The diagnosis of respiratory fungal infections is often aided by cytopathological evidence of fungi in sputum or bronchoalveolar lavage fluid. Grocott's methenamine silver (GMS) stain, a special stain frequently used to detect fungi in cytological specimens, can be challenging to apply stably. There is a need for improved documentation of staining procedures for fungal detection in cytological specimens. In our study, we developed an artificial cytology specimen for fungal detection by combining cultured fungi with artificial sputum. We compared the conventional GMS protocol with the periodic acid-ammoniacal silver (PAAS) protocol, which our institute uses for cytological samples. Our findings revealed that the PAAS protocol, while showing comparable staining properties to the GMS protocol, resulted in fewer non-specific silver granules in the background. Therefore, we conclude that the PAAS protocol offers a valuable alternative for identifying fungi in cytological specimens.

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I report a case of tinea barbae presenting as a tumor in the philtrum of a man in his thirties with comorbid alcoholic liver disease. The patient also had tinea on the auricles, neck, and feet, with direct microscopy confirming the presence of dermatophytes at all sites. A history of multiple pet ownership was noted. The causative organism in the philtrum was identified as the zoophilic fungus Trichophyton mentagrophytes, while the tinea on the feet was caused by the anthropophilic fungus Trichophyton interdigitale ITS genotype II. Despite abnormal liver enzymes, the patient was cured after a three-month course of oral terbinafine following cessation of alcohol intake. This case, encountered by the author approximately 20 years ago, was initially identified as Arthroderma vanbreuseghemii using PCR-RFLP analysis of the ITS region of rRNA genes. Recent sequencing analysis of preserved strains reidentified the organism as T. mentagrophytes. The alignment of this strain showed a query cover of 100% and a percent identity (Per.ident) of 99.84%, matching with T. mentagrophytes ITS genotype VII. As a dermatologist, it is crucial to continuously monitor the evolving taxonomy of fungi and its clinical implications.

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Fungi are categorized into Risk or Hazard Groups, depending on their potential to harm humans, with groupings ranging from 1 (least risky) to 4 (most risky). Similarly, Biosafety or Containment Levels ranging from 1 to 4 denote the level of control over microorganisms in laboratories. This review focuses on fungi categorized as Risk Group 3 by the Biosafety Committee of the Japanese Society for Medical Mycology. One such fungus is Blastomyces dermatitidis, which is primarily found in North America and causes blastomycosis, a condition that can result in a pulmonary or disseminated disease. It is classified as Risk Group 3, as substantiated by 11 laboratory-acquired infections and two fatalities. Cladophialophora bantiana, commonly found in Asia, causes brain abscesses and is also classified as Risk Group 3 due to a high mortality rate of 65.2%. Coccidioides immitis/posadasii, found in the Americas, can cause severe respiratory conditions with the potential for dissemination. Their Risk Group 3 classification is substantiated by a history of laboratory-acquired infections. Histoplasma capsulatum, which is found globally, causes a range of infections, from asymptomatic to fatal. Its classification as Risk Group 3 is substantiated by 81 laboratory-acquired infections and one fatality. Rhinocladiella mackenziei, which primarily affects the nervous system, has a mortality rate of 92.5% and is also classified as Risk Group 3. These fungi necessitate strict containment measures in laboratories owing to their high mortality rates or reported cases of laboratory-acquired infections and fatalities, emphasizing the critical need for heightened awareness and stringent safety protocols.

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A man in his thirties patient visited his previous physician with the chief complaint of a pigmented macule on the sole of his left foot that had steadily grown over the past two years. A dermoscopic examination of the lesion showed a parallel ridge pattern (PRP); therefore, acral-lentiginous melanoma (ALM) was suspected, and the patient was referred to our hospital for a more detailed examination. On closer inspection, PRP had a well-defined and irregular border with no variation in color, which is atypical for ALM which is characterized by asymmetrical structure and variation in colors. Therefore, a skin biopsy was performed for a definite diagnosis, and the histopathological findings showed mycelia in the horny layers. Fungal culture revealed Hortaea werneckii, and the patient was diagnosed with tinea nigra (TN). Although TN is a rare fungal infection in Japan, we emphasize that this fungal infection should be noted as a mimic of ALM and should be considered when PRP is detected on the palms and soles by dermoscopic examination.

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The patient was a girl (case 1) and her mother (case 2). The family had purchased a domestic cat five months previously. Three months later, both patients developed eruptions. Mycological examinations were positive in both cases, and the cat tested positive on the hairbrush test. The macroconidia were thick only in the cat strain, and drug susceptibility testing showed mildly low levels of terbinafine and itraconazole. However, a molecular biological analysis of these three strains showed 100% identity with reference strains of Microsporum canis. Since there have been recent reports of drug-resistant dermatophytosis, drug-susceptibility testing is considered necessary.

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Penicillium brasilianum is an environmental filamentous fungus with useful applications in biotechnology. However, human infections caused by P. brasilianum are rare and not well understood. We present the case of a woman in her sixties with poorly controlled diabetes mellitus who was diagnosed with invasive fungal rhinosinusitis (IFRS) and orbital apex syndrome. She underwent endoscopic sinus surgery and received treatment with liposomal amphotericin B. Notably, β-tubulin gene sequencing identified the filamentous fungus as P. brasilianum, and long-term itraconazole administration suppressed IFRS flares. Our findings underscore the need for increased awareness and understanding of rare fungal pathogens in clinical practice.

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