A clinical and pathologic study of histiocytosis X in adults

Histiocitosis de células de Langerhans

Histiocytoses originate from the proliferation of mononuclear phagocytes in different tissues. These entities make up a heterogeneous group, and are mainly classified as Langerhans cell histiocytoses and non-Langerhans cell histiocytoses. Langerhans cell histiocytoses have as a common characteristic the proliferation of dendritic antigen-presenting cells with phenotypical and ultrastructural characteristics of Langerhans cells. Infiltration may be limited to one organ, or may be disseminated. The prognosis and the treatment especially depend on the age of the patient and the number and dysfunction of the organs involved. Its etiopathogenesis is unknown, although most researchers currently believe that an alteration in the regulation of the immunological system occurs in these patients.

Langerhans cell histiocytosis in the elderly: a report of three cases

Langerhans cell histiocytosis is most common in children and is unusual in the elderly. We describe 3 cases of langerhans cell histiocytosis limited to the skin in elderly patients. Biopsy specimens showed a dermal infiltrate abutting the epidermis composed of atypical langerhans cells with abundant eosinophilic cytoplasm and a "kidney-shaped" nucleus. Immunoperoxidase stain CD1a was positive in all 3 cases and S-100 stain was positive in 2. Electron microscopy revealed Birbeck granules in the cytoplasm of the atypical langerhans cells in 2 cases. Langerhans cell histiocytosis with skin involvement has a chronic course with an overall good prognosis. However, cutaneous manifestations may precede systemic involvement by many years.

Nosology and pathology of Langerhans cell histiocytosis

The pathology of LCH is continuing to be defined and diagnostic features clarified as unprecedented research is done. Although the etiology of LCH remains unknown, new information on cytokines, viruses, immunologic dysfunction, cell surface antigen expression, and clonality in the disease are providing essential pieces of the puzzle.

Juvenile xanthogranuloma occurring in the oral cavity: case report and histopathological findings

Juvenile xanthogranuloma is commonly seen in the dermis, and only very rarely develops in the oral mucosa. Here were report a case that occurred in the anterior palate of a 9-year-old boy. The lesion appeared as a dark red and well-defined nodule measuring 12 x 14 mm. Histologically, it consisted of a proliferation of histiocytes and fibroblastic stroma intermingled with foamy cells. Many lipid droplets without limiting membrane were observed in the cytoplasm under electron microscopy, but no Langerhans' cell granules were observed. The proliferative histiocytes were positive for lysozyme and macrophage HAM56 under immunohistochemical observation, but not for S-100 protein. From these findings, the lesion was diagnosed as juvenile xanthogranuloma. The post-operative course, now amounting to 7 years, has been uneventful.

Physiology and pathophysiology of dendritic cells

Dendritic cells are antigen-presenting cells derived from the hematopoietic stem cell. The dendritic cell family includes Langerhans' cells (CD1a-positive dendritic cells of the skin), and antigen-presenting cells that are found in the lymphoreticular system and throughout the organ parenchyme. Dendritic cells play a key role in both the primary and secondary immune responses. Several studies indicate that these cells participate in antitumor immunity, tumor surveillance, graft-versus-host disease, and in the pathogenesis of clinical syndromes of unknown origin or those induced by viruses, such as the human immunodeficiency virus. Different disorders are characterized by an abnormal proliferation and accumulation of dendritic cells; for example, the Langerhans' histiocytes, which accumulate in Langerhans' cell histiocytosis. In this review the immunophenotypic, morphological, and functional characteristics of the dendritic cell family is described. The clinical and laboratory studies suggesting a unique role for these cells in various syndromes and diseases are reviewed. The Langerhans' cell histiocytoses and the malignant disorders associated with transformation of cells belonging to the dendritic cell family, are discussed.

Langerhans' cell histiocytosis: head and neck manifestations in children

BACKGROUND

Langerhans' cell histiocytosis (LCH) is an uncommon, poorly understood granulomatous disease, characterized by the idiopathic proliferation of Langerhan's cells or their marrow precursors. In 1985, the Philadelphia Work-shop adopted the term "Langerhans' cell histiocytosis" (LCH) to differentiate it from reactive and neoplastic causes of histiocytosis.

METHODS

This study includes 73 pediatric patients diagnosed with this condition in Dublin, Ireland, and Nottingham, England, during a 34-year period (1959 to 1993). These patients are reviewed with respect to clinical presentation, difficulty with making a histological diagnosis, their management, and outcome.

RESULTS

A total of 49 patients (67%) had head and neck involvement. Bony involvement was the most frequent sign, most frequently located in the skull. There were 11 deaths (15%) in this series, all associated with multisystem disease, and nine of these deaths were in children younger than 2 years of age.

CONCLUSIONS

The role of otolaryngologists is important in the early and accurate evaluation, staging, and diagnosis of LCH. It may mimic more common diseases, such as otitis externa, acute mastoiditis, skin rash, gingivitis, or cervical lymphadenopathy. Patients with multisystem disease may be so ill at presentation that the head and neck lesions may be overlooked. The current management of LCH has become increasingly conservative, and in the 1990s, fewer cases are given chemotherapy or radiotherapy. The prognosis is very good for single-system disease and poor for multisystem disseminated disease with early onset.