Reactivity with TdT in Merkel cell carcinoma: a potential diagnostic pitfall
Am J Clin Pathol. 2008 Jun
Buresh CJ, Oliai BR, Miller RT.
Immunohistochemistry Division, ProPath Laboratory, Dallas, TX 75247, USA.
Merkel cell carcinoma (MCC) is a high-grade neuroendocrine carcinoma of skin characterized by cells with a "blastic" appearance, scant cytoplasm, and fine, evenly distributed chromatin. Terminal deoxynucleotidyl transferase (TdT) is a DNA polymerase present in thymic T cells, lymphoblastic lymphoma/leukemia, and some cases of acute myeloid leukemia. After observing TdT immunoreactivity in a case of MCC, we analyzed 26 tumors by immunohistochemical analysis to determine their spectrum of reactivity with TdT and identified TdT in 19 (73%) of 26 MCCs. Staining intensity was variable but was often moderate to strong and present in a significant percentage of cells. Because MCC has cytomorphologic features similar to those of lymphoblastic lymphoma and may manifest as metastatic disease, reactivity with TdT in MCC could represent a diagnostic pitfall in the differential diagnosis with lymphoblastic lymphoma, particularly because the latter may lack CD45 and/or CD20, yet both neoplasms may express PAX-5, a B-cell-associated marker.
MetaPress American Journal of Clinical Pathology
About Me
- Pat O'Connor
- Am old enough to understand the difference between the Bay of Pigs - and roasting a pig at a epicurian feast. Been thru the hippy, yippie and yuppie years - always remaining who I am. Very much believe in "Sing your own song - weave your own tapestry" Am young enough to still know the thrill of new discoveries, the beauty of the evening, to celebrate the joy of another tommorow. Survived these many decades with a severe medical problems. Sorting out the maze of now having two lymphomas and all their nasty little companions, but I continue. Besides, being a simple iconoclastic eclectic, have been called many things. An incurable romanticist - with a strong touch of reality. Thinker, intellectual (God, how I hate that term) - been told I am a lion with the heart of the poet. Know how to wage war and conquer my foes - but would rather be known as one who brings hope and life. To bring hope into anothers life is the ultimate of joys. Life should be about bringing hope, peace, vision... a sense of purpose beyond yourself.