Relationships among DNA Index, S-Phase, and invasive behavior in anterior pituitary adenomas. A cytometric study of 61 cases with Feulgen-positive DNA analysis.

BACKGROUND

Pituitary adenomas are usually well differentiated neoplasms, although in about 1/3 of cases they invade the surrounding dura mater and bone, as confirmed by surgical findings, resulting in a long-term possibility of relapse.

METHODS

To identify the cellular growth rate and to correlate it with surgical evidence of invasiveness, we performed the analysis of DNA with static cytometric quantitation on fresh surgical specimens, using a computer-assisted image processor. The DNA index and the percentage of cells in S-phase (%SPh) were obtained in 61 pituitary tumors consecutively operated on. In relation to surgically verified infiltration of dura and bone, we identified 39 noninvasive and 22 invasive adenomas. The cavernous sinus (CS) was infiltrated in 13 cases. On the basis of immunohistochemical staining and endocrine activity we recognized 27 nonsecreting and 34 secreting adenomas.

RESULTS

The DNA content was aneuploid in 33 cases (11 nonfunctioning, 22 functioning; p = 0.05); there was no correlation with the invasive behavior of the adenomas. The DNA index ranged between 0.93 and 2.50 (median 1.13); the range of %SPh was 0-12.00% (median 2.54%). In invasive adenomas the mean DNA index was 1.33 (p not significant) and the mean %SPh was 4.03% (p = 0.05). In CS-infiltrating pituitary adenomas, the mean DNA index was 1.44 (p = 0.04) and the mean %SPh was 4.52% (p = 0.05).

CONCLUSIONS

Our preliminary results seem to reveal a correlation between DNA index, %SPh, and invasive behavior of pituitary adenomas, encouraging the use of DNA analysis in the prognostic evaluation of these tumors.