Molluscum-like cutaneous cryptococcosis: a histopathological and pathogenetic appraisal.

BACKGROUND: Molluscum-like cutaneous cryptococcosis (MLCC) is characterized by hypopigmented or skin-colored papules with central umbilication. The histomorphological nuances of Cryptococcus neoformans infection that effect mimicry of molluscum contagiosum are undocumented. This histopathological study was undertaken to assess the histopathological characteristics of MLCC and to determine potential evolutionary pathogenetic mechanisms and significance. METHODS: A 5-year retrospective re-appraisal of cutaneous cryptococcosis biopsies with a clinical molluscum-like appearance. RESULTS: All 26 specimens with a molluscum-like appearance showed a dome-shaped architecture with central invagination and dermal C. neoformans of varying size and shape, with capsular fragmentation; 20 biopsies had a paucireactive appearance and 6 combined granulomatous and paucireactive foci. Twenty, two and four biopsies showed transepidermal, transfollicular and combined transepidermal and transfollicular elimination (TFE) of fungi, necrobiotic collagen and debris through the central invagination, respectively. Subepithelial neutrophils and collagen necrobiosis were identified in 8 and 14 cases each, respectively. Varying sized and shaped yeasts, capsules of varying width, capsular fragmentation and collagen necrobiosis were ultrastructurally confirmed. CONCLUSION: Transepithelial and TFE of C. neoformans, necrobiotic collagen, inflammatory cells and cellular debris account for the morphological attributes of MLCC. The eliminatory process is a potential public health hazard, serving as a vehicle for C. neoformans transfer to the exterior.

Early host cell-Molluscum contagiosum virus interactions.

Basal and suprabasal layers of human epidermis infected with the poxvirus Molluscum contagiosum have been examined with the technique of serial sectioning. Phagocytic vacuoles, formerly not observed in human epidermis, were found exclusively in the basal region. They did not fuse with other virus-containing vacuoles or with lysosomes to form digestive vacuoles. Various stages of uncoating, preceding ejection of the virus core into the cytoplasm, were observed in the virus-containing vacuole. Clusters of cores were commonly found close to or even associated with centriolar structures. Their possible interference with mitosis is discussed in relation to alterations observed in the plasma membrane. It is assumed that excision of gap junction elements precedes the induction of mitosis.

Viral diseases of the skin, 1975: a 25-year perspective.

Most of the major advances in modern virology during the past 25 years have been due principally to the development of refined laboratory techniques and tools and have provided a fund of new knowledge and information about the nature of viral infection and pathogenesis. One group of viruses of interest to dermatologists, the herpesviruses, is undergoing intensive biochemical investigation to determine whether it is carcinogenic. As a result of the success of the World Health Organization's campaign to eradicate smallpox, it is predicted that by the end of 1976, smallpox will have been eradicated. Other viruses of dermatologic interest which are now being studied include the agents of warts, molluscum contagiosum, cat-scratch disease, and enteroviruses. Current research in the field of viral chemotherapy may provide the basis for successfully treating these diseases in the future.

Detection of infection by human papillomavirus in genital condylomata. A comparison study using immunocytochemistry and in situ nucleic acid hybridization.

One hundred eighty exophytic genital lesions clinically suspicious for infection by human papillomavirus (HPV) were analyzed by hematoxylin and eosin light microscopy, immunocytochemistry for HPV capsid antigen; and in situ nucleic acid hybridization for HPV messenger RNA (mRNA). Of 96 cases morphologically consistent with infection by HPV, 53% were antigen-positive, and 83% were mRNA positive (P less than 0.01). Of 55 cases suggestive but not diagnostic of HPV infection, 13% were antigen-positive and 26% were mRNA positive. Negative results were obtained in all lesions not believed to be indicative of HPV infection by morphologic criteria. In mRNA positive diagnostic cases, two thirds were of HPV type 6 and one third were HPV type 11. Two cases of coinfection with HPV types 6 and 16 were found. The study concludes that in situ hybridization for HPV mRNA is a more sensitive indicator of HPV infection, and in addition, provides HPV type, which may have prognostic significance.

Molluscum contagiosum. Ultrastructural evidence for its presence in skin adjacent to clinical lesions in patients infected with human immunodeficiency virus type 1. Military Medical Consortium for Applied Retroviral Research.

