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Histiocytosis X is a spectrum of diseases which should be classified among the wide spectrum of histiocytic disorders, consisting of proliferation of the Mononuclear Phagocyte System (MPS). The clinical manifestations reflect the site of histiocytic proliferation and may vary from a solitary bone lesion discovered by chance on X-ray film to a disease with a rapidly fatal course affecting almost any organ. The classic classification into eosinophilic granuloma of bone, Hand-Schüller-Christian disease and Letterer-Siwe disease and other related classifications fail to demonstrate the variable course and the smooth transitions, and do not correlate with the histologic findings and prognosis. The features of the immature and mature macrophage and, in this connection, the histologic findings of non-cutaneous material and the histochemical studies allow a classification into: The clinical manifestations themselves do not allow a distinction to be made between the two entities, but the latter may lead to severe dysfunction of certain organs. A survey of the clinical manifestations is given. Benign Histiocytosis X comprises a widely variable spectrum, ranging from a solitary bone lesion to disseminated disease, but mostly with favourable outcome; malignant Histiocytosis X has a uniform, rapidly fatal, acute course with severe dysfunction of organs. This classification is highly correlated with prognosis, which is based on histology, age at onset, dysfunction of liver, lung and hemopoietic system, and a score system. In differential diagnosis, malignant Histiocytosis X must be distinguished from other histiocytic disorders and combined immunodeficiency, which have very similar symptomatology, but often have a recessive inheritance. The etiology of Histiocytosis X is still unknown, but histochemical and electronmicroscopic studies point to a response of mature and immature histiocytes to an unidentified antigen. Treatment of bone lesions consists in curettage or irradiation (600-1000 rads), if the lesions give rise to symptoms. Relapses are frequent. In benign disseminated Histiocytosis X a treatment protocol similar to that of acute lymphoblastic leukemia (ALL) is proposed and a more intensive protocol in malignant Histiocytosis X. The prognosis of Histiocytosis X has substantially improved with the advent of multiple cytostatic treatment. Histiocytosis X is a spectrum of diseases of unknown etiology, consisting in a proliferation of differentiated cells of the Mononuclear Phagocyte System (MPS), known as histiocytes. The clinical manifestations are widely variable, mirroring the widespread distribution of the MPS, affecting almost any organ. As a result there are numerous smooth transitions between the three classical entities distinguished in the literature: eosinophilic granuloma, Hand-Schüller-Christian disease and Letterer-Siwe disease. Because of the variable course of Histiocytosis X, and for prognostic and therapeutic reasons, a classification based on clinical and histologic manifestations is desirable. The purpose of this report is to review the literature concerning the classification of histiocytic disorders and Histiocytosis X. On the basis of the clinical manifestations, their prognostic value and the histologic findings, a classification (Table 1) is given that will be relatively simple to use in practice as a guide to prognosis and therapy. [ABSTRACT FROM AUTHOR]

Aberrant DNA methylation can occur early in neoplastic transformation and may lead to the development of cancer. We describe the alterations of methylation patterns at the DNA sequence level which occurred in the 5' region of the calcitonin gene in lymphoblasts from 14 pediatric patients with acute lymphoblastic leukemia (ALL). The DNA methylation status of 25 CpG sites was determined by sequence analysis after bisulfite treatment of the DNA. This method showed that 13 out of 14 patients had increased numbers of methylated CpG sites in the calcitonin gene region at initial diagnosis when compared to control DNA from healthy individuals. The 5' region of the calcitonin gene appears to be methylated to a significantly higher degree in T lineage ALL compared to B lineage ALL (P < 0.01). Each of six ALL patients who were investigated at initial diagnosis and at relapse showed alterations in DNA methylation between the two stages. These six cases were also investigated by Southern blot analysis with methylcytosine-sensitive restriction enzymes and this method showed an increase in DNA methylation in only four of the six cases. The DNA sequencing method thus appears to be better suited to assess alterations of DNA methylation than Southern blot analysis. There are marked regional differences in the frequency of methylation of individual CpG sites and in the frequency of alterations between the two stages. Our results show that alterations in DNA methylation continue to occur from the initial stage to the relapse stage of ALL, suggesting that aberrant DNA methylation may play a role in tumor progression. [ABSTRACT FROM AUTHOR]

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Copyright of Tijdschrift Voor Kindergeneeskunde is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The first purpose of this study was to evaluate the saddle prosthesis in patients with periacetabular tumors in terms of the functional results obtained after several postoperative intervals. The second purpose was to evaluate the complications and how they might be prevented in the future. Functional results according to the MSTS functional rating system were evaluated at several postoperative intervals in 15 patients treated with internal hemipelvectomy and reconstruction with the saddle prosthesis because of periacetabular primary (n = 9) or secondary (n = 6) malignancies. All complications were evaluated. Three months postoperatively, 7/9 patients with a primary tumor and 2/4 patients with a secondary tumor were able to walk outside without pain. Median functional results 3 and 6 months postoperatively were 40% and 50%, respectively. Deep infection occurred in 4 patients and fracture of the iliac remnant in 2. Heterotopic ossifications along the interpositional component were seen in 5 patients, but they did not negatively influence the functional outcome. Three (relative) contraindications to reconstruction with the saddle prosthesis could be ascertained: osteoporosis, extended involvement of the iliac wing by tumor, and insufficient soft-tissue quality after previous procedures. (Short-term) functional results after reconstruction with the saddle prosthesis are satisfactory if the above-mentioned contraindications are taken into consideration. [ABSTRACT FROM AUTHOR]