Importance of Clinical and Morphological Correlations in Diagnosing Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is a clonal histiocytic disorder. The variable clinical manifestations from isolated bone lesion to multisystem disease can cause difficulties and delay in diagnosis. We report a 2 years and 8 months-old girl who presented with a 2 weeks history of persistent fever and weight loss associated with progressive abdominal distension. Physical examination revealed pallor, bilateral proptosis, seaborrheic dermatitis over the scalp and hepatosplenomegaly. Skull X-ray demonstrated multiple lytic lesions at the base and the skull vault. Bone marrow morphology showed numerous abnormal Langerhans cells (LCs) and foamy macrophages. The trephine immunohistochemistry (IHC) stains for CD1a, S-100 and CD68 were inconclusive. The diagnosis of multisystem Langerhans cell histiocytosis (MS-LCH) in this patient was based on the clinical presentation, radiological and morphological analysis. She subsequently received chemotherapy and currently she is on maintenance therapy with a good clinical response. LCH is a rare disease and although the IHC was inconclusive, the correlation of clinical, radiological and morphological data are essential for the diagnosis.

The Msi2 Protein Expression Positive Correlation with Favorable Cytogenetics Findings in AML

Acute myeloid leukaemia (AML) is the most common subtype of acute leukaemias with a poor outcome. Msi2 protein is a newly discovered prognostic marker and it has been considered as a new target for therapy in AML. The study of Msi2 protein expression in AML cases has not been performed in Malaysia, to date. The main aim of the present study was to observe the expression of Msi2 protein in AML patients by immunohistochemistry (IHC) and to correlate its expression with the well-established prognostic and clinical parameters in AML as well as the overall survival (OS). Sixty four bone marrow trephine biopsy sections were immunostained for Msi2 protein. The percentage of blasts with positive reaction and the intensity of the cytoplasmic and nuclear staining were evaluated. The expression of Msi2 protein was found in 95.3% cases with Msi2 pattern varying between the cases. In 71.9% of cases, the blasts showed total cellular positivity and 23.4% cases showed only cytoplasmic positivity. Majority showed high expression of Msi2 for cytoplasmic staining. Interestingly, there was significant correlation between total cellular staining and the intermediate cytogenetic subgroup (P= 0.04). In conclusion, the results showed that the majority of the patients had high expression of Msi2 but this did not correlate to OS. However, the Msi2 expression correlated to the cytogenetic findings. The results suggest future extensive research to be conducted in order to ascertain the exact role of Msi2 positive blast cells in AML in our population and their association with prognosis and outcome.