Histoplasmosis: cytodiagnosis and review of literature with special emphasis on differential diagnosis on cytomorphology

The relevance of clinical and epidemiological correlation in the early diagnosis of histoplasmosis: report of two clinical cases in Popayán, Colombia

Histoplasmosis is an endemic mycosis in Colombia. Here we present two cases in the Cauca department, to indicate the clinical impact of histoplasmosis delayed diagnosis and treatment when its epidemiology is unknown. Informed consent was requested to review patients’ medical records and case report publication. The first case was a patient diagnosed with human immunodeficiency virus and generalized presence of skin lesions. Initially, these lesions were diagnosed as herpes, but a postmortem diagnosis confirmed histoplasmosis through fungal cultures of tissues from the skin lesions. The second case is an immunocompetent patient with pulmonary symptoms diagnosed and treated for tuberculosis. However, given the lack of improvement and considering the bat cave entrance history, the patient was treated for possible pulmonary histoplasmosis with an adequate response. We made a review of laboratory tests and histoplasmosis epidemiological data relevant to health professionals. We concluded that health institutions must provide rapid tests, such as antigen ones, to adequately diagnose and treat this mycosis; and also take corrective measures to minimize exposure to Histoplasma.

A Fatal Case of Disseminated Histoplasmosis by Histoplasma capsulatum var. capsulatum Misdiagnosed as Visceral Leishmaniasis-Molecular Diagnosis and Identification

Histoplasmosis is an endemic mycosis in the Americas. However, its diagnosis is challenging due to the complexity and limited availability of conventional laboratory techniques-antigen tests, culture, and staining. Microscopic preparations often confuse with other pathogens, such as Leishmania spp. The genus Histoplasma capsulatum comprises three varieties: var. capsulatum, var. duboissi, and var. farciminosum, which cannot be distinguished using conventional techniques. An infant from a tropical region of Ecuador was hospitalized for fever, bloody diarrhea, and anemia persisting for two months. Upon admission, he received antibiotics and immunosuppressants. Histopathological examination of the lymph nodes, intestines, and bone marrow aspirate reported the presence of Leishmania-like amastigotes, and treatment was initiated with meglumine antimoniate and conventional amphotericin B. However, subsequent analysis of samples using PCR and DNA sequencing identified H. capsulatum var. capsulatum but not Leishmania. Despite fluconazole and amphotericin B, the infant succumbed to the disease. The delay in clinical and laboratory diagnosis of histoplasmosis and the use of nonspecific and ineffective drugs such as fluconazole led to disease dissemination and, ultimately, death. Implementing molecular diagnosis and antigen tests in laboratories located in endemic regions and reference hospitals is crucial.

Histoplasmosis

Histoplasmosis is one of the commonest endemic mycoses in the Americas yet is often underdiagnosed and neglected as a public health priority. This review outlines the evolving understanding of its epidemiology and the clinical syndromes of histoplasmosis, in addition to up-to-date diagnostic and treatment guidelines. A focus on histoplasmosis in advanced HIV is included. The challenges pertinent to histoplasmosis management in Latin America, with recommendations made through international expert consensus are discussed.

Johnson E, Littlechild J, Winlove CP, Vollmer F, Gow NAR. Biosensors and Diagnostics for Fungal Detection

Early detection is critical to the successful treatment of life-threatening infections caused by fungal pathogens, as late diagnosis of systemic infection almost always equates with a poor prognosis. The field of fungal diagnostics has some tests that are relatively simple, rapid to perform and are potentially suitable at the point of care. However, there are also more complex high-technology methodologies that offer new opportunities regarding the scale and precision of fungal diagnosis, but may be more limited in their portability and affordability. Future developments in this field are increasingly incorporating new technologies provided by the use of new format biosensors. This overview provides a critical review of current fungal diagnostics and the development of new biophysical technologies that are being applied for selective new sensitive fungal biosensors to augment traditional diagnostic methodologies.

