Aprosencephaly and cerebellar dysgenesis in sibs.

Aprosencephaly is a rare, lethal malformation sequence of the central nervous system that has been attributed to a postneuralation encephaloclastic process. We describe autopsy findings consistent with aprosencephaly in 2 fetuses conceived from a consanguineous mating (first cousins). Both showed anencephalic manifestations; however, the crania were intact, with fused sutures. The neuropathologic findings were essentially identical. Each fetus had complete absence of the telecephalon and pyramidal tracts, rudimentary diencephalic and mesencephalic structures, primitive cerebellar hemispheres, posterolateral clusters of primitive neural cells in the medullas suggesting an abnormality of neural migration, a normally-formed spinal cord, and retinal dysplasia within normally-formed globes. In addition, both fetuses manifested a peculiar perivascular mesenchymal proliferation seen only within the central nervous system. The similarity of these cases, coupled with parental consanguinity, suggests a primary malformation in brain development due to the homozygous representation of a mutant allele. We hypothesize that these patients may represent a defect in a gene important in brain development, the nature of which has yet to be elucidated.

Utilization of testing for activated protein C resistance in a reference laboratory.

Activated protein C (APC) resistance is a newly described thrombotic disorder accounting for the majority of patients with inherited thrombosis. The authors prospectively evaluated laboratory testing of this disorder over a 1-year period in their reference laboratory, which draws samples from a large number of community and academic hospitals throughout the United States. Testing for other inherited thrombotic disorders (antithrombin III deficiency, protein C and S deficiencies) occurred at a six-fold greater rate than that for APC resistance. Previously published studies have indicated a prevalence of up to 60% for APC resistance in populations with thrombosis; however, the prevalence rate in this study was only 12%. Of patient samples submitted for APC resistance assays, 37% were not evaluable because of concomitant anticoagulant therapy. Clinical pathologists and practitioners need to be made aware of APC resistance and of optimal sample collection to improve the efficiency of laboratory testing for thrombosis.

Purification of DNA topoisomerase I from the spleen of a patient with non-Hodgkin's lymphoma.

DNA topoisomerase I (topo I) was purified 124-fold from the spleen of a patient which was diffusely infiltrated by malignant lymphoma. Extracts prepared from the lymphoma tissue demonstrated elevated topo I activity. The purification uses a new two step chromatographic method involving hydroxylapatite and Fast Protein Liquid Chromatography mono S. The purified enzyme has a molecular weight of 67 kilodaltons as determined by sodium dodecyl sulfate denaturing gel electrophoresis. Western blotting confirms the identity of the protein as topo I. The purified lymphoma topo I has a similar specific activity as topo I isolated by the same procedure from normal placenta. By using a new quantitative radiolabeled DNA relaxation assay, it was estimated that each molecule of topo I is able to relax 9.6 molecules of supercoiled DNA per min at 30C. In addition it was found that both the placental topo I and the lymphoma topo I were each 50% inhibited by 8 microns camptothecin and that the drug stimulates the lymphoma topo I to cleave supercoiled plasmid DNA. These findings indicate that the elevation of topo I measured in crude extracts of this human malignant lymphoma can be entirely accounted for by the increase in topo I protein in the tumor. Furthermore, the sensitivity of the lymphoma topo I towards camptothecin suggests that therapy with topo I directed agents might be beneficial in this tumor.

Malpractice protection: communication of diagnostic uncertainty.

Malpractice claims against pathologists for misdiagnosis have been sharply rising, especially in the areas of breast fine-needle aspirations (BFNAs) and cervical (Pap) smears. The current state of medical malpractice law is reviewed as it relates to pathologists' anatomic reports. Communication is one of the best medical malpractice prevention tools. This article examines anatomic pathology reports in terms of the merits of communicating diagnostic error rates to the clinician/patient. In the areas of BFNAs and cervical smears, dissemination of diagnostic error rates in the cytology report is recommended. This would help safeguard against malpractice liability being imposed without showing a deviation by the cytopathologist from reasonable practice standards.

Inherited thrombotic disorders: an update.

