We report an extremely rare case of multifocal bone disorder in a 3.5-year-old boy who appeared for left forearm and arm pain and multiple periods of fever with an unusual presentation of lymphoma/leukemia and highlight diagnostic challenges leading to a misdiagnosis, which was then diagnosed and treated for chronic recurrent multifocal osteomyelitis (CRMO). Based on a left arm biopsy and whole-body scans, he was eventually diagnosed with CRMO. Taken together, in this case, we noticed a notable amelioration after a 5-month treatment with nonsteroidal anti-inflammatory drugs on multiple bone pains.

COVID-19 outbreak has become a global health concern due to challenges in treatment and high mortality rate; therefore, its therapeutic approaches play an important role in reducing the mortality rate and resolving this concern. Different therapies have been introduced, including interferon beta-1a and purification methods, for instance, plasmapheresis. In this article, we reported a child with severe COVID-19 who fully recovered after receiving plasmapheresis and interferon beta-1a.