Fine-Needle Aspiration and Surgical Pathology of Infectious Lesions: Morphologic Features and the Role of the Clinical Microbiology Laboratory for Rapid Diagnosis

Lung Infections

A review of pulmonary infections of all types with diagnostic and morphological features.

Correlation of microbiologic culture and fine-needle aspiration cytology: A 14-year experience at a single institution

BACKGROUND

Fine-needle aspiration (FNA) is an important tool for the diagnosis of infectious disease. FNA material should be appropriately submitted for cultures when indicated by preliminary findings. Correlation of cytologic diagnoses with culture results are important quality assurance tools. The current study reviewed 14 years of FNA-culture correlation.

METHODS

FNA cytology-culture correlation records from the years 1996 through 2007 and 2010 through 2011 were retrieved from electronic databases compiled for histology and culture correlation. Correlation was limited to those cases for which material was submitted for culture from the FNA sample. Culture results were retrieved from the laboratory or hospital information system.

RESULTS

Correlative data included 770 cases. Cytology, culture, or both were positive for microbes in 416 of 770 samples (54%), excluding cultured bacterial skin contaminants. Among the 204 bacteria cases, 93 (46%) were identified by cytology and culture, 92 (45%) were identified by culture only, and 19 (9%) were identified by cytology only. Among the 16 cases of Actinomycetales, 8 (50%) were identified by cytology and culture, 5 (31%) were identified by culture only, and 3 (19%) were identified by cytology only. Of the 129 cases of mycobacteria, 63 (49%) were identified by cytology and culture, 44 (34%) were identified by culture only, and 22 (17%) were identified by cytology only. Among the 67 cases of fungi, 34 (51%) were identified by cytology only, with 15 of these 34 cases being fungal hyphae; 25 cases (37%) were identified by cytology and culture, with a 100% concordance between the cytology diagnosis and culture result; and 8 cases (12%) were identified by culture only.

CONCLUSIONS

FNA cytology-culture correlation is a valuable tool with which to assess the efficacy and limitations of the direct diagnosis of infectious agents, and to identify types of infections that may be negative on culture but positive on cytology diagnosis.

Fine-needle aspiration may replace skin biopsy for the collection of material for experimental infection of mice with Mycobacterium leprae and Lacazia loboi

BACKGROUND

Procedures involving the use of Mycobacterium leprae and Lacazia loboi, uncultivated organisms, depend on the collection of material from the lesions of patients or experimental animals. This study compared fine-needle aspiration (FNA) and skin biopsy methods for obtaining bacilli and fungal cells to experimentally infect animals.

METHODS

Lepromas from one armadillo and one enlarged footpad of a mouse previously inoculated with L. loboi were submitted to FNA and biopsy. Materials collected were processed for inoculation in mice.

RESULTS

Acid-fast bacilli (AFB) collected by two FNA procedures yielded 7.2×10(7) and 5.3×10(6) AFB/ml and biopsies yielded 1.58×10(8) and 3.5×10(8) AFB/ml from each leproma. Yeast-like cells of L. loboi collected by FNA yielded 1.0×10(6) fungal cells/ml and biopsy 1.0×10(7) fungal cells/ml. After 8 months, inoculated animals were sacrificed and the inoculated footpads submitted to histopathological examination and counting of AFB and fungal cells. The results obtained by the two methods were comparable for both microorganisms.

CONCLUSIONS

Biopsy may be replaced by FNA during harvesting of material for different purposes, especially for experimental inoculation of mice in leprosy and Jorge Lobo's disease, with the advantage of FNA being a simpler, less invasive, and less costly method.

An imprint method for detecting leptospires in the hamster model of vaccine-mediated immunity for leptospirosis

In determining the efficacy of new vaccine candidates for leptospirosis, the primary end point is death and an important secondary end point is sterilizing immunity. However, evaluation of this end point is often hampered by the time-consuming demands and complexity of methods such as culture isolation (CI). In this study, we evaluated the use of an imprint (or touch preparation) method (IM) in detecting the presence of leptospires in tissues of hamsters infected with Leptospira interrogans serovar Copenhageni. In a dissemination study, compared to CI, the IM led to equal or improved detection of leptospires in kidney, liver, lung and blood samples collected post-infection and overall concordance was good (kappa=0.61). Furthermore, in an evaluation of hamsters immunized with a recombinant leptospiral protein-based vaccine candidate and subsequently challenged, the agreement between the CI and IM was very good (kappa=0.84). These findings indicate that the IM is a rapid method for the direct observation of Leptospira spp. that can be readily applied to evaluating infection in experimental animals and determining sterilizing immunity when screening potential vaccine candidates.

