Skeletal muscle metastasis from transitional cell carcinoma of the urinary bladder:Clinicoradiological features

Aim: To define the clinicoradiological characteristics of skeletal muscle metastasis from transitional cell carcinoma of the urinary bladder. Materials and Methods: A retrospective review of all patients with skeletal muscle metastasis was undertaken between January 1999 to December 2001. Patients suspected of having a metastasis on radiological examinations, and subsequently proven to have metastatic disease on histological examination were included in study. The clinical presentation and radiological features of five patients with skeletal muscle metastasis from bladder tumours were reviewed from hospital records. Results: Twenty-four patients had skeletal muscle metastasis from various primaries. Of these five patients had previous or concurrent primary tumours in the bladder. Patients were aged between 27-70 years (mean 52 years), and all had persistent, localized pain with or without accompanying swelling. The muscles involved were psoas in three patients, adductor muscles of thigh in one and rectus abdominis in one. Four patients had radical cystectomy with urinary diversion (two ileal conduit and two orthotopic sigmoid neobladder). One patient presented with bladder tumour and concomitant muscular metastasis. All patients underwent helical computed tomography (CT) before confirmation of diagnosis by fine-needle aspiration (FNA) or biopsy. The typical appearance of low-density enhancing lesions on CT was mistaken for abscess in two patients and failure to respond to conservative treatment led to suspicion of metastasis. Diagnosis was proven histologically in all patients (FNA in three and biopsy in two). All patients had palliative chemotherapy (Mitomycin, Vincristine, Adriamycin and Cyclophosphamide). Two patients had local palliative 3500 rad radiotherapy for persistent pain. Mean survival was 8 months (range 6-12 months). Conclusion: Muscular metastasis from urothelial tumours typically presents with persistent localized pain with or without swelling. The characteristic low-density, ring-enhancing lesions on CT in a patient with previous or concomitant urothelial tumours should raise the suspicion of metastasis until proven otherwise. Prognosis is dismal.