Subcutaneous panniculitis-like T-cell lymphoma presenting with hemophagocytic lymphohistiocytosis and skin lesions with characteristic high-resolution ultrasonographic findings

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is an unusual type of skin lymphoma, characterized by subcutaneous soft tissue infiltration with pleomorphic T-cells and benign macrophages that mimic panniculitis. Hemophagocytic lymphohistiocytosis is a rare but potentially fatal disorder which is thought to result from uncontrolled activation and proliferation of T-cells and excessive activation of macrophages. Hemophagocytic lymphohistiocytosis have been reported as the presenting feature in 37% of SPTCL patients. High-resolution ultrasonographic appearance of SPTCL with a characteristic finding has been described in only one patient. We report a 28-year-old woman with hemophagocytic lymphohistiocytosis presented with nonremitting fever, thrombocytopenia, hypofibrinogenemia, hyperferritinemia, increased serum levels of soluble interleukin (IL)-2 receptors and hemophagocytosis in bone marrow examination. Markedly elevated level of serum IL-18 was also demonstrated in our patient. The fever subsided and the ferritin level declined to normal after treatment with oral steroid and etoposide. No evidence of hemophagocytosis was revealed in a follow-up bone marrow examination. However, nonremitting high fever and panniculitis-like skin lesions over her back, arm, lower abdominal wall, and bilateral pretibial regions developed 1 month later. A high-resolution ultrasonography revealed thickening of the subcutaneous fat layer with homogeneous hyperechogenicity pattern and poor-defined margin over the skin lesions. An ultrasound-guided excision biopsy of the nodular lesion over left upper arm was performed and the histopathology showed neoplastic cells with hyperchromatic nucleoli, which extended from deep dermis to subcutaneous fat. The immunochemical stain showed a T-cell lineage of tumor cells. SPTCL was diagnosed and the skin lesions subsided gradually after treatment with anthracycline-based combination chemotherapy.