How does an imaging finding of additional separate tumor nodules affect the T classification in lung cancer staging?

Updated: Jan 28, 2019
  • Author: Omar Lababede, MD; Chief Editor: Eugene C Lin, MD  more...
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The presence of additional separate tumor nodule(s) renders the tumor's classification as T3 if the nodule is in the same lobe of the primary tumor, or as T4 if the nodule is in a different ipsilateral lobe. A separate tumor nodule in the contralateral lung is considered M1a. CT is the primary modality to evaluate for additional tumor nodules. The differential diagnosis of a separate nodule on CT should include benign entities and synchronous primary tumor in addition to metastasis from the primary lesion. Synchronous primary tumors, which should have different histologic cell types or subtypes, are not considered as T4 but are classified according to the highest the T designation of the lesions with a number of nodules in parentheses. PET CT can further suggest a malignant nature of an additional nodule by demonstrating increased fluorodeoxyglucose (FDG) uptake.

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