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Xanthoma disseminatum (XD) is a nonfamilial type of normolipidemic mucocutaneous xanthomatosis that belongs to the group of non-Langerhans cell histiocytoses. More than 100 cases of XD have been reported. In this study we report a case of XD in a 4-year-old boy with diabetes insipidus (DI). This boy is one of the youngest patients ever to present with XD combined with DI.

Indeterminate cell histiocytosis is an exceptional and controversial entity with variable clinical, histopathologic or immunohistochemical findings, sharing morphologic and immunophenotypic features from both Langerhans and non-Langerhans cell histiocytoses. Neoplastic cells express S-100 and CD1a antigens, but lack Birbeck granules. It has been reported in both adults and children, as solitary or multiple cutaneous lesions with rare extracutaneous involvement. We describe a 12-year-old boy with an indeterminate cell histiocytosis manifesting as a solitary verrucous papule on the mucosa of the glans penis. The morphologic features and diagnostic criteria of cutaneous indeterminate cell histiocytic proliferations are reviewed. The possible relationship between indeterminate cell and Langerhans cell histiocytoses is discussed.

Wiskott-Aldrich syndrome is a rare X-linked primary immunodeficiency clinically characterized by the triad of microthrombocytopenia, immunodeficiency, and eczema. Juvenile xanthogranuloma is a well-recognized benign disorder of infancy and early childhood from the group of non-Langerhans cell histiocytoses, with a good prognosis and spontaneous involution. We report a boy with Wiskott-Aldrich syndrome caused by a new, not previously described mutation associated with multifocal juvenile xanthogranuloma.

The histiocytic syndromes consist of a group of disorders that share in common the proliferation of cells of the monocytic/macrophage lineage. It has been conventional to divide the histiocytoses into two separate groups: Langerhans cell histiocytosis (LCH) and non-LCH. We present a 2-year-old Hispanic boy who was referred to the dermatology clinic for evaluation of an asymptomatic cutaneous eruption of the head and upper trunk. In addition, he had a 3-week history of pain in his right leg and difficulty in walking. The patient's physical examination was normal, excluding the skin findings. On plain radiography, multiple lytic lesions in the skull, lumbar spine, and right tibia were seen. Histopathologic examination of a skin biopsy specimen revealed a predominantly histiocytic infiltrate in the dermis which was negative for S-100 and CD1a stains. A tibial biopsy specimen showed a monomorphous infiltrate of histiocytes that were S-100 and CD1a positive. This patient's concomitant findings of both LCH and non-LCH histiocytoses further support a potential overlap within the histiocytic syndromes, as has been suggested by others.

We describe an infant with a congenital form of non-Langerhans cell histiocytosis with clinical and pathologic features of both disseminated juvenile xanthogranulomatosis and benign cephalic histiocytosis. The findings in this case support the concept of these non-Langerhans cell histiocytoses forming part of a spectrum of disease rather than being separate pathologic entities.

Papular xanthoma was diagnosed in a 14-month-old boy. The eruption cleared spontaneously within four years, immunohistopathologic study revealed that the predominant foamy histiocytic cells had the phenotypic features of the dermal dendrocyte. Giant multinucleated cells, which showed characteristics of monocyte-derived macrophages, were also present. We suggest classifying diseases derived from dermal dendrocytes into a separate group of histiocytoses.

The fourteenth annual meeting of the Society for Pediatric Dennatology was held in Quebec City, Quebec, Canada and hosted by Drs. Beraice Krafchik, Lionel Boxall, and the dennatology staff of L'Hotel-Dieu de Quebec, particularly Drs. Raymond Lessard and Richard Cloutier. The fifth annual Sidney Hurwitz Lecture was presented by Professor Ruggero Caputo of the University of Milan. He discussed the histiocytoses, which he classified by their clinical, histopathological, ultrastructural, and immunohistochemical characteristics. Histiocytosis X is a proliferation of unknown cause of a distinct histiocytic cell type containing Langerhans' granules in the cytoplasm and staining positively for S-100 and OK-T6. The disease can be divided into four clinical subtypes: Letterer-Siwe disease, Hand-SchuDer-Christian disease, eosinophilic granuioma, and congenital self-healing reticulohistiocytosis. Letterer-Siwe is the acute disseminated form of histiocytosis X. Cutaneous lesions are present in approximately 80% of cases, particularly on the trunk and scalp, and these lesions are frequently the presenting sign of the disease. Lesions may present as papules (often with scaling, purpura, or crusts), pustules, petechiae, and purpuric striae of the nail beds.