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| |  Blood Flow Cytometry May Be Preferable Way to Diagnose, Analyse Mycosis Fungoides: Presented at ASCP By John Otrompke CHICAGO -- November 10, 2009 -- Mycosis fungoides, a rare form of skin cancer that is actually a lymphoma, can be very difficult to diagnose based on skin biopsies. However, using blood flow cytometry, pathologists can get a much better look at the cells, and diagnose as well as classify the disease. “The histologic findings of mycosis fungoides are very subtle; furthermore, they overlap with benign dermatitis, skin inflammatory conditions, allergies to a medicine, or even a bug bite,” said Katalin Kelemen, MD, Oregon Health & Science University (OHSU), Portland, Oregon. “Also, the skin of a mycosis fungoides patient will reveal not only T-cell lymphoma, but there will usually be an additional benign inflammation which is also very rich in T cells, and we’re not able to distinguish benign T cells from the lymphocyte T cells,” explained Dr. Kelemen during a poster presentation here on October 29 at the American Society for Clinical Pathology (ASCP) 2009 Annual Meeting. The poster discussed analysis by blood flow cytometry of 47 skin and 56 blood samples from 37 patients with mycosis fungoides. Abnormal peripheral blood findings were present in 16 patients (43%), represented by 29 blood samples. Diagnosis included absolute lymphocytosis (defined as consistently >5,000 lymphocytes per mcL in the blood) in 12, a CD4 to CD8 ratio >10 in 20 samples, and clonal T-cell gene rearrangement in 19. However, blood tests might be no panacea, Dr. Kelemen cautioned. “While mycosis fungoides usually goes on for many years, after 15 or 20 years it can become very aggressive, and enter the bloodstream,” explained Dr. Kelemen. “But just because T lymphocytes are passing through the blood doesn’t mean the disease is already systemic; they could just be on their way to a regional lymph node.” While 43% of patients in the study had lymphocytes in the blood, Dr. Kelemen said the numbers were skewed by the role of OHSU as a regional cancer centre. “We have a higher proportion of patients in the advanced stage of mycosis fungoides; the number of those with cells in the blood in the patient population as a whole is probably much closer to 5%,” she said. The study also suggested that many pathologists frequently mischaracterise mycosis fungoides as being indicated by weak presence of the CD7 antigen. “My findings in the blood show that weakness of CD7 is not even that common,” said Dr. Kelemen. “In fact, CD7 negativity is not a product of mycosis fungoides but of the inflammatory response on the skin.”
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