Interdigitating dendritic cell sarcoma involving bone marrow in a liver transplant recipient.

Liver transplantation is an effective treatment for patients with many kinds of liver diseases. However, an increased risk of de novo malignancy has been reported in liver transplant recipients; immunosuppressive drugs have generally been identified as the primary culprit. Interdigitating dendritic cell sarcoma (IDCS) is an exceedingly rare neoplasm arising from antigen-presenting cells of the immune system. In this study, we have reported a case of IDCS with bone marrow involvement occurring in a 61-year-old female liver transplant recipient at 2 years after the procedure. She was admitted to our center with fever, cough, and expectoration. Physical examination revealed firm and painless nodes in both cervical and axillary fossae. Routine examination revealed an abnormal white blood cell count and elevated serum lactate dehydrogenase. Computerized tomography of the chest, abdomen, and pelvis were negative. Viral infections were also excluded. To obtain a definite diagnosis, we performed an excisional lymph node biopsy and a bone marrow biopsy. Microscopically, the tumor was composed of spindle cells with pale to eosinophilic cytoplasm, ill-defined cell borders, and large pleomorphic nuclei with prominent nucleoli. Immunophenotypic analysis demonstrated positive staining for S-100, vimentin, CD163, and CD68. Follicular dendritic cell, lymphoid, epithelial, myoepithelial, and melanoma markers were negative. Histology revealed bone marrow involvement. Taken together, the above features were consistent with IDCS with bone marrow involvement. She responded to chemotherapy. This case demonstrates the importance of cancer prevention and early detection for liver transplant recipients.