Extrapulmonary silicosis: a clinical, morphologic, and ultrastructural study

Retroperitoneal silicosis mimicking pancreatic carcinoma in an Alpine miner with chronic lung silicosis

A miner, known to have had lung silicosis for 30 years, was investigated for abdominal pain. A retroperitoneal mass was found, in which histological examination showed an inflammatory reaction to silica.

Immunopathology of alkaline phosphatase-induced granulomatous hepatitis in rats

Granulomatous inflammation is a specific type of chronic inflammation in which macrophages and T-cell-mediated immunity to the inciting agent play a pivotal role. In the present study, granulomatous hepatitis was induced in rats by the administration of a single intravenous dose of porcine intestinal alkaline phosphatase. The cellular composition of the hepatic granulomas was analyzed in-situ with a number of recently developed mouse anti-rat monoclonal antibodies to cells of the monocyte-macrophage lineage and lymphocyte subsets. Well-developed granulomas consisted of aggregates of macrophages with central modification into epithelioid cells, a peripheral rim of T- and B-lymphoid cells, including considerable numbers of immunoblasts and plasma cells. In addition, the periphery of the granulomas contained many fat storing cells, a sinusoidal cell type thought to play a central role in hepatic fibrosis. Moreover, intense immunostaining for the extracellular matrix proteins fibronectin and collagen type III was observed at the periphery of the lesions. The granulomas persisted for long periods without eliciting liver cirrhosis. Alkaline phosphatase induced hepatic granulomas in the rat may help to elucidate the contribution of cells of the B-lineage to chronic granulomatous inflammation.

Mineral-associated hepatic injury: a report of seven cases with X-ray microanalysis

The patterns of hepatic injury associated with various minerals were studied in seven patients. The subjects included one patient who was a sandblaster (silica by inhalation), one patient who was a dental laboratory technician (silica and chromium-cobalt alloy by inhalation), one patient with inhalational talcum powder abuse, and four chronic intravenous (IV) drug abusers (talc by IV injection). In all cases, the liver was examined by light and polarizing microscopy, and by scanning electron microscopy with energy-dispersive x-ray microanalysis. In the two patients with silica exposure, silica-containing sclerohyaline nodules were diffusely present in portal tracts and lobules. Both chromium-cobalt alloy and silica were present in the dental technician. In contrast, in all cases of talc exposure, aggregates of talc-laden macrophages were present in portal and centrilobular areas. Three IV drug abusers and the talcum powder abuser had histologic evidence of chronic hepatitis, most probably of viral etiology. We conclude that mineral type plays an important role in the pathogenesis and fibrogenesis of hepatic lesions. Compared with silica, talc primarily elicits a macrophage response without granuloma formation or fibrosis. Hepatic silicosis is a rare complication in dental laboratory technicians, and chromium-cobalt alloy may contribute to hepatic injury and fibrosis in this setting.

Pathobiochemical response of tracheobronchial lymph nodes following intratracheal instillation of polyvinylchloride dust in rats

PVC dust, following a single intratracheal instillation (25 mg/rat), was substantially cleared through the lymphatic circulation and progressively accumulated in the tracheobronchial lymph nodes (TBLN) in a time-dependent manner for up to 1 year. The tissue response in TBLN during 60-270 days post-instillation of PVC dust was characterized by progressive increase in total organ fresh weight, dry weight, DNA, RNA and protein contents, concurrent with the proliferation of macrophages and hyperplasia of reticular cells. Active phagocytosis and enhanced hydrolytic activity in TBLN was evident around 270 days post-instillation by the appearance of PVC-laden macrophages near and within the dust foci, and increased activity of acid phosphatase, DNAse, RNAse and beta-glucuronidase. PVC dust caused degeneration of macrophages, and consequent release of hydrolytic enzymes resulted in limited cytotoxicity without inducing reticulination and fibrosis in the TBLN. The histology and clinical biochemistry of liver, kidney, spleen and serum were not altered and there were no detectable PVC particles in these tissues at up to 365 days. It is therefore concluded that lymphatic clearance of intratracheally instilled PVC dust results in its accumulation and mild foreign body reaction in TBLN which is non-fibrogenic at up to 365 days post-instillation.

