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A rare cause of acromegaly: short review of McCune Albright syndrome/Akromegalinin nadir bir sebebi: McCune Albright sendromu icin kisa literatur ozeti.

Introduction

The original description of McCune-Albright syndrome (MAS) included diffuse fibrous dysplasia, cafe-au-lait macules, and precocious puberty (1,2). More recent studies report that polyostotic fibrous dysplasia and cafe-au-lait macules are invariably present, while monostotic lesions are less common (3). Forms of endocrine hyperfunction reported in association with MAS include precocious puberty, hyperthyroidism, hypercortisolism, hypersomatotropism, and hypophosphatemic rickets (1-3). Hypersomatotropism associated with MAS is rare, and pituitary adenoma is demonstrable in 40% to 50% of these patients (3,4).

Prior to 2002, 51 cases of MAS with acromegaly were reported in English literature (3-5). Since that time, there have been 21 publications regarding MAS in association with acromegaly. Because of the paucity of published information about this association, we report a case of MAS associated with pituitary macroadenoma, resulting in acromegaly.

Case Report

A 34-year-old man with a 20-year history of McCune Albright syndrome presented to the endocrinology department because of increasing multiple hard swellings over his legs and difficulty walking. He had a history of pathologic fractures of the humerus, femur, tibia, and fibula between 4 and 18 years of age. The diagnosis of polyostotic fibrous dysplasia had been established by radiologic and physical examinations.

On examination, there were numerous lumps, on the extremities and one on the right side of his forehead. Brown pigmented macules with irregular borders were present on his back and sides. He had facial asymmetry with coarse features and acral enlargement with excessive sweating. He had difficulty walking and was able to walk only with the aid of a crutch. He had no history of precocious puberty.

When he was 18 years of age, he was diagnosed with a pituitary microadenoma causing acromegaly (acral enlargement, coarse and asymmetrical facial features). The pituitary macroadenoma was diagnosed by a combination of abnormal hormone levels (growth hormone [GH]: 81.13 ng/mL [0.06-1] and insulin-like growth factor-1 [IGF-1]: 1280 ng/mL [182-680]) and by pituitary magnetic resonance imaging (MRI) (3 cmx1.4 cm pituitary tumor). Pituitary surgery was not performed because of extensive skull involvement caused by the fibrous dysplasia. In our investigation, biochemical values and complete blood count (CBC) were in the normal levels. Radiographs of skull showed radiodense lesions in frontoparietal bone and base of the skull. Pituitary MRI revealed a pituitary macroadenoma (30x14 mm) with suprasellar extension and ground-glass appearance (Fig. 1).

After an external irradiation treatment, long-acting octreotide (Sandostatin LAR 30 mg per 28 day) was started in 2002. He received this therapy for approximately 7 years, and his last IGF-1 level while taking this medication was 330 ng/mL (100-494); during glucose-GH suppression test, GH was suppressed to 10.3 ng/mL (0.06-1). Other hormonal results of patient were in table 1 on admision to hospital. Despite receiving the maximum recommended dose (40 mg) of octreotide LAR for 7 years, we could not achieve ideal metabolic control, so we changed the treatment regimen to 120 mg lanreotide per monthly with cabergoline 0.5 mg twice weekly. After 6 months of this treatment, IGF-1 level was 280 ng/mL and morning GH level was 5.8 ng/mL. GH was suppressed to 3.7 ng/mL during GH-glucose suppression test. These levels represented an improvement from those seen during his previous treatment regimen.

[FIGURE 1 OMITTED]

Discussion

MAS is a rare syndrome, diagnosed by the presence of at least two of three following lesions: poly/monostotic fibrous dysplasia, cutaneous pigmented macules, and hypersecretory endocrinopathies (1,2). Our patient has had polystotic fibrous dysplasia (skull, maxilla, long bones), cafe-au-lait macules, and hypersecretory endocrinopathy (acromegaly). In our review of the literature, eight of the reported patients had cafe-au-lait macules, only four of them had monostotic lesions. Fibrodysplasia at the base of the skull is seen in almost all patients with MAS, as is our patient. The course of dysplastic bone disease is independent of time of onset and degree of disease activity (3). Our patient's difficulty walking resulted in inability to perform his daily activities. Chanson et al. reported that in patients with MAS and acromegaly, 34% had precocious puberty, 11% had thyrotoxicosis, and 3% had hypercortisolism (3). No endocrine organ except acromegaly was involved in our patient. Only one patient has been reported to have MAS with acromegaly and hyperthyroidism caused by somatothyrotropinoma (6). GH hypersecretion in MAS differs in several aspects from that observed in classical acromegaly.

