Extranodal NK/T-cell lymphoma with extensive subcutaneous involvement, mimicking subcutaneous panniculitis-like T cell lymphoma

Abstract

A 22-year-old man had a subcutaneous nodule on the left thigh for 3 months. Physical examination showed an ulcerative nodule on the left thigh (Fig. 1). He suffered from a fever for 1 week. Laboratory tests revealed a white blood cell count of 7180/mm3, with 22.4% neutrophils, 68.5% lymphocytes, 8.4% monocytes, 0.3% eosinophils, and 0.4% basophils. Hemoglobin was 9.0 g/dL, hematocrit was 28.1%, and the platelet count was 202 × 109/L. Analysis of serum showed the following abnormal results: aspartate aminotransferase, 102 IU/L (normal, 13–37); alanine aminotransferase, 77 IU/L (normal, 7–43); alkaline phosphatase, 1296 (normal, 70–270); LDH, 1105 (normal, 120–520). Results of other laboratory tests including serum electrolytes, blood and tissue culture, and viral markers for hepatitis were negative or normal. Ultrasonography and computed tomography of abdomen and pelvis showed hepatosplenomegaly with ascites. Whole body bone scan showed an increased long bone activity of the left leg. Bone marrow aspiration was negative for neoplastic cells. Histologic examination from the thigh nodule revealed subcutaneous lymphoid infiltrates with involvement of the deep dermis. Examination at high power magnification showed small, medium, and large-sized, pleomorphic lymphoid cells with hyperchromatic nuclei, nuclear debris, and phagocytic macrophages. Fat necrosis, partial rimming of fat spaces and clustering around blood vessels by pleomorphic lymphoid cells were also seen (Fig. 2). The immunohistochemical studies on paraffin sections revealed that most of the infiltrated lymphoid cells positively stained for CD56 (Fig. 3), granzyme B, TIA-1, cytoplasmic CD3, and CD45RO, whereas CD4, CD8, CD20, and CD30 showed no immunoreactivity. Clonality of the infiltrate was analyzed by polymerase chain reaction (PCR). Nested PCR was performed using FR3A and VLJH as primers for IgH gene and Vγ – Jγ for T-cell receptor γ chain gene. Polymerase chain reaction analysis showed a distinct band for TCR gene, confirming T-cell monoclonality of infiltrating lymphocytes. EBV-encoded small nuclear RNA was evident in lesional tissue by in situ hybridization. He was treated with two cycles of chemotherapy with CHOP-BV (Cytoxan 735 mg, adriamycin 45 mg, vincristine 1.45 mg, prednisolone 75 mg, bleomycin 15 mg, VP-16 150 mg). He died 5 days after chemotherapy.