Seok Jin, Lee Sungin
Department of Veterinary Surgery, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea.
Front Vet Sci. 2024 Jul 26;11:1429094. doi: 10.3389/fvets.2024.1429094. eCollection 2024.
18F-fluorodeoxy-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is used with high sensitivity in human medicine for initial staging and treatment planning of cutaneous squamous cell carcinoma (SCC). To the best of our knowledge, 18F-FDG PET/computed tomography (CT) has not been used for canine cutaneous SCC with lymph node metastasis.
A 13 year-old spayed female Maltese had rapidly growing flank SCC, which had previously recurred twice. Radiography revealed no metastases. On PET/CT imaging, increased FDG uptake was observed not only in the flank but also in the left axillary lymph node and left inguinal lymph node (standardized uptake value max [SUVmax]: 8.602, 5.354, and 1.96, respectively). Despite the evidence of metastasis, palliative skin mass resection with a 3-cm margin and lymph node dissection were performed. Histopathological examination confirmed the presence of metastases in both lymph nodes.
18F-FDG PET/CT is valuable for the detection of metastatic tumors in various organs. Cutaneous SCC can accumulate 18F-FDG, making it detectable on PET/CT. In this dog with flank SCC, 18F-FDG-PET/CT showed high SUVmax values, indicating its potential for tumor assessment. In veterinary medicine, SUVmax values of 2.5-3.5 are commonly used to identify metastatic lymph nodes in other cancers. Therefore, the interpretation of an SUVmax of 1.96 in an inguinal lymph node for metastatic involvement may be uncertain. Owing to the partial volume effect, 18F-FDG PET/CT has limited sensitivity in identifying LN metastases, particularly in cases of small lesions. Lower SUVmax values adjusted for smaller sizes may better distinguish between benign and malignant lymph nodes. Hence, combining differentiated SUVmax cut-offs based on lymph node size with CT assessment could enhance lymph node evaluation and assist in surgical planning.
18F-氟脱氧-2-脱氧-D-葡萄糖（FDG）正电子发射断层扫描（PET）在人类医学中具有高灵敏度，用于皮肤鳞状细胞癌（SCC）的初始分期和治疗规划。据我们所知，18F-FDG PET/计算机断层扫描（CT）尚未用于患有淋巴结转移的犬皮肤SCC。
一只13岁已绝育的雌性马尔济斯犬患有快速生长的胁腹SCC，此前曾复发过两次。放射检查未发现转移。在PET/CT成像中，不仅在胁腹观察到FDG摄取增加，而且在左腋窝淋巴结和左腹股沟淋巴结也观察到FDG摄取增加（最大标准化摄取值[SUVmax]分别为8.602、5.354和1.96）。尽管有转移的证据，但仍进行了切缘为3厘米的姑息性皮肤肿块切除术和淋巴结清扫术。组织病理学检查证实两个淋巴结均存在转移。
18F-FDG PET/CT对于检测各器官的转移性肿瘤很有价值。皮肤SCC可积聚18F-FDG，使其在PET/CT上可被检测到。在这只患有胁腹SCC的犬中，18F-FDG-PET/CT显示出高SUVmax值，表明其在肿瘤评估方面的潜力。在兽医学中，SUVmax值2.5 - 3.5通常用于识别其他癌症中的转移性淋巴结。因此，对于腹股沟淋巴结SUVmax值为1.96的转移累及情况的解读可能不确定。由于部分容积效应，18F-FDG PET/CT在识别淋巴结转移方面的灵敏度有限，尤其是在小病变的情况下。针对较小尺寸调整后的较低SUVmax值可能更有助于区分良性和恶性淋巴结。因此，将基于淋巴结大小的差异化SUVmax临界值与CT评估相结合，可以增强淋巴结评估并辅助手术规划。
