{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:16:04Z","timestamp":1787030164450,"version":"build-2736575974"},"reference-count":22,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2022,1,11]],"date-time":"2022-01-11T00:00:00Z","timestamp":1641859200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"MY LAV s.r.l.u","award":["-"],"award-info":[{"award-number":["-"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Veterinary Sciences"],"abstract":"<jats:p>Cutaneous lymphocytosis (CL) is an uncommon and controversial lymphoproliferative disorder described in dogs and cats. CL is generally characterized by a heterogeneous clinical presentation and histological features that may overlap with epitheliotropic lymphoma. Therefore, its neoplastic or reactive nature is still debated. Here, we describe clinicopathological, immunohistochemical, and clonality features of a retrospective case series of 19 cats and 10 dogs with lesions histologically compatible with CL. In both species, alopecia, erythema, and scales were the most frequent clinical signs. Histologically, a dermal infiltrate of small to medium-sized lymphocytes, occasionally extending to the subcutis, was always identified. Conversely, when present, epitheliotropism was generally mild. In cats, the infiltrate was consistently CD3+; in dogs, a mixture of CD3+ and CD20+ lymphocytes was observed only in 4 cases. The infiltrate was polyclonal in all cats, while BCR and TCR clonal rearrangements were identified in dogs. Overall, cats had a long-term survival (median overall survival = 1080 days) regardless of the treatment received, while dogs showed a shorter and variable clinical course, with no evident associations with clinicopathological features. In conclusion, our results support a reactive nature of the disease in cats, associated with prolonged survival; despite a similar histological picture, canine CL is associated with a more heterogeneous lymphocytic infiltrate, clonality results, and response to treatment, implying a more challenging discrimination between CL and CEL in this species. A complete diagnostic workup and detailed follow-up information on a higher number of cases is warrant for dogs.<\/jats:p>","DOI":"10.3390\/vetsci9010026","type":"journal-article","created":{"date-parts":[[2022,1,11]],"date-time":"2022-01-11T20:33:04Z","timestamp":1641933184000},"page":"26","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Feline and Canine Cutaneous Lymphocytosis: Reactive Process or Indolent Neoplastic Disease?"],"prefix":"10.3390","volume":"9","author":[{"given":"Francesco","family":"Albanese","sequence":"first","affiliation":[{"name":"Laboratorio MYLAV, 20017 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4414-4359","authenticated-orcid":false,"given":"Francesca","family":"Abramo","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, University of Pisa, 56124 Pisa, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4651-6128","authenticated-orcid":false,"given":"Michele","family":"Marino","sequence":"additional","affiliation":[{"name":"Laboratorio MYLAV, 20017 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria","family":"Massaro","sequence":"additional","affiliation":[{"name":"Laboratorio MYLAV, 20017 Milan, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Laura","family":"Marconato","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell\u2019Emilia, 40064 Bologna, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucia","family":"Minoli","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, University of Turin, 10095 Turin, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9882-2867","authenticated-orcid":false,"given":"Valeria","family":"Martini","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, University of Milan, 26900 Lodi, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7893-1740","authenticated-orcid":false,"given":"Luca","family":"Aresu","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, University of Turin, 10095 Turin, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,11]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"877","DOI":"10.1016\/S0190-9622(98)70154-9","article-title":"Cutaneous pseudolymphomas","volume":"38","author":"Ploysangam","year":"1998","journal-title":"J. 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