*Department of Dermatology, Kurume University School of Medicine, and Kurume University Institute of Cutaneous Cell Biology, Fukuoka, Japan
†Department of Pathology, Kurume University School of Medicine, Fukuoka, Japan Tsuruta is now at Department of Dermatology, Osaka City University Graduate School of Medicine, Osaka, Japan
The authors declare no conflicts of interest.
To the Editor:
CD30+ cells are occasionally present around molluscum contagiosum (MC).1 In these settings, T-cell clonality has not been detected, although CD30+ cells do not always belong to T-cells. We report a case of multiple MC with CD30+ cell infiltrate, developing in a patient with mycosis fungoides (MF). MC lesions were not located on MF lesions, however, T-cell clonality was shown.
A 60-year-old Japanese male without any particular family history admitted to our hospital for the treatment of widespread skin lesions. Physical examination revealed erythematous skin lesions on the trunk and extremities (Fig. 1A), and biopsy from the thigh revealed lymphocytic infiltrate in the epidermis and within the dermal papillae with scant spongiosis and patchy lichenoid infiltrate of lymphocytes with wiry bundles of collagen in the papillary dermis (Figs. 1B, C). Immunohistochemistry revealed that the lymphocytes in the upper dermis were positive for CD3 and CD4, and relatively weakly positive for CD8. In contrast, these cells were negative for CD20 and CD30. The patient was diagnosed as MF (patch stage, T2N0M0B0, stage IB). Narrow band UVB therapy (NB-UVB) with topical steroid was successful. However, after discontinuation of NB-UVB, the skin lesions exacerbated.
Two years later, the patient showed relatively ill-demarcated red to brown scaly macules of MF on the entire body. In addition, multiple pink salmon-colored papules of 5 mm in size developed on the trunk and extremities, sparing MF lesions (Fig. 2A). Some papules were umbilicated (Fig. 2B). Laboratory tests revealed no abnormal findings, except for slightly elevated level of soluble IL-2 receptor (673 U/mL).
Histopathology of biopsy from MF macule revealed diffuse infiltrates of lymphocytes without apparent atypia in the upper dermis, with foci of accumulated lymphocytes within the epidermis. These lymphocytes were positive for CD3 and CD4, but negative for CD20 or CD30. Occasional CD8+ lymphocytes were also found.
Histopathology of biopsy from papules revealed tumorous islands of proliferating keratinocytes with eosinophilic molluscum inclusion bodies in the cytoplasm, surrounded by inflammatory infiltrates in the superficial dermis (Fig. 2C). Some of the inflammatory cells showed large cytoplasm with irregular-shaped nuclei (Fig. 2D). From these findings, the papules were diagnosed as MC.
Immunohistochemistry revealed that the infiltrating cells around MC lesions were positive for CD3. The CD3+ cells were relatively weakly positive for CD4 (Fig. 2E), but strongly positive for CD8 (Fig. 2F). Intriguingly, CD3+ large cells were positive for CD30 (Fig. 2G, H). Infiltrating cells were almost negative for CD20.
DNA extracted from the paraffin block of the initial MF and MC showed the same T-cell receptor γ gene clonality performed by polymerase chain reaction analysis (Fig. 2I).2 Monoclonality in MC lesion was considered to be derived from CD4+ cells, CD30+ cells, or both.
All MC lesions were manually removed, and MF was treated again with NB-UVB with topical steroid with slight improvement. MC occurs not only in infants or sexually active adults, but also in immunosuppressive or immune-deficient patients.3 In addition, a patient with MF, in whom MC developed only on MF lesions, was previously reported.4 In that case, Th2 predominance in MF was speculated to cause MC virus (MCV) infection. Similarly, Th2 dominant condition in our patient, evidenced by the exacerbation of MF, might also cause the susceptibility to MCV infection.
In the previous study, most of the lymphocytes around MC lesions in the patients with no significant medical history were positive for CD3 and CD8. CD30+ cells were also present, but in small amount. DNA extracted from the paraffin block showed no evidence of T-cell receptor γ gene.1 CD8+ Th1-T-lymphocytes were considered to seem to clear viral infections.4 In our patient, the smaller CD8+ T-lymphocytes around the MC lesion were considered to be inflammatory Th1-T-lymphocyts, but not MF tumor cells.
Intriguingly, the same T-cell clonality was detected in MC lesion and the initial MF lesion in the present case. The number of CD4+ MF cells in the MC lesion might be large enough to show T-cell clonality, although no MC developed in MF lesion. The CD30+ larger cells infiltrated around the MC lesion showed irregularly-shaped nuclei, suggesting that these cells were MF tumor cells. MF cells are generally CD4+ Th2-T-lymphocytes, and CD30 is considered to be expressed in Th2-T-lymphocytes.5 Thus, some CD4+ cells were considered to be transformed to CD30+ cells. It is speculated that MCV infection first accumulated CD4+ MF tumor cells, and then transformed some of them to CD30+ cells. We do not know whether monoclonality was expressed in CD4+ cells, CD30+ cells, or both.
We gratefully appreciate Ms. Tomoko Tashima, Ms. Mami Nishida and Ms. Shoko Nakamura for secretarial work. We thank the patient for his participation.
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