Spinal epidural lipomatosis: a rare association of Cushing's disease

Abstract

Summary: Excess cortisol is associated with hypertrophy and redistribution of adipose tissue leading to central obesity which is classically seen in Cushing's syndrome. Abnormal accumulation of fatty tissue in the spinal canal is most commonly associated with chronic steroid therapy and rarely reported with endogenous Cushing's syndrome. Herein, we describe a case of spinal epidural lipomatosis (SEL) associated with Cushing's disease. A 17-year-old man was referred with lower limb weakness, weight gain, multiple stretch marks, back pain and loss of height. He had clinical and biochemical features of Cushing's syndrome. MRI and Inferior Petrosal Sinus Sampling (IPSS) confirmed a pituitary adenoma as the source. On day 1 post trans-sphenoidal adenectomy he developed spastic paraparesis with a sensory deficit to the level of T5. MRI spine showed increased fat deposition in the spinal canal from T2 to T9 consistent with a diagnosis of SEL. He was managed conservatively and made a good recovery following restoration of eucortisolism and a period of rehabilitation.

Learning points: SEL is a serious complication of glucocorticoid excess and should be considered in any patient presenting with new lower limb neurological symptoms associated with hypercortisolism. It is important to distinguish symptomatic SEL from cortisol-induced proximal myopathy by good history and clinical examination. MRI of the spine is the gold standard investigation for making a diagnosis of SEL. Restoration of eucortisolism can lead to resolution of fat accumulation and good neurological outcome.

Figure 1

MRI pituitary demonstrating a pituitary microadenoma (Red arrow).

Figure 2

Sagittal T1 weighted (A), Sagittal T2 weighted (B) and STIR (Short T1 Inversion Recovery) sequence (C) demonstrating excessive epidural lipomatosis, multiple vertebral fractures and compression of the thoracic spinal cord. (Red arrows).

Figure 3

One year follow-up MRI spine showing reduction of the excessive epidural fat and compression of the spinal cord. (A) Sagittal T2 weighted MRI showing sliver of brighter CSF signal between cord and bright fat signal. (B) Axial T2 at T6/7 showing thecal sac separation from cord with CSF more evident.