Haruhiko Yoshida

Ossifying fibromyxoid tumor of soft parts.

A histologically uncommon soft‐tissue tumor of the extremities and neck of a 54‐year old male is reported. The solid, bony‐hard tumors occurred at the inner region of the right thigh at 44 years of age with additional tumor formation at the posterior region of the same thigh, at the inner region of the right upper arm and at the neck during the following 10 years. All tumors were located in the deep muscle layer. The neck tumor directly invaded the fifth cervical vertebra and later the upper mediastinum. Histologically, all three tumors of the extremities contained mixed lobular growths of round to fusiform cells with myxoid matrix and an extensive bone formation. The tumor cells showed a small round nucleus and eosinophilic cytoplasm lacking cytoplasmic glycogen. The myxoid matrix was stained significantly by alcian blue and colloidal iron and was digested completely by pretreatment with hyaluronidase. Another major component was mature bone trabeculae showing a dense meshwork throughout the entire tumor with active bone formation toward the periphery. Positive immunostaining was obtained against anti‐vimentin and S‐100 protein antibodies. We suggest that this uncommon tumor can be tentatively distinguished as an ossifying fibromyxoid tumor of soft parts, (an entity defined by Enzinger et al.), differing from other previously described soft‐tissue tumors. Acta Pathol Jpn 41: 480–486, 1991.

Chromosomal rearrangement t(11;22) in extraskeletal Ewing's sarcoma and primitive neuroectodermal tumour analysed by fluorescence in situ hybridization using paraffin-embedded tissue.

The clonal chromosomal rearrangement t(11;22) has been reported by karyotypic analysis to be specific for Ewings sarcoma of bone and soft tissue origin as well as primitive neuroectodermal tumour. In this report, immunohistological analysis of MIC 2 expression and fluorescence in situ hybridization (FISH) were performed using paraffin‐embedded tissues. We examined t(11;22) in the nuclei isolated from two Ewings sarcomas, four primitive neuroectodermal tumours, and three neuroblastomas, which served as negative controls by FISH with an α‐satellite DNA probe for chromosome 11, a chromosome 22 marker probe, and whole chromosome painting probes for both chromosomes 11 and 22. Both cases of Ewings sarcoma and the four primitive neuroectodermal tumour specimens were immunoreactive for MIC 2. Both Ewings sarcomas and three of the four primitive neuroectodermal tumours contained the tumour‐specific t(11;22), but the three neuroblastomas did not show this translocation. Based on the cytogenetic results and on the immunohistological investigation of MIC 2 expression, Ewings sarcoma is suggested to be related closely to primitive neuroectodermal tumour. FISH is a useful aid in determining the tumour type of Ewings sarcoma and putative related tumours.

Giant cell tumor of bone

Three giant cell tumors of bone (2 benign and 1 malignant) were examined enzyme-histochemically, and a tissue culture study of the malignant case was performed. Multinucleated giant cells and mononuclear round cells had similar activities of ACPase and non-specific esterase with a diffuse strong reaction. ATPase and 5′-nucleotidase reactions were strongly positive in the cytoplasm of multinucleated giant cells, and were seen not only in the cytoplasm but also on the cell membrane of round cells. The proliferating spindle cells in the malignant case were faintly positive for ACPase and non-specific esterase and were less positive for ATPase and 5′-nucleotidase on the cell membrane. The multinucleated giant cells and mononuclear round cells resembled histiocytes in the activities of 4 hydrolytic enzymes, and the multinucleated giant cells had enzyme activities similar to those of osteoclasts from new-born rat skull. The malignant giant cell tumor and cells in its tissue culture showed ALPase activity preferentially on the cell membrane of the spindle cells, and rarely on round cells or multinucleated giant cells. ALPase was resistant to heat treatment and was found to be the type IV isoenzyme by diffusion electrophoresis. The origin of the giant cell tumor of bone and the significance of the ALPase activity are discussed.

