Biomedical subjects
Publications and source records attributed to A J Howat.
Two children are described with acute leukemia in remission who both developed a swinging pyrexia and pathologically identical splenic necrotizing granulomata. No organisms were seen in, or isolated from, either spleen. After splenectomy, systemic symptoms persisted and did not resolve until steroids were given. The etiology of this syndrome remains unknown.
Two hundred consecutive cases of the sudden infant death syndrome were reviewed for the presence of fat in the liver; 14 showed diffuse panlobular microvesicular fatty change indistinguishable from that found in Reye's syndrome. Samples of frozen liver were available in five of the 14 cases; histochemical analysis showed well preserved cytochrome oxidase and succinate dehydrogenase activity in all five, uncharacteristic of Reye's syndrome. Fatty acyl-coenzyme A dehydrogenase activity in the liver was assayed biochemically in two of the same five cases with severe hepatic fatty infiltration; both showed a defect in medium chain acyl-coenzyme A dehydrogenase activity using the substrate octanoyl-coenzyme A. Both cases also showed cerebral oedema in association with fatty infiltration of renal tubules, myocardium, and skeletal muscle, characteristic of Reye's syndrome. It is concluded that diffuse panlobular microvesicular fatty change of the liver in victims of the sudden infant death syndrome, although essentially non-specific, indicates that the state of mitochondrial enzymes should be investigated.
Forty-nine Spitz nevi occurring in children were reviewed and sampled extensively in order to assess the incidence of vascular invasion. Evidence of vascular invasion was found in seven (14.3%) cases. The endothelium of such vessels was negative on immunoperoxidase staining for Factor VIII-related antigen suggesting the nevus cells to be in lymphatic channels and not blood vessels. No unusual histological or clinical features characterized the group. All patients are alive and well some years after local excision therapy. It is concluded that lymphatic invasion by nevus cells in Spitz nevi is not uncommon and its presence should not tempt the pathologist into a diagnosis of melanoma.
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A previously unreported congenital malformation was noted in an infant with right atrial isomerism ("asplenia syndrome"). The superior bridging leaflet of a common atrioventricular valve was attached to a band of muscular tissue spanning the atrioventricular junction. A large ventricular diverticulum extended into the substance of this band, possibly due to traction during fetal life.
A case of adenosquamous carcinoma of the renal pelvis is reported, associated with multiple staghorn calculi, occurring in a 35-year-old woman. A review of the literature revealed only two previously reported cases. It is postulated that chronic irritation from the renal calculi had induced squamous and glandular metaplasia with subsequent adenosquamous neoplasia.
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A histopathological study of two cases of the tumor known in the literature as myofibroblastoma of the breast is presented. The tumors occurred in Caucasian males aged 57 and 62 years. Histologically, these were moderately cellular, lobulated spindle-cell lesions, each with a reasonably well-delineated edge with surrounding fatty connective tissue. No breast ducts or lobules were present. Tumor cell nuclei were bland, with small nucleoli and some nuclear grooving. Nuclear atypia and mitoses were absent. Immunostaining revealed positivity for a-smooth-muscle actin, desmin, and CD34. Tumor cells contained rough endoplasmic reticulum, bundles of myofilaments with focal densities, intermediate filaments, attachment plaques alternating with plasmalemmal caveolae, and focal lamina. Ultrastructural findings pointed to true smooth-muscle differentiation, and the cell-surface in particular lacked surface features of myofibroblasts (fibronectin fibrils [microtendons] and fibronexus junctions). These and published data suggest that at least some of the lesions referred to in the literature as myofibroblastoma may not be myofibroblastic and may be better designated as myogenic stromal tumors or as variants of leiomyoma.
Silver staining was used to demonstrate nucleoli and nucleolar organizer regions (NORs) in cytopreparations from breast fine needle aspiration (FNA) biopsies, with the resulting black dots being a combination of silver-binding nucleoli and dispersed NORs. Discrete black dots in 200 nuclei were manually counted in 25 silver-stained biopsies; the cytologic diagnoses were made on routine Papanicolaou-stained cytopreparations from the same aspirates. Although malignant breast lesions showed higher counts than did benign breast disease, an overlap of one malignant and three benign lesions occurred. Therefore, the method cannot be recommended for reliably discriminating between malignant and benign routine breast specimens obtained by FNA; it may have some value in assessing tumor behavior.
The Cytospin method of fine needle aspiration cytology includes flushing the aspirate into 10 mL of Cytospin fluid; the cytocentrifuge preparations are then safely and conveniently prepared in the laboratory. Slides are stained with Papanicolaou stain and hematoxylin and eosin. From November 1989 through October 1992, 1,868 breast aspirates from palpable lumps were examined by this method at our institution. The method detected 398 of 441 cancers (90.2%); of the 43 that were undetected, 16 had inadequate aspirates, and 27 were falsely reported as negative (for a false-negative rate of 6.0%). There were no false positives; the positive predictive value for malignancy was 100%. The inadequacy rate was 14.8%. Excluding inadequate samples, the complete sensitivity was 95.2%, with 96.5% specificity. The Cytospin method of processing breast aspirates from palpable breast lumps is an acceptable alternative to conventional fine needle aspiration using direct smears. It is also highly convenient as an outpatient procedure, obviating the need for skillful preparation of direct smears.
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