title: Caseous granuloma: tuberculosis or chronic recurrent multifocal osteomyelitis?
abstract: BACKGROUND
  Chronic recurrent multifocal osteomyelitis (CREMO) is one of the autoinflammatory bone disorders due to disturbance in innate immune system. Up to now, there is no reported case of caseous granulomas in the CREMO. We report a boy with sterile granolumatous osteomyelitis.
  
  
  METHODS
  A four-year-old boy presented with swelling and pain in the left wrist, malaise and bilateral erythematous pustulosis on the palmar region which had resolved spontaneously after about 7 days. The histopathology of the lesions showed severe acute and chronic inflammatory process and chronic granulomatous reaction with caseating necrosis (granulomatous osteomyelitis). The direct smear, culture and PCR for the mycobacterium tuberculosis and atypical mycobacteria were negative. About five months after initiation of the anti-mycobacterial treatment, he was referred to the rheumatology clinic with left elbow pain, effusion and decreased range of motion, and bilateral erythematous palmar pustulosis. He was diagnosed as CREMO based on two exacerbations, repeatedly negative cultures, and concomitant acute and chronic lesions in the histopathology and X-ray. Naproxen and pamidronate every 3 months were started and all other medications were stopped. Two months after the first dose of pamidronate, he became symptom-free and forearm X-ray showed disappearance of the osteolytic lesions and periosteal reactions.
  
  
  CONCLUSIONS
  The diagnosis of CREMO should be considered in the patients with lytic bone lesions. In addition, the clinicians should be aware of the possibility of caseating granuloma in the cases with possible diagnosis of CREMO.
authors.affiliation: Children's Medical Center, Pediatrics Center of Excellence.
authors.forename: Raheleh
authors.initials: R
authors.lastname: Assari
authors.affiliation: Pediatric Rheumatology Research Group, Rheumatology Research Center, ; Department of Pediatrics.
authors.forename: Vahid
authors.initials: V
authors.lastname: Ziaee
authors.affiliation: Department of Infectious Diseases.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Ahmadinejad
authors.affiliation: Department of Pathology, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Vasei
authors.affiliation: Children's Medical Center, Pediatrics Center of Excellence, ; Department of Pediatrics.
authors.forename: Mohammad-Hassan
authors.initials: MH
authors.lastname: Moradinejad
keywords: Caseous Granuloma; Chronic Recurrent Multifocal Osteomyelitis; Tuberculosis