MAS patients are generally young (<20 years; our patient was 18 years old) at the onset and diagnosed on the basis of growth acceleration rather than facial dysmorphism (often difficult to assess, as in our patient, because of fibrous dysplasia) (3,4). Only half the patients with acromegaly associated with MAS exhibit radiological evidence of pituitary adenoma, compared with 80% to 90% in classical acromegaly (4). Our patient had a sellar mass with suprasellar extension; this was reported in 3 of 17 (17%) patients in the series of Cuttler et al. (7) and 4 of 12 (33%) 12 in the report of Akintoye et al. (5).

Pituitary surgery in this syndrome is difficult because of problems related to fibrous dysplasia and the resultant thickening of bones (3,4,8,9). Occasional instances of sarcomatous transformation of fibrous dysplastic bones have been reported with radiation therapy (10,11), but radiotherapy may be an option for treatment of acromegaly in patients who have MAS when surgery is impossible and somatostatin analog therapy is ineffective (12). Although no sarcomatous transformation was found within the radiation field in our patient, this risk must be considered. Bromocriptine, cabergoline, and long-acting somatostatin analogs have been used with some success in acromegaly associated with MAS (3,4,9). Our patient received external irradiation treatment and long-acting octreotide therapy (Sandostatin LAR). With this treatment, serum growth hormone and serum IGF-1 levels decreased markedly but not to normal range.

GH excess affects approximately 20% of the patients with MAS, which is caused by sporadic, postzygotic, activating mutations in the GNAS gene that codes for the cAMP-regulating protein, G(s) alpha (gsp oncogene). Akintoye et al. examined efficacy of the GH receptor antagonist pegvisomant, to control gsp oncogene-mediated GH excess and skeletal disease (fibrous dysplasia of bone) associated with MAS. Pegvisomant effectively reduces IGF-1 and IGFBP-3 levels in gsp-mediated GH excess but has no effect on fibrous dysplasia. In severely affected patients, pegvisomant therapy may thus be useful to normalize IGF-1 levels rapidly (12,13). We did not use pegvisomant in our patient, because pegvisomant effectively reduced IGF-1 levels but had no effect on fibrous dysplasia.

As conclusion, we presented this case due to multiple bone involvement of fibrous dysplasia accompanying with acromegaly alone as an endocrinopathy. These severe bone deformities affected the social life of our patient. Although the treatment choice of a large pituitary mass is surgery, surgeons chose not to operate because of the bony involvement of the skull. Nonsurgical treatment choices are somatostatin analogs, radiotherapy, and cabergoline at maximum doses.

Recevied: 08.03.2009 Accepted: 12.04.2009

References

(1.) McCune DJ. Osteitis fibrosa cystica: the case of nine year old girl who also exhibits precocious puberty, multiple pigmentation of the skin and hyperthyroidizm. Am J Dis Child 1935; 52: 743-7.

(2.) Albright F, Butler AM, Hampton AO, Smith P. Syndrome characterized by osteitis fibrosa disseminata, areas of pigmentation and endocrine dysfunction, with precocious puberty in females: reports of five cases. N Engl J Med 1937; 216: 727-46.

(3.) Chanson P, Dib A, Visot A, Derome PJ. McCune-Albright syndrome and acromegaly: clinical studies and response to treatment in five cases. Eur J Endocrinol 1994; 131: 229-34.

(4.) Premawardhana LD, Vora JP, Mills R, Scanlon MF. Acromegaly and its treatment in the Mc Cune Albright Syndrome. Clin Endocrinol 1992; 36: 605-8.

