Marleen Renard

Multifocal kaposiform haemangioendothelioma

Kaposiform haemangioendothelioma (KHE) is a rare, locally aggressive vascular spindle cell proliferation, with resemblance to Kaposi’s sarcoma. This tumour usually occurs in skin and retroperitoneum of infants and young children and is often complicated by the Kasabach–Merritt phenomenon (KMP). A 3-year-old boy presented with a right submandibular swelling due to lymphadenopathies, a violaceous skin lesion at the left commissure of the lips and an ill-defined lesion in the right thyroid lobe. There were some signs of KMP. Histological examination revealed a typical infiltrative multilobular spindle cell proliferation with slit-like vascular spaces in these three localisations. Immunohistochemical stains showed positivity for CD34 and CD31 and many alpha-smooth muscle actin-positive spindle cells around the vascular spaces. There was no Herpes virus type 8 expression. The presented case is unique in two ways. First, thyroid involvement of KHE has never been described in the literature until now. Secondly, and most remarkably, the multifocal presentation in three anatomically distinct and separated localisations is extremely unusual.

Imatinib Mesylate in the Treatment of Diffuse Cutaneous Mastocytosis

Diffuse cutaneous mastocytosis is a less common but potentially life-threatening variant of childhood mastocytosis. Here we report 2 children with diffuse cutaneous mastocytosis in whom an activating somatic KIT mutation was detected. Treatment with imatinib, a KIT inhibitor, resulted in resolution of the lesions and were well tolerated by the patients.

Cytokeratin-positive meningeal peripheral PNET/Ewing's sarcoma of the cervical spinal cord: diagnostic value of genetic analysis.

Peripheral primitive neuroectodermal tumor (PNET)/Ewings sarcoma (ES) of the central nervous system is extremely rare and should be differentiated from central PNET and other small blue round cell tumors. We describe a case of a meningeal peripheral PNET/ES of the spinal cord in an 11 -year-old boy. Immunohistochemically, the small blue round cell tumor showed expression of epithelial markers and of CD99, thus posing an important differential diagnostic problem with a poorly differentiated synovial sarcoma. Fluorescence in situ hybridization revealed rearrangement of the EWS gene, as seen in peripheral PNET/ES. Peripheral PNET/ES does occur in the central nervous system, but its diagnosis can be extremely difficult on morphologic and immunohistochemical grounds alone. Genetic analysis plays a key role in its distinction from other small blue round cell tumors.

5q — syndrome in a child

A boy aged 8 years, 10 months presented with refractory anemia. Bone marrow investigation revealed monolobular megakaryocytes. Cytogenetic analysis showed a clonal abnormality: 46, XY, del(5)(q14q32). This is the youngest individual ever reported with this disorder. A year after diagnosis, while on treatment with human recombinant erythropoietin, the bone marrow showed an excess of blasts. No bone marrow donor could be found. Transformation to acute myelomonocytic leukemia occurred 3 months later. In spite of intensive chemotherapy, the child died of progressive disease with massive splenomegaly and jaundice. The case illustrates that the 5q- syndrome can occur de novo in children. The outcome in this child was poor, which may reflect a difference from the adult 5q- syndrome or may possibly be related to the erythropoietin the child received.