The role of histopathology in the diagnosis of dermatophytoses / Značaj patohistološkog nalaza u dijagnostici dermatofitoza

Abstract

Histopathological analysis is not a routine procedure for diagnosing fungal skin infections. In the histopathological specimens, fungi are visible only when using special stain such as periodic acid-Schiff (PAS). However, histopathological analysis may not be performed in small laboratories. Histopathological characteristics of fungal skin infections are not specific. In all skin biopsy cases, obtained without clinical suspicion of fungal infection, the knowledge of certain, most frequent histopathological reaction patterns, as well as specific histopathological indicators (a diagnostic histopathological "clue"), of certain superficial mycoses e.g., dermatophytoses, may raise a suspicion of fungal infection and warrant a fungal-specific staining. A retrospective analysis of all PAS-stained sections was carried out. All PAS-positive biopsy specimens were assessed for clinical features, histopathological patterns of skin reactions, and presence of histopathological indicators. Our results have shown that out of the total of 361 PAS-stained sections, fungal hyphae were identified in 12 (3.3%) specimens. In 5 (1.4%) cases, the diagnosis of fungal infection was suspected on clinical grounds, while in 7 (1.9%) cases detection of fungi was an unexpected finding. The most frequent type of histopathological pattern was spongiotic, and the most frequent histopathological indicator was the presence of neutrophils within the epidermis. Our results confirm that dermatophytoses may present with clinical and histological non-specific findings. PAS staining represents a relatively cheap and simple fungal-specific staining. It has been suggested that it not only confirms that the selected material is actually invaded, but also reduces the number of false-negative direct reports, where fungi are cultured from a microscopically negative specimen. Apart from a small percentage of positive findings, our results justify the need for routine PAS staining of all clinically and histologically non-specific inflammatory skin conditions.

Antifungal activity of aminopyrrolnitrin against Trichophyton verrucosum in a guinea pig model of dermatophytosis

“…Invasion of dermatophytes causes an inflammatory response and histological clue which demonstrates infection. 22 Histopathological examination of the skin reveals focal hyperkeratosis and guinea pigs exhibit epidermal hyperkeratosis as a result of surgical manipulation or stretching, according to previous reports. 23,24 However, spongiosis and neutrophil infiltration, parameters of the inflammatory response due to fungal infection, were detected only in the control group.…”

“…Histopathological evaluation was not routinely used during treatment of dermatophyte infections. Invasion of dermatophytes causes an inflammatory response and histological clue which demonstrates infection 22 . Histopathological examination of the skin reveals focal hyperkeratosis and guinea pigs exhibit epidermal hyperkeratosis as a result of surgical manipulation or stretching, according to previous reports 23,24 .…”

“…In addition, basket-weave patterns, which are a histological indicator of fungal infections, were only detected in the untreated group, providing a histological clue suggesting fungal infection. 22 PAS staining clearly demonstrates infection, by highlighting fungal cell walls. In this study, no fungi were detected in APRN4 and 8 but some hyphae were detected in the enilconazole-treated group.…”

A Clinico-Mycological and Histopathological Study of Recurrent Dermatophytosis

“…The extent of spread of the infection to the hair follicle or other appendageal structures can be determined by histopathology along with special stains, making it an essential diagnostic tool for the assessment and management in chronic and recalcitrant dermatophytosis. [ 11 12 ] In view of the above alarming and rapidly changing trends, the present study was undertaken to determine the clinical patterns, mycological profile, and histopathological changes including invasion of hair follicle in cases of recurrent dermatophytosis.…”

Study of clinico-histopathological correlation of papulosquamous disorders at tertiary care hospital

“…Concordance between pre-biopsy and histopathologic diagnosis was noted in 57.28% of cases was seen in Elbendary et al, 13 while out of the total of 361 PASstained sections, fungal hyphae were identified in 12(3.3%) specimens. In 5(1.4%) cases, the diagnosis of fungal infection was suspected on clinical grounds, while in 7(1.9%) cases detection of fungi was an unexpected finding in Ðor di Gocev et al 14 62.5% positive correlation was noted in Chaudhary Raju G et al 4…”