(5.) Akintoye SO, Chebli C, Booher S, Feuillan P, Kushner H, Leroith D, Cherman N, Bianco P, Wientroub S, Robey PG, Collins MT. Characterization of gsp-mediated growth hormone excess in the context of McCune Albright syndrome. J Clin Endocrinol Metab 2002; 87: 5104-12.

(6.) Gessl A, Freissmuth M, Czech T, Matula C, Hainfellner JA, Buchfelder M, Vierhapper H. Growth hormone-prolactin-thyrotropin secreting pituitary adenoma in atypical McCune Albright Syndrome with functionally normal Gs alpha protein. J Clin Endocrinol Metab 1994; 79: 1128-34.

(7.) Cuttler L, Jackson JK, Uz-Zafar MS, Levitski LL, Mellinger RC, Frohman LA. Hypersecretion of growth hormone and prolactin in McCune-Albright syndrome. J Clin Endocrinol Metab 1998; 68: 1148-54.

(8.) Geffner ME, Nagel RA, Dietrich RB, Kaplan SA. Treatment of acromegaly with a somatostatin analog in a patient with McCune Albright syndrome. J Pediatr 1987; 111: 740-3.

(9.) Cremonini N, Graziano E, Chiarini V, Sforza A, Zampa GA. Atypical McCune-Albright syndrome associated with growth hormone-prolactin secreting pituitary adenoma: natural history, long-term follow-up, and SMS 201-995-bromocriptine combined treatment results. J Clin Endocrinol Metab 1992; 75: 1166-9.

(10.) Present D, Bertoni F, Enneking WF. Osteosarcoma of the mandible arising in fibrous dysplasia. Clin Orthop Relat Res 1986; 204: 238-44.

(11.) Mortensen A, Bojsen-Moller M, Rasmussen P. Fibrous dysplasia of the skull with acromegaly and sarcomatous transformation. J Neurooncol 1989; 7: 25-9.

(12.) Galland F, Kamenicky P, Affres H, Reznik Y, Pontvert D, Le Bouc Y, Young J. McCune-Albright syndrome and acromegaly: effects of hypothalamo-pituitary radiotherapy and/or pegvisomant in somatostatin analog-resistant patients. J Clin Endocrinol Metab 2006; 26: 4957-61.

(13.) Akintoye SO, Kelly MH, Brillante B, Cherman N, Turner S, Butman JA, Robey PG, Collins MT. Pegvisomant fort he treatment of gsp-mediated growth hormone excess in patient with McCune-Albright syndrome. J Clin Endocrinol Metab 2006; 91: 2960-6.

Yusuf Aydin, Dilek Berker, Sercan Bulut *, Yasemin Ates Tutuncu, Serhat Isik, Ihsan Ustun, Tuncay Delibasi, Serdar Guler

Ankara Numune Research and Training Hospital, Endocrinology and Metabolism Clinic, Ankara, Turkey

* Ankara Numune Research and Training Hospital, Department of Family Medicine, Ankara, Turkey

Address for Correspondence: Yusuf Aydin, MD, Pinarbasi mah, Afacan sk. no: 6/9 Kecioren, Ankara, Turkey Phone: +90 505 484 84 65 Fax: +90 312 381 20 89 E-mail: dryusufaydin@yahoo.com
Table l. Hormonal status of patient at the time of admission to
hospital

 Patient's Normal
 results range

Growth hormone (ng/mL) 9.93 0.06-1
Prolactin (ng/mL) 16.4 2.5-18.1
TSH ([micrp]IU/mL) 1.09 0.35-4.2
sT4 (ng/dL) 0.85 0.7-1.48
IGF-1 (insulin-like growth 330 100-494
 factor-1) (ng/mL)
Cortisol ([micro]g/dL) 12.9 8.7-22.4
25-OH vitamin D (mmol/L) 11.4 10-60
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Article Details
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Title Annotation:/Olgu Sunumu
Author:Aydin, Yusuf; Berker, Dilek; Bulut, Sercan; Tutuncu, Yasemin Ates; Isik, Serhat; Ustun, Ihsan; Delib
Publication:Turkish Journal of Endocrinology and Metabolism
Article Type:Case study
Geographic Code:7TURK
Date:Mar 1, 2009
Words:1724
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