Experimental Yersinia enterocolitica enteritis in rabbits

Young rabbits weighing 500 to 800 g were inoculated orogastrically with clinical isolates of Yersinia enterocolitica (serotype O:3; enterotoxigenic; HeLa cell invasive) at a dose of 1.4 X 10(10) bacteria suspended in 10% sodium bicarbonate solution. Diarrhea developed in 41 (87%) of 47 rabbits, with a mean +/- standard deviation onset at 5.4 +/- 2.4 days. The attack rate and onset of diarrhea were correlated with inoculum size. The 50% infectious dose was 2.9 X 10(8) bacteria. Bacterial colonization occurred in almost all rabbits, regardless of inoculum size. Seroconversion was demonstrated in 30 (71%) of 42 rabbits with or without diarrhea. Histopathological alterations were present in the jejuna, ilea, and colons of rabbits with diarrhea; the most pronounced changes were generally noted in the ilea. Crypt abscesses localized at the depth of the intestinal glands were observed consistently and were composed of a bacterial nidus admixed with and enveloped by inflammatory cells comprised of eosinophils, neutrophils, and mononuclear cells. Rabbits inoculated with a raw fish isolate of Y. enterocolitica (serotype O:6,30; non-enterotoxigenic; HeLa cell noninvasive) did not exhibit infection clinically, bacteriologically, or pathologically.

Thymic involution mimicking thymic dysplasia: a consequence of transfusion-induced graft versus host disease in a premature infant

A premature infant with ostensibly normal immunologic function received two exchange blood transfusions for hyperbilirubinemia and several blood and platelet transfusions for pancytopenia. A fatal graft vs host reaction (GvHR) ensued that was diagnosed by skin biopsy one day prior to death at age 40 days. Autopsy revealed characteristic alterations of GvHR in the spleen, lymph nodes, gut, and liver. In addition the thymus was small (3.5 g), lymphoid-depleted, lacked corticomedullary demarcation and Hassall's corpuscles, and demonstrated lymphocyte invasion and injury of epithelial cells. The thymic cytomorphology acquired added meaning when it was discovered that a chest roentgenogram obtained at one day of age demonstrated a normal thymic shadow. It is concluded that the GvHR induced a direct injury to the thymic epithelium, resulting in an acquired form of thymic dysplasia. The theoretical implications of this observation are considered.

On the pathogenesis of sclerosis and nodularity in nodular sclerosing Hodgkin's disease

Ten cases of nodular sclerosing Hodgkin's disease involving lymph nodes were studied by electron microscopy to determine the ultrastructural composition of the nodule-stromal interphase and the collagenized regions. In addition to a few lymphocytes, rare eosinophils and neutrophils, abundant filamentous and granular electron dense material, collagen fibers and myofibroblasts were observed in all instances. Since myofibroblasts possess contractile and synthetic properties, it is likely they contribute to the retraction and sclerosis which together represent one of the morphologic hallmarks of the disease. The dense fibrosis and contractile state of such tissue may constitute a beneficial host response to contain and limit local and vascular invasion by the neoplastic cellular population, thus contributing to the relative benignity of this form of Hodgkin's disease.

T cell functional defect associated with thymid epithelial cell injury induced by a graft-versus-host reaction

The injection of parental strain cells into adrenalectomized (CBA x A)F1 mice induced a graft-versus-host (GVH) reaction which was morphologically characterized by thymus epithelial cell injury but not stress-related thymic involution. Thymocytes from mice undergoing a GVH reaction were studied for their ability to reconstitute allograft reactivity in thymectomized, irradiated, bone marrow reconstituted (ATxBM) (CBA x A)F1 mice. Thymocytes of mice experiencing a GVH reaction were theta-positive during the course of the reaction, however, by 40 days after GVH induction these thymocytes were unable to reconstitute allograft reactivity to H-2-incompatible skin grafts. It is proposed that GVH-induced thymic epithelial cell injury prevents or arrests normal T cell differentiation, resulting in a population of thymocytes which lack complete functional capability.

