Biomedical subjects

G Orchard

Publications and source records attributed to G Orchard.

24 records · Page 2Linked to original sources

PubMed1994

Desmoplastic malignant melanoma. An immunocytochemical study of 25 cases.

Using a panel of seven cell markers, we studied the value of immunocytochemical labelling in the histological diagnosis of desmoplastic malignant melanoma. Sections from routine formalin-fixed tissue of 45 surgical specimens were obtained from 25 cases of malignant melanoma that showed well-marked desmoplastic or neurotropic features. Routinely stained sections (Haematoxylin- and -eosin and melanin stains) were compared with the following panel of seven antibodies: S-100, neuron-specific enolase (NSE), vimentin, factor XIIIa (FXIIIa), desmin and the newer, supposedly more specific antimelanoma antibodies HMB45 and NKIC3. S-100 and NSE were the most sensitive antibodies for desmoplastic malignant melanoma with strong labelling of spindle cells in most cases. In contrast, results for NKIC3 were more variable; results were negative in nearly half the tumours, but strong labelling was seen in six cases (27%). Positive labelling for HMB45 was noted in five tumours (22%); it was mostly confined to small groups of cells in the superficial part of the lesions. Tumour spindle cells were negative for FXIIIa in all cases; there was no increase in the number of positive dermal dendritic cells compared to conventional and spindle cell melanoma. All tumours were desmin-negative, but most were vimentin-positive. Our findings indicate that immunocytochemistry is of less value in the diagnosis of desmoplastic malignant melanoma that it is with other types of malignant melanoma. However, positive or negative labelling for S-100 protein and NSE is useful for suggesting or excluding a diagnosis of desmoplastic malignant melanoma; neither marker is specific and, in particular, positive labelling is also found in most neurofibromas and benign cellular naevi.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Reticulohistiocytoma and multicentric reticulohistiocytosis. Histopathologic and immunophenotypic distinct entities.

The clinicopathological and immunohistochemical features of four patients with systemic multicentric reticulohistiocytosis (MR) were compared with five cases of solitary and one case of multiple reticulohistiocytoma (RH), which were confined to the skin only. The MR cases mostly affected the limbs of older women, while RH affected young male adults without preference to site. Characteristically, both entities consisted of oncocytic mononuclear histiocytes (with granular eosinophilic cytoplasm similar to oncocytic thyroid cells) and multinucleated histiocytes with a ground-glass appearance, which appeared to be much larger (> 200 microns) and bizarre in cases of RH compared with cases of MR (50-100 microns). In RH a variable number of vacuolated, spindle-shaped, and xanthomatized mononuclear histiocytes were also present. Immunohistochemical profiles showed positivity of mononuclear histiocytes with HHF35, factor XIIIa, and LN3 (HLA-DR), with a variable number of multinucleated histiocytes in RH showing binding with peanut agglutinin. In mono- and multinucleated histiocytes in both entities macrophage markers KP1 (CD68), KiM1P, HAM56, lysozyme, and alpha 1-antitrypsin were positive. However, macrophage markers MAC387 (L1 antigen) and Leu-M1 (CD15) were negative. Vimentin was universally positive in both conditions, with all other markers (S100, desmin, smooth muscle-specific actin, and QBEnd 10 [CD34]) negative. This study shows that histology supplemented by immunocytochemistry delineates MR from RH and immunohistochemical profiles indicate a cell lineage relationship between RH and adult xanthogranuloma.

Adolescent↗

PubMed1994

Juvenile and adult xanthogranuloma. A histological and immunohistochemical comparison.

Thirteen cases of juvenile xanthogranuloma (JXG) and 13 cases of adult-type xanthogranuloma (AXG) were compared at the light and immunohistochemical levels. Histologically, four main cell types (vacuolated, xanthomatized, spindle-shaped, and "oncocytic") were seen in variable proportions (from monomorphous to mixed variants) with different types of giant cells (nonspecific, foreign body, Touton, and "ground-glass"). Giant cells were more prominent in AXG than in JXG; oncocytic cells (characterized by an eosinophilic, slightly granular cytoplasm similar to thyroid oncocytic cells) and mostly periodic acid-Schiff (PAS) negative giant cells with a ground-glass appearance (6 of 26) were not observed in classic JXG (i.e., occurring in children < 2 years old). Immunohistochemically, JXG and AXG gave similar results: most xanthogranuloma cells labeled strongly with KiM1P and vimentin, while HHF35 and HAM56 stained less intensively. Factor-XIIIa (FXIIIa), KP1 (CD68), and HAM56 stained mostly in the periphery of the lesions. Some markers gave variable results: peanut agglutinin (PA), 60%; alpha-1-antitrypsin, 50%; lysozyme, 25%; LN3 (HLA-DR), < 10% of cells positive. Others were negative: S-100, MAC387 (L1 antigen), LeuM1 (CD15), desmin, smooth muscle-specific actin, and QBEND10 (CD34). This profile helps to delineate xanthogranuloma from histological stimulants such as dermatofibroma (which is FXIIIa+, LN3+, KP1-, and PA-) and multicentric reticulohistiocytosis (which is FXIIIa-, KP1+, PA-, and HHF35-).