BACKGROUND AND DESIGN: Molluscum contagiosum in acquired immunodeficiency disease, although not life threatening, is often a marker of late-stage disease and may lead to disfiguring cutaneous lesions. Although most current therapy results in at least temporary clearing of individual lesions, lesions frequently recur and new lesions arise. Examination of hematoxylin-eosin-stained histologic sections in two patients showed changes suggestive of viral infection in the epidermis 0.5 cm and 1 cm lateral to obvious clinical lesions. These areas were clinically free of any lesions. Both routine histopathologic examination and ultrastructural examination were performed in two patients infected with human immunodeficiency virus type 1 (HIV-1) and three non-HIV-1-infected patients. RESULTS: All patients showed histologic changes diagnostic of molluscum contagiosum. In addition, the sections from HIV-1-infected patients showed areas of acanthosis, hyperkeratosis, and nuclear atypia. Electron microscopy of these areas revealed rare viral organisms in these areas. Similar acanthotic, hyperkeratotic areas were not seen in the biopsy specimens from the non-HIV-1-infected patients and no viral particles were found in the epidermis around the lesions. CONCLUSION: Viral structures consistent with molluscum contagiosum are present within the clinically normal epidermis around lesions of molluscum contagiosum in some HIV-1-infected patients. This may explain the large number of lesions seen in these patients and the difficulty in controlling the spread and recurrence of molluscum contagiosum in HIV-1-infected patients.

Detection of molluscum contagiosum virus DNA by in situ hybridization.

Three in situ hybridization protocols have been modified and used to comparatively examine formalin-fixed, paraffin-embedded tissue for the presence of molluscum contagiosum virus (MCV) DNA. Two cloned MCV 1 DNA fragments, MCV-1-B-D1 and MCV-1-B-F, were labelled with 32P-dCTP or digoxigenin-11-dUTP and used under conditions of high stringency to detect MCV DNA in sections of molluscum lesions. All methods were sensitive and were capable of detecting MCV after a minimum of 18 hours autoradiography (radiolabelled probes) or 3 to 18 hours (digoxigenin-labelled probes). However, one of the isotopic protocols produced less acceptable results in terms of non-specific background signals. A comparison of the DNA hybridization pattern with the underlying histopathological features of the molluscum sections revealed that there was not always a consistent association between the presence of detectable MCV DNA and cells containing the characteristic cytoplasmic inclusion bodies ("molluscum bodies") which are known to contain large numbers of virus particles. Although there is likely to be only limited scope for the application of this technique to diagnosis, it may prove useful for both retrospective and prospective epidemiological surveys. The in situ detection of MCV DNA may also be valuable for investigations into the cell biology of this imperfectly characterized virus.

[Laboratory diagnosis in sexually transmitted viral diseases. Its importance in medical practice]. / Diagnóstico de laboratorio en las enfermedades virales transmitidas sexualmente. Su importancia en la práctica médica.

We describe the most popular current laboratory techniques used to demonstrate poxvirus, papovavirus and herpes simplex. In the latter case, the microbiological diagnosis was done.

Cytodiagnosis of cutaneous histoplasmosis in HIV positive patient initially presenting with multiple umbilicated disseminated skin nodules.

Histoplasmosis is usually an opportunistic fungal infection in patients with defective cell mediated immunity, and has been considered as one of the acquired immunodeficiency syndrome (AIDS) defining illness. However, cutaneous involvement in human immunodeficiency virus (HIV) positive patients is less common, and very rarely can be the initial presenting symptom for the diagnosis of AIDS. We present here an unusual case of multiple diffuse cutaneous nodular lesions predominantly in face, trunk, and upper extremities diagnosed initially on aspiration cytology as histoplasmosis. Subsequent serological test revealed positivity for HIV 1 and 2, along with a low CD4 count and low CD4:CD3 ratio. The cytomorphological features were further corroborated by histology and histochemical stains. Hence, cutaneous histoplasmosis can cause multiple wide spread nodular or umbilicated lesions in AIDS patients as the initial presentation. Fine needle aspiration cytology (FNAC) is a rapid, cost effective tool for diagnosis of the fungi from such lesions and initiating work up for immunocompromised states including AIDS.

Molluscum contagiosum.

This in-depth review considers the known virological and molecular biological aspects of the molluscum contagiosum virus. Furthermore, the epidemiology of its infection of human skin is detailed, and the clinical, histological, and therapeutic information available at this time are cataloged. It is concluded that molluscum contagiosum has become an almost common skin disease that can prove very difficult to eradicate from an infected patient.

[Molluscum contagiosum virus types found in Japan].

