A histopathologic study including iramunohistochemical stains was made in 30 patients who were presented with gastrointestinal lymphoma. The occurrence was 13 in the stomach, 8 in the ileocecum, 7 in the small intestine and 2 in the colon. The disease more frequently affected males than females and the average ages were 53 years in the patients of gastric lymphoma and 44 years in the patients of intestinal lymphoma. Gastric lymphomas were usually presented with a single lesion, and the antrum and/or body were the most common sites. But intestinal lymphomas were presented with a single or multiple lesion, and the ileocecum was the most common site. The most common gross type of gastrointestinal lymphomas was the ulceroinfiltrating type and most are of the diffuse large noncleaved cell type of B-cell lymphoma, histologically. There were 2 cases of T-cell lymphoma presented in the intestine as the superficially ulcerative gross pattern and diffuse immunoblastic cell type. The distinct MALToma was seen in only one case of stomach but the feature was partially remained in each two cases of stomach and intestine. Their coexistent findings may suggest that diffuse large of immunoblastic component arises through blastic transformation of the low-grade M ALToma component.
Female ; Male ; Humans

To evaluate the differentiation status of smooth muscle in gastric stromal tumors which were negative for S-100 protein, immunohistochemistry using desmin, actin, myosin and vimentin was performed in 14 cases of gastric smooth muscle tumors. Ultrastructural Examination was also performed. For comparison a case of leiomyoma of the esophagus, a case of the sigmoid colon, 10 cases of the uterus were also examined. The results obtained were as follows. All gastric smooth muscle tumors showed vimentin-positivity. Six of 14 gastric smooth muscle tumors, (5 of 8 leiomyoma and 1 of 4 leiomyosarcoma) showed positivity for desmin, actin, and myosin(42.9%). All esophageal, colonic, and uterine leiomyomas showed diffuse positive reaction for desmin, actin, and myosin. Vimentin positivity was also noted in leiomyoma of the colon and uterus. Ultrastructurally, a few cells in the gastric stromal tumors had scattered microfilaments with dense bodies, subplasmalemmal dense plaques, and micropinocytic vesicles. However, most of the tumor cells did not have any of the ultrastructural features of smooth muscle differentiation. Leiomyomas of the esophagus and uterus showed many cytoplasmic microfilaments with dense bodies. These results suggest that most of the benign and malignant tumor cells of gastric stromal tumors have features of the undifferentiated cells, immunohistochemically as well as ultrastructurally, although a few cells have. It is speculated that most gastric stromal tumors may have lost their smooth muscle differentiation.

Adenomatoid tumors are well-recognized neoplasms generally to be of mesothelial derivation. We experienced a case of an adenomatoid tumor of the tail of the epididymis in a 56-year-old male. Grossly the tumor was firm and whitish gray, and microscopically it consisted of glandular, cord-like, microcystic structures which were lined by flattened endothelial like to plump cuboidal cells. Immunohistochemical stains whowed positivity for keratin and negativity for facter VIII related antigen and carcinoembryonic antigen. Ultrastructually, there was many long microvilli projecting into the glandular lumina and intracytoplasmic luminal spaces, desmosomes, and prominent cytoplasmic tonofilaments. Those findings strongly support the mesothelial origin of the adenomatoid tumor especially in the glandular type. It also lead us to suggest that the term adenomatoid tumor should be remain in use for light microscopic diagnosis, and that the term adenomatoid mesothelioma should be applied when the mesothelial nature of an adenomatoid tumor is proven by electron microscopy and immunohistochemical stains.

