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D A Weeks

Publications and source records attributed to D A Weeks.

At least 37 records · Page 2Linked to original sources
PubMed1990

Epidermoid cyst of the spleen presenting as a generalized peritonitis.

In this report we reviewed 159 cases of epidermoid cyst of the spleen reported since 1929 and we added one case of our own with a unique clinical presentation. In these cases, the patients' age at presentation ranged from newborn to 51 years, with a mean age of 17.7 years. Female-to-male ratio was 2.0 to 1.0. Patients with this lesion usually present with asymptomatic abdominal mass and/or abdominal pain. Only in rare reports has there been infection (4 cases) or rupture (4 cases) of the cyst. In our case, the patient presented with an acute surgical abdomen and diffuse peritonitis. As in three of the previously reported cases associated with infection, Salmonella group organisms were cultured from the cyst abscess. Splenectomy is the surgical treatment of choice and the initial antibiotic regime should include Salmonella coverage.

Abscess↗
PubMed1989

Rhabdoid tumor of kidney. A report of 111 cases from the National Wilms' Tumor Study Pathology Center.

We review 111 cases of rhabdoid tumor of kidney (RTK), including 79 entered on the National Wilms' Tumor Study (NWTS). Median age at diagnosis was 11 months, with a range from 0 to 106 months. The male:female ratio was 1.5:1. Gross features included a characteristic involvement of perihilar renal parenchyma. A wide histological spectrum was encountered, including nine major morphological patterns (classical, epithelioid, sclerosing, lymphomatoid, histiocytoid, etc.). These appearances invite confusion with other renal neoplasms. Ultrastructural studies were performed in 20 cases; immunocytochemical studies were performed in 11. Vimentin was demonstrated in all tumors; epithelial membrane antigen was seen in 7. Nonspecific decoration of cytoplasmic inclusions by a variety of immunostains was found in several cases. Several findings suggested that RTK might arise from primitive cells involved in formation of the renal medulla. There was no evidence of a histogenetic relationship to Wilms' tumor, although RTK may overlap with mesoblastic nephroma and clear cell sarcoma. Of the 70 NWTS patients with adequate follow-up, 56 (80%) have died. Every patient presenting with distant metastases died, whereas 10 of 20 with negative nodes survived. Survival rates were higher for girls (56.3% versus 11.1%). None of the histological variables had independent prognostic significance.

Antigens, Neoplasm↗
PubMed1987

Relapse-associated variables in stage I favorable histology Wilms' tumor. A report of the National Wilms' Tumor Study.

All 24 cases of confirmed and evaluable Stage I favorable histology (FH) Wilms' tumor (WT) relapsing to date on the Third National Wilms' Tumor Study (NWTS-3) were compared with 48 matched control subjects who had not relapsed for at least 2 years after diagnosis. Fifteen of the clinical and pathological variables studied, including patient age and tumor size, had no significant relationship to the outcome of this study. Four histologic features, all related to the degree of tumor extension within the "tumor-kidney unit" proved to be significantly associated with relapse. These were (1) invasion of the tumor capsule, (2) presence of an "inflammatory pseudocapsule," (3) renal sinus invasion, and (4) tumor in intrarenal vessels. One or more of these features was present in 100% of relapsed cases (excluding one for which two variables were unevaluable), but occurred in only 46% of controls (P less than 0.0002). Therefore, no relapses occurred in the NWTS-3 when all four variables were negative. This result was confirmed by a review of all Stage I cases in the NWTS-1 who had relapsed and who were treated by single-agent chemotherapy. Again, no relapses occurred when all four factors were negative. These results demonstrate the feasibility of "microsubstaging" and could serve as a basis for future refinements of therapy for Stage I favorable histology Wilms' tumor.

Child↗
PubMed1987

Ultrastructure and histogenesis of the renal tumors of childhood: an overview.

This review discusses the ultrastructural and immunohistochemical features of the common childhood renal tumors, with an emphasis on their diagnostic usefulness. Speculations regarding their histogenesis also are presented, with the hope that these may serve to diminish some of the confusion surrounding the classification of these morphologically diverse lesions.

Antibodies, Neoplasm↗
PubMed1987

Chondroid chordoma.

