Page 121 - Atlas of Small Animal CT and MRI

Lymph Nodes 111

Figure 1.8.8 Regional Lymph Node Metastasis (Canine) CT

(a) CT+C, TP (b) CT+C, TP
8y MC Labrador Retriever with previously excised right tonsillar squamous‐cell carcinoma. Representative CT images are at the level of
the medial retropharyngeal lymph nodes and are ordered from rostral to caudal. The left medial retropharyngeal lymph node (a: arrow)
is normal in size, shape, and contrast enhancement. The central linear filling defect represents the normal fat‐filled lymph node hilus. The
right medial retropharyngeal lymph node is markedly enlarged and has irregular margins (b: arrow). Multiple parenchymal contrast filling
defects are characteristic of lymph node metastatic deposits. Aspiration cytology of the right medial retropharyngeal node confirmed
metastatic squamous cell carcinoma.

Figure 1.8.9 Regional Lymph Node Metastasis (Canine) CT

7y MC Springer Spaniel cross with previously
excised right tonsillar squamous cell carci-
noma. Representative unenhanced (a,b) and
contrast‐enhanced (c,d) images are at the
level of the medial retropharyngeal lymph
nodes and are ordered from rostral to caudal.
The right medial retropharyngeal lymph node
(a–d: arrow) is markedly enlarged and irregu-
larly shaped, has mildly indistinct margins,
and nonuniformly contrast enhances. Filling
defects, most clearly seen in (d), are indica-
(a) CT, TP (b) CT, TP
tive of nodal metastasis. By comparison, the
left medial retropharyngeal node (a,c: arrow-
head) is normal in size, shape, and contrast
enhancement characteristics. Aspiration
cytology of the right medial retropharyngeal
node confirmed metastasis of the tonsillar
squamous cell carcinoma as well as moder-
ate plasmacytic and lymphocytic reactivity.

(c) CT+C, TP (d) CT+C, TP

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