No abstract available.
Diagnosis, Differential*

No abstract available.
Diagnosis, Differential*

Lymphoid lesions of the orbit and conjunctiva may be divided histologically into three groups: monomorphous and cytologically atypical malignant lymphomas, benign reactive follicular hyperplasia or inflammatory pseudotumor, and borderline lymphoid lesions mainly composed of small, non-atypical lymphocytes with or without evidence of plasmacytic differentiation or germinal centers which are difficult to clarify its nature by histologic criteria alone. From 1984 to 1992 at Seoul National University Hospital, 20 cases of orbital lymphoid infiltrates were reviewed to find out histopathologic characteristics of malignant lymphomas and try to classify them properly. Also, we sought histologic findings helpful for differential diagnosis between malignant and borderline cases. Histologic examination of malignant lesions usually revealed the features of low-grade B cell lymphomas of mucosa-associated lymphoid tissue(MALT) origin, which predominantly consist of centrocyte-like(CCL) cells. Among 13 primary orbital lymphomas, six cases were classified as MALT lymphomas of Isaacson, six were more apt to be the type of immunocytoma by kiel classification, and remaining one showed mixed pattern of both types in areas. The one case of malignant lymphoma with diffuse large cell type was confirmed by secondary involvement of intestinal lymphoma. Five cases were confirmed by immunoglobulin k-light chain monoclonality on flow cytometry and immunofluorescence study. The histologic findings such as Dutcher bodies, hemosiderin, deposits and polykaryocytes tended to be more frequently encountered in malignant lymphoma rather than indeterminate lesions and were thought to be helpful ones in making differential diagnosis between malignant and benign lesions. With above findings, we assume that the principal neoplastic cells in the low grade lymphoma arising in the orbit and conjunctiva are CCL cells, which might be originated from the localized memory B cells, and also several kinds of B lymphocytes in on-going differentiation stages such as medium-sized monocytoid B cell, lymphoplasmacytoid cell, plasma cell, and mature small lymphocyte also contribute to the tumor progression.
Diagnosis, Differential

The differential diagnosis between Spitz nevus and malignant melanoma is difficult due to similar histologic findings. To obtain the useful aids for the differential diagnosis between two diseases, we studied 13 cases of Spitz nevus, 8 benign nevi of compound and intradermal, and 9 melanomas of primary and metastatic, using the immunohistochemical stain for S-100 protein, HMB.45 and proliferating cell nuclear antigen(PCNA). The staining pattern and intensity of S-100 protein showed homogenously strong positive reactivity in all cases. The frequency of HMB.45 positive cell in Spitz nevus was significantly lower than that in melanoma. When compared with the usual compound and intradermal nevi, Spitz nevi showed more significantly positive reaction in the dermal component of nevus cells. The expression of PCNA was higher in melanoma than in Spitz nevus. The immunohistochemical stains for HMB.45 and PCNA are considered as a useful methods for differentiation between Spitz nevus and melanoma, while stain for S-100 protein is not helpful.
Diagnosis, Differential

The authors report four cases of ependymal cysts. Among the benign cystic lesions of neuroepithelial origin, ependymal cysts have been reportedly located in the cerebral parenchyme. This usually become symptomatic after 40 years of age, although it is generally thought to be congenital in origin. Symptomatic cases have been treated effectively with resection of the cyst or shunting procedures. Stereotactic removal of the cyst was also a good alternative as management in the authors' cases. Differential diagnosis is mandatory with other benign intraparenchymal cystic diseases.
Diagnosis, Differential

Cellular blue nevus is an benign variant of blue nevus group, characterized by cellular islands composed of closely aggregated spindle cells with little or no melanin. The other variants include atypical and malignant blue nevus which often had the difficulties in the differential diagnosis from the malignant melanoma. A 4-year-old boy presented with hemispheric scalp nodule, which has been slowly grown since birth, measuring 3.5x3x1.5 cm. The surface showed geographic black pigmentation without hairs, hemorrhage, and ulceration. The excised mass disclosed homogeneoulsy dark black, glistening, and muddy cut surface. Histological examination revealed exuberant melanocytic proliferation with both spindle and dendritic components. Heavily pigment ed spindle cells, melanophages, focal necrosis, and vacuolated epithelioid cells were unusually noted in our case and diagnosed as cellular blue nevus. Electron microscopy disclosed largely mature melanosomes in tumor cells and melanophages. During about 16 months since operation, he has been relatively well with no evidence of disease.
Diagnosis, Differential

