A 71-year-old man, former smoker, referred to the department of neurology from the department of vascular surgery with progressive pain in the right thigh. At time of referral, the pain has been present for at least 2 years, but the patient reports aggravation through the last 6 months, with pain (murmurs) in the thigh aggravated after 200–300 m walk, difficulty in maintaining balance and increased fatigue. The department of vascular surgery found an ankle blood pressure of 80/85 mm Hg (L/R) and an ankle-brachial index of 48/52% and intermittent claudication on the right leg that could, only partly, be related to arterial insufficiency. The patient had experienced problems passing urine for 2 years, and had been examined at the department of urology, where a rectal examination showed a prostate of normal size and texture. Sonography of the prostate was normal, with a slight hypertrophy (32 ml). PSA was 1.7. The patient had been examined urodynamically, including cystometry and because the pressure/flow examination showed no obstruction the patient was diagnosed with detrusor insufficiency (bladder atony). For this the patient performed intermittent self-catheterisation.
Physical examination upon admission at the department of neurology was unremarkable apart from difficulty in walking the line and decreased right-sided muscle strength for knee flexion (strength 4) and extension (5-) and foot plantar flexion (3) and extension (5-) in contrast to normal responses on the left. In the right leg, the proprioception and the sense of vibration were decreased from the ankle level, and the plantar response could not be elicited. Spinal stenosis was suspected, and CT showed slight spinal stenosis at L3–L4 without spinal root affection. Blood work, including haematological, biochemical and immunological tests were all normal, apart from a slightly elevated sedimentation rate (18 AU). Nerve conduction velocity test of the right tibial nerve showed no motor response and no sensory response from the right sural nerve. Electromyography (EMG) showed neurogenic changes with denervation in the right anterior muscle and mild neurogenic changes in the right medial vastus muscle. The neurophysiological examination pointed towards a right-sided sciatic neuropathy with possible involvement of the lumbosacral plexus. There were normal findings on the left side.
Within weeks, the patient reported intensifying of the pain which impaired walking. MRI of the lumbar-sacral plexus did not show relevant pathology. The patient strength had faded; knee flexion (strength 3) and extension (4) and foot plantar flexion (2) and extension (3), and hallucis extension (2). The patients most pronounced deficits were distally, in the innervations area of the sciatic nerve; a new MRI showed thickening of the nerve from the sacral bone and through obturator foramen with oedema in the area ( and ). The department of neurosurgery was contacted and advised against nerve biopsy due to the risk of nerve lesion, but recommended a PET scan. 18-Fluorodeoxyglucose-PET (FDG-PET) showed slightly increased activity in the prostate but it was assumed that this was due to hypertrophy, no malignancy was suspected. Four months later the patient reported a 5 kg weight loss and oedema of the right leg. The motor responses were unchanged but the patient was now troubled by faecal incontinence. A medullary compression syndrome was suspected and MRI showed a possible S3-affection by a process as well as thickening of the sciatic nerve and pathological signals from the right pubic bone. CT showed osteolytic/sclerosing changes in the right pubic bone and the inferior ramus of the ischium. PSA was now 7.1 but it was assumed that this was due to the intermittent self-catheterisation. 99-mTc-MDP bone scintigraphy showed intense signals from the right inferior ramus. A biopsy from the bone showed adenocarcinoma staining positive for KL-1, CK18, epithelial membrane antigen and PSA, but negative for other markers, thus diagnosing the tissue as a metastasis from a carcinoma of the prostate, Gleason 4 + 4. Trans-rectal sonography showed malignant transformation of the prostate, and it was deemed superfluous with prostate biopsies. The patient was again referred to the department of urology and treated conservatively with Zoladex (goserelin) and palliative radiotherapy. PSA before start of treatment was >11, and <0.1 after start of treatment.
MRI-picture. Arrow shows thickened sciatic nerve on right side.
MRI-picture. White arrow shows thickened sciatic nerve on right side. Dotted arrows show oedema in gluteus medius and piriformis muscles.