Lung carcinoids. Tumor angiogenesis in relation to clinicopathologic characteristics

To evaluate the prognostic value of carcinoid angiogenesis for the presence of lymph node metastases, histologic subtype and tumor size.

The study group consisted of 72 resected primary lung carcinoids, 57 typical and 15 atypical. TNM staging was performed. The histologic criteria for carcinoids was based on the Flieder classification. Angiogenesis, expressed as tumor microvessel density, was estimated in sections stained with CD34 antibody, according to Weidner's method.

The size of carcinoids was related to the histologic type: the average tumor diameter of typical carcinoids was significantly smaller than the average diameter of atypical carcinoids (P = .003, U = 207, Z = -3.023). Atypical carcinoids represented a more aggressive form of tumors than typical carcinoids; patients with typical carcinoids developed lymph node metastases less frequently (10% vs. 33%) as compared to patients with atypical carcinoids; the difference was statistically significant (P = .032). Tumor angiogenesis failed to distinguish the histologic type of carcinoids and did not indicate the presence or absence of regional lymph node metastases; neither did pTN stage or tumor size.

Angiogenesis is not a determining factor of the metastatic potential of pulmonary carcinoids.