'Proximal-type' epithelioid sarcoma: is Agent Orange still at large?

BACKGROUND AND AIMS

Proximal-type epithelioid sarcomas of the perineum are extremely rare. The authors provide an overview of this condition in relation to the history of exposure to Agent Orange.

PATIENT AND METHODS

A 54-year-old man presented with a rapidly growing perineal subcutaneous mass that was shown to be a proximal-type epithelioid sarcoma. The case is discussed. An Internet Medline search was performed and the current literature reviewed.

RESULTS

Only 4 primary perineal sarcomas have been described in the literature. Epithelioid sarcomas are uncommon, aggressive tumours with a propensity for locoregional recurrence. They are recognised by the US Veterans Affairs department as linked to exposure to Agent Orange, an organochlorine defoliant containing the contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, the role of Agent Orange in sarcomagenesis is still controversial.

CONCLUSION

Unusual soft tissue swellings in a background of chemical exposure should be investigated thoroughly with a view to early, appropriate treatment.

Carcinogenicity studies after intraperitoneal injection of two types of stone wool fibres in rats

A summary is given of the pathology results after intraperitoneal (i.p.) injection in rats of insulation wool HT, representing the new biosoluble types. The pathology results are compared with a previously conducted i.p. study with traditional stone wool D6 (with similar chemical composition to MMVF21). The HT fibre is characterized by a relatively high content of aluminium and a relatively low content of silica compared to MMVF21. HT has a high in vitro dissolution rate at pH 4.5, a relatively low dissolution rate at pH 7.5 and is less biopersistent than the MMVF21 fibre. Female Wistar rats received a dose of 2 x 10(9) WHO HT fibres by i.p. injection. The fibres had been size-selected to be largely rat respirable. The negative control group was exposed to saline. Following exposure, the animals were maintained until survival in one group fell below 20%. At this time, all animals were killed. All animals were subjected to a necropsy examination; any gross abnormalities observed at necropsy were subjected to histopathological examination. In addition, histopathology was carried out on a predefined list of tissues. The incidences of lesions and survival in the control and fibre dosed animals were compared using appropriate statistical methods to determine whether the dosed animals showed adverse effects on survival or a positive carcinogenic response. The main protocol for the previously conducted study with D6 (MMVF21) was similar, but the animals were maintained as long as they survived, and the WHO fibre dose was lower. The results of the comparative study showed a marked difference in the i.p. pathogenicity of D6 (MMVF21) and HT in terms of their carcinogenic potential. D6 (MMVF21) caused a statistically significant increase of mesotheliomas in the peritoneal cavity compared to the negative control, but the HT fibre did not cause any mesotheliomas or any increase in other tumour types.

Fiber-specific molecular features of tumors induced in rat peritoneum

Molecular markers such as mutational spectra or mRNA expression patterns may give some indication of the mechanisms of carcinogenesis induced by fibers and other carcinogens. In our study, tumors were induced by application of crocidolite asbestos or benzo[a]pyrene (B[a]P) to rat peritoneum. DNA and RNA of these tumors were subjected to analysis of point mutations and to investigation of mRNA expression patterns. With both assays we found typical features depending on the type of carcinogen applied. The analysis of point mutations in the tumor suppressor gene p53 revealed mutations in the B[a]P-induced tumors. However, in the tumors induced by crocidolite asbestos that were of the same tumor type as those induced by B[a]P, mutations in p53 were not detectable. Every mutation detected on the DNA level causes an amino acid substitution within one of the functional domains of the tumor suppressor protein. Therefore, these mutations seem to be of biological relevance for tumor progression and indicate a difference in the carcinogenesis regarding the type of the carcinogenic substance. An additional specificity of crocidolite-induced tumors was detectable by analyzing the mRNA expression of the tumor suppressor gene WT1, which is known to be expressed in human mesothelial and mesothelioma cells. A relatively high amount of WT1 mRNA was measured by quantitative competitive reverse transcription-polymerase using RNA extracted from crocidolite-induced tumors. However, WT1 seems to be expressed on a rather low level in tumors induced by B[a]P.

