Thymic Langerhans cell histiocytosis mimicking lymphoma

Langerhans cell histiocytosis (LCH) is a rare disorder characterized by clonal expansion of antigen presenting Langerhans cells. Different clinical features can be seen according to the involved organs and systems. Multisystem disease with organ dysfunction is more common in infants, whereas single system disease is usually observed in older children. The disease can affect any system or organ throughout the body. Thymus is a rarely involvement site reported in LCH and usually is accompanied by skin, bone or lung disease. Here we report a 12-year-old male with thymic involvement by LCH clinically mimicking lymphoma.     

Congenital histiocytosis X

Congenital histiocytosis X involving multiple organs is a rare disease that causes rapid mortality in intrauterine and neonatal life. The diagnosis of histiocytosis X (Litterer-Siwe disease should be considered in a neonate with vesiculated crusting skin lesions. We present clinical, radiographic and histopathological findings in a neonate with congenital histiocytosis who died of respiratory failure due to diffuse infilteration of lungs with histiocytic cells.     

Prognostic factors in histiocytosis X

Evaluation of prognostic factors and therapeutic strategies in histiocytosis X is difficult because of this disease's low incidence, heterogeneity related to the multiplicity of possible localizations, unpredictable course, and incompletely elucidated pathogenesis. At the time of diagnosis, parameters with a bearing on prognosis include age, number of involved organs, presence or absence of organ dysfunction, and initial response to treatment. Chemotherapy regimens, of which the most effective are vinblastine-corticosteroids and etoposide-corticosteroids, should be used only in patients with organ dysfunction or involvement of two or more organs before two years of age or three or more organs after two years of age. Duration of treatment ranges from three to twelve months according to the quality of the response. Other treatments, including low dose cytosine, alpha-interferon, or even autologous or allogeneic bone marrow transplantation have yielded promising results that need to be confirmed in a larger number of patients.     

Radionuclide imaging in histiocytosis X

Radionuclide imaging (^99mTc bone scans,^99mTc S colloid scans,^99mTc brain scans and⁶⁷gallium scans) and bone radiographs were done in 54 children with histiocytosis X. The results are discussed, compared with the literature and indications for the different nuclear medicine studies are given.     

Colonic ulceration in histiocytosis X

Gastrointestinal symptoms in histiocytosis X are distinctly unusual. This report describes a 5-month-old infant with a prolonged history of lower gastrointestinal bleeding which was found to be caused by diffuse histiocytic infiltration of the colon. Immunopathologic and electron microscopic studies confirmed the diagnosis of histiocytosis X. The differential diagnosis of lower gastrointestinal bleeding in young children should include histiocytosis X.     

Combination chemotherapy in histiocytosis X.

Twenty-five children with generalized histiocytosis X were treated with a combination of cyclophosphamide, vinblastine, and prednisone: 8 patients experienced complete response, 8 partial response, 2 imporvement, and 7 no response. Response rates for children over 1 year of age were higher than those reported for single agents. Twelve children are now off therapy with no evidence of disease for 10--50 months. Very poor response rates and high toxicity were seen in children less than 1 year of age. The two infants who eventually achieved CR did so by other therapies. Further trials in combination chemotherapy must weight possible long-term effects of such therapy against the prospect of more rapid disease control.     

Thymus in untreated systemic histiocytosis X

Histology, ultrastructure, and lymphocyte subsets were evaluated in thymic tissue obtained from a child with disseminated histiocytosis X (HX) prior to therapy. Extensive medullary infiltration by typical HX cells was associated with active destruction of thymic epithelium, medullary pseudocysts, and prevalence of calcospherites, some of which were in HX cells. The presence of minimally affected Hassall bodies indicates that the thymus was probably normal prior to onset of disease. Conventional studies of immunologic function showed no deficits, but reduction of OKT6- and OKT8-labeled lymphocytes in a thymic suspension may mean that thymic processing of lymphocytes was impaired. Destruction of thymic epithelium occurs regularly in HX, but it may be an insignificant epiphenomenon resulting from the affinity of HX cells for squamous epithelium.     

Myelofibrosis arising in treated histiocytosis X

Myelofibrosis, or fibrous replacement of hematopoietic bone marrow, is rarely encountered in pediatric patients. An unusual, reversible case arising in the setting of treated histiocytosis X is reported, a previously undescribed association. The clinical, pathologic, radiographic, and scintigraphic characteristics of myelofibrosis are reviewed.     

Spontaneous remission in disseminated histiocytosis X

An 8 months old girl presented with biopsy-proven, disseminated histiocytosis X affecting at least two organ systems. Within one year there was spontaneous regression of the disease lasting for 10 years until today. Considering this case and others from literature the necessity of aggressive chemotherapy in selected cases is discussed.     

Bone marrow involvement in histiocytosis X

Twenty-eight patients with histiocytosis X (HX) who had bone marrow aspirates and/or trephine biopsies taken at diagnosis were studied. Five of the 28 patients (18%) had bone marrow specimens with clusters of benign histiocytes characteristic of histiocytosis X. Several statistically significant clinical and laboratory differences were found between those patients with positive marrows versus those with uninvolved bone marrows. Presence of HX in the bone marrow was more frequently associated with fever (P less than 0.01), splenomegaly (P less than 0.01), rash (P = 0.04), diabetes insipidus (P = 0.09), and platelet counts less than 175 X 10(9)/L(P = 0.01). Two of the five patients with bone marrow involvement died, whereas there were no deaths due to HX in the other 23 patients. From this review, it is suggested that bone marrow involvement at diagnosis may be associated with more extensive and potentially fatal disease. HX of the marrow was more easily diagnosed from trephine biopsy sections than aspiration smears.     

Sclerosing cholangitis revealing histiocytosis X

The case of a 3 year-old boy who presented isolated cholestasis as the initial symptom of histiocytosis X is described. Other symptoms occurred later on. Despite treatment (corticosteroid and Vinblastin), the disease continued to progress and the child died at the age of 4 1/2 years with HIV infection (contaminated blood product) and tuberculosis.     

Radiation therapy in soft-tissue lesions in histiocytosis X (Langerhans' cell histiocytosis)

Langerhans' cell histiocytosis (LCH) (previously histiocytosis X) is an infrequent disease with protean clinical manifestations and an unpredictable course. The role of radiotherapy in the soft tissue complications of LCH was evaluated in this retrospective study of 40 patients seen in two major Philadelphia institutions between 1970 and 1984. The patients were divided into two groups according to the extent of disease: unifocal versus multifocal. There was a higher rate of complete response in the unifocal form (4 of 12 patients), but this was associated with a high rate of spontaneous remissions (6 out of 12 patients). Multifocal LCH has a more aggressive course, and the major organs involved (lung, liver, and spleen) did not respond to radiotherapy. Eight patients had diabetes insipidus, and none of them responded to radiotherapy or chemotherapy. Autopsies were performed in two patients with diabetes insipidus who died of disease. There were no pathologic changes in the pituitary gland or stalk, hypothalamus, or supraoptic nuclei.     

Intestinal malabsorption in infants with histiocytosis X

An infant with histiocytosis X had unequivocal evidence of intestinal malabsorption which was associated with histiocytic infiltration of the small intestine. 11 other fatal cases where histological material from the gastrointestinal tract was available are reviewed.