We reject the notion that the concept of "chondroid chordoma" be abandoned in favor of an interpretation of the cartilaginous origin of these lesions. We have demonstrated by electron microscopic and immunohistochemical means that these neoplasms can exhibit distinctly epithelial characteristics in their chondroid as well as their epithelial areas. The presence of desmosomes, cytokeratin, carcinoembryonic, and epithelial membrane antigen in the cells of the chondroid as well as the epithelial areas; the presence of the microtubular inclusions, vimentin, and S-100 protein in the cells of the epithelial as well as chondroid areas; and the intermingling of the two and gradual transitions from one to the other all point to the conclusion that the chondroid and epithelial areas are only differing morphologic expressions of the same entity. The gradual evolution witnessed in the sequential biopsies of this case study, through which a predominantly chondromatous neoplasm became a chordoma of typical histologic appearance, provides further strong evidence to support the contention that chondroid chordoma is a variant of chordoma and not a primary chondrocytic neoplasm.

Adolescent↗
PubMedDate not supplied

Anaplastic Wilms' tumor and other clinically aggressive childhood renal neoplasms: ultrastructural and immunocytochemical features.

The ultrastructural and immunocytochemical findings in a series of 32 rarely encountered childhood renal malignancies are reviewed. The discussion includes anaplastic Wilms' tumors, renal clear cell sarcomas, rhabdoid tumors, carcinomas, sarcomas, neuroendocrine tumors, and lymphomas. An attempt is made to assess the relative merits of these two techniques in the differential diagnosis of these often troublesome lesions.

Carcinoma↗
PubMedDate not supplied

Lipid-rich rhabdomyosarcoma--a potential source of diagnostic confusion.

Rhabdomyosarcoma is an often primitive tumor capable of diverse morphologic manifestations. The article describes three cases of childhood rhabdomyosarcoma in which a significant population of lipid-rich tumor cells was present. The lack of specificity and potentially confusing nature of this feature are discussed, and the ultrastructural diagnosis of rhabdomyosarcoma is briefly reviewed.

Abdominal Neoplasms↗
PubMedDate not supplied

Primitive pelvic sarcoma resembling clear cell sarcoma of kidney.

Clear cell sarcoma of kidney (CCSK) is an aggressive childhood renal tumor of unknown histogenesis that has not been reported to occur outside the kidney. The article describes an extrarenal neoplasm arising in the pelvic soft tissues of a 13-year-old boy that was composed predominantly of uniform mesenchymal cells with optically clear cytoplasm supported by an arborizing network of small blood vessels, which was indistinguishable in appearance from CCSK. The electron microscopic findings, although nonspecific, were essentially identical to those of CCSK, with tumor cells displaying fine chromatin, electron-lucent cytoplasm, and intercellular collagen but no evidence of tissue-specific differentiation. Immunocytochemical studies showed positivity for vimentin but negative results for desmin, myoglobin, cytokeratin, epithelial membrane antigen, S-100 protein, neuron-specific enolase and factor VIII-related antigen. Tumor cells were also nonreactive with Ulex lectin. This unusual pelvic tumor and CCSK may both derive from primitive mesenchymal cells and may represent phenotypic but not necessarily histogenetic analogs.

Adolescent↗
PubMedDate not supplied

Hepatic angiomyolipoma with striated granules and positivity with melanoma--specific antibody (HMB-45): a report of two cases.

Angiomyolipoma occurs rarely in the liver, with only 25 previous cases being reported in the English literature. The article describes two additional cases, one of which was multicentric, with results of ultrastructural and immunocytochemical studies. Many of the tumor cells contained numerous electron-dense granules, some with transverse striations like those found in melanosomes. Both tumors stained positively for S-100 protein and melanoma-specific antibody HMB-45. One case also expressed vimentin and neuron-specific enolase. Both were negative for cytokeratin, carcinoembryonic antigen, alpha-fetoprotein, desmin, muscle-specific actin, factor VIII antigen, and chromogranin. Comparison of our ultrastructural findings with those of classic renal angiomyolipoma raises the possibility that the melanosomelike structures may represent renin granules rather than melanosomes, although the latter are not excluded. Expression of HMB-45 in angiomyolipoma has important biologic and diagnostic implications, whether or not it reflects melanocytic differentiation.

Adult↗
PubMedDate not supplied

The role of electron microscopy in evaluating ciliary dysfunction: report of a workshop.

This report summarizes the proceedings of a workshop organized with the purpose of bringing together many of those with substantial experience in this troublesome area of pathology for an active interchange of ideas, opinions, problems, and solutions. Recognition was given the fact that current knowledge and technical capabilities are woefully inadequate for dealing with the diagnostic questions now being asked. Until such time as these inadequacies can be remedied, a very conservative approach to the interpretation of ultrastructural studies is advocated.

Adolescent↗
PubMedDate not supplied

Primitive cerebral tumor with rhabdoid features: a case of phenotypic rhabdoid tumor of the central nervous system.