Myofibroblasts in the stroma of invasive and metastatic carcinoma: a possible host response to neoplasia

After observing the presence of numerous stromal myofibroblasts in scirrhous mammary carcinomas, a series of invasive and metastatic carcinomas from diverse sites was examined by electron microscopy to determine whether myofibroblasts might also be present in their stroma. Myofibroblasts were identified in each instance and were most abundant in neoplasms which were hard, sclerotic, and retracted. This finding suggests that myofibroblasts represent a component of the stromal reaction to many carcinomas and contribute to the desmoplasia and retraction which characterize many of these neoplasms. The host commands several responses to neoplasia. As a result of the expression of tumor-associated antigens, the immune system contributes lymphocytes, macrophages, and antibodies, a reflection of immunologic surveillance against neoplasia. In contrast to experimental systems tumor neoantigens are poorly expressed or even lacking in many human neoplasms; thus, the immune system may be weakly stimulated or not activated at all. Tumor neovascularization induced by a tumor-angiogenesis factor represents a second host response, possibly deleterious, for it may facilitate tumor dissemination. The stromal myofibroblast reaction to many invasive and metastatic carcinomas may constitute a third, albeit more primitive response. The density of collagen produced and contractile state of such tissue may signify an attempt by the host stroma to contain the neoplasm and impede vascular invasion. If so, myofibroblast induction may complement immune surveillance or constitute a separate mechanism of response to invasive neoplasia in man.

Desmoplastic fibroma of bone. An ultrastructural study

The ultrastructure of three cases of desmoplastic fibroma of bone is presented. The lesion is principally characterized by myofibroblasts admixed with lesser numbers of fibroblasts and primitive mesenchymal cells. Thus, the cellular composition is similar to that described in a variety of nonneoplastic proliferative processes of soft tissue. It is postulated that the myofibroblastic proliferation develops in response to unknown factors acting on marrow fibroblasts or primitive mesenchymal cells.

Myxoid liposarcoma. An electronmicroscopic study: biological and histogenetic considerations

Ten myxoid liposarcomas (ML) were studied ultrastructurally in an attempt to determine the histogenesis of this neoplasm and structural associations which might contribute to their relatively benign clinical behavior. The findings were compared with normal and neoplastic adipose tissue. Three cell types were observed, i.e., "primitive" mesenchymal cells, intermediate cell types, and lipoblasts at various stages of development. The principle differences between the lipoblastic elements were the number and the size of intracytoplasmic fat vacuoles, the development of basement membrane-like material, micropinocytotic vesicles along the plasma membrane and the quantity and pleomorphism of mitochondria. The tumor vasculature was complex but consistently demonstrated a multilayered basal lamina. This finding has been described in neoplasms associated with a relatively good prognosis. This study demonstrates that the better differentiated lipoblasts in ML share some features with normal brown fetal fat and hibernoma. It is, thus, suggested that ML may be derived from brown adipose tissue.

Myxoid variant of malignant fibrous histiocytoma: ultrastructural observations

The ultrastructural findings in 4 cases of the myxoid variant of malignant fibrous histiocytoma (MFH) are described. Although this neoplasm is characterized by a high rate of local recurrence, the overall prognosis is considerably better than the usual nonmyxoid MFH. The neoplasm is composed of an admixture of round, stellate and multinucleated giant cells within a myxoid and well-vascularized stroma. Electron microscopy demonstrated four principal cell types: a primitive mesenchymal cell, spindle cells of fibroblastic and histiocytic nature, and multinucleated giant cells. These observations complement the light microscopic features but probably are insufficient to differentiate critically this entity from other myxomatous lesions of mesenchymal soft tissue such as myxoma, pseudosarcomatous fasciitis, myxoid liposarcoma. The polymorphic cellular composition lends support to the concept that the neoplasm is probably derived from a primitive multipotent mesenchymal cell capable of structural and functional modulation toward more cytodifferentiated forms.