T25: a simplified carcinogenic potency index: description of the system and study of correlations between carcinogenic potency and species/site specificity and mutagenicity

A simplified carcinogenic potency index, the T25, is proposed as a practical method for the inclusion of potency considerations in carcinogen classification systems. The T25 is the chronic daily dose in mg per kg bodyweight which will give 25% of the animals tumours at a specific tissue site, after correction for spontaneous incidence, within the standard life span of that species. Calculated T25 values of a set of 113 US National Cancer Institute/National Toxicology Program (NC/NTP) carcinogens showed excellent correlation (correlation coefficient 0.96, P < 0.0001) with the carcinogenic potency index TD50 of Peto et al. (1984). The mean of T25 values for 51 transspecies, multiple common site NCI/NTP carcinogens were 10-fold lower than those for 62 NCI/NTP single species, single site carcinogens. For these 113 carcinogens, the mean T25 values were approximately 3-fold lower for agents that were also mutagenic in Salmonella compared to the non-mutagenic agents.

Differential diagnosis of malignant tumours in the abdominal cavity of rats after intraperitoneal injection of crocidolite or benzo[a]pyrene

In our investigation (i.p. test), crocidolite and benzo[a]pyrene, both caused a progression from initially reactive, then autonomously transformed proliferation of myofibroblasts and undifferentiated mesenchymal cells to malignant, multidirectionally differentiated (desmin and ED-1 positive) fibro-histiocytic tumours. Immunohistochemically these tumours showed no morphological characteristics (for example co-expression of vimentin and keratin in spindle-shaped tumour cells) of human asbestos-associated malignant mesotheliomas. On the other hand many tumour cells induced by crocidolite and benzo[a]pyrene had an ultrastructural appearance resembling fibroblasts and myofibroblasts. These have been demonstrated in only a few desmoplastic and sarcomatous mesotheliomas in human beings. None of the tumours revealed the typical ultrastructural features of epitheloid or transitional mesotheliomas. Apparently, both carcinogenic substances induce the transformation of undifferentiated pluripotent mesenchymal cells in rat peritoneum, regardless of their localization in the submesothelial compartment or perivascular connective tissue (preferentially after crocidolite application) or in the connective tissue pseudocapsule of major benzo[a]pyrene containing beeswax/tricaprylin depots in the mesometrium and mesenterial fatty tissue. In this way asbestos fibres in this animal experiment do not seem to induce an arrest in differentiation of intermediate or immature mesothelial cells as supposed formerly, but rather affect undifferentiated mesenchyme cells and myofibroblasts. This is an explanation for the immunohistochemical expression of markers of muscular differentiation in these tumour cells, which is known to occur in human malignant fibro-histiocytic tumours. If supplementary immunohistochemical investigations with different keratin antibodies also fail to confirm the mesothelial differentiation of the tumours induced in our i.p. test, the decision to call them "mesotheliomas" should be reconsidered. Further immuno-transmission-electron microscopical investigations with intermediate filament or macrophage antibodies are needed to clarify whether the term malignant "fibrohistiocytic sarcoma", "mesenchymoma" or "mesothelioblastoma" would be more correct from the morphological point of view.

Results of current intraperitoneal carcinogenicity studies with mineral and vitreous fibres

