[Satellite cells in pulmonary carcinoid tumorlets and carcinoids]

Pulmonary tissue of twenty-four patients with carcinoid tumorlets and twenty-three typical carcinoid tumors was studied immunohistochemically for stellate-shaped S-100 protein positive (sustentacular) cells. Sustentacular cells (SCs) have been calculated per 10,000 tumorlet or carcinoid elements. The presence of SCs was proved in 18 subjects (75%) of all examined tumorlet cases with quantitative frequency between 13 and 196 SCs per 10,000 tumorlet cells. These elements were also found in 18 carcinoid tumors (79%) of all 23 investigated cases with quantitative frequency between 5 and 927 SCs per 10,000 carcinoid cells. The cluster analysis showed two separate clusters in both groups of lesions with strikingly high frequency of SCs, i.e., from 66 up to 196 SCs/10,000 tumorlet elements and from 138 up to 923 CSs/10.000 carcinoid cells, respectively. SCs may not be used as an indicator of biological behaviour of pulmonary neuroendocrine tumors for their a broad frequency spectrum in examined benign lesions, i.e. tumorlets and typical carcinoid tumors.