Myofibroblastic fibrosarcoma with multifocal osseous metaplasia at the site of equine influenza vaccination.

We describe a fibrosarcoma in a 12-year-old Quarterhorse x Arabian gelding as a sequela to equine influenza vaccination. Shortly after the second vaccination, swelling at the site was noticed by the owner and it continued to increase in size over the following 6 months. Biopsy of the mass indicated a fibrosarcoma had developed at the vaccination site. It was approximately 20 cm in diameter and elevated well above the level of the skin. There was no clinical evidence of metastases to the lungs or local lymph nodes. Surgical resection of the mass was performed and the wound healed by first and second intention. Histopathological examination and immunohistochemical staining confirmed a myofibroblastic fibrosarcoma with multifocal osseous metaplasia. To the authors' knowledge, this is the first equine case of a vaccine-associated fibrosarcoma.

Angiomyofibroblastoma of the vagina in a postmenopausal breast cancer patient treated with tamoxifen: clinicopathologic analysis of a case and review of the literature.

Angiomyofibroblastoma is a rare mesenchymal tumor. This study presents the clinical, histologic, and immunohistochemical features of an angiomyofibroblastoma of the vagina occurring in an 80-year-old breast cancer patient under prolonged treatment with tamoxifen. Histologically, the tumor was characterized by alternating hypercellular and hypocellular edematous zones and small- to medium-sized blood vessels, which were characteristically thin walled. The tumor cells were spindle shaped (mainly) or round shaped (occasionally) arranged in cords and nests. The stroma was edematous and contained inflammatory cells, especially lymphocytes and mast cells. Immunohistochemistry of the tumor cells revealed diffuse and intense immunoreactivity for vimentin and desmin. The staining for estrogen receptors and progesterone receptors was positive, with a percentage of 70% and 40%, respectively. In conclusion, the tumor was diagnosed as an angiomyofibroblastoma based on its typical histologic and immunohistochemical features. The expression of estrogen and progesterone receptors suggests that it might arise as a neoplastic proliferation of hormonally responsible mesenchymal cells. Tamoxifen may exert stimuli effects upon mesenchymal cells.

Mesenchymal tumors of the mouse urinary bladder with vascular and smooth muscle differentiation.

Bifenthrin, a synthetic pyrethroid insecticide/miticide, has been fed to male and female Swiss Webster mice at levels of 0, 50, 200, 500, and 600 ppm in the diet for between 604 and 644 days. Tumors of the urinary bladder were observed and initially reported as leiomyosarcomas. Subsequently, the bladders were reviewed and the tumors showed a pattern of both epithelioid cells and spindle cells forming irregular vascular channels. The tumors appeared to arise from the trigone of the bladder and, in some cases, invaded the bladder wall. No metastases were recorded. The tumor is usually considered rare; however, in this study, it was commonly observed in all groups but predominantly in males. The histogenesis of the tumor is uncertain, but from its pleomorphic histological features, including smooth muscle and vascularity, it is probably derived from vascular mesenchyme.

Establishment of three rat soft tissue tumor cell lines with different degrees of myogenic differentiation.

Soft tissue malignancies often show divergent differentiation, including myogenic lineage. Five rat tumors induced with 20-hydroxymethylcholanthrene (20-OH-MCA), were cultured in vitro, and three cell lines (YMC-1, YMC-2, YMC-3) were established from them. YMC-2 and -3 cells were spindle-shaped, and YMS-1 cells round and epithelioid. In confluency, YMC-3 cells formed myotubes. The nude mouse xenotransplants showed morphological features consistent with their myogenic phenotypes. Muscle-specific enzyme activities were highest in YMC-3 cells. These lines may be useful in the investigation of the myogenic differentiation of undifferentiated mesenchymal cells.

Aortic rupture and aortic smooth muscle tumors in mice. Induction by p-hydrazinobenzoic acid hydrochloride of the cultivated mushroom Agaricus bisporus.

p-Hydrazinobenzoic acid (HBA), an ingredient of the cultivated mushroom Agaricus bisporus, was given in hydrochloride form at a dosage of 0.125% in drinking water for life to randomly bred Swiss mice. Previous studies had demonstrated that either synthetic or naturally occurring hydrazines are carcinogenic in mice with the main tumors so-induced being peripheral angiomas and angiosarcomas. As a result of HBA treatment in the present experiments, smooth muscle cell tumors of the aorta and large arteries were induced in 14% of females and 42% of males, whereas the corresponding frequency of tumors in untreated female and male controls was 0 and 4%, respectively. Tumors were observed as early as at 17 weeks of age. Numerous experimental animals (32% of females and 50% of males) died of aortic rupture. Histopathologically, two major changes were observed to explain both the ruptures and tumors. First, the intimal and inner medial aspect of the aortic walls had undergone effacement with widespread fibrinoid necrosis, accompanied by medial elastinolysis. Second, a proliferation of cells arising in the media, benign in some aortae and frankly malignant in others, was strikingly positive by immunohistochemistry for cytoplasmic actin and myosin, moderately positive for desmin, weakly positive for vimentin, and negative for factor VIII-related antigen. When malignant, the tumors extended into the periaortic adventitial connective tissue. The tumors were classifiable as leiomyomas and leiomyosarcomas. Thus, HBA is an additional carcinogenic ingredient of the widely consumed mushroom, A. bisporus. A continuum from toxic tissue injury to cellular hyperplasia, dysplasia, and ultimate neoplasia is well-illustrated by HBA.

