Dear Editor: The patient was a female newborn, 3200 g in weight, 50 Cm in length, who presented at birth with a firm mass on the left upper arm, measuring 25×16×45 mm in size. Physical examination revealed a non-movable mass with firm consistency and mild tenderness on the left upper arm. Family and maternal histories were unnoteworthy, and the laboratory examination was normal. An excisional biopsy of the mass was performed and the histopathological findings of the excised lesion were ES/PNET. Immunohistochemistry was positive for CD99, NSE, PCK, desmin, and negative for CK. In enhanced chest CT, abdominal ultrasonography, and whole body bone scan no evidence of abnormality or metastasis was detected. Bone marrow biopsy and further treatment were refused by her parents.

Primitive neuroectodermal tumor (PNET) of kidney is an extremely rare renal neoplasm with only about fifty reported cases in literature. Presumably, of neural crest origin, these tumors behave aggressively and carry a poor prognosis. We report a case of 22-year old female patient complaining of left loin pain with recurrent hematuria for last 3 months. On clinical examination, the abdomen was soft and no palpable mass was felt. She underwent ultrasonography and computed tomography, which revealed a left renal mass. A left radical nephrectomy was performed.Histopathological examination of the nephrectomy specimen showed features of primitive neuroectodermal tumor arising from left kidney, which was confirmed by immunohistochemistry (IHC). The patient was treated with post-nephrectomy chemotherapy and was symptom-free at six-month follow-up.

Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/PNET) typically occurs in long or flat bones, soft tissues, or less often, solid organs. Ewing sarcoma/peripheral primitive neuroectodermal tumor arising from the adrenal gland is extremely rare, especially in children, and only limited cases are reported previously. Herein, we review a case of a 22-month-old girl who presented to our department with abdominal pain, bulging of the left flank, and a nonfunctioning adrenal lesion which was found to be an adrenal ES/PNET. The patient was successfully treated with surgery and adjuvant chemotherapy. Since delayed diagnosis may result in metastatic lesions, this case underscores the importance of considering ES/PNET in the differential diagnosis of large adrenal masses.

Embryonic stem (ES) cells are regarded as a very promising source of differentiated cells for tissue regeneration. ES cell-derived cardiomyocytes could functionally replace irreversibly lost cardiac tissue in various animal models of ischaemic heart disease. However, clinical application of this therapeutic approach will be hampered by immunological rejection of transplanted cells by histoincompatible recipients. To address the question of immunological properties of murine ES cell-derived cardiomyocytes we have utilized a transgenic murine ES cell line D3αPIG engineered to express GFP and antibiotic resistance specifically in ES cell-derived heart cells. This cell line enabled us to highly purify GFP-positive cardiac progenitor cells and to specifically address the question of their immunogenic properties. To this end, we have determined their immunophenotype by flow cytometry, assessed their response to the inflammatory cytokine interferon gamma, assayed their physical interaction with cytotoxic T lymphocytes and tested their susceptibility to lysis by activated NK cells and cytotoxic T cells. These studies have demonstrated that ES cell-derived cardiomyocytes constitutively express very low levels of MHC class I molecules on their cell surface, which were strongly upregulated by interferon gamma. Interestingly, the cytotoxicity experiments revealed that ES cell-derived cardiac cells were resistant to killing by poly I: C activated syngeneic and allogeneic NK cells as well as by allogeneic cytotoxic T cells. Even strong upregulation of MHC class I molecules on the surface of cardiac cells by interferon gamma did not render them sensitive to lysis by immune effector cells, indicating that transplanted ES cell-derived cardiomyocytes might be less susceptible to rejection as compared to whole organ transplants. Ongoing studies are aimed at elucidating the molecular basis of this resistance and assessing the engraftment capacity and immunogenicity of ES cell-derived cardiomyocytes in vivo upon allotransplantation.