Albanese Francesco, Abramo Francesca, Marino Michele, Massaro Maria, Marconato Laura, Minoli Lucia, Martini Valeria, Aresu Luca
Laboratorio MYLAV, 20017 Milan, Italy.
Department of Veterinary Sciences, University of Pisa, 56124 Pisa, Italy.
Vet Sci. 2022 Jan 11;9(1):26. doi: 10.3390/vetsci9010026.
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.
皮肤淋巴细胞增多症（CL）是一种在犬猫中描述的罕见且存在争议的淋巴增殖性疾病。CL的一般特征是临床表现异质性和组织学特征可能与亲上皮性淋巴瘤重叠。因此，其肿瘤性或反应性本质仍存在争议。在此，我们描述了19只猫和10只狗的回顾性病例系列的临床病理、免疫组化和克隆性特征，这些动物的病变在组织学上与CL相符。在这两个物种中，脱毛、红斑和鳞屑是最常见的临床症状。组织学上，总是能发现真皮内有小到中等大小淋巴细胞浸润，偶尔延伸至皮下组织。相反，当出现亲上皮性时，通常较轻。在猫中，浸润细胞始终为CD3阳性；在狗中，仅在4例中观察到CD3阳性和CD20阳性淋巴细胞的混合。所有猫的浸润均为多克隆性，而在狗中鉴定出BCR和TCR克隆重排。总体而言，无论接受何种治疗，猫的长期生存率（中位总生存期 = 1080天），而狗的临床病程较短且多变，与临床病理特征无明显关联。总之，我们的结果支持猫的这种疾病具有反应性本质，且生存期延长；尽管组织学表现相似，但犬CL与更异质性的淋巴细胞浸润、克隆性结果及对治疗的反应相关，这意味着在该物种中区分CL和CEL更具挑战性。对于狗，需要对更多病例进行完整的诊断检查和详细的随访信息。