Chromosomal translocations in human soft tissue sarcomas by interphase fluorescence in situ hybridization

In soft tissue sarcomes, clonal rearrangement of chromosomes has been shown by cytogenetic analysls to be unique and specific for tumor types. The development of fluorescence in situ hybridbation (FISH) has allowed detection of chromosomal rearrangements In the interphase nuclel isolated from paraffin‐embedded tissues. Three kinds of trans‐locations in the interphase nuclel that were isolated from 47 cases of soft tissue sarcomas ware examined by FISH with chromosome‐speclfic DNA probes of centromeric and total probes. of 47 soft tissue sarcomas 42 (89.4%) revealed tumor‐specitic transiocations by retrospective cytogenetic analysis. Transiocation t(X;18) was detected In 25/28 synovial sarcomas; translocation t(11;22) In 5/6 Ewlngs sarcomas and primitive neuroectodermal tumors (PNET); and translocation t(12;16) was found in 12/13 liposarcomas, including 10 myxold and two round cell lypes as clonal chromosomal aberrations specific for both subtypes. Based on the cytogenetic analysis, Ewings sarcoma is related closely with PNET as shown by MIC2–protein reactivity. Other cytogenetic findings of translocation t(12;16) Indicate that round cell liposarcomas share chromosomal changes with myxoid lipo sarcomas, and further suggest that both tumor subtypes of liposarcoma may possess common precursor cells. FISH is a useful aid in determining the tumor type of soft tissue sarcomas with regard to histogenetic origin.

Combined Choriocarcinoma and Adenocarcinoma of the Lung

Combined choriocarcinoma and adenocarcinoma in the lung of a 71‐year‐old Japanese male is reported. In the upper lobe of the right lung (S1+ 2), a choriocarcinoma coexisted with an adenocarcinoma, but distinct metastatic lesions were noticed separately in the lungs, kidney, bone marrow and lymph nodes. Although immunohistochemical examination revealed intensely positive reactivity with anti‐human chorionic gonadotropin (HCG) in trophoblastic cells, weak immunoreactivities were also observed in a few cells with anti‐human placental lactogen (HPL), anti‐pregnancy specific β glycoprotein (SPI), anti‐epithelial membrane antigen (EMA), anti‐carcinoembryonic antigen (CEA), anti cytokeratin (keratin) and KM‐93 (lung adenocarcinoma‐associated antibody). In the adenocarcinoma, the tumor cells were positively stained for CEA, EMA, keratin and KM‐93, but there were no positive reactivities for HCG, HPL and SPI. These findings suggest that primary choriocarcinoma of the lung may arise through dedifferentiation of adenocarcinoma.

Mxi1 Mutations in Human Neurofibrosarcomas

Mxi1 is thought to negatively regulate Myc function and may therefore be a potential tumor suppressor gene. Little effort has yet been made to find alterations involving this gene in human solid tumors. We screened 31 human gastric cancers, 7 esophageal cancers, 85 bone and soft tissue tumors of various types, including 4 neurofibrosarcomas. We also examined 29 human tumor celllines consisting of 12 esophageal cancers, 7 glioma/glioblastomas and 10 others for Mxi1 mutations in exons 1, 2, 4 (HLH domain), 5 and 6. Polymerase chain reaction‐single‐strand conformation polymorphism (PCR‐SSCP) and subsequent sequencing revealed three distinct polymorphisms in the intron‐exon boundary upstream from exon 6. We discovered a missense mutation, GCA to GTA (Ala 54 Val), in exon 2 in a neurofibrosarcoma patient (case 1), two missense mutations, AAA to CAA (Lys 118 Gln) and GAA to GGA (Glu 154 Gly) in exon 5 of another neurofibrosarcoma patient (case 2), and 3 amino acid substitutions, GTG to GCG (Val 179 Ala), GTT to GCT (Val 181 Ala) and TTC to CTC (Phe 186 Leu), in a third neurofibrosarcoma patient (case 3). In case 3, loss of heterozygosity was also demonstrated by informative (TTC)3/(TTC)2 polymorphism. Our data demonstrate that mutations occur in the Mxi1 gene in neurofibrosarcoma. Missense mutations in the functional domain of Mxi1 in these cases may be involved in the pathogenesis of neurofibrosarcoma.

Osteosarcoma with Prominent Epithelioid Features

Osteosarcoma in the metaphysis to epiphysis of the left femur of a 17 year old male is reported. The lesion appeared osteolytic with sclerotic foci on roentgenographs, accompanied by an extensive tumor shadow in the surrounding soft tissue. While 60% of the tumor was necrotic, histological examination of the remaining viable tissue revealed that it consisted almost entirely of a sheet of epithelioid cells, separated by thin, fibrovascular septa with an alveolar‐like pattern, suggestive of metastatic carcinoma. Only a few areas were characterized by malignant osteoid tissue intermingled with the above cells, showing significant positivity for bone‐specific alkaline phosphatase and 5 nucleotidase, thus permitting a diagnosis of osteosarcoma. Autopsy findings revealed that the metastatic foci were histologically similar to those of the primary tumor. Electron microscopy revealed poor development of cytoplasmic organelles, supporting possible derivation from an osteoblastic cell lineage at an early stage. Acta Pathol Jpn 39: 439 445, 1989.