Significant advances in identification of etiologies of inherited thrombosis have been recently reported. A point mutation in coagulation factor V (factor V Leiden) results in resistance to activated protein C and probably represents the most common genetic risk factor for venous thrombosis. A metabolic disorder, homocysteinemia, is now known to be an important risk factor for both arterial and venous thrombosis. Many patients with recurrent thrombosis will have more than one genetic risk factor identified. Recognition of these new disorders should permit a diagnosis to be achieved in at least half of patients evaluated for inherited thrombosis.

Basal cell carcinomas are populated by melanocytes and Langerhans [correction of Langerhan's] cells.

Several reports have documented the coexistence of basal cell carcinoma (BCC) with other lesions, including melanoma. This study was performed to determine whether nests of BCC contain benign melanocytes and Langerhans [corrected] cells. Ten cases of BCC were investigated to determine whether benign melanocytes and Langerhans [corrected] cells populate tumor nests. The BCCs were stained with antibodies to cytokeratin AEI/AE3, S-100, HMB-45, Melan-A, and CD1a proteins. We report that all 10 BCCs were populated by dendritic melanocytes distributed at the periphery (5/10 cases) or evenly throughout tumor nests (5/10 cases). Clusters of melanocytes were not identified in any of the BCCs. A total of 9 of 10 tumors showed staining of dendritic Langerhans cells with CD1a. A total of 8 of 10 tumors stained with cytokeratin AEI/AE3; in 6 of the 8 tumors, the staining was focal. We compared these findings with a single example of a BCC and melanoma in situ (MIS) collision tumor in which the cytokeratin AE1/AE3-positive epithelial nests of BCC were populated by a high density of malignant melanocytes that stained with S-100 and HMB-45. Melanocytes were disposed singly and in clusters of two or more cells within BCC tumor nests. We conclude from this study that BCCs are regularly populated by benign melanocytes and Langerhans [corrected] cells. Furthermore, when BCC is infiltrated with malignant melanocytes of MIS, the melanocyte density is higher and clusters of melanocytes can be observed. The significance of these two findings is unclear, as additional cases of BCC MIS collision tumor need to be studied.

A comparison of touch imprint cytology and Mohs frozen-section histology in the evaluation of Mohs micrographic surgical margins.

BACKGROUND: Touch imprint cytology (TIC) is commonly used in the diagnosis of tumors and has been applied to margin analysis of breast lumpectomy specimens with good success. OBJECTIVE: Our purpose was to determine the diagnostic adequacy of TIC for identifying positive and negative Mohs surgical margins for basal cell carcinoma (BCC) excisions, compared with the "gold" standard, Mohs tangential sectioning. METHODS: Fifty-eight patients undergoing 69 Mohs micrographic surgical procedures for biopsy-proven BCC were included in this study between October 1998 and January 1999. Patients were excluded if the neoplasms were of another histologic type, including BCCs with squamous features. One hundred sixty-six touch imprint slides were prepared from 166 fragments of skin tissue excised during MMS. Touch imprint slides were evaluated blindly and independently by two pathologists, one of whom was also a cytopathologist. The slides were diagnosed as positive for tumor, negative for tumor, or, rarely, atypical but suspect for tumor. Discrepancies between the pathologists' interpretations were re-evaluated with the use of a two-headed microscope and a consensus was reached. After all cytologic interpretation was completed, the results were compared with the histologic diagnosis rendered for each fragment of tissue by the Mohs surgeon. RESULTS: The prevalence of a positive margin by histologic confirmation was 55% overall, 60% for recurrent or sclerosing lesions, and 51% for nonsclerosing or recurrent lesions. The overall accuracy of this technique in identifying true positive and true negative margins was 71%. The sensitivity of TIC for identifying a positive margin was approximately 50% for all BCC types. The specificity was approximately 90% for all BCC types. CONCLUSION: TIC is inadequate for identifying positive margins compared with the "gold" standard, MMS.

Localized bullous pemphigoid in a patient with B-cell lymphoma.

