Immunohistochemical detection of hepatitis C virus antigen in paraffin embedded liver biopsies from patients with chronic liver disease.

A simple and reproducible immunohistochemical (IHC) staining method that adequately identifies and localizes hepatitis C virus (HCV) in human livers is still not available. We performed IHC staining using both a new monoclonal antibody against HCV and a polyclonal human anti-HCV IgG to 94 liver biopsies from HCV seropositive patients with chronic hepatitis and 15 control liver biopsies. Positive nuclear staining was consistently observed predominantly in hepatocytes and much less in lymphocytes with either antibody in 57% of anti-HCV seropositive cases but in none of the controls. However, the monoclonal antibody yielded a stronger positive reaction and in a greater proportion of hepatocytes. In 78% of the positive cases, more than a quarter of the hepatocytes showed nuclear staining. The degree of hepatic HCV load as revealed by intensity and extent of positive staining did not correlate with histological changes in the liver. The new monoclonal antibody against HCV appeared to be suitable for identifying HCV in tissues by a simple IHC stain and can be used to explore the pathogenesis of liver injury induced by this virus.

Immunohistochemical study of proliferating mesenchymal spindle cells in heterogenous soft tissue lesions.

Proliferation of mesenchymal spindle cells is a main event in a variety of lesions with similar morphological features but widely divergent biological behaviour. In order to identify criteria for precise histological diagnosis, 60 human soft tissue lesions, divided into 40 cases of fibroblastic cell proliferation, 10 smooth muscle cell tumours and 10 nerve sheath cell tumours, were examined for the immunohistochemical profile of the main lesional cell in addition to other histological features. The three groups could be differentiated by determining the lineage of the constituent spindle cell on the pattern of expression of vimentin, alpha-smooth muscle actin (ASMA) and macrophage antigen CD68 (MA-CD68). Smooth muscle cells expressed ASMA and vimentin but not MA-CD68, while nerve sheath cells were negative for ASMA but positive for vimentin and MA-CD68. The fibroblastic cell lesions as a group were easily differentiated on the basis of positive reactivity for all three markers but individual lesions could only be distinguished by additional assessment of histological features. Because of consistent co-expression of ASMA, vimentin and MA-CD68 in the spindle mesenchymal cell present in all varieties of lesions in this heterogeneous group, we suggest that this proliferating "fibroblastic" cell is phenotypically a fibromyohistiocyte.

Benign disorders of the prostate: A histopathological study.

Although the medical literature contains adequate accounts of the pathophysiology of various benign prostatic disorders, it is often necessary to revisit these lesions, to reexamine the relationships between known benign lesions and more sinister, malignant disorders, in the light of new advances in our understanding of the processes. We carried out a histopathological review of prostatic surgical pathology material seen over a sevenyear period in our hospital. Our findings show that benign enlargement of the prostate or benign prostatic hyperplasia (BPH) is initially fibromuscular in many cases, becoming glandulostromal with advancing age. While we found no relationship between prostatitis and age, individual gland necrosis tended to occur relatively early and correlated well with stromal repair, which we believe forms the basis of fibromuscular hyperplasia. Epithelial hyperplasia may result from glandular regeneration, and basal cell hyperplasia, papillary hyperplasia and cribriform hyperplasia all showed significant correlation with prostatic intraepithelial neoplasia (PIN). On the other hand, only cribriform hyperplasia showed correlation with atypical adenomatous hyperplasia (AAH), and also demonstrated an increase in incidence with advancing age. Our findings underline the positive relationships between benign events such as glandular necrosis with repair and epithelial hyperplasia, which may itself predispose to recognized premalignant lesions such as PIN.

Case report: tuberculosis of the parotid gland--diagnosis by CT.

A case of parenchymal and intraparotid lymph node tuberculosis is reported in a young Asian male. The diagnosis was suggested pre-operatively by the contrast enhanced CT (CECT) appearance. There were no systemic symptoms of tuberculosis and this is a characteristic feature of the 100 cases reported in the literature. The presence of thick walled rim enhancing lesions with a central lucency on CECT should suggest the diagnosis. Filling defects with or without thin walls are non-specific findings and are seen in tumours and other inflammatory processes. In an appropriate clinical setting, thick walled round rim enhancing lesions with a central lucency are characteristic of tuberculosis.

The nature and significance of liver cell vacuolation following hepatocellular injury--an analysis based on observations on rats rendered tolerant to hepatotoxic damage.

Swelling with nonlipid cytoplasmic vacuolation of diffusely distributed hepatocytes is seen consistently after mild acute and subacute liver injury. Several lines of evidence point to the possibility that this change may reflect a cellular adaptation beneficial to the host, rather than a degenerative change. The nature and significance of this morphological manifestation were tested in batches of albino rats given small doses of a variety of hepatotoxins, some of which were subsequently challenged with a large highly necrogenic dose of carbon tetrachloride (CCl4). Morphological and biochemical investigations showed that cytoplasmic vacuolation of liver cells following low doses of toxins was due to excess accumulation of glycogen, predominantly of the monoparticulate form. These cells lacked features of degeneration or regeneration and were much less susceptible to injury by the large dose CCl4, as assessed by structural and serum enzyme analyses. This tolerance to toxic damage seemed to be associated with excess accumulation of intracellular glycogen. We conclude from these and other observations on animal and human livers that many of the vacuolated hepatocytes seen in liver injury are cells adaptively altered to resist further insult rather than cells undergoing hydropic degeneration, as is commonly believed.

Chronic lymphocytic (Hashimoto's) thyroiditis in Kuwait diagnosed by fine needle aspirates.

A retrospective analysis of 4185 consecutive fine needle aspirates (FNA) of the thyroid over an eight year period at a teaching hospital in Kuwait revealed that 14.3% of all the aspirates had features of chronic lymphocytic (Hashimoto's) thyroiditis (HT). The proportion of patients with HT showed a slight increase in the last two years but the pattern of clinical presentation has remained unchanged. Hashimoto's thyroiditis was most prevalent in the age group from 16 to 35 and the majority of young patients with Hashimoto's thyroiditis presented with diffuse goiter (DG) whereas multinodular goiter (MNG) and solitary thyroid nodule (STN) were more common in the older age group. Of patients who presented with STN, the most common abnormality on thyroid scan was a "cold nodule". Functional disturbances (hypo and hyperthyroidism) occurred less frequently in patients presenting as STN than in patients presenting with DG or MNG. We conclude that FNA is indicated in all young patients with diffuse goiter in this region in order to facilitate early detection and initiation of suppressive thyroxine therapy. Further, when young patients present with "cold" solitary nodules of the thyroid, HT is a more common cause than a thyroid carcinoma in Kuwait.