Retrospective review of immunocompromised children undergoing skin biopsy for suspected invasive infection: Analysis of factors predictive of invasive mold

Skin Biopsy in Pediatric Oncology/Hematopoietic Stem Cell Transplantation Patients

ABSTRACT

The aim of this study was to review the dermatopathological findings in skin biopsy specimens from pediatric oncology and hematopoietic stem cell transplantation patients over a 20-year period. Three hundred fifty-two skin biopsies from 240 patients were reviewed, and the findings were grouped into 6 categories: index neoplasms, nonindex neoplasms, infections, graft-versus-host disease, other treatment complications, and others. Among the index neoplasms identified on skin biopsy, the most common conditions were Langerhans cell histiocytosis (14 patients) and melanoma (7 patients), with other hematological malignancies and an array of soft-tissue tumors accounting for the bulk of the remainder. Neoplastic conditions common in general dermatopathological practice such as basal cell carcinoma and squamous cell carcinoma were uncommon, each being identified in only 1 patient younger than the age of 18, although basal cell carcinomas developing subsequently in young adult life were identified in 7 patients. Infections were common, with infectious agents or viral cytopathic effects (not including human papillomavirus) identified in 34 biopsies. A significant proportion (74%) represented invasive fungal infections, which are of very significant clinical importance. Biopsies performed for a clinical suspicion of graft-versus-host seldom showed histological features to suggest an alternative diagnosis, with only a single case suggesting a diagnosis of toxic erythema of chemotherapy identified.

The Myth of Mycotoxins and Mold Injury

In recent years, mold has been blamed for many symptoms or a constellation of symptoms. These symptoms are usually vague and subjective and difficult or impossible to measure or quantify. Moreover, there is no scientific evidence that mold has anything to do with these symptoms. In particular, the concept of toxic mold syndrome has permeated the public consciousness, and mycotoxins have falsely been associated with autoimmune diseases and a variety of other conditions. In fact, there is no evidence that the presence of mycotoxins in the air is enough to cause any disease known to man. Molds legitimately can cause allergies and can be a trigger for asthma. Certain specific molds such as Aspergillus can be a cause of hypersensitivity pneumonitis. In immunocompromised hosts, both dermatologic and systemic infections can result from various fungi and can be associated with significant morbidity or even mortality. However, the existence of toxic mold syndrome has been disproven, despite the numerous disreputable practices such as testing homes for mold spores, measuring "mycotoxins" in the urine, and testing patients for IgG to mold. In truth, none of these techniques have been validated, nor do they have any relevance to any clinical disease. All that these tests that are being performed by laboratories of disrepute does is to further propagate misinformation and inflict unnecessary and often exorbitant costs on patients desperate for a clinical diagnosis, right or wrong, for their constellation of maladies.

Fungal infections in children with haematologic malignancies and stem cell transplant recipients

Children with haematologic malignancies and haematopoietic stem cell transplant recipients are at high risk for invasive fungal diseases (IFD). There has been an increased number of at-risk children over the past two decades due to improvements in cancer therapies resulting in improved survival of children with high-risk and refractory malignancies. The predominant organisms that cause IFD include Candida spp., Aspergillus spp. and the Mucorales molds. Clinical presentations of IFD vary based on host immune status and the causative organism. Though serum biomarkers such as the galactomannan assay and beta-D-glucan assay have been validated in adults, there are limited data regarding their diagnostic value in children. Thus, the gold standard for IFD diagnosis remains tissue biopsy with histopathological and microbiological evaluation. Treatment of IFD is multimodal and involves antifungal drugs, correction of immune dysfunction and surgical resection when feasible. Paediatric practice regarding IFD is largely extrapolated from data generated in adult patients; in this review, we evaluate both primary paediatric studies and guidelines intended for adult patients that are applied to paediatric patients. There remain significant knowledge gaps with respect to the prevention, diagnosis and treatment of IFD in immunocompromised children, and further research is needed to help guide management decisions.

Comparison between organismal staining on histology and tissue culture in the diagnosis of cutaneous infection: A retrospective study

BACKGROUND

In instances of suspected cutaneous infection, the standard of care includes obtaining skin biopsy specimens for histology and tissue culture. Few studies have compared the clinical utility of each test.

OBJECTIVE

To assess the concordance of results between tissue culture and histology, as well as the clinicopathologic features that may influence the diagnostic yield of each test.

METHODS

A retrospective review of all patients who underwent skin biopsy for histology and tissue culture at New York University from 2013 through 2018.

RESULTS

Of 179 patients, 10% had positive concordance, 21% had positive tissue culture only, and 7% had positive histology only. We calculated a kappa correlation coefficient of 0.25 between histology and tissue culture (reference, 0.21-0.39 indicates minimal agreement). Histology exhibited higher sensitivity in detecting fungi, whereas tissue culture was more sensitive in identifying Gram-negative bacteria. Antimicrobial use before biopsy led to significantly fewer positive cultures (37.5% vs 71%; P = .023) in patients ultimately diagnosed with infection.

LIMITATIONS

This study was conducted at a single institution, thereby restricting its broad applicability. The lack of a validated criterion standard to diagnose infection also limits interpretation of the results.

CONCLUSION

Tissue culture and histopathology often yield discordant results. Dermatologists should recognize specific limitations, yet high clinical utility in special circumstances, of tests when approaching cases of suspected infection.