A classic case of subcutaneous cysticercosis : a rare case with sonological findings and review of literature

BACKGROUND: Cysticercosis is a parasitic infection caused by the larval stages of the pork tapeworm, Taenia solium. The subcutaneous form of the disease is a relatively rare clinical entity. Despite its rarity, it is imperative for a radiologist to be aware of this subcutaneous form of the disease and its various radiological patterns while evaluating any subcutaneous swelling. In this paper, we aimed to describe a typical case of ‘subcutaneous cysticercosis involving the left anterior chest wall’ with high resolution ultrasound findings. We also discussed the role of other imaging modalities in a case of subcutaneous cysticercosis. To the best of our knowledge, our case is only the second documented case report of sonological evaluation of subcutaneous cysticercosis involving the left anterior chest wall and the first case with high resolution ultrasound images of the lesion. CASE REPORT: An 11-year-old male presented with a painless, subcutaneous swelling over the left anterior chest wall for the last 2 months. High resolution ultrasound showed a well-defined, thin-walled, cystic lesion with an eccentric, echogenic focus in the subcutaneous plane. On change of the posture of the patient, this focus showed mobility. The hypoechoic area surrounding this cyst showed significant exudative fluid collection with diffuse, floating echoes and thin, incomplete internal septations. The adjacent soft tissues were thickened and irregular, suggestive of edema. This was followed by an excision biopsy. Histopathological examination revealed cysticercus cellulose parasite with an extensive mixed inflammatory cell infiltrate in the surrounding tissue. The patient was also administered oral antihelminthic therapy. Repeat ultrasound examination at the end of this management regimen showed complete healing with no e/o any remnant or recurrent cystic lesion, abscess or edema in the subcutaneous plane. CONCLUSIONS: Subcutaneous cysticercosis is a relatively rare form of cysticercosis but should always be born in mind during the evaluation of subcutaneous swellings. High resolution ultrasound is a valuable, safe, nonionizing, cost-effective, widely-available, and easily-reproducible imaging tool for diagnosis of subcutaneous cysticercosis. There is a wide spectrum of ultrasound patterns of subcutaneous cysticercosis. In classic cases with a cyst containing a scolex within and with a surrounding abscess, high resolution ultrasound should always be the primary mode of diagnosis, thus avoiding unnecessary fine needle aspiration cytologies