Expert Opinion :
This child has presented with swelling and fever, hence one may consider it to be either infective origin or a malignancy. Fracture and trauma is unlikely as the child has no bruise and there is no tenderness of bones. Malignancy is also unlikely because the bones are not tender, and the child has no organomegaly or lymphadenopathy. Thus, the most likely cause of swelling in this child would be infective. Among the infections, one may consider the following:
• Superficial skin abscess
• Subcutaneous tissue infection (cellulitis)
• Muscle abscesses (Pyomyositis)
• Osteomyelitis
In this child, the skin can be freely moved over the swelling. Thus superficial skin abscess seems unlikely. Cellulitis does not cause a swelling but comes as diffuse redness and tenderness. Osteomyelitis is also ruled out as the swelling over the back is not related to a bone. Thus, the cause of swellings in this child is pyomyositis. Infact tropical polymyositis is a common infection and presents with multiple abscesses in various muscles. In this child, both abscesses were drained and culture was positive for staphylococcal infection. Serum CPK was high suggestive of pyomyositis.