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.

Cutaneous Histoplasmosis: An Unusual Presentation with Nasal Obstruction

Histoplasmosis is a systemic fungal disease that may be presented with a variety of clinical manifestations, usually as an opportunistic infection in immunocompromised individuals. We present an HIV seropositive patient with a large fleshy growth causing left-sided nasal obstruction, as an unusual presentation. The lesions shrunk dramatically and almost completely on intravenous amphotericin-B lipid complex (ABLC) given for 2 weeks followed by long-term oral itraconazole.

Disseminated Histoplasmosis as AIDS-presentation. Case Report and Comprehensive Review of Current Literature

Progressive disseminated histoplasmosis (PDH) is an AIDS-defining illness with a high lethality rate if not promptly treated. The wide range of its possible clinical manifestations represents the main barrier to diagnosis in non-endemic countries. Here we present a case of PDH with haemophagocytic syndrome in a newly diagnosed HIV patient and a comprehensive review of disseminated histoplasmosis focused on epidemiology, clinical features, diagnostic tools and treatment options in HIV-infected patients.

Urinary tract blastomycosis diagnosed by urine cytology

Urinary tract blastomycosis is an uncommon manifestation of disseminated Blastomyces infection. Here, we report a 50-year-old male with common variable immunodeficiency who presented with urinary symptoms and a renal mass concerning for a kidney neoplasm. Urine cytology revealed typical broad-based budding yeasts with thick-walled refractile capsules, leading to diagnosis of urinary tract blastomycosis. In this case, urine cultures were negative, and urine cytology was the main method of diagnosis of blastomycosis. Thus, urine cytology represents a rapid and reliable method of diagnosing blastomycosis, which in the current case led to prompt treatment of this potentially life threatening infection.

Challenges in the Diagnosis of Invasive Fungal Infections in Immunocompromised Hosts

Purpose of review

The expanding population of immunocompromised patients coupled with the recognition of a growing number of different species of fungi responsible for diseases in such hosts makes the diagnosis of invasive fungal infection (IFI) a challenging task. The recent advances and challenges in the diagnosis of IFI in the setting of immunocompromised hosts are reviewed. The advantages and limitations of histopathology and the role of culture-independent methods, such as those based on the use of nucleic acids applied to fresh and formalin-fixed, paraffin-embedded sections, besides culture- and non-culture-based diagnostic methods, to obtain a timely and correct diagnosis of IFI are highlighted.

Recent findings

The therapeutic implications of identifying the genus and species of the fungus present in the specimen with the molecular diagnostics applied to tissue specimens are reviewed. No method alone is efficient in correctly identifying fungi and it is essential to combine the traditional histochemical staining with molecular methods to achieve a rapid and genus-/species-specific diagnosis of IFI.

Summary

We review the recent findings and challenges in the hystopathologic diagnosis of IFI in the setting of immunocompromised hosts. Non method alone is efficient in correctly identify fungi and pathologists should combine classic staining with molecular methods to achieve a rapid and genus/species fungal diagnosis.

A Twenty-First-Century Perspective of Disseminated Histoplasmosis in India: Literature Review and Retrospective Analysis of Published and Unpublished Cases at a Tertiary Care Hospital in North India

PURPOSE

Published literature lacks systematic studies on disseminated histoplasmosis in India, and previous reviews on its epidemiology in India were conducted two decades back. Thus, we review the Indian studies published in this century to understand the recent epidemiology of histoplasmosis in India and do a retrospective analysis of all cases diagnosed at our institute.

METHODS

A literature of review search was done in Pubmed/Medline and Scopus. Studies published during January 2001-December 2015 were considered along with retrospective analysis of cases presented to us. A distinction was made in the clinical presentation of immunocompetent and immunocompromised cases.

