Dermatopathology and the Diagnosis of Fungal Infections.

Diagnosis of superficial/cutaneous fungal infections from skin, hair and nail samples is generally achieved using microscopy and culture in a microbiology laboratory, however, any presentation that is unusual or subcutaneous is sampled by taking a biopsy. Using histological techniques a tissue biopsy enables a pathologist to perform a full examination of the skin structure, detect any inflammatory processes or the presence of an infectious agent or foreign body. Histopathological examination can give a presumptive diagnosis while a culture result is pending, and may provide valuable diagnostic information if culture fails. This review demonstrates how histopathology contributes to the diagnosis of fungal infections from the superficial to the life threatening.

Gout-like hands.

A 65-year-old man presented to our hospital with a 1-year history of multiple nodules on his arms and hands without itching or pain.

Histoplasma capsulatum var. duboisii: A KwaZulu-Natal, South Africa public sector perspective.

BACKGROUND: Histoplasma capsulatum var. duboisii (H. duboisii) causes potentially fatal disease in the immunocompromised patient, and the literature on these cases is limited. The study was undertaken to describe the cases of H. duboisii seen in a resource-limited setting. METHODS: A 5-year retrospective, laboratory-based histopathologic review of all H. duboisii cases. RESULTS: A total of 24 patients were diagnosed with cutaneous H. duboisii infection. The male-to-female ratio was 1.4. All the patients were human immunodeficiency virus (HIV) positive, and 70.83% (17 of 24 patients) were on antiretroviral therapy. The clinically identified lesions were as follows: plaques, nodular plaques, papules, papulo-pustules, and umbilicated papules. Histopathological appraisal revealed organisms typical of H. duboisii. The commonest epidermal alterations were interface change, parakeratosis, spongiosis, ulceration, acanthosis, hyperkeratosis, transepidermal elimination, and exocytosis in decreasing order. The dermal changes included histiocytic pattern (n = 14), neutrophil-rich (n = 13), non-necrotizing granulomatous inflammation (n = 9), and karyorrhexis (n = 6). Histoplasma was confirmed in 53% (8 of 15 samples) of the tissue samples submitted for routine fungal culture. CONCLUSION: This study showed the demographics, clinical and histopathology features of H. duboisii infection in a resource-limited setting. Further research on histopathological features of this rare infection is essential to expand on the knowledge base and support findings in this study.

Cutaneous Histoplasmosis in HIV Seronegative Patients: A Clinicopathological Analysis.

BACKGROUND: Diagnosis of extrapulmonary histoplasmosis in HIV seronegative and immunocompetent patients is often challenging, so a high index of suspicion is required. Cutaneous manifestation of infection shows a wide spectrum of lesions including erythematous plaques; maculopapules; crusted, verrucous, or desquamative papules and nodules; abscesses; and mucocutaneous ulcers among others. Due to the variations in its clinical presentation, histopathology plays a very important role in the detection of spores and the confirmation of diagnosis. OBJECTIVES: The aim of our study was to analyze clinicopathological characteristics of cutaneous manifestations of biopsy-proven histoplasmosis in HIV seronegative individuals. We also examined the utility of Fite stain for the diagnosis of Histoplasma capsulatum on tissue biopsy sections. METHODS: This was a retrospective, observational study on 7 patients who were HIV seronegative and clinically manifested with isolated cutaneous lesions or disseminated disease. Skin biopsy from the lesions was performed on all 7 patients. In addition to H&E staining and special stains for detecting fungus, Fite staining was performed on all of the cases to study its utility in detecting H. capsulatum spores. RESULTS: The skin lesions were widely disseminated in all patients and the most common cutaneous lesions were papules, present in all 7 patients. On review of the H&E-stained slides, the most common pattern was histiocytic lobular panniculitis-like infiltrate observed in 4 cases. Fite stain highlighted the yeast as magenta-colored spores on a blue background in all cases, except for 1 with a granulomatous pattern. CONCLUSION: A primary cutaneous manifestation of H. capsulatum infection in non-HIV-infected individuals is extremely rare. Fite stain could aid in differentiating the spores of H. capsulatum from those of other fungi, Cryptococcus and Candida in particular.

