Hitoshi Kubosawa

Coexistence of adenocarcinoma and choriocarcinoma in the sigmoid colon.

A rare case of a colon carcinoma that developed in a 50‐year‐old woman is documented. Histologically, the removed tumor was composed of two distinctive elements, i.e., well‐differentiated papillary adenocarcinoma and choriocarcinoma. It was strongly suggested that the latter malignancy derived from the pre‐existing colonic carcinoma through metaplastic proliferation. A very high human chorionic gonadotropin level was noted in the patienťs serum obtained at the preoperative stage. Autopsy materials revealed that metastatic foci in the liver, lungs, and lymph nodes were exclusively composed of choriocarcinoma.

Ultrastructural organization of the glomerular basement membrane as revealed by a deep-etch replica method

SummaryThe fine structure of the glomerular basement membrane was re-evaluated by using a deep-etch replica method.The structure of the laminae rarae interna and externa of the rat glomerular basement membrane was basically identical in that 6 to 8 nm fibrils were interconnected to form a three-dimensional, polygonal network. The size of the mesh was quite variable but most often ranged from 20 to 25 nm in width. In addition, a zipper-like substructure of the epithelial slit diaphragm was observed. By contrast, the lamina densa was composed of closely packed particles.After exposure of the bovine glomerular basement membrane to ultrasonic waves or trypsin, the particles of the lamina densa were effectively removed. The underlying structure showed the fibrillar network closely resembled that seen in the laminae rarae of the rat glomerular basement membrane.The glomerular basement membrane thus revealed was as principally composed of a fibrillar network, which might be regularly arranged units of type-IV collagen. Numerous fine particles, most likely proper components of the glomerular basement membrane, were attached onto this basic fibrillar structure, giving rise to a morphologic appearance different from that of the laminae rarae.

Hepatocellular carcinoma with rhabdomyoblastic differentiation

An extremely unique case of a liver tumor occurring in a 70‐year‐old man is documented in this article. The primary tumor was well encapsulated by a thick, connective capsule and was histologically composed of two distinct elements, i.e., a common hepatocellular carcinoma (HCC) and a rhabdomyosarcoma. Metastasis of HCC was only seen in the left adrenal gland, whereas intrahepatic metastatic foci as well as tumor thrombi occluding the portal vein branches were composed exclusively of rhabdomyosarcoma. The possibility that the rhabdomyoblastic component might have come from the preexisting HCC by way of metaplastic proliferation is discussed.

Modulation of cytoskeletal organization of podocytes during the course of aminonucleoside nephrosis in rats

By immunoelectron microscopy the modulation of cytoskeletal organization of podocytes during the course of puromycin aminonucleoside‐induced nephrosis was examined. In control rats, tubulin and vimentin were present, limited to the podocyte cell body and the major processes. Their distribution in the foot processes was virtually negative. Myosin exhibited the same distribution pattern, albeit much more scattered, with no relation to any podocyte organelles or cell structures. Actin was scattered over the fibrillar zones of the cell body and its processes, including the foot processes. In proteinuric rats, loss of foot processes occurred and the glomerular basement membrane was covered by broad cytoplasmic sheets of podocytes, which contained these four subunits of cytoplasmic filaments. Accompanied by the disappearance of proteinuria, the structural organization of the foot processes was completely restored, in which tubulin, vimentin, and myosin were scarcely observed. Our results confirmed that the loss of foot processes is caused by their retraction, and indicated that the specific localization of the podocytic cytoskeleton contributes to the maintenance of the particular cell shape. Its reorganization may account for the structural modification of podocytes.

Xanthogranulomatous gastritis with pseudosarcomatous changes.

Reported herein is a rare case of xanthogranulomatous inflammation of the gastric wall occurring in a 77‐year‐old man. Two submucosal lesions presented as rapidly enlarging nodules, and biopsy showed interweaving bundles of spindle cells with numerous atypical cells with marked nuclear pleomorphism. The differential diagnosis from mesenchymal malignancies, particularly from a malignant gastrointestinal stromal tumor, was difficult and immunohistochemical investigations could not improve the diagnostic accuracy of HE histology alone. Thus, an erroneous diagnosis of malignancy was made and a partial gastrectomy was performed. On macroscopic examination of the resected material, spontaneous regression of the lesions was observed and microscopic examination showed characteristic features of xanthogranulomatous inflammation; large numbers of foamy histiocytes including multinucleated giant cells were admixed with chronic inflammatory cells and fibrous reaction. Although the precise pathogenesis could not be elucidated, recognition of this unusual morphological appearance is of importance to avoid an overdiagnosis of malignancy.

