Stage I Pleural Diffuse Malignant Mesothelioma AJCC v9

**Semantic type:** Neoplastic Process

**Definition:** Stage I includes: T1, N0, M0. cT1: Tumor limited to the ipsilateral parietal pleura with Psum 12 mm or less and no involvement of the fissure (Fmax 5 mm or less). Note: Psum: pmax1+pmax2+pmax3 (sum of 3 measurements of maximal pleural thickness measured on axial images along the chest wall or mediastinum in each of the three divisions of the chest - upper, middle and lower divided by two lines; one at the top of the aortic arch and the second drawn at the top of the left atrium). Fmax: maximal thickness of pleural tumor along the fissures measured on sagittal images. pT1: Tumor limited to the ipsilateral parietal pleura with no involvement of the fissure. N0: No tumor involvement of regional lymph node(s). M0: No distant metastasis. (AJCC 9th ed.)