Pseudomycetoma of the scalp caused by Microsporum canis

Abstract Pseudomycetoma is an extremely rare deep mycosis, caused by dermatophytic fungi that penetrate the tissue from infected follicles of tinea capitis. Both clinically and histopathology are similar to eumycetoma, being distinguished through the isolation of the fungus, which in the case of pseudomycetoma can be Microsporum spp. or Trichophyton spp. genre. We present a 24-year-old man with an exuberant tumor in the occipital region with fistula, whose histopathological examination evidenced grains composed of hyaline hyphae and the culture for fungi isolated the agent Microsporum canis. Combined treatment of surgical excision followed by oral griseofulvin for two years was performed, with resolution of the condition.

Pseudomycetoma of the scalp caused by Microsporum canis.

Pseudomycetoma is an extremely rare deep mycosis, caused by dermatophytic fungi that penetrate the tissue from infected follicles of tinea capitis. Both clinically and histopathology are similar to eumycetoma, being distinguished through the isolation of the fungus, which in the case of pseudomycetoma can be Microsporum spp. or Trichophyton spp. genre. We present a 24-year-old man with an exuberant tumor in the occipital region with fistula, whose histopathological examination evidenced grains composed of hyaline hyphae and the culture for fungi isolated the agent Microsporum canis. Combined treatment of surgical excision followed by oral griseofulvin for two years was performed, with resolution of the condition.

Disseminated and ulcerative basidiobolomycosis simulating a Buruli ulcer in an immunocompetent girl in Southern Benin.

Basidiobolomycosis is a subcutaneous mycosis, for which non-specific clinical presentation can be a source of diagnostic wandering. A 5-year-old girl was brought for consultation with chronic ulcers of the pelvic limbs evolving for 8 months. The lesions started when the girl was 18 months old with a painless, pruritic nodule of the right buttock, indurated placard following progressive extension to the pelvic limbs, back and abdomen, and secondarily ulcerated in several places. On examination, there was an alteration of the general condition, a large, indurated and erythematous plaque, with sharp edges. On this plaque, there were nodular lesions and necrotic ulcers, with detached margins. The left knee was blocked in flexion. Ziehl staining and polymerase chain reaction for Mycobacterium ulcerans were negative. The histopathological picture was suggestive of basidiobolomycosis. The evolution was favorable after giving her ketoconazole (100mg per day) for 14 weeks associated with surgery and physiotherapy. This clinical case confirms the difficulties in diagnosing basidiobolomycosis, especially in endemic areas of Buruli ulcer.

Deep cutaneous ulcers and sinus formation in an immunocompetent adult

Abstract This report describes a case of unusual deep skin ulcers with tortuous sinus tract formation in an immunocompetent woman. She was initially diagnosed with a Staphylococcus aureus skin infection and histopathologically diagnosed with pyoderma gangrenosum. However, culture from the deep end of ribbon gauze inserted into the subcutaneous sinus tract revealed shiny, light-yellow mucoid colonies, which were identified as Cryptococcus neoformans var. grubii. She was treated with fluconazole for nine months and completely healed. Cryptococcosis is an opportunistic infection caused by variants of C. neoformans species. Cutaneous manifestations of cryptococcosis are quite divergent, rarely occurring as deep skin ulcers with sinus formation.

Early necrotic skin lesions after a ABO-incompatible kidney transplantation: The threat of Cunninghamella Spp.

A 49-year-old man underwent ABO-incompatible kidney transplantation with a living donor. At day 33 post-transplantation, he presented with undiagnosed epilepsy with generalized tonic-clonic seizures. At day 44 post-transplantation, he developed left-sided pneumonia attributed to Aspergillus fumigatus and treatment with liposomal amphotericin B was initiated. At day 51 post-transplantation, necrotic skin lesions appeared. DNA sequencing in a fresh cutaneous biopsy finally identified Cunninghamella Spp., a member of the order Mucorales. Unfortunately, the necrotic lesions spread, and the patient died at day 60 post-transplantation. This case report highlights the infectious risk related to ABO-incompatible kidney transplantation and suggests a requirement for rapid identification of every skin lesion, even in the early phases of immunosuppression.