Fibrohistiocytic tumors are a diverse group of benign and malignant soft tissue lesions, including dermatofibroma, dermatofibrosarcomaprotuberans, and malignant fibrous histiocytoma. On the clinical point of view, the distinction between benign and malignant lesions and malignancy grading is far more important. Therefore, we investigated 23 fibrohistiocytic tumors, using PCNA (PC10) which was a useful marker of proliferating activity, to differentiate the benign lesions from the malignant and correlate with other prognostic factors including tumor necrosis. cellularity, histologic grade, and mitotic counts. The results obtained were as follows 1) Positive tumor cells were clearly identified by the characteristic diffuse or granular nuclear staining. 2) The number of PCNA-positive tumor cells were 2.16+/-2.39% in dermatofibroma, 16.12+/-7.38% in dermatofibrosacoma protuberans, and 28.02+/-17.47% in the malignant fibrous histiocytoma. The numbers of PCNA-positive tumor cells in the malignant lesions higher than in the benign (p<0.001). 3) Deep seated, large size (>5 cm) and recurred or metastatic cases of MFH were more the high PCNA index (more than 20%) than the low index (less than 20%) groups. 4) PCNA index in MFHs had positive correlation with the number of mitotic counts (r=0.7582, p<0.001), cellularity (r=0.5908, p<0.05) and histologic grade (r=0.4164, p<0.05). These results suggested that reactivity on PCNA might assist in the distinction between benign and malignant lesions in fibrohistiocytic tumors, and could be a useful prognostic factor in the patients with malignant fibrous histiocytoma.
Neoplasm Metastasis

Hemangioblastomas comprise 1 to 2% of all intracranial neoplasm, and 8 to 12% of tumors within the posterior fossa. They are composed of admixtures of three different cell types; endothelial cells, pericytes and stromal cells. Although most hemangioblastomas arise sporadically, they are associated with von Hippel-Lindau disease in about 20% cases. We have experienced a case of multiple hemangioblastomas occuiing in the cerebellum, medulla oblongata and cervical spinal cord simultaneously in a 55-year-old male. He had complained of headache, dizziness, generalized weakness and gait disturbance for 2 weeks. The patient had neither specific family history nor increased hematocrit. MRI showed a nonenhancing cystic lesion with an enhancing mural nodule in the right cerebellar hemisphere and two separate enhancing nodules in the medulla oblongata and dorsal cervical spinal cord at the 5-6th. Grossly, the excised mass of the cerebellum, 2.5 x 2 x 1.8cm, was solid to partly cystic, and that of spinal cord, lcm in diameter, was mostly solid. Microscopically, the tumor was composed of thin-walled blood vessels in variable size and interspersed stromal cells. The stromal cells revealed dimorphic cytoplasm that were either homogeneous and eosinophilic, or clear and vacuolated. Immunohistochemically, the endothelial cells reacted positively for glial fibrfllaty acidic protein(GFAP) and vimentin. The stromal cells reacted diffusely positively for vimentin, focally positively for GFAP and S-100 protein near the periphery of the tumor, focally positivel for neuro specipic enolase(NSE), and negatively for lysozyme, desmin and chromogranin. Ultrastructurally, the stromal cells contained numerous microfilaments and lipid droplets.

Hemangioblastomas comprise 1 to 2% of all intracranial neoplasm, and 8 to 12% of tumors within the posterior fossa. They are composed of admixtures of three different cell types; endothelial cells, pericytes and stromal cells. Although most hemangioblastomas arise sporadically, they are associated with von Hippel-Lindau disease in about 20% cases. We have experienced a case of multiple hemangioblastomas occuiing in the cerebellum, medulla oblongata and cervical spinal cord simultaneously in a 55-year-old male. He had complained of headache, dizziness, generalized weakness and gait disturbance for 2 weeks. The patient had neither specific family history nor increased hematocrit. MRI showed a nonenhancing cystic lesion with an enhancing mural nodule in the right cerebellar hemisphere and two separate enhancing nodules in the medulla oblongata and dorsal cervical spinal cord at the 5-6th. Grossly, the excised mass of the cerebellum, 2.5 x 2 x 1.8cm, was solid to partly cystic, and that of spinal cord, lcm in diameter, was mostly solid. Microscopically, the tumor was composed of thin-walled blood vessels in variable size and interspersed stromal cells. The stromal cells revealed dimorphic cytoplasm that were either homogeneous and eosinophilic, or clear and vacuolated. Immunohistochemically, the endothelial cells reacted positively for glial fibrfllaty acidic protein(GFAP) and vimentin. The stromal cells reacted diffusely positively for vimentin, focally positively for GFAP and S-100 protein near the periphery of the tumor, focally positivel for neuro specipic enolase(NSE), and negatively for lysozyme, desmin and chromogranin. Ultrastructurally, the stromal cells contained numerous microfilaments and lipid droplets.

