Five extracardiac rhabdomyomas were studied by light and electron microscopy: two of the adult type, two of the fetal type, and one of the female genital tract type. The three types can be distinguished histologically and ultrastructurally. Adult type rhabdomyomas are encapsulated and reveal histologically closely packed, large tumor cells with granular or vacuolated cytoplasm and only scant stroma. Electron microscopically, myofibrils are haphazardly arranged with rodlike Z-band material. Sometimes a sarcomeric arrangement of myofibrils is seen. The tumor cells are packed with mitochondria bearing lamellar inclusions. Fetal type rhabdomyomas contain a mixture of muscle cells in different stages of differentiations; the amount of stroma is increased. The myofilaments are usually disorganized and in only a few cells is rodlike Z-band material found. The cytoplasm reveals few mitochondria. In the rhabdomyoma of the female genital tract, the tumor cells are large and resemble more mature muscle fibers; the stroma is abundant and the myofilaments are usually arranged in an orderly fashion. Generally, the prognosis for rhabdomyomas is good. Metastases are not known. Two of the five rhabdomyomas studied recurred. One rhabdomyoma was found at autopsy. Embryonal rhabdomyosarcoma must be considered in differential diagnosis particularly for fetal type rhabdomyoma.
Schwannoma of the orbit is an encapsulated, benign, noninvasive, slow-growing nerve sheath tumor which, when large enough, causes exophthalmos, optic neuropathy, diplopia, anterior orbital mass or sinusitis. An orbital schwannoma in a 84-year-old man with infiltration of the os spenoidale is reported. Schwannoma may arise anywhere within or adjacent to the orbit and is usually curable by local excision. The malignant counterpart, the malignant schwannoma, is exceedingly rare in the orbit. In orbital tumors many diagnostic steps are necessary, but the exact diagnosis is often determined only by histological examination. Schwannomas (synonyms neurilemoma, neurinoma) of the orbit are rare; they account for 1–6% of all orbital tumors. Here presented is a description of their appearance on clinical examination and on light and electron microscopy, together with a report on preoperative investigations and operative findings.
With 60 cases of osteosarcomas a histological evaluation from + to +++ carried out for mitoses, osteoid formation, presence of multinucleated giant cells, and tumor necrosis. A subclassification in osteoblastic, chondroblastic, and fibroblastic type of osteosarcoma (according to Dahlin) and a histological grading from + to +++ based on degree of cellular atypism was also done. In our material no relations between these three types of osteosarcoma and chance for survival became evident. There was, however, a significant correlation between grade of atypism and rate of mitoses. Grading of oestosarcomas from + to +++ showed that cases with grade III osteosarcoma remained only seldomly without metastases during the course of the disease. Grade I osteosarcomas and also grade II tumors showed a higher number of patients with 2-year survival. However, neither correlation between tumor grade and incidence of metastases, nor with chances for survival were statistically significant. Nevertheless, characterization of osteosarcomas, by a histological grading from + to +++ based on cellular atypism and mitotic count is advisable, in addition to the TNM stages. This histological grading appeared to be more practicable than subclassifications of osteosarcoma by type which had been tested by us in a previous study (Konrad et al., in press).
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