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The nomenclature of non-carcinoid epithelial proliferations of the appendix is confused and many of the terms used have no histogenetic basis. A classification based on the well-established diagnostic categories of colonic epithelial polyps has been proposed recently. We have applied this classification to 42 benign epithelial lesions of the appendix in order to determine its suitability for routine diagnostic use, and in order to determine the prognosis of patients with these lesions. All lesions could be classified as either hyperplastic, adenomatous, mixed hyperplastic/adenomatous or dilated appendices. Six cases were associated with a synchronous carcinoma of the colon with all types of appendiceal histology being represented. Follow-up of the remainder of the patients revealed two subsequent colonic carcinomas, at 3 and 6 years post-appendicectomy respectively. In both of these patients, the appendix had shown adenomatous epithelium. We suggest that adenomas of the appendix may have a similar prognostic significance to adenomas elsewhere in the large bowel.

A female teenager, without familial history, presented, since the age of 13 years, with gradually worsening pyramidal signs and a parkinsonian syndrome controlled by L-Dopa in small doses. The clinical complex was suggestive of the pallido-pyramidal syndrome, an entity which was individualized in 1954 by Davison on the basis of 5 young patients who had pyramidal signs and a parkinsonian syndrome. In only one of these patients a pathological study was carried out, disclosing a non specific degeneration without inclusions, involving the pallidum, substantia nigra and pyramidal tract. We hope that this report will encourage other authors to report similar cases, since only the study of new cases will determine whether the pallido-pyramidal syndrome is a true entity.

In a study of 101 autopsy appendices and over 3000 surgically resected appendices the range of histopathological features seen in each group is described. Fibrosis and faecoliths were more common in the older autopsy group than in the younger surgically resected group. The high incidence of fibrosis in the autopsy group suggests that this is an age-related change, although some may be due to previous inflammation. The low incidence of faecoliths in the surgically resected group does not support the hypothesis that they are a major cause of appendicitis.

The immunoreactivity of a range of vascular and non-vascular smooth muscle tumours, rhabdomyosarcomas, and non-myoid lesions has been examined with the use of a monoclonal antibody to smooth muscle-specific actin and the muscle intermediate filament, desmin. In all cases of smooth muscle-derived tumours, the alpha-actin antibody yielded superior results. Staining of the myofibroblasts of fibromatoses was also seen. In contrast to desmin, immunoreactivity was not exhibited by rhabdomyosarcomas. We propose that this monoclonal antibody to alpha-smooth muscle actin is a useful addition to the panel of reagents used for the characterization of soft tissue proliferations and tumours. The technical aspects of the application of this monoclonal antibody to immunohistochemistry are discussed.

A variety of reactive, benign and malignant soft tissue lesions have been stained for fibronectin using the immunoperoxidase technique. Two patterns of mesenchymal staining have emerged. The first has a diffuse stromal collagen and basement membrane distribution within normal and neoplastic mesenchyme and the second a more specific intracytoplasmic granular staining pattern. The latter is seen only in lesions derived from fibrous-histiocytic and synovial cells, a finding which may be of diagnostic use. The possible significance of intracellular fibronectin in neoplastic mesenchyme is discussed.

Formalin-fixed, paraffin-embedded jejunal, lymph nodal, and splenic tissues were obtained from four patients with Whipple's disease. Using antisera to a variety of bacteria, sections were stained by the immunoperoxidase technique. Positive staining was obtained with antiserum to streptococcus group B in all tissues examined. The distinctive pattern of staining was similar to the findings of previous workers using fluorescein-labeled antibodies. However, when rigorous controls for specificity were applied in this study, it was not possible to confirm the presence of streptococcus B antigen in the tissues. The discrepancy between the specificity of the technique on control and test sections is interesting and emphasizes the need for adequate controls when the immunoperoxidase technique is used to look for microorganisms in tissues. It is suggested that the unknown microorganism observed in the macrophages of patients with Whipple's disease has been altered in some way to resemble streptococcus B antigenically or that it shares common antigens with streptococcus B.

A skin lesion previously unassociated with Crohn's disease is described. Although superficially resembling erythema nodosum it runs a different clinical course and has different histological appearances, the central feature being necrobiotic collagen. The term ;nodular necrobiosis' is suggested.

There is considerable confusion surrounding the histogenesis and nomenclature of squamous cell carcinomas of the oesophagus with spindle cell elements. These tumours, many of which are polypoid, have been variously called carcinosarcoma, pseudosarcoma and polypoid carcinoma of the oesophagus. A study of three recent cases strongly supports the theory that these tumours are squamous cell carcinomas with spindle cell metaplasia. They are not necessarily polypoid and adenocarcinomatous elements may also be present.

The drug BW12C, which increases the oxygen affinity of hemoglobin, reduces oxygen availability to tissues. This results in protection against radiation damage to the hemopoietic system and epidermal Langerhans cells in CBA mice. The drug also protects against beta-irradiation damage in pig epidermis. BW12C increases the hypoxic cell fraction in tumors and histological examination of an experimental T cell lymphoma shows that the induced hypoxia leads to tumor necrosis.

The diagnosis and classification of soft tissue sarcomas can pose difficult problems for the histopathologist. Many sarcomas are too poorly differentiated to exhibit morphological features specific enough to define their histogenesis. Using the immunoperoxidase technique with commercially available antisera as a routine adjunct to other diagnostic aids, it is possible to arrive at more accurate diagnoses on which treatment protocols can be based. In addition a better understanding of mesenchymal neoplasms and their origins can be obtained by functional immunohistochemical studies.