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Int J Clin Exp Pathol 2013;6(4):749-756

Case Report
Mycosis fungoides in plaque stage with pronounced eosinophilic infil-tration,
folliculotropism, and concomitant invasive squamous cell carcinoma

Tadashi Terada

Departments of Pathology, Shizuoka City Shimizu Hospital, Shizuoka, Japan

Received January 30, 2013; Accepted February 20, 2013; Epub March 15, 2013; Published April 1, 2013

Abstract: Mycosis fungoides (MF) is a relatively rare cutaneous T-cell malignancy. Only two cases of MF with marked eosinophilia have been
reported. In addition, MF with concomitant squamous cell carcinoma (SCC) occurring in the site of MF has not been reported. The author
reports herein a very rare case of MF in the plaque stage showing pronounced eosinophilic infiltration, folliculotropic pattern, and in situ
development of poorly differentiated squamous cell carcinoma (SCC). A 75-year-old man was found to show high prostate specific antigen
(PSA, 13 hg/ml) and prostatic biopsy showed well differentiated prostatic adenocarcinoma of Gleason score 6. Imaging techniques showed no
metastatic lesions. He was treated by estrogen therapy. At 80 years, he consulted our hospital because of erythematous patch in the trunk.
Biopsy showed mild infiltrations of lymphocyte and eosinophils. The lesion disappeared spontaneously. At 82 years, he consulted our hospital
of because of erythematous patch at the back, and biopsy showed mildly atypical lymphocytes positive for CD20 and CD45, but negative for
CD30, CD45RO, S100 protein, and cytokeratin (CK). Lymphoma was suspected but not definite. The lesions spontaneously disappeared. At 86
ages, he also consulted our hospital because of plaques in the face. Biopsy showed proliferation of atypical lymphocytes, marked infiltration of
mature eosinophils, marked infiltration of these cells in the fair follicles (folliculotropism), and poorly differentiated invasive SCC arising from
follicular cells. An immunohistochemical analysis showed that the atypical lymphocytes are T-lymphoma cells with T-cell markers, cyclinD1,
p53, and high Ki67 labeling (50%) but without B-cell markers, NK-cell markers and plasma cell markers. The eosinophils were mature, and
lacked p53 and showed low Ki67 labeling (4%). The carcinoma was positive for CK, p53, cyclinD1, and high Ki67 labeling (35%). A diagnosis
of MF in the plaque stage with marked non-neoplastic eosinophilic infiltration, marked folliculotropism, and coexistent poorly differentiated
invasive SCC was made by the author. Post-biopsy imaging techniques showed no metastasis or lymphadenopathy in the body. The patient
was now treated by chemotherapy. (IJCEP1301060).

Keywords: Mycosis fungoides, eosinophils, squamous cell carcinoma

Address correspondence to: Dr. Tadashi Terada, Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231 Shimizu-Ku,
Shi-zuoka 424-8636, Japan. Tel: +81-54-336-1111; Fax: +81-54-334-1173; E-mail: piyo0111jp@yahoo.co.jp