[Actomyosin preparations obtained from a skeletal muscle tumor of low differentiation using the traditional methods of muscle biochemistry]. / Aktomiozinovye preparaty, poluchennye iz nizkodifferentsirovannoi skeletno-myshechnoi opukholi s pomoshch'iu traditsionnykh metodov myshechnoi biokhimii.

Tumor actomysion preparations isolated by three different extracting solutions are very similar in composition. A characteristic feature of the preparations obtained is a very rapid presumably proteolytic degradation of their components. It is shown that the major polypeptides of freshly prepared samples are not products of proteolysis. The major protein components of these preparations are identified.

[Isolation of actomyosin from a skeletal muscle tumor of low differentiation]. / Vydelenie aktomiozina iz nizkodifferentsirovannoi skeletnomyshechnoi opukholi.

A method of actomyosin (AM) isolation from low-differentiated rhabdomyocarcoma (LD RMS) has been worked out. The preparations obtained are sufficiently pure to be used for determination of the composition and some properties of major contractile proteins. Data on the composition of AM preparations isolated from LD RMS by traditional muscular biochemical methods (Matveyev, 1984) and morphological peculiarities of LD RMS cells, which help to distinguish them from definitive skeletal muscle cells and to relate them to non-muscle and low-differentiated muscle cells (mitotic myoblasts), served the main prerequisite to developing the method. Thus, this method may be regarded as a rational basis for isolation of non-muscle and embryonic contractile proteins, but it can be used, probably, for such purposes without special any adjustment to non-muscle or embryonic cells. The cytoplasmic localization has been shown for the tumor myosin.

A study of sarcogenicity associated with Co-Cr-Mo particles implanted in animal muscle.

A study has been made of the sarcogenicity of particles of cobalt-chromium-molybdenum alloy. The particles were implanted as a dry powder into a surgical incision into the dorsal paraspinal muscle of adult female rats and guinea pigs. Two preparations were used. In one, the particles had a size range of 100-250 micrometers. This preparation was implanted into 51 Wistar rats. In the other, the particles had a size range of 0.5-50 micrometers, 85% being in the range 0.5-5 micrometers. This preparation was implanted into 61 Wistar rats, 53 hooded rats, and 46 Dunkin Hartley guinea pigs. Sham operations were carried out on a control group of 50 Wistar rats. No malignant neoplasms developed at the test or control operation sites during the time periods for which the animals survived. This negative finding contrasts with that from a previous study by Health, Freeman and Swanson, who observed sarcomas in rats at sites of intramuscular injection of cobalt-chromium-molybdenum particles suspended in horse serum. Possible explanations for this difference in results are discussed.

[Cerebral granular cell tumor in the rat after intraperitoneal application of aflatoxin b1 during pregnancy (author's transl)]. / Granularzelltumor des ZNS bei der Rate nach intraperitonealer Applikation von Aflatoxin B1 während der Tragezeit

On a rat, which has spontaneous died 12 months after 4 times i.p. application of aflatoxin during pregnancy, there has been found a frontal tumor barely of the size of a pepper-corn which came out from the leptomeninx. A comparison to the Abrikossoff tumor concerning the light- and electron-microscope as well as the nucleic-acid concentration is justified. The protein content of the granula of the tumor cells is higher than the values known in the granular-cell myoblastoma of man.

Sarcoma after injection of intramuscular iron.

Two cases are presented of sarcomata arising at the site of previous iron dextran injections. One of the tumours showed a histological pattern associated with iron dextran administration in animal experiments.

The effect of growth hormone, insulin and alloxan-induced diabetes on carcinogenesis in the genital tract of intact and castrate female rats.

Castrate female rats given weekly applications of DMBA to the genital tract and treated additionally with growth hormone, insulin or alloxan (to induce diabetes) are heavier and have more sarcomatous and epithelial cervico-vaginal neoplasms than intact animals under the same experimental conditions. Promotion of carcinogenesis and gain in body weight are independent phenomena caused by castration in the medicated rats. Growth hormone is most effective in enhancing body weight in all animals, but least as regards tumour formation. It reduces the incidence of sarcomas in intacts, but raises that of epithelial neoplasms, and promotes both types of neoplasms in castrates. The highest incidence of cervico-vaginal epithelial and sarcomatous tumours occurs in spayed diabetics.Squamous celled epitheliomas of the vulva are not affected by castration or additional medication, while basal celled neoplasms tend to be more frequent in intacts than in castrates and particularly numerous in intact failed diabetics. Vulval sarcomas are usually rare but are increased in numbers in diabetic and in insulin treated intacts.Granular myoblastomas of the cervico-vaginal tract occur in intacts only and particularly in diabetics and those medicated with growth hormone or insulin.

Transplacental chemical carcinogenesis in man.

PIP: This editorial was prompted by the published association of maternal diethylstilbestrol (DES) ingestion during pregnancy and subsequent development of vaginal adenocarcinoma among female offspring, and explores various factors involved in transplacental chemical carcinogenesis in humans. Known prenatal determinants of carcinogenic transmission are 1) germ cells, 2) transplantation, and 3) ionizing radiation. Other chemicals besides DES which may be implicated in transplacental carcinogenesis are cytotoxic anticancer agents, such as therapy. The hypothesis of DES-associated maternal-fetal exchange was developed as a result of physician recognition of a cluster of cases with commonality; it is hoped that further epidemiological studies, more systemitized, will lead to hypotheses regarding the epidemiology of other in utero carcinogenesis.^ieng