Histiomonocytic malignancy. A spectrum of disease in an 11-month-old infant

Leukemic Phase of Histiocytic Sarcoma of the Digestive System: A Rare Manifestation of a Rare Disease

Histiocytic sarcoma (HS) is a rare, malignant, and aggressive subtype of histiocytosis. We present an unusual case of aggressive HS presenting in the gastrointestinal tract and gallbladder that progressed after several lines of chemotherapy with a leukemic phase. We review the clinical, pathological, and molecular characteristics of HS in this case and review the literature on HS involving the digestive system as well as on overt leukemic phase of this disease. HS is often diagnosed at an advanced stage, and mortality is high. We discuss the therapeutic approach to patients with HS. We highlight the role of overexpression and somatic alterations in the RAF-MEK-ERK pathway in the pathogenesis of HS and discuss potential targeted approaches to treat these rare tumors.

Anaplastic large cell lymphoma of true histiocytic origin in an infant: unusual clinical, hematological, and cytogenetic features

We report here the case of a 7-month-old boy who developed anaplastic large cell lymphoma of true histiocytic origin or malignant histiocytosis, with fever, bone and bone marrow infiltration. Usual clinical features were absent. The neoplastic nature of the disease was supported by the presence of clonal chromosomal abnormalities [t(6;8)(p23;p21),der(8)del(8)(q11aq13), der(22) t(11;22) (q13;13)]. Neither B nor T lineage could be demonstrated here. Morphology, ultrastructural analysis, surface antigens expression, and cytogenetics were more specific for the monocyte-macrophage lineage.

Hemophagocytosis and acute monoblastic leukemia

A 16-month-old girl presented with hepatosplenomegaly and pancytopenia. Bone marrow aspiration showed a florid increase in macrophages with marked hemophagocytosis. She subsequently improved spontaneously with no therapeutic intervention, but 2 months later presented with frank acute monoblastic leukemia. This case illustrates the difficulties in classifying malignancies of the monocyte-macrophage lineage and how hemophagocytosis can be the presenting feature of a range of diseases.

Monocytic leukemia in infancy. A review of eight children

The clinical and pathologic features of eight infants with monocytic leukemia are reviewed. The children were all aged 12 months or less at diagnosis and had a high incidence of extramedullary features, skin infiltration being particularly common. The diagnosis was established by conventional morphologic and cytochemical techniques. Using the French-American-British (FAB) classification, five infants had FAB 5a disease, and three had FAB 5b. The difficulties in making the diagnosis from extramedullary sites and the overlap that exists at this age between monocytic leukemia, true histiocytic lymphoma, and malignant histiocytosis are discussed. The treatments given to the group and their response are reviewed. Five of the patients received VP-16-213 and cyclophosphamide as primary induction chemotherapy, a combination that merits further evaluation in leukemia with monocytic features.