development of an Interferon-Gamma Release Assay (IGRA) to Aid Diagnosis of Histoplasmosis

Establishing diagnosis of latent and active histoplasmosis is challenging. Interferon gamma-release assays (IGRAs) may provide evidence of latent and active infection. An enzyme-linked immunospot (ELISpot) assay was developed using yeast cell lysate (YCL) antigen prepared from a representative North American Histoplasma capsulatum strain. Assay parameters were optimized by measuring responses in healthy volunteers with and without Histoplasma infection. Assay performance as an aid for diagnosing histoplasmosis was assessed in a prospective cohort of 88 people with suspected or confirmed infection, and 44 healthy controls enrolled in two centers in North America (2013 to 2018). Antigen specificity of IFN-γ release was demonstrated using ELISpot and enzyme-linked immunosorbent assay (ELISA). Antigen-evoked, single-cell mRNA expression by memory T cells was shown using flow cytometry. The area under the receiver operating characteristic curve (AUC) was estimated at 0.89 (95% confidence interval [CI]: 78.5% to 99.9%). At optimal cutoff, sensitivity was 77.2% (95% CI: 54.6% to 92.2%) and specificity was 100% (95% CI: 89.7% to 100%). Sixteen of 44 healthy volunteers (36.4%) from a region of hyperendemicity had positive responses, suggesting detection of previously unrecognized (latent) infection. The ELISpot assay is sensitive and specific as an aid to diagnose H. capsulatum infection and disease, supporting proof of concept and further development.

Causes of necrotic features in fine-needle aspirates from cervical lymph nodes

BACKGROUND

Lymph node fine-needle aspiration (LN FNA) cytology indicates necrosis in various diseases. Dominant necrotic features make the diagnosis of underlying conditions very difficult.

METHODS

We retrospectively reviewed 460 patients who underwent cervical LN aspiration cytology that revealed necrotic findings at Keimyung University Dongsan Hospital in Daegu, Korea, from 2003-2017. Each specimen was evaluated and analyzed in association with the clinical findings, biopsy findings, and/or other ancillary tests, including acid-fast bacilli staining and molecular testing for Mycobacterium tuberculosis.

RESULTS

When necrotic features were noted upon cervical LN FNA cytology, the most common pathologic LN FNA category was necrosis alone (31.5%). The second most common category was granulomatous inflammation (31.3%), followed by Kikuchi disease (20.0%) and malignant neoplasm (8.7%). In cases where the cervical LN FNA revealed necrosis alone, the most common final diagnosis was tuberculosis. In young patients, Kikuchi disease should be considered as one cervical LN FNA category, while metastatic carcinoma should be suspected in older patients.

CONCLUSIONS

Even when necrosis alone is observed in LN FNA cytology, it is important to determine the cause through further evaluation.

Clinical and Morphological Spectrum of Histoplasmosis on Cytology Along with the Review of Literature

OBJECTIVE

The aim of the study was to study the clinical and morphological spectrum of histoplasmosis diagnosed by fine needle aspiration cytology (FNAC).

STUDY DESIGN

A total of 17 patients diagnosed with histoplasmosis on FNAC were studied over a period of 5 years. The cytology smears were studied and analysed for the cytomorphological spectrum of histoplasmosis.

RESULTS

Among the 17 patients studied, the mean age was 51.3 years (range 6-84 years). Male-to-female ratio was 3.25:1 with 4 females and 13 males. The frequent sites of involvement were the lung (5), lymph node (4), adrenal gland (4), and skin (4). The most common cytological patterns were histiocytic collection, followed by granulomas and multinucleated giant cells. Necrosis was noted in only 4 cases.

CONCLUSION

Fine needle aspiration is a highly accurate, rapid, and cheap technique for the diagnosis of histoplasmosis due to its distinct morphological features.

Role of fine-needle aspiration cytology in diagnosis of disseminated histoplasmosis in an immunocompetent patient: A case report

Histoplasmosis is a mycotic infection caused by dimorphic fungus, Histoplasma capsulatum. The organisms are usually found within the cells (macrophages). This organism mostly affects lungs in immunocompetent individuals and disseminated forms are seen in immunocompromised cases. Here, we describe a case of disseminated histoplasmosis in an immunocompetent, 35-year-old female with lymphadenopathy diagnosed by fine-needle aspiration cytology and cell block.

Usefulness of lymphoid granulomatous inflammation culture obtained by endobronchial ultrasound-guided transbronchial needle aspiration in a fungal endemic area

Background and Objectives:

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is the procedure of choice for the evaluation of mediastinal/hilar lymph node enlargements. Granulomatous inflammation of the mediastinal/hilar lymph nodes is often identified on routine histology. In addition, mediastinal lymphadenopathy may be present with undiagnosed infection. We sought to determine the usefulness of routine cultures and histology for infectious etiologies in a fungal endemic area when granulomatous inflammation is identified.