The study includes some 50 groups of male or female Wistar rats tested in three series. Except for one untreated group and 3 vehicle control groups, the animals were injected intraperitoneally (i.p.) once or repeatedly with dust suspensions and then examined, after lifetime observation up to 30 months, for tumours in the abdominal cavity. 1 granular dust (silicon carbide), 2 asbestos dusts (crocidolite, tremolite) and 11 vitreous fibre dust samples were administered. 5 of the vitreous fibre types were fine fibre fractions from 4 commercial insulation wools and 1 experimental wool, the others were prepared by milling glass microfibres, which have, per se, a small diameter range. The dosage per rat differed over a wide range in accordance with experience from earlier studies. The lowest dose was 0.04 x 10(9) crocidolite fibres in 0.5 mg dust, and the highest amounted to 20 x 10(9) glass fibres in 1000 mg divided into 40 weekly injections. Two mesotheliomas were found in a total of 395 rats treated with saline or granular silicon carbide (250 or 1000 mg). Eleven fibre dusts produced dose-dependent mesotheliomas at rates of up to 97 %, but the calculated fibre number > 5 micrometers in length required for inducing a 25 % tumour risk differed between the fibre samples tested in the relation of 1 to about 1000. UICC-like crocidolite heads the ranking order; the glass fibre B-01, which possesses a low durability in the body, ends it together with a rather thin sample of glass fibre type B-09. The stone fibre MMVF-21 takes a high place in the ranking order, similar to the tremolite sample. The results correspond to those of earlier i.p. tests.

Phenobarbital promotes the development of adenocarcinomas in the accessory sex glands of MNU-inoculated L-W rats

Aged Lobund-Wistar (L-W) rats develop: (i) spontaneous and induced metastasizing adenocarcinomas in the prostate and seminal vesicle (P-SV) complex; and (ii) spontaneous hepatomas and hepatocarcinomas. Within the time-frame of 14 months, similar adenocarcinomas were induced in the P-SV complex in 70-90% of younger L-W rats by a single i.v. inoculation of methylnitrosourea (MNU) which was followed by slow release s.c. implants of testosterone propionate (TP). Within the same time-frame, neither MNU nor TP alone induced significant incidences of P-SV tumors; and untreated control L-W rats were disease-free. Methylnitrosourea or TP and combinations thereof did not induce liver tumors. However, when MNU-inoculated L-W rats were fed phenobarbital (PB), they developed (i) metastasizing adenocarcinomas in the P-SV complex and (ii) altered cellular foci and nodules in the livers. Methylnitrosourea induced a high incidence of benign lung adenomas which progressed to lung cancers in numbers which were of marginal significance. Thus, dormant MNU-initiated cells in the P-SV complex were activated by phenobarbital, to produce adenocarcinomas in that complex.

[Acute leukemia as secondary neoplasms in children with advanced lymphomas]

In 1985 a new treatment regimen for advanced non-Hodgkin's lymphoma was started in the "Instituto da Criança-HC-FMUSP". The final results are remarkably better than those achieved with former programs. Two cases of children who developed a second neoplasm after the therapy was completed are described and discussed.

Fatal abdominal thorotrast granuloma

We report a case of fatal abdominal thorotrast granuloma seen in a 65-year-old man who had undergone a femoral angiography of thorotrast with some accidental extravasation 49 years previously. As the thorotrast granuloma gradually increased in size, it caused ureteral obstruction, venous thrombosis, and perforation of the urinary bladder and rectum. Symptomatic abdominal thorotrast granuloma is quite rare and this is the first reported case of the granuloma associated with perforation through the urinary bladder and rectum.

Characteristics of tumors and tumor cells cultured from experimental asbestos-induced mesotheliomas in rats

Mesotheliomas developed in rats in the abdominal cavity 6-23 months after peritoneal introduction of chrysotile and crocidolite asbestos. The tumors were strikingly similar to those occurring in man both with regard to histologic features and growth patterns. The authors have cultured cells from these tumors and established epithelial lines with a variety of karyologic features and doubling times shorter than those of normal mesothelial cells. Lines of diploid or near-diploid tumor cells required serum in the medium to replicate, whereas most aneuploid cell lines were maintained in a serum-free medium. In serum-free medium, the aneuploid line monolayers produced anchorage-independent excrescent masses of cells which "bud" and float free. These spheroids, which strikingly resemble the papillary structures in human mesotheliomas, are composed of mesothelial-like cells that produce hyaluronic acid and have a rich complement of intermediate filaments, predominantly cytokeratins. Aneuploid cells also replicated in soft agar with high efficiency, whereas the diploid and near-diploid cells did not. All but one cultured cell line, regardless of karyotype, produced tumors after subcutaneous or intraperitoneal inoculation (or both). Aneuploid cells caused lung tumors sporadically when introduced intravenously. Comparative analysis of the nuclear DNA of primary tumors and cultured cells demonstrated a high degree of chromosomal instability and selection among cells during early passage in vitro.

