PMC3139134_01
Axial view from fused PET/CT study demonstrates an enlarged right jugulodigastric node with heterogeneous but overall increased FDG avidity with peak SUV of 7.3.
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A repeat PET/CT was performed for the purposes of radiotherapy planning and this study confirmed the presence of a 3 cm right neck level II lymph node with an SUV of 7.3, with central necrosis (Figure 1).
(a) Coronal FDG PET showing bilateral but asymmetric tonsillar FDG avidity. The patient had undergone diagnostic right tonsillectomy prior to this PET/CT study. However, peak SUV in the contralateral left palatine tonsil measured 8.7. (b) Axial CT showing pronounced left-sided tonsillar enlargement corresponding to the high FDG avidity.
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FDG-avidity was again noted bilaterally in the oropharynx, with the intact left tonsil showing a maximum SUV of 8.7 as compared to maximum SUV of 6.6 in the tonsillar bed on the right (Figure 2(a)). However, the left tonsil was noted to be unusually bulky and irregular on the CT portion of the imaging study (Figure 2(b)).
Coronal FDG-PET shows mild mediastinal and bilateral hilar FDG uptake, which is nonspecific but consistent with sarcoidosis.
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The PET/CT also demonstrated mild, symmetric FDG avidity in the mediastinal and hilar regions, which was considered more consistent with an inflammatory rather than neoplastic process, given the low FDG uptake (Figure 3).
(a) Hematoxylin and eosin stained section of the left tonsil showing invasive squamous cell carcinoma, magnification 100X (b) Immunohistochemical stain for p16 performed on a serial section, magnification 100X.
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While the appearance of the left tonsil was still normal on examination, pathologic analysis revealed extensive in situ and invasive squamous cell carcinoma (Figure 4(a)). Immunohistochemical staining for p16 was diffusely and strongly positive (Figure 4(b)).