Tomomitsu Tsuru

Cryptic t(12;15)(p13;q26) producing the ETV6-NTRK3 fusion gene and no loss of IGF2 imprinting in congenital mesoblastic nephroma with trisomy 11: fluorescence in situ hybridization and IGF2 allelic expression analysis.

In the present fluorescence in situ hybridization (FISH) study of six congenital mesoblastic nephromas (CMNs) using ETV6 and NTRK3 probes as well as a chromosome 15 painting probe, we identified a cryptic reciprocal translocation, t(12;15)(p13;q26), in one tumor, and an insertion, ins(12;15)(p13;q22q26), in another that were not previously identified by cytogenetic analysis. An interphase FISH study with the same probes detected the ETV6-NTRK3 fusion signal in all three cellular or mixed type tumors, but not in all three classical type tumors. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis detected the ETV6-NTRK3 fusion transcript in the three cellular or mixed type tumors, but not in the three classical type tumors. FISH analysis using a chromosome 11-centromere probe detected trisomy or tetrasomy 11 in all three tumors with the ETV6-NTRK3 fusion signal. To clarify whether IGF2, a paternally expressed gene on chromosome 11, has a certain role in the tumorigenic process of CMN through a loss of imprinting (LOI), we studied IGF2 allelic expression. We found no LOI in two cellular or mixed type tumors or in two classical type tumors, and concluded that the role of the LOI of IGF2 is not essential for the development and progression of CMN with or without trisomy 11. Furthermore, we showed no rearrangements of the MLL gene, which is frequently rearranged in acute leukemia with +11 in the three CMN tumors with +11.

Mesenchymal Hamartoma of the Liver Accompanied by a Daughter Nodule: Report of a Case

Mesenchymal hamartoma of the liver (MHL) is an uncommon benign tumor found primarily in children younger than 2 years of age. We report a rare case of MHL with a daughter nodule and atypical histological findings in a 14-month-old girl. On admission, computed tomography, magnetic resonance imaging, and angiography showed a solid hypovascular mass with a central cystic area in the liver. Laparotomy revealed a tumor, 8 cm in size, occupying segment 5 and parts of segments 4 and 6 of the liver, and a small nodule, 10 mm in size, in segment 7. Thus, we performed a partial hepatic resection (S4–6) and tumor extirpation (S7). The histological findings of both tumors were the same, but atypical of MHL. Recent studies on the pathogenesis of this tumor have found neoplastic features such as genetic anomalies and malignant transformation. These findings suggest that the conventional approach of completely resecting the tumor whenever possible is the best treatment.

Thoracic Lymphangiomatosis with Massive Chylothorax After a Tumor Biopsy and with Disseminated Intravenous Coagulation-Lymphoscintigraphy, an Alternative Minimally Invasive Imaging Technique : Report of a Case

Thoracic lymphangiomatosis in childhood is a rare disorder that frequently has poor response to medical therapy as well as a poor prognosis. This disease is often misdiagnosed, and a definitive diagnosis is usually delayed because of the rarity and slow course of the disease. No previous reports have so far described the usefulness of lymphoscintigraphy in the diagnosis of lymphangiomatosis, although some authors have reported the efficacy of lymphoscintigraphy for evaluating chylothorax. A 6-year-old boy presented with a diffuse mediastinal mass and received an open mediastinal biopsy for a definitive diagnosis, which led to the occurrence of massive chylothorax postoperatively. A diagnosis of lymphangiomatosis was finally made based on the lymphoscintigraphic findings demonstrating an obstruction of the thoracic duct. This report describes a rare case of thoracic lymphangiomatosis diagnosed at autopsy, and suggests that the minimally invasive technique of lymphoscintigraphy should be employed to obtain a definitive diagnosis at an early stage.