To the Editor: The medical mystery in the July 1 issue1 involved50-year-old identical twins (Figure 1A). The patient is thetwin on the left side of the photograph. He has acromegaly causedby a growth hormone–hypersecreting pituitary macroadenoma.He presented with visual-field impairment, and magnetic resonanceimaging showed a pituitary macroadenoma with extrasellar extension(Figure 1B shows a coronal section, and Figure 1C a sagittalsection). A few months earlier, obstructive sleep apnea hadbeen diagnosed. The history also included headache, enlargementof the feet, increased sweating, and joint stiffness. The patient'sserum insulin-like growth factor level was elevated, at 56.5nmol per liter (mean for age, 17.0 nmol per liter), and an oralglucose-tolerance test showed a failure to suppress growth hormone(5 mU per liter; normal value, <2 mU per liter).
Panel A shows the identical twins; the twin on the left has acromegaly caused by a growth hormone–hypersecreting pituitary macroadenoma. Panel B shows a coronal section and Panel C a sagittal section of the macroadenoma on magnetic resonance imaging.
The patient's coarse facial features were evident in comparisonwith the facial features of his identical twin. The acral enlargement(nose and lips) and enlargement of the facial soft tissue (skinfolds and infraorbital puffiness) are striking. Few patientswith acromegaly seek care owing to the very slow progression.The patient underwent transsphenoidal surgery, with visual-fieldimprovement. Complete relief from symptoms was not attained,and treatment with a somatostatin analogue was started, whichreduced the patient's headache, fatigue, and sweating.
Willy-Anne Nieuwlaat, M.D. Gerlach Pieters, M.D., Ph.D. University Medical Center Sint Radboud 6500 HB Nijmegen, the Netherlands
Editor's note: We received 2655 responses to this medical mystery:57 percent from physicians in practice, 19 percent from physiciansin training, 12 percent from medical students, and 12 percentfrom other readers. Responses were received from 86 countries.Sixty-four percent of respondents correctly diagnosed acromegalyin the twin in the white shirt; 23 percent suggested other endocrinopathiessuch as hypothyroidism, Hashimoto's thyroiditis, and Cushing'ssyndrome. Other, less common diagnoses included Paget's disease,the superior vena cava syndrome, lung cancer, chronic obstructivepulmonary disease, chronic renal failure, nephrosis, amyloidosis,Dilantin (phenytoin) toxicity, leprosy, scleroderma, myotonicdystrophy, Parkinson's disease, and hemochromatosis. Two percentof respondents suggested that the twin in the red shirt hadBell's palsy — he did not.
References
Nieuwlaat W-A, Pieters G. A medical mystery -- which twin is the patient? N Engl J Med 2004;351:68-68. [Free Full Text]
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