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Strut fracture, with embolization of the disc occluder, caused the death of a 64-year-old man who had a Beall model 105 heart valve prosthesis in the mitral position for 13 years. Scanning electron microscopy of the fractured surface revealed evidence of a fatigue failure mechanism in the metal wire. The case is unique in that strut fractures affecting this prosthesis had only been observed previously in the range of 141 to 342 days after implantation. Morphological changes in this valve prompted reexamination of three other model 105 prostheses that had been recovered from the mitral area at necropsy or surgery 9 to 10 years after insertion in 1972 or 1973. All had been kept in dry storage. The three prostheses and the valve described above showed previously unrecognized cracks in the pyrolytic carbon coating of the struts, which form the cage that limits occluder movement. The defects were located at or near the base of struts, where they entered the sewing ring and were bent to pass into the strut supporting ring. We believe that the cracks in the carbon coating precede total strut fracture and postulate that they are needed for the metal wire to be subject to a fatigue failure mechanism.

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Relapsing polychondritis (RP) is a multisystem autoimmune disease characterized by the presence of antibodies to type II collagen. This collagen is found predominantly in cartilaginous tissues, vitreous humor, aorta and notochord. Involvement of the kidney is rare, only 7 cases having been recorded, and there is no type II collagen in glomeruli. Six of the previous cases had crescentic glomerulonephritis. We report here two cases of biopsy proven RP in which IgA nephropathy was seen, the first examples recorded. Both patients had hematuria and slight proteinuria, with mild impairment of renal function. The histological and immunofluorescence pattern on both biopsies was in keeping with IgA nephropathy. Both patients received steroids with diminution/disappearance of hematuria and proteinuria. In view of the potentially progressive nature of glomerular disease with RP, the renal status should be investigated in all patients with RP.

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Kappa light chain determinants were identified by immunoelectron microscopy in nodular glomerulosclerotic lesions and systemic interstitial deposits from a man who died several years after the onset of proteinuric renal failure treated by hemodialysis. He developed adrenal and hepatic failure preterminally but not overt malignant myeloma. Specific labeling was most concentrated over the inner aspect of glomerular basement membrane and the mesangium, which suggested that the protein was nonfiltrable. Tubular basement membrane labeling was densest over the outer aspect, which suggested that the protein perfused from the interstitium rather than from the tubular lumen. We identified the source of the protein as a population of plasma cells present within bone marrow and renal interstitium; these showed specific immunogold labeling for kappa light chain protein over organelles concerned with protein synthesis, secretion, and storage. This appears to be the first identification of light chain determinants in human interstitial para-amyloid deposits with the use of immunogold ultrastructural techniques in tissues prepared for electron microscopy by standard methods and stored as epoxy resin blocks.

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We have investigated 40 cases of malignant melanoma (MM) and 81 other lesions including benign melanocytic neoplasms, other malignancies with a potential for confusion with MM, and tissues with biogenic amine-synthesizing apparatus for induction of formaldehyde-induced fluorescence (FIF). Unstained sections were examined with an ultraviolet light source for yellowish fluorescence. Twenty-four of 27 primary cutaneous MMs and 11 of 13 metastatic MMs were positive. Formaldehyde-induced fluorescence was quenched by prior sodium borohydride treatment, suggesting monoamine origin. None of the ten intradermal, five junctional, or three blue nevi showed FIF, but two of eight compound nevi and two of six spindle cell nevi were positive for FIF. One of six large-cell undifferentiated carcinomas was positive; none of six mesenchymal sarcomas were positive; one of seven histiocytic lymphomas showed weak, granular, cytoplasmic fluorescence. Two of five carcinoid tumors and one case of medullary carcinoma of thyroid showed FIF. We conclude that FIF is a simple, reproducible, technique for aiding in the diagnosis of amelanotic melanomas.

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The authors' experience in dealing with three cases of malignant Schwannoma in the head and neck is outlined. The symptomatology of this tumor is discussed with its investigation and management. A correct diagnosis with a CT scan to delineate tumor extent is imperative. A wide surgical resection is the preferred method of treatment with postoperative irradiation of value for residual microscopic disease. The pernicious nature of this tumor often leads to a dismal outcome despite aggressive therapy.

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Four cases of epithelial-myoepithelial carcinoma of salivary gland origin are presented and discussed. The mean age of these four patients was 68 years, with an age range of 51 to 78 years. Three of the patients were women, and one was a man. This article emphasizes the light microscopic, histochemical, and ultrastructural features of the neoplasm. Electron microscopic examination of glutaraldehyde-fixed fresh tissue and previously formalin-fixed tissue reveals that the characteristic clear cytoplasm of abluminal cells is caused, in part, by glycogen storage granules and the paucity of organelles but largely by an artifact of fixation.

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Verrucous carcinoma is an unusual, non-metastasizing, distinct variant of a well differentiated squamous cell carcinoma. Multiple biopsies are frequently necessary to establish its diagnosis. Seven of 10 patients treated with irradiation showed no evidence of anaplastic transformation. A high recurrence rate in tumors of the oral cavity treated with either irradiation or surgery alone is noted. Extensive lesions in this area may benefit from combined therapy. A good response to radiotherapy with a low recurrence rate in small laryngeal lesions is recognized. Irradiation should be considered in the management of this tumor without undue concern for change in its biologic behavior.

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In a natural outbreak of sialodacryoadenitis virus it was observed that the incidence of clinical signs in spontaneous-hypertensive rats was 100%, and that these signs were of a severity not observed before in other strains of rats. Rats free of the virus were introduced so that the progress of the disease could be studied under natural conditions of spontaneous spread from the enzootically-affected breeding colony. The pathogenesis of the infection in these Sprague-Dawley rats has been recorded over a period of 10 days after their introduction to the colony, and the results of extensive serological screening have shown that the antibody response of the spontaneous-hypertensive rats to the virus is lower than in other strains of rat.

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Granulomatosis with vasculitis presenting as a parotid tumor is discussed. Review of the literature reveals no similar case to date. The clinical manifestations and pathological findings are described with the surgical and medical management of the case discussed.

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Two primary adenoid cystic carcinomas of skin were studied histologically and histochemically. Histologically, they closely resemble adenoid cystic carcinoma found in other tissues but in the skin must be distinguished from aggressive basal cell carcinomas. The natural history of these tumors and of those collected from the literature suggest a long indolent and progressive course. Local excision with meticulous histologic control of the surgical margins appears to be an appropriate therapeutic strategy. Thus far lymph node metastases have not been observed.

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