RESULTS

Ninety-five included studies described 204 cases, and 10 cases from our retrospective analysis were included. The mean age at presentation was 45.1 ± 15.4 years [range 3-83, median 45, interquartile range 37-55], and male-to-female ratio was 6:1. Most cases were reported from northern and northeastern states of India along the rivers Ganges, Yamuna and Brahmaputra and in people associated with agricultural activity. About 33% of cases were immunocompromised, out of which immunosuppression due to HIV was seen in 72% cases. The mean age of presentation was significantly lower in immunocompromised cases (37.9 vs. 49.2 years; p < 0.00001, Mann-Whitney test), and mortality was also higher (10 vs. 27.5%, p = 0.01, Fisher's exact test). Adrenal involvement was in significantly higher proportion of immunocompetent patients compared to immunocompromised population.

CONCLUSIONS

Disseminated histoplasmosis is being increasingly recognized in India. There is a need to undertake well-designed, analytical studies utilizing appropriate diagnostic modalities to understand the epidemiology of this neglected disease in proper perspective.

Clinical Perspectives in the Diagnosis and Management of Histoplasmosis

With increasing numbers of travelers and immunocompromised patients, histoplasmosis, caused by the dimorphic fungus Histoplasma capsulatum, has become a disease of national extent. The clinical spectrum of histoplasmosis is very wide, in terms of disease cadence, onset, distribution, and severity. A multipronged approach is recommended for diagnosis. Manifestations that are always treated include moderate to severe acute pulmonary histoplasmosis, disseminated disease, and histoplasmosis in immunocompromised individuals. Amphotericin B is the drug of choice for moderate to severe and disseminated presentations, whereas itraconazole is appropriate for mild disease and as step-down therapy.

Human immunodeficiency virus and fungal infections

The discovery of HIV was largely due to the presence of Pneumocystis pneumonia (PCP) in young patients that did not have the usual known causes of immune deficiencies in the early 1980s. Currently, treatment with highly active anti-retroviral therapy (HAART) and the use of prophylaxis for PCP have lowered the frequency of fungal infections; however, these infections continue to cause morbidity and mortality in those patients that fall out or are not in care. The frequency of specific fungal diseases in HIV patients will depend on the prevalence of fungi in the particular geographic location. Nowadays, superficial and invasive Candida infections, PCP, and cryptococci are the most frequent fungal infections seen in HIV positive patients worldwide. The role of pathology in diagnosing fungal infections is crucial because a lesion may be biopsied without obtaining mycology cultures, certain organisms may take several weeks to grow, or the sample sent to the mycology laboratory may not have the organism. Following we will describe fungal infections that are particularly frequent in HIV infected patients and their key pathological features.

Laboratory Diagnostics for Histoplasmosis

The diagnosis of histoplasmosis is based on a multifaceted approach that includes clinical, radiographic, and laboratory evidence of disease. The gold standards for laboratory diagnosis include demonstration of yeast on pathological examination of tissue and isolation of the mold in the culture of clinical specimens; however, antigen detection has provided a rapid, noninvasive, and highly sensitive method for diagnosis and is a useful marker of treatment response. Molecular methods with improved sensitivity on clinical specimens are being developed but are not yet ready for widespread clinical use. This review synthesizes currently available laboratory diagnostics for histoplasmosis, with an emphasis on complexities of testing and performance in various clinical contexts.

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.

Cytodiagnosis of disseminated histoplasmosis in an immunocompetent individual with molluscum contagiosum-like skin lesions and lymphadenopathy

Disseminated histoplasmosis is caused by the dimorphic fungus Histoplasma capsulatum (H. capsulatum). The early clinical manifestations are nonspecific, often lead to diagnostic difficulty, and is misdiagnosed as tuberculosis and seen usually in immunosuppressed states. Fine needle aspiration cytology (FNAC) is a simple, safe, and quick technique to establish the initial diagnosis of H. capsulatum, thereby prompting early treatment. The skin involvement is rare in disseminated disease and we describe a case of disseminated histoplasmosis in an immunocompetent patient with unusual molluscum contagiosum like umbilicated skin lesions and FNAC of the cervical lymph node was the only tool for rapid and early confirmatory diagnosis.

