We studied 24 cases of cutaneous T-cell lymphomas and six cases of benign lymphoproliferative diseases of the skin (2 Jessner's lymphocytic infiltration, 2 pseudolymphoma, 2 lymphomatoid papulosis) for the presence of Epstein-Barr Virus(EBV) RNA, using the in situ hybridization(ISH) method.
Among the 24 cases of cutaneous T-cell lymphomas (CTCL), 18 cases including 12 cases of mycosis fungoides(MF) were primary CTCL, and the other 6 cases were secondary CTCL. The ISH study demonstrated a positive reaction for EBER probe in 6 out of the 24 cases(25%) of CTCL, and a negative reaction for BHLF nuclear RNA probe in all the cases studied.
Double-labelling immunohistochemistry/ISH studies revealed that the EBV positive cells were CD45RO positive and CD20 negative. EBV genome was not demonstrated in any benign lymphoproliferative diseases of the skin. Among the EBER positive cases, none of the 12 cases of MF demonstrated EBER signals, and 6 out of the 12(50%) cases of CTCL were positive for EBER probe. In conclusion, latent infection of EBV may play a role in the development of non-mycosis fungoides T-cell lymphomas involving the skin.
Forty eight skin biopsies obtained from 24 patients were reviewed, and clinical, histological and immunohistochemical findings were analyzed. Results obtained are as follows: 1) Skin manifestation was plaque, erythroderma, scale and hyperpigmentation in mycosis fungoides, and subcutaneous nodule, mass and ulcerated patch in cutaneous lymphoma. The skin of lymphomatoid papulosis revealed hemorrhagic ulcerated and erythematous papules which healed spontaneously. 2) Histologically, mycosis fungoides showed epidermotropism in most cases. Pautrier's micro-abscesses were present in one-fourth of the cases. Malignant lymphoma was different in histology from mycosis fungoides. As compared with mycosis fungoides, it showed less frequent epidermotropism, more compact and diffuse infiltration of atypical lymphocytes, more often association with ulcer and necrosis, and more frequent mitotic figures. Lymphomatoid papulosis showed striking hemorrhage and edema of the papillary dermis. 3) Based on the results of immunohistochemical study, mycosis fungoides and lymphomatoid papulosis were considered as a T cell proliferative disorder of the skin. According to these findings, lymphoproliferative disorders of the skin occurred predominantly in the elderly and males. Clinical and histopathologic findings overlapped and were similar each other. It was difficult to make a definite diagnosis in early lesions, and a sequential follow up biopsy was required. It is concluded that strict criteria such as marked atypia and clustering of atypical cells are necessary for a histologic diagnosis of malignant lymphoproliferative disorder of the skin.