Pituitary Adenoma Causing Acromegaly

June 4, 2013
Amar Udare, MBBS

Clinical History: A 34-year-old male presented to the outpatient department with the chief complaints of gradual enlargement of the hands and feet. On examination there was enlargement of hands and feet, and coarse features with broad nose, frontal bossing and protruding jaw line.

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Figure 1. Radiograph of the hand showing generalised increased soft tissue, broadened phalangeal tufts, minimal widening of the metacarpal spaces and few carpal cysts. The base of the terminal phalnges appears more broad giving the appearance of a spade like deformity.The laboratory results showed an increase in the growth hormone.

A skeletal survey was hence ordered. Radiograph of the foot showed increased in the heel pad thickness.

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Figure 2. Radiograph of the foot, lateral view, shows increase in the heel pad thickness.

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Figure 3. Radiograph of the skull (lateral and frontal views) shows thickening of the cranial vault, enlarged frontal sinus, prominence of the occipital protuberance, prominent supra-orbital ridge, widened space between the upper incisors and an enlarged mandible.

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Figure 4. Lateral radiograph of the skull depicting the increased size of the sella turcica.

Diagnosis: A provisional diagnosis of a pituitary adenoma causing acromegaly was made which was further confirmed on MRI examination. The tumor was later resected via the transphenoidal route.

Discussion: Acromegaly is a disorder caused due to the overproduction of growth hormone after fusion of the epiphyses, i.e. after skeletal maturity. It is most commonly due to a GH-secreting adenoma in the anterior pituitary gland. Owing to the increased production of growth hormone there is marked connective tissue hyperplasia resulting in soft tissue swelling leading to increased heel pad thickness, increased shoe or glove size, ring tightening, characteristic coarse facial features, and a large fleshy nose. The onset is insidious and on examination there is frontal bossing, increased hand and foot size, mandibular enlargement with prognathism due to acral bony overgrowth.

The earliest manifestations include enlargement of hands and feet and coarsened facial features. On a plain radiograph the features include thickening of the cranial vault, widening of the sella turcica, increased n the size of the paranasal sinuses and hyperpneumatisation of the mastoid and overgrowth of the mandible. In the hand the changes include enlargement of the base of the distal phalanges and spur like projections from the tuft leading to a spade like appearance. Also due to cartilage overgrowth there is widening of the joint spaces on the metacarpophalangeal joints. The heel pad thickness which is the distance from the posteroinferior surface of the calcaneum to the nearest skin surface serves an important aid for diagnosis. The criteria used for an increased heel pad thickness includes: For a 150-pound subject, the heel-pad thickness should not exceed 22 mm and for every 25 pounds add 1mm to the cut-off limit.

Once the diagnosis is confirmed by laboratory results and MRI examination, surgical resection is the primary modality of treatment. Somatisation analogues can be used for preoperative shrinkage of the tumor. The morbidity and mortality is attributed to cardiorespiratory and cerebrovascular disease.

Amar Udare, MD
Radiodiagnosis, Tata Memorial Hospital
Mumbai, India

References:

  • Shlomo Melmed, J. Larry Jameson. . In: DL Long, AS Fauci, DL Kasper, SL Hauser, JL Jameson, J Loscaizo, eds. Harrison’s Principles of Internal Medicine, 18e. http://www.accessmedicine.com. Accessed on 10/09/2012;Chapter 339
  • Greenspan A. Orthopedic imaging, a practical approach. Lippincott Williams & Wilkins. (2004) ISBN:0781750067
  • Nwaneri E, Lieberman G .Radiologic Features of Acromegaly [Internet]. Gillian Lieberman, MD ;2003 [cited 2012 Sep 10].Available from http://eradiology.bidmc.harvard.edu/LearningLab/musculo.html