Adolescent↗

PubMed1994

Heat shock protein 65 immunoreactivity in experimentally induced polymorphic light eruption.

The expression of 65 kiloDalton heat shock protein (HSP65) immunoreactivity of skin biopsies from experimentally induced polymorphic light eruption (PLE) lesions was studied, to investigate its possible role as a photo-induced antigen responsible for precipitating lesions. In each subject the 24-h minimal erythema dose of solar simulated radiation was determined and an area of skin previously affected by PLE subjected to 70% of the minimal erythema dose in order to induce PLE lesions. The irradiated areas were sequentially biopsied between 0 and 6 days. ML-30, a monoclonal antibody which recognises heat shock protein 65, was used to label the sections by means of an indirect immunoperoxidase technique. In PLE patients clinical inflammation was noted by 5 h post-irradiation, with subsequent evolution of PLE-like lesions; these were still present at 6 days. Increased ML-30 antibody labelling in epidermal keratinocyte and endothelial cell cytoplasm was recognisable from 1 h post-irradiation, and in dermal dendritic cells from 5 h sustained through to 6 days. In normal subjects neither clinical nor histological features of inflammation were noted after irradiation, nor any increase in HSP65 labelling.

Bacterial Proteins↗

PubMed1994

Immunocytochemistry in the diagnosis of malignant melanoma.

The role of immunocytochemistry in the routine diagnosis of malignant melanoma is reviewed, with particular emphasis on the potential technical and pathological interpretive problems that may occur. Careful evaluation of the appropriate panel of markers is discussed, along with details of cross-reactivity of markers with tumours of non-melanocytic derivation. Future developments in immunocytochemistry within the field of proliferation indices assessments are highlighted.

Antibodies↗

PubMed1992

Histologic and immunohistochemical study comparing xanthoma disseminatum and histiocytosis X.

BACKGROUND AND DESIGN: As xanthoma disseminatum and histiocytosis X share clinicopathologic features, difficulties in diagnosis can arise. The use of immunocytochemical markers for S100 protein, factor XIIIa, lysozyme, alpha 1-antitrypsin, for adherence of peanut agglutinin and of antibodies LN3 (HLA-DR), Leu-M1 (CD15), QBEnd/10 (CD34), MAC 387, and KP1 (CD68) as an aid to conventional histology has been studied in routinely fixed skin biopsy specimens from seven patients with xanthoma disseminatum and 12 patients with histiocytosis X. RESULTS: Typically xanthoma disseminatum occurs in discrete foci below an intact epidermis with individual cells set within a delicate fibrillary connective tissue stroma. In contrast, histiocytosis X usually occurs as a diffuse lichenoid infiltrate that can extend to deeper tissues. Epidermal invasion is common and the cells tend to lie free separated by edema fluid. Characteristic histiocytosis X cells are ovoid with an indented or kidney-shaped nucleus that occupies half or more of the cell. Xanthoma disseminatum cells differ in showing irregular scalloped borders, a more extensive cytoplasm, and an ovoid vesicular nucleus. Most xanthoma disseminatum cells labeled strongly for factor XIIIa and with KP1; a few cells labeled only weakly with peanut agglutinin. In contrast, most histiocytosis X cells labeled for S100 protein and with LN3 and peanut agglutinin. All the other markers remained negative in both conditions and were thus noncontributory for differentiating xanthoma disseminatum from histiocytosis X. CONCLUSIONS: We conclude that the differences in labeling patterns are a useful aid to histologic diagnosis of histiocytosis X and xanthoma disseminatum and they also reflect their separate histiogenesis.

Adolescent↗