A Case of Fibrous Dysplasia (McCune Albright Syndrome) Associated with Acromegaly

Abstract

We report a case of a 47-year-old woman with McCune-Albright syndrome associated with unusual growth-hormone and prolactin hypersecretion. Acromegaly was suspected on clinical examination, and she was referred to us. She had no history of precocious puberty or pathological fracture. She was 154cm tall, weighing 62kg with so-called acromegalic facies. There were two lumps, one of which was on her right lateral forehead. The other on the right lower extremity seemed to be due to a bone deformity. Some brown pigmented macules with irregular borders were present on her lips and oral mucosa. Endocrine examination revealed elevated basal levels of plasma GH (54ng/ml) and PRL (36.2ng/ml), which paradoxically increased after injection of TRH. Plasma levels of these hormones did not change after LHRH test, and plasma GH level increased after GHRH test. A skull X-ray film showed a double floor of the sella turcia and hyperostotic formation of the right sphenoid bone. MRI and CT showed a tumor shadow in the right sella turcica. Bone roentogenography of the right fibula and tibia showed a large centrally expanding lesion with a ground-glass or cystic appearance and a thin cortex. The left fibula showed a similar lesion. We recognized similar findings in other bones which also showed abnormal accumulation in a radionuclide bone scan with 99mTc. On the basis of physical, endocrinological and roentogenographical examination, we diagnosed her as displaying McCune-Albright syndrome. We operated on her by transsphenoidal surgery and confirmed a functioning chromophobe adenoma which was removed during surgery. She has been free of GH and PRL hypersecretion since then. The pathology of the sphenoidal sinus affected with fibrous bone was in accordance with the findings of fibrous dysplasia. McCune-Albright syndrome (MCAS) is known as a syndrome characterized by polyostotic fibrous dysplasia and cutaneous pigmentation and multiple endocrinopathy. Its etiology is unknown. This syndrome with acromegaly is rare, and although 26 cases have been described in literature, pathological examinations have been undertaken in only three cases. This case was very rare and valuable because, by operating on her by the transsphenoidal route in spite of the sphenoidal sinus being affected with fibrous bone, we were able to confirm a chromophobe adenoma secreting both GH and PRL. We recognized that acromegaly with MCAS was endocrinologically, morphologically and immunohistologically the same as acromegaly without MCAS. Therefore, we concluded that acromegaly with MCAS is much the same as acromegaly without MCAS.