We describe a 14-year-old boy who exhibited left palatine tonsillar enlargement after 6 cycles of aggressive chemotherapy for diffuse large B-cell lymphoma of the right palatine tonsil. The cervical computed tomography scan at 4 months after completion of chemotherapy revealed enlargement of the left palatine tonsil in addition to the thymus without any clinical symptoms. The F-fluorodeoxyglucose positron emission tomography indicated focal areas of strong F-fluorodeoxyglucose uptake in the left palatine tonsil. Histologic examination confirmed tonsillar hyperplasia with no evidence of recurrence. Reactive tonsillar hyperplasia after chemotherapy is rarely reported.

This study suggests the importance of the NUB domain in host defense against mycobacteria. The unique presenting features in our patient indicate that a hypomorphic NEMO mutation can be associated with atypical pathological findings of the epithelial tissues in patients with BCG infection.

No abstract

Histiocytic sarcoma, a rare hematopoietic neoplasm with evidence of histiocytic differentiation, is often refractory to conventional chemotherapy and radiotherapy, and its prognosis is generally dismal. The optimal management of this malignancy has not been established. We report a case of 8-year-old girl with histiocytic sarcoma involving the left femur. The tumor rapidly responded to a combination of cladribine and high-dose cytosine arabinoside, an aggressive salvage regimen for refractory Langerhans cell histiocytosis, and became impalpable during the first cycle. The patient has remained in complete remission more than 7 years from diagnosis.

To clarify the mechanism of progression and acquired drug resistance of leukemia, we searched for an overexpressed gene in drug-resistant leukemia cells and identified an approximately 5-kb transcript by using the subtraction method. The nucleotide sequence of the gene was highly homologous to those of human endogenous retrovirus (HERV) transcripts. Reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that the gene was overexpressed in cells from 6 childhood acute lymphoblastic leukemia patients (60%) but not in bone marrow cells at remission. Peripheral blood mononuclear cells from normal controls (n=11) and bone marrow cells from non-leukemia patients (n=13) did not express the gene. These findings indicate that the gene may play a role in leukemogenesis and may be a novel leukemia marker. Further studies on the functional role of the gene are needed.