Role of neutrophils in sinusoidal endothelial cell injury after extensive hepatectomy in cholestatic rats

Background and Aims : The authors have shown previously that sinusoidal endothelial cell injury developed concomitantly with the accumulation of neutrophils in the hepatic sinusoidal space in cholestatic rats after extensive hepatectomy. The aim of the present study was to investigate the role of neutrophils in the development of this kind of endothelial cell injury.

Metastatic Malignant Meningioma of the Liver with Hypoglycemia : Report of a Case

We herein present the case of a 68-year-old male who suffered an episode of hypoglycemic shock 2 years after undergoing total removal of a bifrontal parasagittal malignant meningioma. Imaging studies revealed three giant hypervascular tumors with a cystic portion in the right lobe, but no confirmed preoperative diagnosis could be made. At laparotomy, liver tumors were found in the medial segment of the left lobe as well as in the right lobe, and thus an extended right lobectomy was performed. All the resected tumors were histologically diagnosed as metastatic malignant meningiomas of the liver. Despite subsequent transarterial chemoembolization for a recurrence in the residual liver, the patient died 11 months after surgery. To the best of our knowledge, only one other case of a hepatectomy for liver metastases from an intracranial malignant meningioma has been reported in the literature, but there has never been any report of surgical treatment for a metastatic meningeal tumor in the liver associated with hypoglycemia. Although our surgical treatment provided effective palliation, the prognostic significance of a surgical strategy for such patients has yet to be established.

COMBINED HEPATOCELLULAR AND MUCINOUS CARCINOMA

A rare autopsy case of combined liver cell and bile duct carcinoma (CLBC) occurring in a 51‐year‐old male with alcoholic liver cirrhosis is presented. Histologically, while the primary lesion was solely composed of well differentiated hepatocellular carcinoma (HCC), intrahepatic metastases consisted of a variable admixture of HCC and cholangiocarcinoma (CC) with excessive mucin production. Interestingly, the tumor cell cluster showing a trabecular growth pattern produced both bile and mucin, thus converting from HCC to mucinous CC. It is concluded that this liver malignancy is principally HCC with a marked tendency to transform into CC. The importance of the findings, especially the simultaneous production of bile and mucin within the same cell cluster, is emphasized in terms of the classification of CLBCs.

DAUNOMYCIN-INDUCED NEPHROPATHY IN RATS

A single intravenous injection of daunomycin into rats Induced severe glomerular injury with massive proteinuria. Mesangial thickening due to an increase in the matrix appeared as early as 5 weeks after injection. Focal and segmental glomerular tuft distortion developed by 10 weeks associated with a progressive mesangial change, which was accompanied by detachments of endothelial cells and podocytes from the glomerular basement membrane (GBM) resulting in obliteration of the affected tufts. After 20 weeks, the lesion ultimately progressed to cause diffuse and global glomerular obliteration. Scattered glomeruli also showed frank shrinkage with a mild obliterative change. By observing a number of isolated glomeruli in scanning electron microscopy, it was revealed that podocyte alterations were variable from case to case and foot processes remained discrete in some cases until 10 weeks, despite the presence of marked proteinuria. Anionic sites distributed throughout the GBM and on the surface of podocytes were usually preserved in proteinuric rats as far as evaluated by ruthenium red and colloidal iron stainings. Our results indicate that loss of foot processes and of glomerular anionic sites are not causative factors but consequences of proteinuria.

An Unusual Case Involving the Spleen and Lymph Nodes

A case of peliosis hepatis in a 52‐year old woman with unusual involvement of the spleen and lymph nodes is described. The initial sign was intraperitoneal hemorrhage from the splenic lesion, recessitating splenectomy. The hepatic lesion, which was first noticed during the operation, rapidly progressed and eventually resulted in hepatic rupture with fatal intraperitoneal hemorrhage. Serial sections treated by silver impregnation revealed degeneration and dissolution of the fine reticulin framework in the involved organs, suggesting the possible morphogenesis of the peliotic lesion. The patient had no history of any underlying disorders or of medication with steroids. Acta Pathol. Jpn. 32: 212∼215, 1989.