SUMMARYA 22-year-old man known to have β-thalassaemia intermedia since childhood presented with bilateral lower limb weakness after spinal anaesthesia for an elective minor operation of his left leg. MRI and CT scans were performed to rule out acute epidural haematoma; coincidental imaging features of marrow hyperplasia and spinal epidural extramedullary haematopoiesis were found. This article will present and discuss the imaging features, differential diagnosis, management and literature review of the rare occurrence of extramedullary haematopoiesis in the spinal epidural space. BACKGROUND

Denervation of muscle usually leads to muscle atrophy with fatty replacement but, uncommonly, also results in muscle hypertrophy or pseudohypertrophy with fatty replacement. We report the ultrasonographic and magnetic resonance imaging (MRI) findings of a patient with diffuse fatty infiltration of calf muscles as a result of denervation pseudohypertrophy. The elevated fasting glucose, neurogenic electromyographic changes, and muscle atrophy with adipose tissue infiltration are consistent with diabetic neuropathy as the cause of denervation pseudohypertrophy. Lumbosacral radiculopathy and plexopathy were excluded by MRI. The imaging features reported in the literature are reviewed. The important differential diagnosis of infiltrating lipoma and denervation hypertrophy, as well as other causes of monomelic hypertrophy or swelling, is discussed. This case report demonstrates the importance of MRI, with clinical, biochemical, electrophysiological, and histologic correlation in the diagnosis of denervation pseudohypertrophy. Correct diagnosis of denervation pseudohypertrophy has an important role in guiding further investigations and treatment of the disease and the underlying cause.