Malignant histiocytosis with central nervous system involvement and hepatic mucinous cystadenoma in a single patient with review of the literature.

Malignant histiocytosis is a rare neoplasm of the reticuloendothelial system characterized by neoplastic proliferation of tissue histiocytes. We report a case of malignant histiocytosis in a 64-year-old female initially operated on for a mucinous cystadenoma of her liver. Four months after the operation, skin induration on the neck and anterior thoracic wall and systemic lymphadenopathy were noted. Histology and immunohistochemistry of the lymph node and bone marrow specimens showed extensive infiltration with atypical cells, resembling malignant histiocytes (CD45, CD45RO, CD11c, CD68, lysozyme, antitrypsin and alpha1-antichymotrypsin positive; CD1, CD35, B-cell and T-cells markers negative). She was treated with vinblastine, methotrexate and dexamethasone (3 cycles) without response. The therapy was switched to CHOP (cyclophosphamide, vincristine, doxorubicin, and prednisone) with disappearance of lymphadenopathy. Bone marrow infiltration by histiocytes was reduced to 20%. Two months after completion of 8 cycles of CHOP she experienced severe headaches, vomiting, loss of consciousness, and developed paraparesis. A CT scan of the brain was normal but the cerebrospinal fluid cytology showed presence of histiocytes. The patient was then treated with intrathecal methotrexate, prednisolone and cytosine-arabinoside and systemic chemotherapy with etoposide and cyclophosphamide. Her condition improved, she became conscious, her headache diminished, she became mobile but skin and nodal lesions reappeared along with extensive marrow histiocytic infiltration. She finally died 22 months after diagnosis.