November 2003

Misleading Kaposi's Sarcoma: Usefulness of Anti HHV-8 Immunostining

[Article in French]

Audard V, Lok C, Trabattoni M, Wechsler J, Brousse N, Fraitag S.

            The authors report two cases of early Kaposi's sarcoma illustrating the risk of misdiagnosis. Both lesions showed histological features and clinical aspects that mimicked lymphangioendothelioma. The diagnosis of lymphangioma-like Kaposi's sarcoma was not made until a few years later, after the lesions had become more extensive and bilateral. Because of this evolution which is uncommon for a lymphangioendothelioma, immunohistochemical staining with anti-HHV8 antibody was done, and was positive in successive biopsies of our two patients. These results reveal that these vascular lesions had been Kaposi's sarcomas of the lymphangioma-like type since the beginning. In conclusion, it seems essential to search for HHV8 within endothelial cells of any vascular lesion mimicking lymphangioendothelioma or any other vascular proliferation difficult to classify.

Ann Pathol. 23(4): 345-8, 2003

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Ocular Surface Impression Cytology

McKelvie P

Impression cytology, either using cellulose acetate strips or the Biopore membrane device, is a simple, noninvasive technique that aids in the diagnosis of several disorders of the ocular surface. These disorders include ocular surface squamous neoplasia, dry eye syndrome, limbal stem-cell deficiency, specific viral infections, vitamin A deficiency, allergic disorders, conjunctival melanosis, and malignant melanoma. Another advantage is the preservation of limbal stem cells, which occur in the basal layer of the limbal epithelium and are responsible for renewal of the corneal epithelium. The Biopore membrane device is particularly user friendly, with little expertise required and adequate specimens obtained in a very high percentage of cases. The most common applications in diagnostic ocular pathology are:(i) primary diagnosis and follow-up of ocular surface squamous neoplasia, including after therapy with topical mitomycin C. The sensitivity is high (78-87%); and (ii) dry eye syndrome where squamous metaplasia and/ or hyperkeratosis are noted. Certain limitations of the technique for diagnosis of squamous neoplasia include the fact that dysplasias are often keratinizing and may yield very few or even no dysplastic cells with impression cytology. Secondly, no definite cytologic criteria reliably distinguish invasive SCC of ocular surface from in situ disease. Other applications include the rapid specific diagnosis of ocular surface infections with herpes simplex, adeno-, and varicella zoster viruses. Impression cytology samples may also be used to obtain mRNA, cells for phenotyping by flow cytometry, and proteins for Western blotting for research studies.

Adv Anat Pathol 10(6): 328-37, Nov 10, 2003

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   Apolipoprotein B May Be Superior to LDL for Predicting Cardiovascular Risk

Sniderman AD et al

Apolipoprotein B (apoB) appears to represent a better index of risk than does low-density lipoprotein cholesterol (LDLC) level.

The study showed that patients who had a high triglyceride level and a high apoB were the ones more likely to have high blood sugar, more insulin resistance, more inflammation, and more prothrombogenic factors. The investigators analyzed data from 1522 subjects, ages 49 to 69 years old. "Hyper-LDLC" was defined as levels of 130 mg/dL or higher, and "hyper-apoB" 99 mg/dL or higher. Approximately 10% of subjects met the definition for elevated LDLC but not for apoB, and another 10% had elevated apoB in the presence of normal LDLC. After combining these two groups, the authors note, 19% of the cohort would have a different treatment recommendation if apoB were used to guide treatment instead of LDLC. According to their findings, normo-LDLC hyper-apoB individuals have significantly lower mean age, HDL cholesterol, and LDL particle size and higher body mass index, waist circumference, triglycerides, fasting insulin, 2-hour insulin, and plasminogen activator inhibit-1 values than the hyper-LDLC normo-apoB group.

The data relate back to fatty acid metabolism. If patients have excess energy intake, it is difficult for adipose tissue to store fatty acids, which in turn increases cardiovascular risk.

Authors suggest two choices for assessing patients at risk. In his own practice,  Sniderman measures apoB as part of a routine panel. An alternative is that when patients present with high triglyceride levels or a low HDL, measuring apoB would produce a more complete estimate of patient risk and potential for benefit from statin treatment.

Circulation, Volume 108,No.19, November 11,2003

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Dengue Fever Mimicking Plasma Cell Leukemia

Gawoski JM and Winnie W. Ooi

Extreme plasmacytosis in peripheral blood is a rare finding most often associated with plasma cell leukemia but rarely with other malignancies, infectious diseases, or drug reactions.  Authors report the case of a 40-year-old man who was a US expatriate working and traveling in East Asia. He presented with complaints of fever, myalgia, headache, vomiting, and diarrhea of 3 days' duration. An initial evaluation revealed elevated liver function tests, thrombocytopenia (68 103/ L), and a white blood cell count of 5.8 103/ L with 19% plasma cells (1100/ L), 9% abnormal plasmacytoid lymphocytes (520/ L), 37% polymorphonuclear leukocytes, 3% band forms, 27% lymphocytes, 4% monocytes, and 1% eosinophils. An extensive evaluation was performed, including infectious disease serologies, a bone marrow biopsy, and flow cytometry. During the course of 3 days, his symptoms and hematologic findings improved dramatically. Serologic results were reactive for dengue (immunoglobulin M [IgM] positive, reciprocal IgG titer, 655 360), consistent with a secondary infection of unknown serotype. He remains well 4 years later. According to authors, plasmacytosis to this degree has not been described in dengue fever, but atypical lymphocytosis is common. In patients from dengue-endemic areas, even extreme plasmacytosis should be assessed to determine whether it is transient and related to an acute illness before proceeding to an extensive evaluation.

Arch  Pathol Lab Med  127, 10261027, 2003

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            ADA Expert Committee Re-defines Impaired Fasting Glucose

American Diabetes Association

An international expert committee aligned to re-examine the diagnostic and classification criteria for diabetes announced new guidelines for doctors to use when looking for pre-diabetes.  The recommendations are published in the November 2003 issue of Diabetes Care.  The acceptable results of one method used to identify pre-diabetes, impaired fasting glucose, have been changed from <110 mg/dl to <100 mg/dl.  Using the new criteria, the number of Americans classified as having pre-diabetes is expected to rise by twenty percent.

Diabetic Care 26: 3160-3167, 2003

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