PCR assay fails to detect molluscum contagiosum virus-related sequences in AIDS-related Kaposi's sarcoma

Kaposi sarcoma in association with molluscum contagiosum: an uncommon diagnosis in a single biopsy and potential diagnostic pitfall

Molluscum contagiosum is a cutaneous poxviral infection that is rarely associated with other skin diseases, such as cutaneous neoplasms. Such associations are likely to be coincidental, except in immunocompromised patients. Kaposi sarcoma, an angioproliferative neoplasm derived from lymphatic endothelium, is mediated by human herpes virus-8 infection and occurs with increased frequency in immunocompromised individuals. We report an unusual case of molluscum contagiosum with underlying cutaneous Kaposi sarcoma diagnosed in a single skin biopsy of a human immunodeficiency virus-positive patient. Our case highlights the importance of adequate sampling to avoid missing secondary diagnoses in histopathologic sections and alerts pathologists and dermatologists to the possibility of coinfection in high-risk patients by 2 virally-mediated skin conditions.

Molluscum contagiosum: new perspectives on an old virus

Renewed interest in molluscum contagiosum virus has been stimulated by the availability of the entire genomic sequence and the identification of more than 160 putative genes, some of whose functions are now under analysis. Important findings have been generated by the recognition that certain viral proteins have anti-chemotactic and anti-apoptotic properties. Other advances include the characterization of two recombinant immunoreactive proteins, and the publication of the first seroepidemiological survey of the general population. Recent clinical studies indicate that some of the newer antiviral agents and physical treatment modalities offer significant benefits for the treatment of recalcitrant infections in the immunosuppressed.

An immunohistochemical study of abnormal keratinocyte proliferation in molluscum contagiosum

BACKGROUND

Molluscum contagiosum is a common cutaneous tumour that is characterized by usually spontaneous involution and self-limited spreading in immunocompetent individuals.

OBJECTIVE

We aimed to investigate the apoptosis and the expression of cell-cycle proteins in molluscum contagiosum lesions.

METHODS

The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL)-based apoptotic index and the expression of the cell-cycle proteins Ki-67, p53, p21WAF and Bcl-2 were investigated in molluscum contagiosum lesions obtained from the trunk of 20 immunocompetent patients and in normal skin samples from the trunk of six healthy volunteers.

RESULTS

Whereas molluscum contagiosum lesions displayed a TUNEL-based apoptotic index similar to that of normal skin, they exhibited an increased Ki-67 index, which was confined to the basal and first suprabasal layers (P < 0.001). Compared with normal non-sun-exposed skin, molluscum contagiosum lesions also exhibited increased p53 staining in basal cells (P < 0.01), increased p21WAF in suprabasal cells (P < 0.001) and loss of Bcl-2 expression.

CONCLUSIONS

These results indicate that molluscum contagiosum lesions exhibit an increased proliferation rate of keratinocytes, which is likely to be partially counteracted by accumulation of p53.