Primary CD30/Ki-1 positive anaplastic large cell lymphoma of skeletal muscle with der(17)t(1;17)(q11;p11)

Abstract

CD30/Ki-1 positive anaplastic large cell lymphoma (Ki-1 ALCL) frequently exhibits extranodal disease and chromosomal t(2;5)(p23;q35). An 11-year-old girl presented with an intramuscular tumor of the right upper arm. Tumors of the chest wall, left arm and leg, hepatomegaly, pleural effusion, and enlarged lymph nodes then developed. The intramuscular tumor and pleural effusion showed a diffuse infiltration of large atypical cells with abundant amphophilic cytoplasms. The tumor cells were positive for CD30, CD2, CD45RO, and p80, but were negative for other T-cell, B-cell, and myeloid cell antigens. She was diagnosed as having Ki-1 ALCL with a T-cell origin. Cytogenetic studies showed an abnormal karyotype including a der(17)t(1;17)(q11;p11). She received seven cycles of intensive chemotherapy followed by an autologous peripheral blood stem cell transplantation, and has been in complete remission for more than two years. The primary involvement of skeletal muscle is quite uncommon in ALCL, and an abnormal karyotype including t(1;17)(q11;p11) has not been reported previously. Since a high frequency of aberrations of 1p36/1q12 or 17p13.3 was detected in sarcoma cells, the presence of suppressor genes is suggestive in these sites.

Introduction

Ki-1 anaplastic large cell lymphoma (Ki-1 ALCL), which was first described by Stein et al. [1], is now classified as a high-grade non-Hodgkin lymphoma (NHL) [2]. Ki-1 ALCL is characterized by the proliferation of large bizarre blasts expressing the CD30/Ki-1 antigen 1, 3. Ki-1 ALCL frequently exhibits extranodal disease sites including the skin, lung, bone, soft tissue, and gastrointestinal tract 4, 5, 6. However, true primary involvement of skeletal muscle is quite uncommon and only a few cases have been reported in the literature [7].

Phenotypically, the majority of Ki-1 ALCL cases have been shown to express T-cell markers, whereas some of them express neither T-cell nor B-cell markers 8, 9, 10. In earlier reports, the t(2;5)(p23;q35) was a specific chromosomal marker in Ki-1 ALCL 11, 12; however, it has been reported that t(2;5) is only present in 12% to 50% of Ki-1 ALCL cases, usually of T-cell phenotype 13, 14. It was reported that the t(2;5)(p23;q35) in Ki-1 ALCL is associated with advanced stage disease with nodal involvement, as well as chemosensitivity at diagnosis and relapse [4].

We report a case of Ki-1 ALCL originating from a skeletal muscle. A der(17)t(1;17)(q11;p11) was detected in malignant cells, which has not been reported previously. The patient has been in complete remission with intensive chemotherapy followed by an autologous peripheral stem cell transplantation for more than two years. The clinical and cytogenetic features of Ki-1 ALCL in children has also been discussed.