Cutaneous Manifestation of Underlying Disseminated Histoplasmosis in an Immunocompetent Host of Nonendemic Area with Reversible CD4 Cell Depletion and its Recovery on Antifungal Therapy

We present the case of an 18-year-old male patient admitted with complaints of fever and rapid weight loss since 3 months. Patient had multiple umbilicated papular to nodular lesions over chin and forehead region. Complete blood count revealed bicytopenia. An excisional biopsy of the skin lesions had revealed cutaneous histoplasmosis. On further investigations for bicytopenia, histoplasmosis had been diagnosed on bone marrow trephine biopsy. For the immune status, patient's serology against HIV was negative and his CD4 lymphocyte counts were low at 161. Patient received antifungal therapy including amphotericin B and itraconazole. He showed remarkable improvement in his general condition and blood counts. A repeat CD4 count showed normal counts, and idiopathic CD4 lymphocytopenia was excluded. Disseminated histoplasmosis presenting as cutaneous lesions in an immunocompetent host is very rare, and we are not aware of any case report in the literature where there is reversible depletion of CD4 counts following antifungal treatment in an immunocompetent host of nonendemic area.

Differentiation of histoplasma and cryptococcus in cytology smears: a diagnostic dilemma in severely necrotic cases

OBJECTIVE

The correct identification of fungal organisms is important for the appropriate clinical management of patients. It becomes difficult in necrotic smears when the tissue response is not clearly discernible. It is difficult to distinguish between histoplasma and cryptococcus in severely necrotic cases, where both appear as variably sized clear refractile haloes.

METHODS

Four cases of adrenal necrotic histoplasma infection were studied and the morphology was compared with that of non-necrotic histoplasmosis and cases of cryptococcal infection. Eleven cases were analysed in fine needle aspiration cytology (FNAC) smears. Ziehl-Neelsen (ZN) stain was performed to exclude tuberculosis in necrotic smears. A clinical and serology correlation was performed where available.

RESULTS

Necrotic cases of histoplasma infection revealed negative refractile clear haloes similar to those of cryptococcus. Histoplasma showed methylene blue-stained organisms in ZN stains, whereas the cryptococcus cases were negative. Similar methylene blue-stained organisms were seen in non-necrotic histoplasma infection.

CONCLUSION

As a result of morphological overlap between cryptococcus and histoplasma, the distinction between the two fungi can be difficult in many cases. ZN staining appears to have a role in the differentiation of these fungi in severely necrotic cases. This observation needs to be validated on a larger number of cases with complete correlation with clinical, serology and treatment records.

Tularemia in differential diagnosis of cervical lymphadenopathy: cytologic features of tularemia lymphadenitis

OBJECTIVE

Tularemia can cause cervical lymphadenopathy. Fine-needle aspiration (FNA) cytology is the first step in the workup for cervical lymphadenopathy; however, little has been published regarding the cytomorphological features of tularemia lymphadenitis. The aim of this study was to evaluate the FNA cytology of tularemia lymphadenitis.

STUDY DESIGN

Review of medical records identified 36 patients with serologically proven tularemia, and who had undergone lymph node FNA. In each case, the original May-Grünwald-Giemsa-stained FNA smears from enlarged cervical lymph node were reevaluated.

RESULTS

Suppuration and cytolysis were frequent cytological findings. Twenty-three (63.8%) of the 36 cases were assessed as suppurative inflammation. In 10 of these cases (27.8% of the total), cytolysis was prominent. In 7 cases (19.4%) the smears featured microgranulomas as well as suppuration, and 2 of these (5.6%) also featured giant cells. In 1 case (2.8%), there was caseous necrosis. In 2 cases (5.6%), the cytopathological findings were consistent with reactive lymphoid hyperplasia. Three aspirates (8.3%) were inadequate for evaluation.

