Background:

Classification of growth hormone (GH) - secreting tumors by the granular pattern might predict their clinical behavior in acromegalic patients. There are several other prognostic factors.

Aim:

To compare the features at presentation and cure rates of patients with GH secreting tumors according to the granular pattern, and to define independent prognostic factors for surgical treatment in these patients.

Material and Methods:

A retrospective, observational study of 85 active acromegalic patients surgically treated in two medical centers.

Results:

Seventy-four patients (87%) were classified as having densely granulated (DG) and 11 (13%) as sparsely granulated (SG) tumors. The latter were less active biochemically, had a higher rate of macroadenoma and cavernous sinus invasion and had a lower rate of biochemical cure than the DG group. Several characteristics were associated with disease persistence but only age (Odds ratio (OR) = 0.93) and cavernous sinus invasion (OR = 21.7) were independently associated in the logistic regression model.

Conclusions:

The sparsely granulated pattern is associated with a more aggressive behavior, but the main determinants of prognosis are age and cavernous sinus invasion.