Practical application and clinical impact of the WHO histopathological criteria on bone marrow biopsy for the diagnosis of essential thrombocythemia versus prefibrotic primary myelofibrosis.

AIMS: To evaluate the feasibility of the histopathological diagnosis of prefibrotic-early primary myelofibrosis (PM) as described in the World Health Organization (WHO) classification and to evaluate the clinical implications of prefibrotic-early PM in a series of patients previously diagnosed as having essential thrombocythemia (ET) according to the Polycythemia Vera Study Group criteria. METHODS AND RESULTS: WHO criteria were applied to bone marrow biopsy specimens by two pathologists who then reclassified 127 cases as 102 ET (80.3%), 18 prefibrotic-early PM (14.2%) and seven fibrotic PM (5.5%). In 45 cases (35%), the final diagnosis was only reached by consensus. The megakaryocytic criteria that best discriminated between ET and prefibrotic-early PM were an increased nucleo-cytoplasmic ratio, presence of cloudlike nuclei, hyperchromatic-dysplastic nuclei, paratrabecular megakaryocytes and tight clusters. A histological score discriminated between ET (score < or =3) and PM (score > or =6), but 21 cases showed an intermediate ambiguous score. No significant differences were observed at diagnosis and at follow-up (median time 93 months) for thrombosis, major haemorrhage, laboratory data, transformation into overt myeloid metaplasia and survival. CONCLUSIONS: The distinction between ET and prefibrotic-early PM is impaired by subjectivity in pathological practice and is of questionable clinical relevance, at least when considering individual patients.

Hyperdiploidy is a common finding in monoclonal gammopathy of undetermined significance and monosomy 13 is restricted to these hyperdiploid patients.

PURPOSE: Two pathways, hyperdiploid and nonhyperdiploid, are proposed for progression to plasma cell neoplasia. Implication of monosomy 13 (Delta13) is unclear in monoclonal gammopathy of undetermined significance (MGUS), and data on DNA content of plasma cells [DNA index (DI)] are rare. EXPERIMENTAL DESIGN: We ascertained DI in 169 multiple myeloma (MM) and 96 MGUS patients. Interphase fluorescence in situ hybridization (FISH) coupled to cytoplasmic staining of specific Ig (cIg-FISH) was done to look for trisomies and to ascertain Delta13. RESULTS: Hyperdiploidy and hypodiploidy were found in 54% and 11.5% of MGUS patients and in 59.5% and 25% of MM patients, respectively. In MGUS patients tested using probes for odd chromosomes, cIg-FISH showed association between trisomies for chromosomes 3, 7, 9, 11, or 15 and hyperdiploidy. Delta13 was found in 45.3% and 24.6% of MM and MGUS patients, respectively. Most Delta13 cases observed in MGUS were found within hyperdiploid clones, 38% versus 11% in hypodiploid cases, in sharp contrast with the occurrence of Delta13 in MM patients, 31.9% and 76.3%, respectively. That peculiar distribution of Delta13 according to DI persisted with other thresholds used to ascertain hyperdiploidy, such as DI >or= 1.05. A strong relationship between IgA peak and hypodiploidy (P = 0.007) was only observed in MM, whereas lambda light chain was significantly associated with hypodiploidy in MGUS (P = 0.001) and MM (P = 0.05). Hyperdiploidy shows similar pattern in MGUS and MM. CONCLUSION: This fits well a hyperdiploid pathway leading to MM after a preceding MGUS stage. Yet-to-be-determined secondary event(s) needs to occur for the transition to MM, unrelated to changes in chromosome number or to loss of chromosome 13. In contrast, the "nonhyperdiploid" pathway needs to be clarified further because hypodiploidy is less common in MGUS than in MM and Delta13 is rare in hypodiploid MGUS patients compared with hypodiploid MM patients.

[Acral myxoinflammatory fibroblastic sarcoma: a report of two cases]. / Sarcome fibroblastique myxoinflammatoire acral: à propos de deux cas.

Acral myxoinflammatory fibroblastic sarcoma is a rare low-grade malignant soft tissue tumor, usually observed in the extremities of middle-aged adults. We report two cases which occurred in the thumb and knee of middle-aged women. Both tumors showed a multinodular architecture, with cellular areas, occasional foci of hyalinized fibrosis, and hypocellular areas with a myxoid background. Various neoplastic cells were identified including spindled or rounded epithelioid cells and occasional bizarre giant cells, morphologically mimicking Reed-Sternberg cells or ganglion cells. Tumor cells were strongly immunoreactive for vimentin, and variably positive for CD68 and CD34. Both tumors were completely resected and patients were free of disease without any further treatment after a mean follow-up of 14 months.