OSTEOSARCOMA Ultrastructural and Immunohistochemical Studies on Alkaline Phosphatase‐positive Tumor Cells Constituting a Variety of Histologic Types

The osteosarcomas were subclassified into osteoblastic, fibroblastic, chondroblastic and telangiectatic types and examined by electron microscopy. Their immunohistochemical reactions were also studied. In an overall survey of the above types, fibroblast‐like cells revealed poorly developed cytoplasmic organelles with rather short, branching rough endoplasmic reticulum, mixed with osteoblast‐like cells that were hardly distinguishable from the former. They appeared to be an early stage of an osteoblastic cell lineage from the distribution and development of their cell organelles and highly positive vimentin activity. The tumor cells in malignant cartilage varied in appearance from chondroblast‐like to osteoblast‐like cells. All types of tumor cells expressed alkaline phosphatase activity to a significant degree. Immunohistochemical staining showed a mixture of procollagen type I‐positive cells among the cells positive for both procollagen type II and S‐100 protein in the malignant cartilage. Irrespective of any ultrastructural differences between these various tumor cell types, they all revealed a significant degree of ALPase activity unlike other types of bone tumors, suggesting that the tumor cells which constitute the various types of osteosarcoma are derived from a common precursor cell.

Expression of cardiac ankyrin repeat protein, CARP, in malignant tumors: diagnostic use of CARP protein immunostaining in rhabdomyosarcoma

Cardiac ankyrin repeat protein (CARP) is highly expressed in cardiac muscles and detectable in normal skeletal muscles. Arpp, a close homolog of CARP, has been demonstrated to be useful for distinguishing rhabdomyosarcoma from other malignant tumors. However, the CARP distributions among malignant tumors have been poorly investigated. Here, we analyzed the comprehensive expression of CARP in malignant tumors and evaluated its potential use for rhabdomyosarcoma diagnosis. A total of 159 malignant tumors, including 34 rhabdomyosarcomas, 85 non-rhabdomyosarcomas, and 40 carcinomas, were immunohistochemically analyzed for CARP expression. Cytoplasmic expression of CARP was detected in 29 (85%) of 34 rhabdomyosarcomas. The immunoreactivity was observed in both small cells with little differentiation and differentiated tumor cells with abundant eosinophilic cytoplasm. In contrast, focal immunoreactivity for CARP was only observed in 5 (4%) of 125 non-rhabdomyosarcomas, comprising 2 malignant fibrous histiocytomas, 1 angiosarcoma, 1 epithelioid sarcoma, and 1 squamous cell carcinoma of the lung. Comparative analysis of the CARP expression profiles with those of myogenic markers in rhabdomyosarcomas revealed that myogenin (88%) and desmin (88%) exhibited the best sensitivity, followed by CARP (85%), MyoD (82%), muscle-specific actin (79%), and myoglobin (65%). MyoD (96%) and myoglobin (96%) had the best specificity, followed by CARP (95%), myogenin (95%), desmin (89%), and muscle-specific actin (86%). Our results indicate that CARP is a sensitive and specific marker for rhabdomyosarcoma and that it will be useful for the differential diagnosis of rhabdomyosarcoma.

PRELYMPHOMATOUS AND LYMPHOMATOUS CHANGES SPLENOMEGALY OF NEW ZEALAND BLACK MICE

The incidence of splenomegaly was 39.6% in the nontreated group 41.0% in the treated group, not significantly different between both gr Thymic lymphoma group shared 27.6%, while the nonthymic lymphoma gr 67.9%, significantly different between both. Histological findings of sp megaly of the nonlymphoma groups were divided into the following types. 1) follicular form, 2) periarterial lymphatic sheath form, 3) red hematopoietic form, 4) marginal zone form, and 5) red pulp reticulosis Histology of the spleen in the lymphoma group resembled each form of of splenomegaly in the nonlymphoma group. Lymphoma based upon mune abnormality and specific to this kind of mouse in nonthymic lympl continuously takes place from prelymphomatous changes in the nonlympl group. Splenic origin and role of marginal zone of nonthymic lymphor murine lymphoma is discussed.