Silica-associated systemic sclerosis is clinically, serologically and immunologically indistinguishable from idiopathic systemic sclerosis

To determine whether the clinical, immunological and serological features of patients with silica-associated systemic sclerosis are different from patients with the 'idiopathic' form of systemic sclerosis (SS) we studied 22 underground coal miners who were exposed to silica dust (SD), 30 mine workers who later developed silicosis (S) and 17 mine workers exposed to silica dust who subsequently developed a systemic sclerosis-like disease (SA-SS). The patients with SA-SS had features clinically indistinguishable from individual patients with SS. They all had Raynaud's phenomenon, 14 had cutaneous sclerosis identical to that seen in acrosclerosis and three had a generalized cutaneous sclerosis. Sixteen patients had bibasilar pulmonary fibrosis, 10 had necrosis of the fingertip pulps, nine had oesophageal involvement and only one patient had renal involvement. Antinuclear antibodies and circulating immune complexes were detected in three and eight patients with SD, 14 and five patients with S and in 16 and nine patients with SA-SS, respectively. Anti-Scl-70 antibody was detected in eight of the 17 patients with SA-SS. Evidence for in vivo endothelial cell damage, as determined by elevated levels of von Willebrand factor, was found in nine patients with SD, 14 patients with S and in 10 patients with SA-SS. Following incubation of the patient's serum with confluent cultures of human umbilical vein endothelial cells there was only a significant reduction in calcium ionophore-induced release of prostacyclin with the serum from SA-SS patients compared to that with control serum (NC). The mean +/- SEM release of 6-keto-PGF1 alpha (the stable metabolite of prostacyclin expressed as ng/10(4) cells) decreased from 2.90 +/- 0.27 to 2.01 +/- 0.33 (SD), 3.34 +/- 0.42 to 1.76 +/- 0.31 (S), 1.98 +/- 0.12 to 0.64 +/- 0.07 (SA-SS) and 2.28 +/- 0.33 to 1.36 +/- 0.21 (NC) with 1 and 20% serum, respectively. This study demonstrates that immune complex and antinuclear antibody formation and in vivo endothelial cell damage occurs following occupational exposure to silica. The patients who subsequently develop a systemic sclerosis-like disease have clinical, immunological and serological features which are indistinguishable from the idiopathic form of the disease although as a group the SA-SS patients have a higher prevalence of pulmonary involvement and the anti-Scl-70 antibody.

Silica and glomerulonephritis: case report and review of the literature

A 54-year-old foundry worker with extensive silica exposure, but no pulmonary disease, developed the nephrotic syndrome and renal failure over a 3-month period. Renal biopsy demonstrated a proliferative glomerulonephritis; energy dispersive x-ray analysis detected silicon within the renal tubules. Measurements of respirable silica at the foundry revealed levels up to 2.5 times the current occupational standard. Similar glomerular disease has been reported in silica-exposed animals and workers with silicosis. This case suggests that clinicians should include silica exposure in the differential diagnosis of unexplained diffuse proliferative glomerulonephritis, renal disease may occur without clinically evident pulmonary disease in silica exposure, and silica-induced glomerulonephritis warrants further clinical and epidemiologic research.

Asbestos related interstitial pneumonitis associated with glomerulonephritis and lymphomatoid granulomatosis

We report a case of pulmonary asbestosis in a patient who also developed glomerulonephritis and lymphomatoid granulomatosis. The pulmonary reaction was unusual, characterized clinically by an acute onset of symptoms after a prolonged latent period and morphologically by an interstitial pneumonitis with prominent desquamative features and a paucity of fibrosis. The association of pulmonary asbestosis with glomerulonephritis and lymphomatoid granulomatosis has been hitherto unreported.