Erythroid sarcoma is very rare form of pure erythroid leukemia with undetermined biological features. Here, we present an infant with a multifocal erythroid sarcoma, diagnosed because the tumor cells were positive for glycophorin A. After acute myeloid leukemia-oriented chemotherapy and surgical resection followed by cord blood transplantation, he has successfully maintained complete remission without any late effects. Total transcriptome analysis of the tumor identified a novel fusion gene, RCC1-LCK, and high LCK expression levels, suggesting that LCK overexpression was involved in leukemogenesis in this case.

Rhabdoid tumors (RTs) are a rare and aggressive pediatric cancer that commonly show alterations in the tumor suppressor gene SMARCB1. However, RT prognosis is still poor, with no standard treatment, predictive biomarkers for its aggressiveness, or chemo- and radio-sensitivity. Herein, four cases of extra-cranial RTs are described, two of which were in long-term survivors. These two surviving cases were positive for p16, whereas the other two were p16-negative. These findings suggest that p16 expression may represent a potential positive prognostic biomarker in RTs; nevertheless, further studies are required.