Thymic epithelial injury in graft-versus-host reactions following adrenalectomy

In four separate experiments 140 adults A(H-2a) x C57BL/6(H-2b) F1hybrid mice were surgically adrenalectomized and divided into three experimental groups. Seventy-one additional adult F1hybrids (AXC57BL/6) which had not been adrenalectomized were divided into three similar groups. In Group 1 (GvH group), GvH reactions were induced by the injection of 50 x 106 pooled parental lymphoid cells intravenously. The second group (syngeneic group) received 50 x 106 pooled F1 hybrid lymphoid cells intravenously. The third group (uninoculated group) received no lymphoid inoculum. At regular intervals the animals were killed, autopsied, and histologically studied. Visceral alterations of GvH reaction were recorded in the thymus, lymph nodes, spleen, and liver in the GvH groups; none was present in the other groups. The thymuses in the nonadrenalectomized GvH group underwent prompt involution characterized by size reduction and cortical lymphoid cell depletion. These changes were not apparent in the GvH adrenalectomized group. Both GvH groups, however, demonstrated an effacement of the medulla, lymphocyte incursion into the medulla, lymphocyte emperipolesis of medullary epithelial cells, gradual disappearance of Hassall's corpuscles, epithelial cell injury, and an ingress of macrophages laden with nuclear and cellular debris. This study suggests that the stress and corticosteroid response which accompany a GvH reaction account for the reduction in the thymic size and cortical lymphoid cell mass. The medullary alterations, therefore, would appear to be initiated by the GvH reaction per se.

Bile acid conjugation in organ culture of human fetal liver

An organ culture system for prolonged maintenance of human fetal liver has been developed and used to investigate the formation of bile acid conjugates. Multiple liver specimens were obtained from human abortuses and stillbirths ranging from 10 to 29 weeks of gestation. Within 3 hr of hysterotomy, small fragments of liver were established in organ culture. The morphological integrity of the explants was demonstrated by light and electron microscopy. Functional viability was determined by adding radiolabeled primary bile acid to the medium and assaying the taurine and glycine conjugates formed. Primary bile acid was taken up by the tissues, conjugated with taurine and glycine, and secreted into the medium at a constant rate during 10 days in vitro and in constant increments during a selected 24-hr period. The results establish that human fetal liver survives intact for periods up to 10 days in vitro. Taurine conjugates of the primary bile acids predominate throughout gestation and conjugates of cholic acid are synthesized in preference to those of chenodeoxycholic acid. Supplementation of the medium with taurine results in enhanced taurocholate formation with competitive inhibition of glycocholate synthesis, suggesting one acyl transferase system for both taurine and glycine. Finally, in medium supplemented with hydrocortisone there is a reversal of the glycine-taurine ratio seen in fetal liver.

Renal failure secondary to angiomyolipoma. Case of Forme-Fruste tuberous sclerosis

A fifty-four-year-old woman without the clinical features of tuberous sclerosis underwent nephrectomy at age thirty-three years for angiomyolipoma, and twenty-one years later severe renal failure developed. At necropsy the remaining kidney had extensive angiomyolipomatous involvement; not until the brain was examined was the diagnosis of tuberous sclerosis made. To date, this would appear to be the third case without clinical tuberous sclerosis in which renal involvement was the sole clinical expression of tuberous sclerosis, and the seventh reported instance of renal failure due to renal angiomyolipomatous hamartomatous transformation.