Granulocytic sarcoma is a rare localized tumor composed of granulocytic precusor cells. Granu-locytic sarcoma occurs in a variety of clinical conditions and it is often misdiagnosed histologically. Differential diagnosis frorh lymphoma or nonhematopoietic malignancies such as undifferentiated carcinoma or sarcoma is difficult in the routing histologic examination. An evaluation of clinical and histopathologic features was done on 4 cases of granulocytic sarcoma which were diagnosed at Pusan Paik Hospital from 1988 to 1992. During the period, 282 cases of myelogenous leukemia were diagnosed. Immunohistochemical reaction for lysozyme, myelopero-xidase, leukocyte common antigen, epthelial membrane antigen and cytokeratin was assessed comparing to lymphoma and undifferentiated carcinoma. The histologic features of the granulocytic sarcoma revealed thin nuclear membrane, fine chromatin pattern and one or two small nucleoli. It also often involved the vascular wall and infiltrated the native structures without destruction. Immunohistochemical stain revealed that all(4 cases) of granulocytic sarcoma showed diffuse and strong positivity for myeloperoxidase, and partial but strong positivity for lysozyme. One case of granulocytic sarcoma was negative and 3 cases revealed focal positive reaction for LCA, and all 4 cases was negative for cytokeratin and EMA. In summary, careful observation under light microscopy with immunohistochemical stain for myeloperoxidase, lysozyme, and LCA is helpful in the differential diagnosis of granulocytic sarcoma from malignant lymphoma and cytokeratin and EMA is useful for differential diagnosis from undifferentiated carcinoma.
Diagnosis, Differential

The fine needle aspiration (FNA) cytologic findings in 16 cases of histologically confirmed thymoma are reported. The aspirates were obtained under fluoroscopic guidance. The cytologic diagnoses were inadequate sample in one case, thymoma in 12 (75%), small cell carcinoma or thymoma in 1, benign mesenchymal tumor in 1, and germ cell tumor in one. The cytologic features were detailed according to the constituent epithelial cell type, and to the ratio of epithelial cells and lymphocytes. Fifteen cases were classified into 4 small epithelial cell type, 6 intermediate epithelial cell type, 1 large epithelial cell type, 1 large pleomorphic epithelial cell type, and 3 spindle-shaped epithelial cell type. Cytologic differential diagnosis was discussed, and the important criteria for the cytologic diagnosis of thymoma were reviewed. This review leads us to think that nonoperative cytologic approaches in the diagnosis of the thymoma are possible, and that correct cytologic diagnosis of thymoma with FNAs can easily be made, if adequate samples are obtained. However, the invasiveness and histologic type could not be predicted by cytological features only. Knowing various cytologic and histologic features of thymoma will be helpful for the diagnosis of thymoma and the differential diagnosis of mediastinal tumors.
Diagnosis, Differential

Although a great deal has been written about porencephaly during the past 100 years, there is much that remains obscure. The clinical recognition of porencephaly is important because it occurs with sufficient frequency to require consideration in the differential diagnosis of focal cerebral lesions. The authors considered and discussed to fulfill the pathogensis for this case.
Diagnosis, Differential

Cutaneous focal mucinosis was first described by Johnson and Helwig in 1961 and is histo logically characterized by localized accumulation of mucin in the upper and middermis with scattered spindle-shaped fibroblasts. The mucin is jelly-like acid mucopolysaccharide consisting of hyaluronic acid bound to small amounts of chondroitin sulfate and heparin. The pathogenesis of cutaneous mucinosis is unclear. However, studies of various cutaneous mucinoses suggest that there may be an unknown circulating factor that stimulates fibroblasts to produce this material. Differential diagnoses include papular mucinosis, myxoid cyst, cutaneous myxoma. Simple surgical excision is the treatment of choice. In the present case, cutaneous focal mucinosis occurs on the nail bed with onycho mycosis.
Diagnosis, Differential