A 62 year old lady is brought in after falling down and finding herself unable to get back up. She had experienced insidious, progressive upper and lower limb weakness for the last month but was otherwise asymptomatic. She was diagnosed with stage 3 vulval cancer 10 years ago, which was treated by a radical vulvectomy with bilateral groin node dissection and chemo-irradiation, with no recurrence since. Her FBC, urinalysis, electrolytes and renal functions are normal.
Her CPK is 3056 U/L (normal: < 200)
NCS: a myopathic pattern EMG: fibrillation potentials consistent with inflammatory myopathy. Muscle biopsy: mononuclear cell infiltrate within the endomysial area with atrophic muscle fibres. No inclusion bodies or vasculitis.
The full body CT scan shows no lymphadenopathy or abnormal masses suggestive of metastasis.
All tumor marker levels are normal.