Thymic involution in murine graft-versus-host reaction. Epithelial injury mimicking human thymic dysplasia

Mild, moderate, and severe graft-versus-host (GVH) reactions were induced in four series of experiments in 71 CBA X A and C57BL/6 X A F1 hybrid mice. At regular intervals post-GVH reaction induction (Days 4-42), the animals were sacrificed, autopsied, and histologically studied. Visceral alterations of GVH reaction were recorded in the spleen, lymph nodes, liver, kidney, gut, and thymus. A spectrum of thymic changes was documented, ranging from obliteration of a definable cortex and medulla with loss of Hassall's corpuscles to marked involution with complete disappearance of the gland. Ultrastructural studies revealed damage to both lymphocytes and epithelial cells along with lymphocyte emperipolesis of epithelial cells, lymphocytolysis within epithelial cells, and accumulation of numerous autophagic vacuoles containing fragments of cellular debris within epithelial cells and histiocytes. The resemblance of these alterations to human thymic dysplasia as observed in primary immunodeficient conditions was striking. The theoretical implications of these studies for the pathogenesis of human congenital immunodeficiency states are considered.

Elastosis in benign sclerosing ductal proliferation of the female breast

Elastosis, an abundance of elastic tissue, is commonly present in breast carcinoma. However, its diagnostic significance remaines an unsettled issue. This study documents 17 cases of elastosis occurring in a distinctive benign sclerosing ductal lesion of the female breast (Fenoglio and Lattes: Cancer 33: 691-700, 1974). Elastosis was characterized by staining reactions and, in several instances, by elastase digestion and electron microscopy. Yellow streaks and flecks may be apparent grossly and probably reflect the increased elastic tissue. Histologically, the lesion is generally stellate with central sclerosis and marked peripheral intraductal and ductular hyperplasia which is often papillary. Elastosis, which may be marked, is a constant finding and is predominantly periductal in location. It is emphasized that the gross and histologic features of the lesion may mimic carcinoma and that elastosis may be found in benign ductal lesions of the breast.

Bilateral temporal bone metastases of a uterine cervix carcinoma

A case is reviewed of bilateral temporal bone metastases from a carcinoma of the uterine cervix. The pertinent literature is reviewed and the temporal bone histology is described.

Endobronchial plasma cell granuloma (xanthomatous pseudotumor); a light and electron microscopic study

Plasma cell granuloma (xanthomatous pseudotumor) is polymorphic at light as well as electron microscopic examination. At light microscopy the endobronchial variant of this entity was rich in plasma cells and interwoven, whorl-like, or concentrically arranged spindle cells. Foamy histiocytes and macrophages usually abundant in the intrapulmonary variant were rare. At electron microscopy particles 20 to 50 nm. in size were found at the bronchial mucosal surface but not elsewhere in the lesion. Plasma cells near the bronchial surface contained cytoplasmic fibrils, mitochondria with concentric cristae, and inclusions that bore a close resemblance to adjacent extracellular crystallized hemoglobin. Those in the center of the lesion ordinary round inclusions and none of the other changes. Spindle cells in the interlaced areas were mostly fibroblasts or myofibroblasts, whereas those whorled around capillaries resembled pericytes with basement membranes and nuxes-like intercellular junctions. Year rings like multilayered basal laminae were frequently present between the pericyte-like cells and the endothelial cells of the capillaries. The ultrastructure of plasma cell granuloma, like the histologic and clinical aspects, differs from that of sclerosing hemangioma, pseudolymphoma, and malignant plasma cell tumor affecting the lung.

Spindle-cell epithelial thymoma. Fine-structural and tumor lymphocyte observations

A fine-structural study of a spindle-cell epithelial thymoma in a patient with pemphigus and autoimmune hemolytic anemia is presented and compared with the few previously described. Because light-microscopic features suggested hemangiopericytoma, critical fine-structural comparisons between spindle-cell epithelial thymoma and hemangiopericytoma are detailed. Based upon groups of tonofilaments with desmosomal insertions, abundant well-formed desmosomes, negligible numbers of pinocytotic vesicles, and an absence of myofilaments and dense bodies, an epithelial origin for this tumor is proposed. Langerhans' cell granules, a new observation in thymoma, were found in cells of probably histiocytic origin. Tumor lymphocyte studies revealed that more than 95% of cells formed E rosettes, 36% formed EAC rosettes, yet none contained surface immunoglobulin. The significance of these observations is discussed.

