{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,3]],"date-time":"2026-10-03T03:54:41Z","timestamp":1790999681348,"version":"4.1.0"},"reference-count":11,"publisher":"Wiley","issue":"11","license":[{"start":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T00:00:00Z","timestamp":1784505600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T00:00:00Z","timestamp":1784505600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Diagnostic Cytopathology"],"published-print":{"date-parts":[[2026,11]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    The coexistence of chronic lymphocytic leukemia\/small lymphocytic lymphoma (CLL\/SLL) and Merkel cell carcinoma (MCC) is a well\u2010established but rare association. Collision tumors involving both entities within a single lymph node are exceptionally uncommon and pose considerable diagnostic challenges, particularly on cytological specimens. Here, we report the case of a 68\u2010year\u2010old male presenting with right axillary lymphadenomegaly. Fine\u2010needle cytology (FNC) demonstrated a monomorphic population of intermediate\u2010sized lymphoid cells, along with occasional larger cells exhibiting plasmacytoid features. Flow cytometric immunophenotyping showed a CD19+\/CD5+\/CD23dim B\u2010cell population with lambda light chain restriction consistent with CLL\/SLL, and a second CD45\u2212\/CD138+\/CD200+\/CD81+ population suspicious for aberrant plasma cells,\n                    <jats:italic>raising the differential diagnosis of plasmacytoma or plasmacytic differentiation of CLL\/SLL<\/jats:italic>\n                    . Subsequent lymph node excision and histological examination revealed a collision tumor comprising MCC and CLL\/SLL. This case highlights a rare but significant p\n                    <jats:italic>itfall in lymph node FNC specimens<\/jats:italic>\n                    , in which small neuroendocrine carcinoma was\n                    <jats:italic>misinterpreted as an aberrant hematopoietic population<\/jats:italic>\n                    .\n                  <\/jats:p>","DOI":"10.1002\/dc.70176","type":"journal-article","created":{"date-parts":[[2026,7,21]],"date-time":"2026-07-21T04:13:32Z","timestamp":1784607212000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Collision Tumor of Merkel Cell Carcinoma and Chronic Lymphocytic Leukemia\/Small Lymphocytic Lymphoma: A Cytological and Flow Cytometric Diagnostic Pitfall"],"prefix":"10.1002","volume":"54","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0803-0293","authenticated-orcid":false,"given":"Gennaro","family":"Acanfora","sequence":"first","affiliation":[{"name":"Department of Public Health University of Naples Federico II  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vincenza","family":"Cerbone","sequence":"additional","affiliation":[{"name":"CEINGE\u2010Advanced Biotechnologies  Napoli Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5813-9097","authenticated-orcid":false,"given":"Maddalena","family":"Raia","sequence":"additional","affiliation":[{"name":"CEINGE\u2010Advanced Biotechnologies  Napoli Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-6636-3564","authenticated-orcid":false,"given":"Rosaria","family":"Cappiello","sequence":"additional","affiliation":[{"name":"Department of Advanced Biomedical Sciences, Unit of Pathology University of Naples Federico II  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3943-4263","authenticated-orcid":false,"given":"Claudia","family":"Giordano","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine and Surgery, Hematology Unit Federico II University Medical School  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8508-2524","authenticated-orcid":false,"given":"Marco","family":"Picardi","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine and Surgery, Hematology Unit Federico II University Medical School  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2576-220X","authenticated-orcid":false,"given":"Massimo","family":"Mascolo","sequence":"additional","affiliation":[{"name":"Department of Advanced Biomedical Sciences, Unit of Pathology University of Naples Federico II  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7479-6457","authenticated-orcid":false,"given":"Claudio","family":"Bellevicine","sequence":"additional","affiliation":[{"name":"Department of Public Health University of Naples Federico II  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1630-5805","authenticated-orcid":false,"given":"Giancarlo","family":"Troncone","sequence":"additional","affiliation":[{"name":"Department of Public Health University of Naples Federico II  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2856-9023","authenticated-orcid":false,"given":"Elena","family":"Vigliar","sequence":"additional","affiliation":[{"name":"Department of Public Health University of Naples Federico II  Naples Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,7,20]]},"reference":[{"key":"e_1_2_7_2_1","doi-asserted-by":"publisher","DOI":"10.1097\/01.coc.0000037108.86294.5E"},{"key":"e_1_2_7_3_1","doi-asserted-by":"publisher","DOI":"10.1093\/annonc\/mdq308"},{"key":"e_1_2_7_4_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-0560.2008.01115.x"},{"key":"e_1_2_7_5_1","doi-asserted-by":"publisher","DOI":"10.1007\/s12288-014-0447-4"},{"key":"e_1_2_7_6_1","doi-asserted-by":"publisher","DOI":"10.1002\/dc.20616"},{"key":"e_1_2_7_7_1","doi-asserted-by":"publisher","DOI":"10.1002\/dc.23127"},{"key":"e_1_2_7_8_1","doi-asserted-by":"publisher","DOI":"10.3390\/curroncol32100550"},{"key":"e_1_2_7_9_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00277-019-03784-x"},{"key":"e_1_2_7_10_1","doi-asserted-by":"publisher","DOI":"10.1309\/617DWB5GNFWXHW4L"},{"key":"e_1_2_7_11_1","doi-asserted-by":"publisher","DOI":"10.1080\/2162402X.2018.1426517"},{"key":"e_1_2_7_12_1","doi-asserted-by":"publisher","DOI":"10.4103\/1742-6413.70966"}],"container-title":["Diagnostic 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