A. Evrard et al., POSITIVE SOMATOSTATIN RECEPTOR SCINTIGRAP HY IN A CASE OF GONADOTROPIN-SECRETING ADENOMA - LACK OF RELATIONSHIP WITH THERAPEUTIC EFFECT, Annales d'Endocrinologie, 57(3), 1996, pp. 209-214
Somatotropin and thyrotropin-secreting adenomas are well known for pos
itive uptake of radio-labeled octreotide in vivo. this fact is not SO
well assessed for gonadotropin-secreting adenomas (GSA). We report one
case of positive somatostatin receptor scintigraphy in a woman suffer
ing from histologically proven GSA. This 63 year old patient has been
suffering for two years of akinetic syndrome when the outcome of diplo
pia led to the discovery of a large hypophyseal tumor spreading till V
3 floor and in left cavernous sinus by resonance magnetic imaging (RMI
). Clinical examination showed anterior hypopituitarism and bitemporal
hemianopsia. Biologically, blood gonadotropins were decreased more on
LH (0,6 UI/l, N > 15) than on FSH (10 UI/1; N > 20). A lack of respon
se of gonado-tropins to LHRH with low blood estradiol concentration (<
10 pg/ml) was noticed. Basal blood measurement of alpha subunit was a
t 0.17 mu g/l (N = 0.10-1.6) and increased at 0.39 mu g/l after stimul
ation by LNRH. Although in low range of normal values, other,hypophyse
al hormones were normal except prolactinemia (45 mg/L; N < 20), howeve
r stimulated by TRH and related to dopaminergic deconnection; Indium I
II labeled octreotide scintigraphy showed an over uptake of the tumor.
Three month treatment by octreotide (100 mu g x 3/day subcutaneously)
did not allow to decrease significantly FSH concentration or to reduc
e the tumoral mass. Incomplete removal of the tumor was performed by t
ransphenoidal route. Immunohistochemical analysis revealed positive im
munostaining for alpha subunit and FSH beta on numerous cells while th
e labeling was slightly less strong for LH beta. These data evoked a G
SA. This case record depicts the possibility of detection of GSA by so
matostatin receptor imaging. However a positive result does not preclu
de of somatostatin analog therapeutic efficiency.