ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Merkel cell carcinoma (MCC) has a small cell variant, indistinguishable in hematoxylin-eosin sections from metastatic small cell carcinoma of the lung (SCCL). To investigate whether intermediate filament expression is helpful in this distinction, 17 MCCs of the small cell type were examined for cytokeratin, as well as neurofilament protein immunostaining, and compared with 59 intermediate-type MCCs and 22 SCCL. With a pan-cytokeratin cocktail (cytokeratin 1-8, 10, 13-16, 19), most (39 of 55) intermediate-type tumors and, more important, 11 of 16 cases of the small cell variant exhibited focal paranuclear staining with dot-like positivity, crescentic positivity, or both. A combined focal (dot-like/crescentic) and diffuse cytoplasmic pan-cytokeratin staining was seen in additional 8 of 55 intermediate and 4 of 16 small cell MCCs. Cytokeratin 20 also evoked focal cytoplasmic staining and occasionally focal and diffuse positivity in the MCCs, irrespective of the subtype. Exclusively diffuse cytokeratin 20 patterns did not occur. Conversely, most SCCL showed a diffuse expression of pancytokeratin, and all cases remained cytokeratin 20 negative. When neurofilament protein was applied, approximately half of the MCCs (25 of 40), including 7 of 11 of the small cell variant, were positive, whereas all SCCL were negative. In conclusion, the cytokeratin and neurofilament protein patterns of small cell MCCs are identical to the pattern of intermediate MCCs but differ from the profile of SCCL, which may help in the differential diagnosis.

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The presence of asymmetry is a major diagnostic criterion for the differentiation of melanoma from benign melanocytic proliferations. It is helpful in both clinical and histological evaluation. The underlying biological features that determine asymmetry have not yet been evaluated. Using computer simulation of the growth of neoplasms, we demonstrate that a functionally homogeneous cell population can give rise to asymmetric lesions when the cells respond to autocrine growth signals. In contrast, neoplastic cells that depend on paracrine stimuli tend to form symmetric lesions. Since the progression of melanocytic neoplasms has been demonstrated to be accompanied by increasing independence of paracrine growth signals and the development of autocrine loops, autocrine growth stimulation has to be considered as a potential source of asymmetry in melanoma.

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The accumulation of excessive amounts of melanin in melanocytic lesions can obscure cellular morphology and can further hinder immunocytochemical procedures. We have used a modification of the potassium permanganate/oxalic acid melanin-bleaching technique, involving much reduced bleaching times, in order to remove melanin granules prior to incubation with primary antibody. We have assessed a panel of antibodies applicable to the evaluation of melanocytic lesions and in addition have also assessed antibodies that may be more useful in research. The study attempts to determine which antigens may be affected by bleaching and which are not. Antigens S100, HMB 45, NKIC3, CD34, and L26 are relatively unaffected by this procedure. Factor-VIII-related antigen and vimentin and CD68 antigens produced enhanced staining. In contrast, antigens CD3, CD31, and CD45RO were abolished. In addition, smooth muscle actin and desmin antigens demonstrated considerable nonspecific background staining and were not reliable in this study. This technique demonstrates that a fairly wide range of antigens are preserved after bleaching and that distinction between melanocytes and melanophages can reliably be performed using the conventional immunocytochemical chromogen 3,3-diaminobenzidine and without the need for elaborate counterstaining.

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Dendritic cells that express factor XIIIa are present in the normal dermis and are increased in a variety of pathologic conditions. Atypical dermal cells are often seen in biopsy specimens of skin that has been previously irradiated. We sought to determine whether the atypical dermal cells in chronic radiation dermatitis express factor XIIIa. We employed standard immunohistochemical techniques with antibodies to factor XIIIa and CD34 to study 16 biopsy samples showing changes of radiation dermatitis. All cases showed diffuse positive cytoplasmic staining of atypical dermal cells with antibody to factor XIIIa. Of 16 cases, 10 showed focal staining of dermal cells with antibody to CD34, but this antibody did not react with most of the atypical dermal cells. We conclude that the majority of atypical dermal cells in radiation dermatitis are derived from dermal dendritic cells which express factor XIIIa.

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Recently, the term sebomatricoma has been proposed as the most appropriate denomination to avoid controversial and confusing terms and to encompass all benign neoplasms with sebaceous differentiation. We report on two specimens that may be interpreted as examples of two new histopathologic patterns in sebomatricoma, namely, pigmented and nested sebomatricoma, or as seborrheic keratosis with sebaceous differentiation. The first case consisted of a neoplasm composed of basaloid immature cells with features of sebaceous differentiation in the form of clusters of sebocytes and sebaceous ducts, in addition to the proliferation of dendritic melanocytes arranged as solitary units scattered through the neoplastic aggregations of immature germinative sebaceous cells. The second case, in addition to the proliferation of single dendritic melanocytes as the first case, showed well-defined nests of basaloid and heavily pigmented germinative sebaceous cells connected to the skin surface and numerous sebaceous ducts. In the first case, the pigmented nature of the lesion was the most striking histopathologic characteristic, whereas the nested pattern was remarkable in the second one. Immunohistochemical investigations demonstrated positivity of cytokeratin MNF116 in neoplastic aggregations of germinative sebaceous cells, whereas the clusters of mature sebocytes and sebaceous ducts expressed epithelial membrane antigen positivity. S-100 protein made evident the scattered dendritic melanocytes, but neoplastic cells resulted negative.

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

The authors report on the case of a 33-year-old white woman who developed melanoma during pregnancy, with widespread metastatic disease involving the placenta. The melanoma developed during two consecutive pregnancies and was untreated throughout the course of both. The patient died with widespread metastases shortly after attempted Cesarean delivery of her second child. Histopathologic and immunohistochemical studies were made with anti-S-100 protein and HMB45 antibodies. The authors discuss the possible influence of pregnancy on the prognosis of melanoma.

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Aleukemic leukemia cutis is a rare condition characterized by the infiltration of the skin by leukemic cells before their appearance in the peripheral blood. The authors report a case of aleukemic leukemia cutis in a 30-year-old seemingly healthy man who presented with multiple skin papulonodular lesions and lack of peripheral blood involvement. Histopathologically, the skin infiltrates showed prominent granulomatous features that masked the underlying malignant process. Immunophenotypic studies of skin and bone marrow infiltrates revealed the myelomonocytic lineage of the atypical cells, consistent with M4 acute myelomonocytic leukemia. The authors emphasize the value of immunohistochemical studies in diagnosing a cutaneous atypical infiltrate and discuss problems of histopathologic differential diagnosis.

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID

ISSN:0193-1091    

出版商:OVID    

年代:1998

数据来源: OVID