A Case of Malignant Histiocytosis having Polyploid Clones Characterized by an Isochromosome of the Long Arm of Chromosome 17 [i(17q)] and t(9;22) Translocation

We report an interesting case of Malignant Histiocytosis (MH) with polyploid clones characterized by i(17q) and t(9; 22) translocation. A 47-year-old man had lymphadenopthy, splenomegaly and leukopenia at presentation. Bone marrow (BM) cytology showed 10.5% abnormal histiocytes. Karyotypic analyses with R- and G-banding techniques on BM cells revealed complex abnormalities: 88, XXYY, add(2) (p25), -4, -8, -11, i(17q), -21[4]/89, idem, t(9; 22) (q34; q11), +22[26]/46, XY [47], of which, t(9; 22) was confirmed by fluorescence in situhybridization using a chromosome 22 paint wcp 22+. This patient was treated with interferon-alpha and COP regimen. 10 months later he achieved a complete hematologic and cytogenetic remission (CR). However, relapse occurred one year after achieving CR. At that time, cytogenetic examination showed a new polyploid clone characterized by add(1) (p36), add(2) (p25), -4, -8, t(9; 22), -11, i(17q), -21, +22 in addition to the other two polyploid clones observed previously. RT-PCR indicated that the BCR/ABL transcript (165bp) observed in classic chronic myeloid leukemia, was present, MH with t(9; 22) has not previously been described in the literature. This case may be the first one of MH with t(9; 22), and is likely a secondary event.