Intestinal infection with Isospora belli.

A review article discussing the taxonomy, parasite life cycle and laboratory diagnosis of Isospora belli is presented. The pathology, epidemiology, clinical findings and therapy of human intestinal infection with Isospora belli are also addressed.

Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) and extranodal involvement of the orbit.

We present the case of a 5-year-old boy who was referred to the Neurosurgical Service of the San Jorge Children's Hospital for evaluation of right eye proptosis. At the age of one year the diagnosis of sinus histiocytosis with massive lymphadenopathy (SHML) had been rendered on a cervical lymph node biopsy. The right orbit mass causing the proptosis was the result of extranodal involvement of the orbital tissue by SHML. The clinical and pathologic features of this entity are discussed.

Bone tumors of mixed origin: osteo-liposarcoma and osteo-rhabdomyosarcoma.

1. A complete perusal of the literature revealed twenty cases of primary liposarcoma of bone acceptable as such to the authors. These were tabulated as to location and age. 2. Eight cases of osteo-liposarcoma, primary in bone, were encountered in the literature and an additional case was reported by the authors. 3. The authors described for the first time in the literature a new primary tumor of bone of mixed origin: osteo-rhabdomyosarcoma. After careful perusal of the literature they added three additional cases: two cases, previously reported as primary rhabdomyosarcoma of bone, which on careful evaluation of the radiographs in said publications and the paucity of microphotographs they considered to be osteo-rhabdomyosarcomas, and the other case, previously reported as malignant mesenchymoma of the sternum following radiotherapy for breast cancer. 4. The authors prefer to classify these tumors (osteo-liposarcoma and osteo-rhabdomyosarcoma) as "Tumors of Mixed Origin" and not as "Malignant Mesenchymomas". 5. A complete review of the literature revealed 219 reported "dedifferentiated" chondrosarcomas, or chondrosarcomas "with additional mesenchymal component", among which only nine (9) contained a bona fide rhabdomyosarcomatous component. The rest exhibited other mesenchymal tumors as osteogenic sarcoma, fibrosarcoma, malignant fibrous histiocytoma, angiosarcoma, and undifferentiated sarcoma. The authors recommend to continue classifying these tumors as chondrosarcomas with additional mesenchymal component or even as "dedifferentiated" chondrosarcomas but not as malignant mesenchymomas.

Extraskeletal chondromas.

1. Extraskeletal chondromas occur in three variants: (a) as multiple nodules of synovial chondromatosis within a joint, (b) as a solitary lesion in association with articulations, within or adjacent to them, and (c) as an isolated cartilagenous lesion in the soft tissues, mostly of the hands and feet. 2. There are no histological characteristics which could differentiate articular, para-articular and soft tissue chondromas among themselves. 3. The latter two groups of extraskeletal chondromas are rare and frequently exhibit areas of immature cartilage with worrisome histologic features which could mislead the pathologist to an overdiagnosis of chondrosarcoma. 4. As a general rule, no matter how worrisome the histologic appearance of an extraskeletal, well delimited cartilagenous tumor may be, metastasis have not been recorded. Local recurrences are not infrequent after inadequate surgical removal; however, the tumor can always be controlled by adequate wide re-exision or resection. 5. Two cases of extraskeletal chondromas, one para-articular in the knee and the other in the soft tissue of the arm, have been presented with an exhaustive review of the literature on the subject. 6. It is of interest to note that our para-articular chondroma represents the first case reported in the literature where computerized tomography was utilized in the diagnosis. 7. The location of a soft tissue chondroma in the upper arm is extremely rare and only one previous case has been reported in said location.