Fine-needle aspiration biopsy of disseminated sporotrichosis: a case report

In this report, we describe a case of disseminated sporotrichosis that was diagnosed by fine-needle aspiration biopsy (FNAB). The cytologic smears exhibited a large number of macrophages, few polymorphonuclear neutrophils and numerous round or oval, sometimes elongated, isolated and scattered yeast-like structures localized extracellularly or inside macrophages. These structures were clearly visualized by Giemsa and Papanicolaou methods. Cultures from skin biopsy material revealed fungal colonies which were subsequently identified as Sporothrix schenckii. The cytologic aspects, the correlation with histologic findings and the differential cytologic diagnosis were reviewed.

Diagnostic value and cost-effectiveness of on-site evaluation of fine-needle aspiration specimens: review of 5,688 cases

Fine-needle aspiration (FNA) has proven to be a safe, economical, accurate, and rapid diagnostic technique. A successful FNA requires a specimen with adequate cellularity, high-quality preparation, an experienced aspirator, and cytopathologist. Up to 32% of FNAs in various organs (thyroid, breast, lung, etc.) may be nondiagnostic due to scant cellularity and poor preparation. On-site immediate evaluation of FNA specimens can be beneficial in determination of adequacy: triage for ancillary studies and provide a preliminary diagnosis of the specimen, which often facilitates rapid clinical decisions. In this study, we compared the on-site FNA interpretation with the final diagnosis and calculated its cost benefit. Reports of 5,688 on-site FNA cases from the files of the University of Pennsylvania Medical Center over a 5-yr period (1/1/96-12/31/00) were reviewed. Data of the immediate on-site interpretation and the final diagnosis in each case were compared to determine the diagnostic accuracy, clinical utility, and cost-effectiveness of on-site FNA evaluation. At our institution the average cost per FNA based on laboratory technical and professional fees (1,743 dollars) and the weighted average cost, based on utilization, of ancillary laboratory studies (328 dollars) and guidance procedures (1,025 dollars) is 3,096 dollars. An additional fee of 231 dollars per case is charged for on-site FNA evaluation by an attending cytopathologist. The average reported rate of nondiagnostic FNAs without on-site evaluation is 20%. Our own nondiagnostic rate for FNAs with on-site evaluation is 0.98%. If one assumes that patients will undergo a repeat FNA for each nondiagnostic specimen, the estimated additional cost in direct institutional charges is 2,022,626 dollars over 5 yr or 404,525 dollars per yr without on-site evaluation. This potential cost savings would be realized by utilizing on-site evaluation despite the additional fee due to a higher rate of specimen adequacy. Based on this study, on-site cytopathologic evaluation of FNA specimens is accurate, cost-effective, and has improved patient care at our institution.

Infectious disease pathology

The anatomic pathologist performs an important role in the diagnosis or exclusion of infectious diseases. The morphologic interpretation of biopsies and cytologic preparations allows for the definitive establishment or exclusion of a wide variety of diseases. Once the pathologist has determined that a disease is likely to be due to an infection and has characterized the inflammatory response, associated microorganisms or viral-associated cytopathic effects should be recorded. Although some microorganisms or their cytopathic effects may be clearly visible on routine hematoxylin and eosin-stained sections, additional histochemical stains are often needed for their complete characterization. Highly specific molecular techniques, such as immunohistochemistry, in situ hybridization, and nucleic acid amplification, may be needed in certain instances to establish the diagnosis of infection. Through appropriate morphologic diagnoses and interlaboratory communication and collaboration, the anatomic pathologist contributes greatly to the diagnosis and treatment of infectious diseases.

Fine needle aspiration (FNA) in HIV+ patients: results from a series of 655 aspirates

There are many selected small series or case reports of FNAs in patients with HIV infection, but large series are rare and epidemic's characteristics have evolved over time. The current study, from a large public hospital in the USA, included women as well as men, hetero- and homosexuals, in-patients and out-patients, and deep radiologically guided aspirates as well as superficial masses. Of 655 FNAs, reactive or benign changes were present in 37% confirmed or suspected malignancy in 13%, specific infection with stainable organisms in 14%, and inflammation in 16%. Twenty percent of cases were inadequate for diagnosis. Most of the identifiable infections were associated with Mycobacterium tuberculosis, with fewer atypical mycobacteria, fungi and other bacteria. Clinically significant diagnoses were correlated with deep aspirate location and lesion size > 2 cm, confirming other studies which also identified tenderness and recent enlargement as important indicators. The liberal use of FNA in our HIV+ population has greatly reduced the necessity for surgical nodal resection, reassured clinicians in continuing observation of reactive lymphadenopathy, and allowed immediate therapy for specific infection, cyst or malignancy.