CONCLUSION

Cytopathological findings on FNA of tularemia lymphadenitis are nonspecific; however, in regions where tularemia is endemic, this disease should be considered in the differential diagnosis for suppurative lymphadenitis.

Histoplasmosis presenting as bilateral adrenal masses: cytomorphological diagnosis of three cases

Histoplasmosis is a worldwide infectious disease caused by inhalation of spores of a fungus, called Histoplasma capsulatum.Adrenals can be involved as a part of disseminated infection in immunocompromized patients. However, histoplasmosis presenting primarily as a bilateral adrenal masses in an immunocompetent patient is very unusual and rare. We encountered three such cases in which fine-needle aspiration (FNA) performed under ultrasonographic (USG) guidance from bilateral adrenal masses primarily established the diagnosis. This report emphasizes the importance of considering localized fungal infection as differential diagnoses of mass lesions involving bilateral adrenals even if the patients are immunocompetent, along with the commoner lesions at these sites.

Histopathologic diagnosis of fungal infections in the 21st century

Fungal infections are becoming more frequent because of expansion of at-risk populations and the use of treatment modalities that permit longer survival of these patients. Because histopathologic examination of tissues detects fungal invasion of tissues and vessels as well as the host reaction to the fungus, it is and will remain an important tool to define the diagnostic significance of positive culture isolates or results from PCR testing. However, there are very few instances where the morphological characteristics of fungi are specific. Therefore, histopathologic diagnosis should be primarily descriptive of the fungus and should include the presence or absence of tissue invasion and the host reaction to the infection. The pathology report should also include a comment stating the most frequent fungi associated with that morphology as well as other possible fungi and parasites that should be considered in the differential diagnosis. Alternate techniques have been used to determine the specific agent present in the histopathologic specimen, including immunohistochemistry, in situ hybridization, and PCR. In addition, techniques such as laser microdissection will be useful to detect the now more frequently recognized dual fungal infections and the local environment in which this phenomenon occurs.

Microbiology

In order to render an accurate diagnosis, and correctly identify clinically important microorganisms, a good understanding and knowledge of microbiology is essential. This chapter provides a broad overview of microbiology that is relevant to the practicing cytologist. Virology addresses the cytopathic effects caused by viruses and discusses many key infections. Bacteriology covers important bacterial causes of infection including those due to mycobacteria and filamentous bacteria. Mycology deals with common fungi as well as deep mycoses, particularly those caused by invasive and dimorphic fungal organisms. Parasitology highlights the protozoa, apicomplexans, and helminths likely to be seen in cytology samples. Algae are also briefly mentioned.

Use of oral erythromycin for the treatment of gastrointestinal dysmotility in preterm infants

Milk intolerance due to functional gastrointestinal (GI) dysmotility is a common problem in preterm infants. In the past decade, erythromycin has been used for its motilinomimetric effect to facilitate enteral feeding in preterm infants. Although earlier studies suggested that erythromycin is an effective prokinetic agent, recent randomized control trials (RCTs) reveal conflicting findings. This review assesses the evidence from all RCTs performed to date on erythromycin for preterm infants. The results suggest that oral erythromycin administered in intermediate or high doses as a rescue treatment is associated with a shorter time to attain full enteral feeding and decrease in the duration of requirement for parenteral nutrition. More importantly, the outcome study further indicates that oral erythromycin can reduce the incidence of parenteral nutrition-associated cholestasis by almost 50% and decreases the incidence of recurrent septicemia. None of the RCTs reported any sinister adverse effects, in particular, hypertrophic infantile pyloric stenosis or fatal cardiac arrhythmia. Nonetheless, as long-term outcomes have not been fully evaluated, neonatologists should use this treatment cautiously and selectively in preterm infants with moderately severe GI dysmotility.