A review of reported cases suggests that leptomeningeal implantation may be an important step in metastases of craniopharyngioma, although the mechanism is poorly understood. Attention to tumor spillage at the time of surgery may be important in preventing distant recurrences.

A previously healthy 16-year-old female with no family history of neuromuscular disorders presented with a seven year history of hand incoordination. On examination, she had wasting of the intrinsic hand muscles bilaterally, right worse than left. There was no sensory loss, muscle cramping, or pain. Magnetic resonance imaging (MRI) of the cervical spine did not reveal any abnormal findings. Nerve conduction studies identified moderate slowing of the conduction velocity in the right ulnar nerve.One year later, the patient's complaint of hand incoordination continued. Repeat nerve conduction studies revealed conduction blocks in both median nerves in addition to the previously noted decreased conduction velocity in the right ulnar nerve. Followup cervical spine MRI was performed (Figures 1, 2).Magnetic resonance imaging in the neutral position demonstrated subjectively decreased volume and subtly increased T2 hyperintensity in the anterocentral portion of the cervical spinal cord from C5-7 (Figures 1, 2 DISCUSSIONHirayama disease (HD) was first reported in Japan by Dr. K. Hirayama in 1959 and initially labeled "juvenile muscular atrophy of a unilateral (later distal) upper extremity." 1 Hirayama disease is sporadic juvenile muscular atrophy of the distal upper extremities, which predominantly affects young men between 15 and 25 years-of-age. Hirayama disease is characterized by insidious onset of unilateral muscular atrophy and weakness of the hand and forearm, in the absence of sensory or pyramidal signs. Bilateral presentation, though less common, is also known to occur. 2 The clinical course is initially progressive for six to nine years, followed by spontaneous stabilization by the middle of the third decade.1 This disease has had a number of other names some of which include brachial monomelic amyotrophy, benign focal atrophy, benign focal amyotrophy, Sobue's disease, and juvenile segmental muscular atrophy.

Limiting unnecessary occupational radiation exposure is a critical issue in radiology. There was a statistically and clinically significant association between radiation safety education and the decreased number of adult fingers seen on PICU chest radiographs. This study provides preliminary evidence in favour of the benefit of radiation safety seminars.