Cytology of transitional cell carcinoma in situ of urinary bladder with extensive prostatic involvement

Cytologic differences in the urine of 6 patients with transitional cell carcinoma in situ (CIS) of the urinary bladder with and without prostatic duct involvement are described. In the former group, there was an admixture of CIS cells along with many bizarre malignant cells which increased with time and showed malignant criteria indicative of changes more than CIS alone.

Giant cell carcinoma of the lung. A light and electron microscopic study

Three cases of giant cell carcinoma of lung and six other lung carcinomas with large atypical cell formation were studied by both light and electron microscopy. The giant cell carcinomas showed unique light and electron microscopic features, whereas large atypical cells from other lung carcinomas usually retained some ultrastructural characteristics of their cellular origin. The giant cell carcinoma is characterized by abundant mitochondria, a concentric whorl of tonofilament-like fibrils, and aggregates of several pairs of centrioles. The "phagocytic activity" of the giant cell carcinoma is more likely attributable to the so-called tumor cell-tumor cell or leukocyte-tumor cell emperipolesis. Giant cell carcinoma of lung may originate from a primitive multipotential cell in the distal bronchiole or be associated with a squamous, glandular, or clear cell pattern. Whether in pure or mixed form, this tumor should still be considered a specific entity because of its unique light and electron microscopic features and the fulminant clinical course it follows despite rate reported exceptions.

On the ultrastructure of hibernoma

An electron-microscopic study of hibernoma and a review of the histogenesis, development, and post-natal structural composition of brown and white adipose tissue are presented. The ultrastructural features of hibernoma include multivacuolated and univacuolated cells containing variable numbers of lipid vacuoles, abundant moderately pleomorphic mitochondria with transverse cristae, lysosomes, lipofuscin granules, pinocytotic vesicles, well-formed basal lamina, and prominent subplasmalemmal condensations. The latter have not been previously reported in hibernoma, brown adipose tissue or white adipose tissue, although gap junctions have been observed in brown adipose tissue of newborn mice. It is concluded that the ultrastructural observations support the concept proposed decades ago that hibernoma represents the neoplastic counterpart of brown adipose tissue.

Small cell malignant tumors of the thyroid. A light and electron microscopic study

Three small cell malignant tumors involving the thyroid gland were examined by light and electron microscopy. In each, numerous similarities were presented on light microscopic analysis rendering interpretation difficult. In the first patient the small cells were identified on electron microscopy as moderately well differentiated lymphocytes. This tumor occurred in an elderly woman as a locally invasive thyroid tumor, subsequently involving distant sites, including the liver, spleen, lymph nodes, and soft tissue. The tumor repeatedly regressed following radiotherapy. The patients eventually died with disseminated lymphocytic lymphoma. In the second patient the thyroid tumor, also locally invasive, was composed principally of neoplastic epithelial cells when studied on electron microscopy. This patient responded poorly to radiation and died within a year after diagnosis. The third patient presented with an enlarging thyroid mass, which ultrastructurally was found to be composed principally of well differentiated lymphocytes. Subsequent clinical evaluation established a diagnosis of chronic lymphocytic leukemia. Small cell malignant tumors of the thyroid represent a difficult diagnosis problem for surgical pathologists. Ultrastructural study, we believe, is a useful adjunct in the differentiation of these tumors.

The unique association of mammary stromal sarcoma with intraductal carcinoma

The unique combination of clinically unsuspected stromal sarcoma and noninfiltrating intraductal mammary carcinoma is presented. This association has not been previously documented. The clinicopathologic features of cystosarcoma phyllodes and mammary stromal sarcoma are reviewed to provide background perspectives to illuminate the unusual aspects of this case.