A case of fugitive acromegaly, initially presented as invasive prolactinoma

Abstract

Fugitive acromegaly is most commonly caused by pituitary acidophil stem cell adenomas, and is characterized by a relatively short clinical history, a large and locally invasive tumor, and relatively low hormonal activity. Here, we report an unusual case of fugitive acromegaly that initially presented as invasive prolactinoma. A 48-year-old man with a huge pituitary mass extending to the suprasellar area was referred to our hospital in December 2007. He had undergone transsphenoidal surgery in November 1999 because of a large invasive prolactinoma. The tumor had grown progressively, despite therapy with dopamine agonists. Subtle features of acromegaly were noted and serum IGF-1 levels were high (733 ng/ml). An oral glucose tolerance test revealed that basal and nadir levels of growth hormone (GH) were 1.56 and 1 ng/ml, respectively. As a therapeutic trial, long-acting octreotide (20 mg IM, monthly) was added, and the tumor size markedly reduced within 6 months on magnetic resonance imaging examination. Immunohistochemical staining of the tumor tissue obtained at the surgery in 1999 showed positive staining for GH and prolactin (PRL). Double immunofluorescence staining showed a mixed positivity for GH and PRL in the majority of tumor cells; however, the two hormones colocalized in a minority of tumor cells, indicating that the tumor was composed of three different cell types (GH, PRL, and GH/PRL). The diagnosis of fugitive acromegaly was initially overlooked in this patient because of normal serum GH levels and a lack of acromegalic features, although histological evidence for GH production was present. IGF-1 determinations would be helpful for the diagnosis of fugitive acromegaly.

Pituitary Carcinoma: Difficult Diagnosis and Treatment

“…Given that the majority of PRL-secreting adenomas respond within 6 -9 months on doses typically less than 3 mg/wk, these patients usually eventually come to notice. Given the rarity of pituitary carcinoma, it is often a diagnosis of exclusion, and the possibility that cosecretion of an additional pituitary hormone (typically GH as in socalled fugitive acromegaly) may have been overlooked or actions of sex steroids to interfere with D2-agonist antitumor effects must first be considered (17,18). Additionally, if the patient has previously undergone pituitary tumor biopsy, repeated review of tumor histopathology may be instructive, including evaluation of specific proliferative markers (see Role of histopathology and molecular studies in diagnosing pituitary carcinoma), although one must be mindful that histopathology and resultant behavior may change in the course of time as illustrated where multiple tumor biopsies are examined in cases that transform from adenoma to carcinoma (19).…”

The relationship between serum levels of prolactin and growth hormone in the early postnatal period

“…Publications on the relationship between the secretion of PRL and hGH in different conditions are scant. Concomitant measurements of both hormones were performed in patients with acromegaly (17), prolactinomas (18), pituitary adenomas that secrete both hormones (19), Parkinson's disease (20), obesity (21), and Laron syndrome (22). Few studies report simultaneous measurements of these hormones in the postnatal period (23,24).…”