Subcutaneous cysticercosis diagnosed by mitochondrial DNA analysis

Background: Cysticercosis is caused by the larval stage of the pork tapeworm, Taenia solium. Central nervous system, eyes, skeletal muscle, and subcutaneous tissue are the most frequent sites of involvement. Methods: We report a case of subcutaneous larval cestode where no diagnostic histological features such as scolex or bladder wall can be seen on serial sections. Identification of the pathogen was attempted using mitochondrial DNA analysis of the histopathologic specimen. Results: Analysis of PCR-amplified DNA sequences targeting T. solium mitochondrial cox1 gene and cob gene confirmed the diagnosis. Conclusions: When characteristic morphology is absent in histopathology specimen, mitochondrial DNA diagnosis is a powerful tool for a definitive diagnosis of cysticercosis. The DNA diagnosis using such histopathologic specimens would also be applicable for identification of other parasites as extensive DNA sequence data are currently available.