Diffuse histiocytic lymphoma in a patient treated with cyclophosphamide for Wegener's granulomatosis

Diffuse histiocytic lymphoma developed in a 48-year-old man with Wegener's granulomatosis after nine years of therapy with cyclophosphamide. He died despite aggressive surgical and medical therapy for the lymphoma. This may be the first report of diffuse histiocytic lymphoma following treatment of Wegener's granulomatosis with cyclophosphamide. Recommendations for the approach towards extended therapy of smoldering Wegener's granulomatosis are discussed.

[Histogenetic considerations of experimentally induced adenomatoid tumor-like nodules produced by sex steroids]

Glandlike structures with intervening fibrous stroma were observed in about 20% of subperitoneal nodules produced in the abdominal cavities of guinea pigs treated with various doses of estradiol benzoate (E) for 3 months. These glandlike structures were composed of cells resembling mesothelium, ciliated cells, cells with mucin in the cytoplasm and cells with a squamous appearance. Glandlike structures similar to those following estrogen treatment alone were also observed in about 20% of the nodules produced in the guinea pigs by pre-treatment with E and followed by combination treatment with E and progesterone (P) for 1 to 3 months. However, the glandlike structures were composed only of cells resembling mesothelium and cells with cilia. Both of these glandlike structures resembled adenomatoid tumors. We therefore conjecture that the formation of gland-like structures in the subperitoneal nodules is the result of mesothelial inclusions and their proliferation, and that some of these mesothelial cells were differentiated into ciliated, mucinous and squamous cells by estrogen.

Progesterone-induced smooth muscle-like cells in the subperitoneal nodules produced by estrogen. Experimental approach to leiomyomatosis peritonealis disseminata

In order to examine the pathogenesis and histogenesis of leiomyomatosis peritonealis disseminata (LPD), guinea pigs were treated with various doses of estradiol benzoate (E) (40, 80, 100, and 200 microgram/day, three times a week, by intramuscular injection). After treatment for 3 months, each dose of E produced lesions simulating the disseminated pattern of LPD. Ultrastructurally, the nodules were considered to be composed of cells resembling those of fibroblast. In guinea pigs, pretreatment with estradiol benzoate (100 microgram/day, three times a week intramuscularly for 3 months followed by combination treatment with E and progesterone (P) (0.5 and 1.0 mg/day, once a week, intramuscularly) for 1 to 3 months produced nodules similar to those with estrogen alone. Ultrastructurally, these nodules were composed of cells resembling smooth muscle and decidual cells. According to these results, we conjectured that estrogen differentiates and proliferates cells with the features of fibroblast-like cells from the subcoelomic totipotential mesenchyme, and these cells are differentiated into smooth muscle-like cells and decidua-like cells under the influence of both estrogen and progesterone, resulting in the production of multiple subperitoneal nodules.

[The oncogenic effect of fibrous dust. Animal experiments and their relationship with human carcinogenesis]

The results after intraperitoneal injection of fibrous and granular dusts in rats suggest, that the fibrous shape of asbestos is the cause of its cancerogenicity. Fibrous dusts other than asbestos (for example glass fibers) may induce tumours, when their diameters are like that of asbestos and the fibres are invariable in tissue. It is supposed, that a fibre with a diameter less than 1 mum and a length greater than 3 mum has a cancerogenic effect. The interpretation of the experimental results considering the cancerogenesis in humans is discussed, especially concerning the effect of fibrous glass.