Total DNAs obtained from Japanese patients with molluscum contagiosum (MC) were analyzed by agarose gel electrophoresis after digestion with Bam HI, Hind III or Cla I restriction enzymes, which revealed the presence of four different cleavage patterns of MC virus (MCV) DNAs. The comparison with previously reported MCV types clarified that two of them were identical with MCV-1 and -2, respectively. The other two isolates were considered as yet unrecognized types and named MCV-3 and -4, respectively.

Three-dimensional ultrastructural study of molluscum contagiosum in the skin using scanning-electron microscopy.

The three-dimensional ultrastructure of molluscum contagiosum virus (MCV) in human skin was visualized using scanning-electron microscopy with the osmium-dimethyl sulphoxide-osmium method. There were spherical, ellipsoidal, brick-shaped, miniature and incomplete forms of MCV. In all the forms the surface had densely distributed small protrusions and all had the same ultrastructure. All the forms had one or two long cord-like substances that appeared to be linked together, but became short, vestigial or absent on the surface of the mature virus. The cord-like substances were connected to the core of the MCV. In the matrix between the viruses, the cord-like substances formed an intricate fine network.

The identification of molluscum infection by immunohistochemical means.

Tissue obtained from formalin-fixed, paraffin-embedded blocks containing molluscum contagiosum virus was used as a source of antigen to generate a polyclonal antibody against molluscum contagiosum virus. This antibody recognized an antigen in molluscum bodies which was preserved during routine fixation and embedding. The antibody can be used with standard immunohistochemical methods to identify molluscum contagiosuminfection in inflamed and distorted tissue specimens. Our data indicate that paraffin-embedded, formalin-fixed material can be used as an antigenic source to generate antibodies with diagnostic potential.

Molecular epidemiological study of molluscum contagiosum virus in two urban areas of western Japan by the in-gel endonuclease digestion method.

The in-gel endonuclease digestion method was introduced for the molecular epidemiology of molluscum contagiosum virus (MCV). We obtained clear electrophoretic patterns from 90.3% of single lesions. The distribution of MCV types in Western Japan was revealed to be different from that in other countries.

Molluscum contagiosum.

Molluscum contagiosum, a benign cutaneous infection of children and young adults, occurs throughout the world. Infectious virions apparently are transferred from the visible lesions to the skin of susceptible persons, either by direct contact or by fomites. Circumstantial evidence suggests that this infection is transmitted between young adults during sexual intercourse. The lesions of molluscum contagiosum are usually small, firm, umbilicated papules located on exposed skin of children or on genital skin in young adults. Such lesions are pathognomonic. Molluscum lesions resolve spontaneously; however, various treatments that remove the infected epidermis may be used to minimize transmission of the disease or for cosmetic reasons. In vitro culture techniques that have been successful for other viruses fail to propagate this virus. Successful inoculations of humans were reported early in the 20th century, but attempts to repeat these experiments have failed. Consequently, precise knowledge of this infection is lacking.

Characterisation by restriction mapping of three subtypes of molluscum contagiosum virus.

DNA from Molluscum contagiosum virus (MCV) isolates was analysed by restriction endonuclease digestion, identifying three virus subtypes. The structural features of MCV DNA are typical of poxviral DNA. Physical maps of cleavage sites for BamHI, CIaI, and HindIII were constructed for single isolates of each subtype. These differ extensively, indicating the independence of the three subtypes. However, they are closely related, as determined by molecular hybridisation and nucleotide sequence analysis, and their genomes are essentially colinear. There is marked geographical variation in the relative incidence of MCV I and II, whilst MCV III is uniformly rare.

Analysis of the genome of molluscum contagiosum virus by restriction endonuclease analysis and molecular cloning.

Virions of molluscum contagiosum virus (MCV), a member of the poxviridae, were isolated directly from lesions of individual patients and characterized by restriction enzyme analysis. The comparative analysis of the cleavage patterns and Southern blot hybridization of 14 independently isolated virus samples revealed that MCV isolates can be classified into two different types. The majority of MCV isolated from clinically typical skin lesions (13 of 14) showed similar DNA cleavage patterns and were termed MCV type 1, whereas one isolate derived from a vaginal lesion showed a completely different DNA cleavage pattern and therefore was termed MCV type 2. For detailed investigation of the viral genome, a defined gene library of MCV DNA sequences was established. The Bam HI DNA fragments of the viral genome of MCV type 1 prototype isolate 1/80 was inserted into the bacterial plasmid vector pAT153. With the exception of terminal fragments (fragments A and B) of the viral genome, all other DNA fragments were cloned. All cloned Bam HI DNA fragments were individually identified by digestion of the recombinant plasmid DNA with different restriction enzymes and screened by hybridization of plasmid DNA to viral DNA.