Materials and Methods:

We identified 56 of 210 patients with granulomatous inflammation on EBUS-TBNA biopsies from October 2012 through October 2014. An onsite cytologist evaluated all biopsies and an additional TBNA pass for microbiologic stains and cultures were obtained in those with granulomatous inflammation.

Results:

Of the 56 patients with granulomatous inflammation, 20 patients had caseating (necrotizing) granulomas while noncaseating (nonnecrotizing) granulomas were detected in 36 of the remainder patients. In patients with caseating granulomas, fungal elements were identified in 6 of 20 (30%) patients (histoplasma; N = 5, blastomyces; N = 1) on Grocott methenamine silver (GMS) stain. Lymph node cultures identified 3 of 20 (20%) patients as being positive for Mycobacterium tuberculosis (N = 1), Histoplasma capsulatum (N = 1), and Blastomyces dermatitidis (N = 1). Among patients with noncaseating granulomas, only 2 out of 36 (5%) were positive for fungal elements on GMS stain, identified as Histoplasma, although the lymph node cultures remained negative.

Conclusion:

The incidence of granulomatous inflammation of mediastinal lymph nodes was 26.6% in our series. Of these patients, noncaseating granulomas were more common (64% vs. 36%). Infectious organisms, fungal or acid-fast bacilli (AFB), on either staining or lymph node culture were rarely identified in noncaseating granulomas, 5% and none, respectively. Caseating granulomas were more commonly associated with positive lymph node fungal stain and culture, 35% and 15%, respectively. In a fungal endemic area, lymph node staining and culture can be considered in cases with caseating granulomatous inflammation, if known at the time of biopsy.

DISSEMINATED FUNGAL INFECTION WITH ADRENAL INVOLVEMENT: REPORT OF TWO HIV NEGATIVE BRAZILIAN PATIENTS

Paracoccidioidomycosis and histoplasmosis are systemic fungal infections endemic in Brazil. Disseminated clinical forms are uncommon in immunocompetent individuals. We describe two HIV-negative patients with disseminated fungal infections, paracoccidioidomycosis and histoplasmosis, who were diagnosed by biopsies of suprarenal lesions. Both were treated for a prolonged period with oral antifungal agents, and both showed favorable outcomes.

Utility of microbiological testing of thoracic lymph nodes sampled by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in patients with mediastinal lymphadenopathy

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) represents a minimally invasive technique to sample peribronchial and mediastinal lymph nodes for diagnosis of cancer, lymphoma, or sarcoidosis. However, the value of EBUS-TBNA in diagnosis of respiratory infections has not been well explored. Here, microbiologic testing data for EBUS-TBNA samples collected from 82 patients over a 30-month period were retrospectively reviewed. No organisms were identified on Gram, acid-fast, or fungal stains. Bacterial cultures were positive in 52% of samples; however, all but 1 culture were considered contaminants. Mycobacterial cultures yielded Mycobacterium avium-intracellulare not identified in a concurrent bronchoalveolar lavage sample in 1 patient. Fungal cultures were negative. Overall, routine microbiologic tests on EBUS-TBNA samples do not appear sufficiently sensitive to rule out infectious causes of adenopathy. High clinical suspicion for infection may require modification of sampling techniques or more sensitive detection methods.

A cytomorphometric analysis of pulmonary and mediastinal granulomas: differentiating histoplasmosis from sarcoidosis by fine-needle aspiration

BACKGROUND

Histoplasmosis and sarcoidosis are commonly included in the differential diagnosis of mass lesions at lung and mediastinal sites. Once cancer is excluded on aspiration biopsy, further classification is essential for proper treatment.

METHODS

A search identified patients with histoplasmosis and sarcoidosis for whom the diagnosis was made by clinicopathologic correlation. Cases were reviewed for various cytologic parameters along with patient demographic, clinical, and laboratory data.

RESULTS

Fifty-eight cases of histoplasmosis and 44 cases of sarcoidosis were reviewed. Thirty-seven of 58 (64%) Histoplasma cases exhibited abundant, bland necrosis, and 76% of cases contained <2 angular and ragged granulomas per slide. Yeasts were identified in 36 of 37 (97%) specimens with necrosis and in 44 of 58 (76%) cases overall. These cases had an acute (14%) and/or chronic (67%) inflammatory component and uncommonly had a giant cell infiltrate (12%). Sarcoid granulomas were round with crisp, sharp borders: 80% of these granulomas contained >3 granulomas per slide, and 32% contained >10 granulomas per slide. All sarcoid granulomas had a chronic inflammatory background without acute inflammatory cells, and 50% contained giant cell infiltrates.

CONCLUSIONS

Differentiation between histoplasmosis and sarcoidosis is possible in the majority of cases. Histoplasmosis usually exhibits few angular, ragged granulomas (<2 granulomas per slide) in a background of bland necrosis. Yeasts are identified on special stains performed in aspirate smears. Sarcoidosis typically contains many more granulomas (often >10 per slide) than histoplasmosis and has a rounded morphology with crisp and sharp borders. Typically, there is no necrosis or acute inflammation, and giant cell infiltrates are frequent.