Historically, gastrointestinal stroma tumors (GIST) have been considered as smooth muscle tumors, but the controversy over this histogenesis is provoked due to various results with utilizing immunohistochemical methods. In andeffort to further clarify the histogenesis of GIST, we performed the immunohistochemical study, as well as histopathologic reexamination, of 24 cases, all diagnosed as smooth muscle tumors of gastrointestinal tract, from Seoul Paik Hospital and Ewha University Hospital between 1980 and 1989, and the main results were as follows; 1) In the histopathologic features by light microscopic study, 11 benign and 13 malignant lesions (including one high grade malignancy and 12 low-grade malignant lesions) were disclosed. 2) In the immunohistochemical study, all tumors showed Vimentin positivity (100%), but no tumor showed S-100 protein positivity (0%), and 7 cases (29.1%) showed Desmin positivity. Positive reaction for Desmin made it possible to suggest that the histogenesis of GIST be in smooth muscle, and neurogenic origin would be excluded by all negativity for S-100 protein. In summary, we would like to conclude that GIST would be smooth muscle tumors on account of their morphological characteristics and their intramural location, but most of them appear poorly differentiated by immunohistochemical method.

The term malignant mesenchymoma has been applied to those tumors of the soft tissue of mesenchymal origin which are composed of tumor cells differentiating into two or more unrelated malignant forms in addition to the fibrosarcomatous element. Recently authors experienced a case of malignant mesenchymoma in the right axillary area. Microscopically the sarcoma revealed multiple pattern of differentiation, including liposarcoma, malignant schwannoma, fibrosarcoma, malignant fibrous histiocytoma and rhabdomyoblastoma. The presence of rhabdomyblastic cells were proved by immunochemical study utilizing desmin. This patient was treated with surgical excision and radiation.

Somatostatinoma is rare endocrine tumor that was first described in 1977 by Ganda et al. and Larsson et al. simultaneously. It seems nonfunctioning at clinical level. But it may present with diabetes, diarrhea, cholelithiasis, steatorrhea, indigestion, hypochlorhydria, and anemia. In contrast with pancreatic somatostatinoma, duodenal somatostatinoma, in general, is clinically silent. Duodenal endocrine tumors show similar histologic pattern. Therefore, the definite diagnosis is performed by immunohistochemistry and electron microscopic examination. We have experienced a case of somatostatinoma of duodenum in a 62-year-old male. He has complained generalized pruritus for one year and jaundice for 2 weeks. Grossly, the mass was a intraluminary protruding, polypoid lesion with focal mucosal erosion at immediately distal to Ampulla of Vater. Histologically, it showed tall, cylindrical cells with distinct cell membranes, having granular cytoplasm and small innocent looking nuclei. No mitosis was seen. The tumor cells were arraged in small solid groups and trabeculae, separated by fibrovascular stroma. Immunohistochemically, the tumor cells were strongly positive with somatostatin and negative with several other hormonal and neuroendocrine markers. Ultrastructurally, the cytoplasm contains numerous, homogeneous low electron dense secretory granules, which are essentially similar to those seen in normal delta cells.

Sclerosing hemangioma of the lung is uncommon benign neoplasm of uncertain histogenesis, although their radiological appearance is relatively distinct and well-defined. Recently, we experienced 2 cases of sclerosing hemangiomas of the lungs in 61 and 39 years old women. The light microscopic findings of the tissues are similar to the features reported by Liebow and Hubbell(1956). The basic cellular response is thought to be type II pneumonocytes because of findings of multilamellar-like bodies within stromal cells with electron microscopy in case I in addition to other characteristics generally found in epithelial cells.
Female ; Humans ; Hemangioma