Polymyositis as presenting manifestation of gallbladder carcinoma: A case report.

INTRODUCTION: Inflammatory myositis as a paraneoplastic presentation of gallbladder cancer is an extremely rare event. In this paper we reported the first case of gallbladder carcinoma presented as polymyositis. PRESENTATION OF CASE: A 68-year-old housewife presented with proximal muscles weakness, pain, significant decrease in force of proximal muscles, and globally decreased deep tendon reflexes. Laboratory studies revealed an anemia, increased acute phase reactants and increased serum creatine phosphokinase (CPK) levels. Electromyography (EMG) and nerve conduction velocity test (NCV) demonstrated mild myopathic changes. Muscle biopsy was suggestive for polymyositis. Corticosteroid therapy initiated and a meticulous search for probable underlying malignancy performed concurrently. Malignancy workup finally revealed a gallbladder tumor. Patient candidated for extended cholecystectomy. Pathologic evaluation of gallbladder tumor demonstrated a moderately differentiated carcinoma. Progressive improvement in clinical conditions and complete normalization of laboratory parameters occurred post-operatively. After 8 months of follow-up patient is still alive and in good state of health. There is no evidence of metastatic or local recurrence of tumor. Musculoskeletal complaints subsided completely. DISCUSSION: Gallbladder carcinoma is a rare and usually aggressive malignancy. Its primary presentation by paraneoplastic syndromes especially in the form of paraneoplastic neurological syndromes is an extremely rare event. Some believes that increased association between inflammatory myopathy and malignancy is limited to the dermatomyositis; however, presentation of our patient as polymyositis is contrary to this. This is the first reported case of gallbladder cancer who presented with polymyositis.
CONCLUSION: Gallbladder cancer though rare, should be considered in patients with inflammatory myositis.