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470 Brief reports cellular stroma. The S-100 positive cells were conReferences sidered myoepithelial in nature, possibly representing differentiated basal cells as they were also positive for cytokeratins.We conclude that S-100 immunostaining is of no value in identifying the outer layer of cells that persists in benign proliferative prostatic lesions and is typically absent from around malignant acini (Kovi 1985); this is in contrast to the usefulness of the technique in breast pathology (Egan et al. 1987). The histogenesis of the basal cells in the prostatic acini remains unclear.We report a case of intravenous leiomyomatosis extending from the ovarian vein to the right atrium. Immunohistochemical studies confirmed that the tumour not only consisted of smooth muscle elements, but also of vascular components, findings which suggest an origin in the wall of the uterine vein.

A case of primary gastric plasmacytoma expressing various surface and cytoplasmic antigens is reported. With the use of formalin‐fixed and deparaffinized sections, 13 different antibodies were applied. Neoplastic plasma cells revealed monoclonal IgG and x light chain in the cytoplasm, and expressed epithelial membrane antigen, Ki 67 antigen, cytokeratin, CD 22 antigen, interleukin‐2 receptor antigen, leukocyte common antigen and Ki‐1 (CD 30) antigen. However, tumor cells were devoid of HLA‐DR antigen. These data suggest that the neoplastic plasma cells are at the plasmoblastic stage of maturation and express various surface and cytoplasmic phenotypes.

Malignant granular cell tumor of the esophagus found in a 70‐year‐old female was reported. Microscopically, the tumor showed a variety of the histology from compact proliferation of polygonal granular cells in pseudo‐epitheliomatous pattern to plexiform proliferation of elongated granular and fibroblastic cells in neuroflbromatous pattern, and the tumor cells frequently contained eosinophilic globules in the cytoplasm. Histochemically, argyrophilic neurofibrils in the stroma and argyrophilic cytoplasmic processes or grains were seen. Immunohistochemically, the tumor cells showed positive reaction with S–100 protein (S–100), but all reactions with myoglobin (MG), desmin (DM), fibronectin (FN), creatinine phosphokinase–mm (CPK), factor gthrelated antigen (F8RA), alpha–1–antitrypsin (AIAT), alpha–1–anti–chymotrypsin (AIACT), keratin (KN), and carcinoembryonic antigen (CEA) were negative. Electron microscopy revealed that the tumor cells had typical lysosomal granules filled with proteinaceous electron dense materials and fine membrane‐bound particles sized 15 to 45 nm resembling virus or neurosecretory granule.

The influence upon nickel subsulfide (α‐Ni3S2; Ni‐SS)‐induced carcinogenesis in the soft tissue of bone fracture at the site of Ni‐SS exposure was studied using female Fischer rats. During the one year of the experiment, the group subjected to bone fracture exhibited the shortest tumor induction time and survival time, and a significantly higher metastatic rate. The present study may suggest a model for the metastasis of human soft tissue tumors.