Bullous pemphigoid (BP) is an immunobullous disease characterized by circulating IgG antibodies directed towards cutaneous basement zone antigens. We report the case of a patient who had BP localized to a stoma site. At initial examination, a nodule was noted on the temple, which proved to be a large cell lymphoma, B-cell phenotype. On Western immunoblot, the patient's serum showed circulating IgG antibodies reactive with the 230 kDa BP antigen and the 97 kDa linear IgA bullous dermatosis antigen. The co-incident onset of the two diseases suggest that this may represent a case of paraneoplastic BP.

Eosinophilic fasciitis occurring four weeks after the onset of dialysis in a renal failure patient.

BACKGROUND: Eosinophilic fasciitis is a rare, scleroderma-like disease that usually affects the extremities of young to middle-aged males. The disease may cause flexion contractures and limit joint mobility and is associated with peripheral eosinophilia. The fascia, by definition, is infiltrated with mononuclear cells and typically with eosinophils. Eosinophilic fasciitis may be separated from another sclerodermatous disorder, linear scleroderma, by its response to systemic corticosteroids. The etiology is unclear but eosinophilic fasciitis has numerous disease associations. However, it has not previously been associated with renal failure and hemodialysis. OBJECTIVE: This article reports a case of eosinophilic fasciitis occurring four weeks following the onset of hemodialysis. METHODS: The clinical and histologic features confirmed the diagnosis of eosinophilic fasciitis. He was treated with systemic corticosteroids with good response. CONCLUSION: This is the first reported patient who developed eosinophilic fasciitis in close temporal relationship with the start of hemodialysis. While eosinophilic fasciitis may be coincidental with a common disorder, namely, renal failure, it is interesting to note that hemodialysis patients often have immune-regulation abnormalities and peripheral eosinophilia.

Preservation of RNA for functional genomic studies: a multidisciplinary tumor bank protocol.

Few human tumors are collected such that RNA is preserved for molecular analysis. Completion of the Human Genome Project will soon result in the identification of more than 100,000 new genes. Consequently, increasing attention is being diverted to identifying the function of these newly described genes. Here we describe a multidisciplinary tumor bank procurement protocol that preserves both the integrity of tissue for pathologic diagnosis, and the RNA for molecular analyses. Freshly excised normal skin was obtained from five patients undergoing wound reconstruction following Mohs micrographic surgery for cutaneous neoplasia. Tissues treated for 24 hours with RNAlater were compared histologically and immunohistochemically to tissues not treated with RNAlater. Immunohistochemical stains studied included: CD45, CEA, cytokeratin AE1/3, vimentin, S-100, and CD34 on formalin-fixed, paraffin embedded tissue and CD45 staining of frozen tissue. Slides were blinded and evaluated independently by three pathologists. The histologic and immunohistochemical parameters of tissue stored in RNAlater were indistinguishable from tissue processed in standard fashion with the exception of S-100 stain which failed to identify melanocytes or Langerhan's cells within the epidermis in any of the RNAlater-treated tissues. Interestingly, nerve trunks within the dermis stained appropriately for S-100. Multiple non-cutaneous autopsy tissues were treated with RNAlater, formalin, liquid nitrogen (LN2), and TRIzol Reagent. The pathologists were unable to distinguish between tissues treated with RNAlater, formalin, or frozen in LN2, but could easily distinguish tissues treated with TRIzol Reagent because of extensive cytolysis. RNA was isolated from a portion of the tissue treated with RNAlater and used for molecular studies including Northern blotting and microarray analysis. RNA was adequate for Northern blot analysis and mRNA purified from RNAlater-treated tissues consistently provided excellent templates for reverse transcription and subsequent microarray analysis. We conclude that tissues treated with RNAlater before routine processing are indistinguishable histologically and immunohistochemically from tissues processed in routine fashion and that the RNA isolated from these tissues is of high quality and can be used for molecular studies. Based on this study, we developed a multidisciplinary tumor bank procurement protocol in which fresh tissue from resection specimens are routinely stored in RNAlater at the time of preliminary dissection. Thus, precious human tissue can be utilized for functional genomic studies without compromising the tissue's diagnostic and prognostic qualities.