The rhabdoid tumor (RT) was first described as an aggressive neoplasm of unknown histogenesis affecting the kidneys of infants and young children, but has since been reported in all ages and in many other primary sites, including the central nervous system. It has been shown, however, that the histologic and cytologic features of RT can be mimicked by many other tumors of known histogenesis. For this and other reasons it remains controversial whether cases of putative extrarenal RT represent the same histogenetic entity as RT of the kidney (RTK), another entity or entities, or merely a diverse collection of unrelated tumors sharing a common morphologic phenotype. The present paper describes a lethal primary cerebral tumor in a 26-month-old Hispanic boy that was composed predominantly of cells exhibiting the "classic" rhabdoid phenotype by light microscopy. Immunocytochemical and ultrastructural studies disclosed features of primitive neuroglial differentiation not seen in RTK. The findings in this case, as well as evidence from other studies, would seem to support the notion that primary RT of the brain may in fact constitute a morphologic and clinicopathologic entity. However, that entity likely represents a distinctive type of neuroglial neoplasm, more closely related to other primitive brain tumors than to RTK.

Brain Neoplasms↗
PubMedDate not supplied

Meningioma with chordoid features.

Meningioma is a relatively common intracranial tumor, occurring most frequently in adults, and is capable of a wide variety of growth patterns. We describe a meningioma in a child that had a peculiar chordomalike appearance. The pathologic findings and distinction from chordoma are discussed.

Brain Neoplasms↗
PubMedDate not supplied

Ependymoma with signet-ring cells.

Two patients presented with unusual primary brain tumors having abundant signet-ring cells, for which electron microscopic study was necessary to establish the diagnosis of ependymoma. The light and electron microscopic features of these tumors are discussed, with brief comments on the differential diagnosis.

Adult↗
PubMedDate not supplied

Extrarenal angiomyolipoma with melanocytic and hibernoma-like features.

Angiomyolipoma is a tumor commonly occurring in the kidney, but occasionally found in extrarenal sites. Retroperitoneal angiomyolipoma with unusual features presenting in a 39 year old woman with hypertension is reported in this paper. Tumor fat was inconspicuous, and present largely as hibernoma-like microvesicular lipid. Tumor cells also demonstrated positivity for HMB-45 and S-100 protein, and by electron microscopy showed occasional cytoplasmic striated granules indistinguishable from stage II premelanosomes. However, electron microscopy and immunocytochemistry also confirmed the presence of a substantial myogenous component in the tumor, establishing the diagnosis of angiomyolipoma. The implications of these findings, and the role of immunocytochemistry and electron microscopy in the diagnosis of this tumor are discussed.

Adult↗
PubMedDate not supplied

Ultrastructure of cellular congenital mesoblastic nephroma.

A detailed ultrastructural description of the cellular variant of congenital mesoblastic nephroma (CMN) is presented and compared to the classical form. Studied were 9 cases of the cellular variant, 6 mixed (cellular/classical) tumors, and 1 classical CMN. The occurrence of a broad selection of ultrastructural features was assessed using a semiquantitative scoring system. The results indicate that cellular CMNs are composed mainly of primitive mesenchymal cells, but also usually contain varying numbers of differentiating fibroblasts and myofibroblasts. This entity thus bears a closer resemblance at the ultrastructural level of organization to infantile fibrosarcoma than to conventional fibrosarcoma. Electron microscopy can be useful in distinguishing this relatively benign entity from the several malignancies with which it is sometimes confused.

Cell Nucleus↗
PubMedDate not supplied

Appraisal of the comparative utility of immunohistochemistry and electron microscopy in the diagnosis of childhood round cell tumors.

To provide an objective assessment of the comparative utility of fluorescence- and peroxidase-based immunohistochemistry and electron microscopy, an observer blinded study was conducted under realistic study conditions utilizing a large sampling of poorly differentiated pediatric round cell tumors. Working independently, using a single ancillary technique of particular expertise, each of three investigators attempted to render a specific diagnosis with regard to 50 diagnostically challenging tumors. The results were compared against the subsequent "file diagnosis" established by consensus with all relevant information made available. A grading scheme was applied wherein points were awarded based on the accuracy and confidence of diagnosis. A comparative efficiency rating, expressed as a percentage, was formulated by dividing the number of points awarded each technique by the total number of points theoretically available. Electron microscopy proved superior overall, with an efficiency rating of 89%. Immunoperoxidase and immunofluorescence studies yielded efficiency ratings of 71 and 61%, respectively. Used in combination, the techniques achieved an efficiency rating of 95%. Application of these ancillary techniques resulted in a revision of the provisional diagnosis in 11 of 50 cases, and left only two cases without a firm specific diagnosis.

Adolescent↗