Histopathological diagnosis of mycoses

Infectious diseases emerge as a cause of pathology in our patients. Among the possible etiologies, mycoses have shown a considerable increase in the two last decades. In general, the clinical features of fungal diseases are not very distinctive. The morphology and the clinical aspects of the fungi serve as a protocol for their correct identification. Clinicians, microbiologists and pathologists are essential for the diagnosis. The pathologist using a simple and fast methodology can diagnose some types of mycosis, but they do not only identify the causal agent, but also the kind of injury that produces, the inflammatory response and the affected organ or organs. Moreover, they can classify the mycosis as superficial, cutaneous, subcutaneous, deep and systemic depending on the location. The present review paper describes study guidelines for the pathologist faced with a fungal infection and new technical advances that are established in pathology laboratories for a more precise identification of the mycoses.     

Histopathological diagnosis of mycoses in veterinary pathology

Histopathological analysis demonstrates the morphology of the fungi and shows their relationship with tissue lesions, which is a valuable information in the diagnosis of veterinary mycoses, especially in superficial infections where reservoirs make difficult the diagnosis using other techniques. On the other hand, histopathological analysis should be complementary to other methods such as culture, immunohistochemistry, serology, PCR, etc. In this work, the most relevant histopathological features of some of the most common mycoses of domestic animals, some of which have zoonotic potential, are described and their differential diagnosis is discussed. To facilitate the discussion of the differential diagnoses, mycoses have been grouped by the sites of the infections and by the nature of the fungi (dimorphic and filamentous). Mycoses included in the study were 1) Superficial and deep infections: dermatophytosis, dermatophytic pseudomycetoma, eumycotic mycetoma, phaeohyphomycosis and malasezziasis. 2) Systemic mycoses: aspergillosis and zygomycosis. 3) Mycoses due to dimorphic fungi: candidiasis, cryptococcosis, blastomycosis, sporotrichosis, coccidioidomycosis and histoplasmosis. 4) Infections by algae and other fungi: protothecosis and pneumocystosis.     

PAS染色及真菌荧光染色在皮下真菌病诊断中的应用

皮下真菌病(subcutaneous mycoses)是指侵犯真皮、皮下组织和骨骼的真菌感染[1],部分可播及周边组织,如足菌肿等,有些则沿淋巴管扩散,如孢子丝菌病、着色芽生菌病,对人体造成较大危害。这类疾病病程缓慢,早期临床表现不典型,为疾病的早期诊断带来一定困难。真菌培养是其诊断的“金标准”,然而,真菌培养阳性率偏低,重要的是部分早期病例不容易考虑到真菌感染,多在组织病理提示后才考虑到深部真菌感染的可能性。     

A study of 3891 cases of mycoses in the tropics.

4103 cases suspected of mycoses were analysed as to sex, age and site of disease and 3891 were proved cases. This group formed 50% of total mycoses or 13-93% of all dermatoses recorded in the Government General Hospital, Madras, during the period of study. There were 66-26% adult female, 27-6% adult male and 6-14% were below 13 years. Dermatophytoses were found in 73-5%; the other common diseases were tinea versicolor (17-68%) and candidiasis (12-43%). Multiple sites of involvement or more than 1 disease in the same individual were mostly observed. The incidence of piedra (0-1%) and deep mycoses (0-156%) was very low. Mycetoma was the common disease (5/6) in deep mycoses. In dermatophytoses, tinea corporis (49-71%) and tinea cruris (47-85%) commonest; tinea axillaris (3-42%), tinea capitis (1-72%) and tinea barbae (1-29%) were less common. The incidence of tinea manuum, tinea pedis and tinea unguium was similar (4-97%-6-38%). High temperature and humidity were related to the higher incidence of tinea corporis, tinea cruris and tinea versicolor. Mainly children suffered from tinea capitis. All other mycoses were commonly found in adults between 2nd and 3rd decades. In all mycoses but candidiasis, female predominated. Cutaneous candidiasis was mainly a problem of housewives. Among the dermatophytes Trichophyton violaceum was predominant (33-7%) followed by T. rubrum (32-6%). Trichophyton schoenleinii and M. gypseum were rarely isolated. From mycetoma, Madurella mycetomii, Nocardia braziliensis, N. asteroides and Actinomadura spp. were isolated. Demonstration of Cryptococcus laurentii in 1 case is reported in this area for the first time.     

Role of polypeptides in the treatment and diagnosis of osteoporosis.

Osteoporosis is a common disorder characterized by reduced bone mineral density, deterioration of the microarchitecture of bone tissue and increased risk of fracture. The aim of treatment of osteoporosis is to maintain and, ideally, to restore bone strength safely. In recent years the role of polypeptide growth factors in bone metabolism has begun to appear. It has been proposed that alterations in the expression or production of growth factor can modulate the proliferation and activity of bone forming cells. In this direction, the role of structurally diverse peptides for the management and diagnosis of osteoporosis has attracted the attention of many investigators. This paper reviews numerous findings concerning the use of polypeptides, hormones, and growth factors, for the management of osteoporosis. Many of the compounds mentioned here are experimental prototypes of new therapeutic classes. Though it is unlikely that some of the compounds may ever be used clinically, development of safe and efficacious agents in each class will define the future course of therapy for osteoporosis.     

Use of terbinafine in rare and refractory mycoses.

Terbinafine is the only systemic allylamine antifungal currently available. Its mechanism of action is unique and sets it apart from other agents. Although it is primarily used for dermatophyte infections, such as onychomycosis and tinea pedis, terbinafine has broad in vitro activity against a variety of non-dermatophyte fungal pathogens, including Candida spp. and many molds. In addition, synergistic activity is noted with other antifungals, notably triazoles. Multiple case reports exist of its use for unusual and refractory fungal infections, but no systematic review is available. We review the current literature with regard to in vitro data and clinical experience with terbinafine in the treatment of rare and refractory mycoses.     

Imidazoles in the treatment of ocular mycoses

The use of a new class of broad spectrum antifungal drugs i.e. imidazoles and in particular ketoconazole in treatment of severe affections of the eye such as mycoses is described. The clinical trials included 40 patients with various forms of mycosis: mycotic canaliculitis (6 patients), mycotic blepharitis (4 patients), mycotic conjunctivitis (7 patients), keratomycosis (17 patients) and mycotic endophthalmitis (6 patients). Ketoconazole was used in the form of tablets and instillations. The combined treatment included nonsteroid antiinflammatory drugs and antibacterial agents. The clinical trials showed that ketoconazole had pronounced antifungal activity and was rather efficient in treatment of ocular mycoses. Its broad spectrum and low toxicity were recorded.     

Miconazole in the treatment of superficial mycoses

Miconazole nitrate (2%) cream was evaluated in the treatment of superficial mycoses. Out of 116 patients having multiple clinical diagnoses, 66 cases were found to be positive by culture. Species of Trichophyton were the predominant etiological agents (in over 60%) followed by Candida species (20%) and Epidermophyton floccosum (15%). All the cases selected for study were followed up to a period of 4–18 months. A cure rate of 94.6 per cent was observed in all the cases where causal organisms were isolated. Significantly high cure rate (66%) was also seen in cases where causal organisms could not be isolated, including cases of tinea versicolor. Results of mycological examination were in confirmity with the clinical results. Read at the Symposium on Human Mycoses and Miconazole held in New Delhi, India, February, 1975.