Keywords
CT proliferative periostitis - MRI Garré's osteomyelitis - suppurative osteomyelitis
Introduction
Chronic osteomyelitis with proliferative periostitis (also known as periostitis ossificans
or Garré's sclerosing osteomyelitis) is a distinctive form of chronic osteomyelitis.[1] It is commonly associated with odontogenic infections in children and young adults.[1]
[2] The first case was reported in tibia[2] and Berger described this condition to affect mandible for the first time.[1] The common causative pathogens of this condition are Staphylococci, Klebsiella, and Streptococci.[2] The underlying pathology is the periosteal reaction to inflammation and hence, precisely
known as chronic osteomyelitis with proliferative periostitis.[1]
This condition is usually nonsuppurative and asymptomatic without signs of inflammation.[2]
[3]
[4] The SAPHO—synovitis, acne, pustulosis, hyperostosis, osteitis—syndrome is characterized
by the presence of osteomyelitis in other bones, arthritis, and skin diseases.[2] However, rare instances of this condition, resulting in abscess and fistula formation,
are described in literature.[3]
[4] We report one such rare case of Garré's sclerosing osteomyelitis associated with
unusual surrounding soft tissue inflammation and intramuscular abscess and fistula
to skin.
Discussion
Garré's sclerosing osteomyelitis was first described by Carl Garre ́in 1893 in tibia,
which resulted from radiation exposure.[1] However, it was Berger who first described this condition affecting the jaw bones.[1] This chronic form of osteomyelitis is usually asymptomatic without any signs of
local inflammation.[2] The common organisms encountered in the disease process include Staphylococcus, Klebsiella, and Streptococcus, resulting in phases of remission and exacerbation.[2] The commonest cause is odontogenic infection but it can also occur in gunshot wounds,
fractures, pyoderma, postoperative bone interventions, etc.[2] The severity and duration of disease depends of many factors like the virulence
of the causative organisms, the presence of underlying diseases, and the immunity
of the host.[2] It is often unilateral and nonsuppurative.[1] However, rare instances of this condition, resulting in abscess and fistula formation,
are described in literature.[3]
[4]
Facial asymmetry is often the presenting complaint and pain is not a characteristic
finding.[3]
[5] The other markers of acute inflammation like fever, white blood cell count, and
C-reactive protein may also not elevate characteristically.[5] The disease process starts in the spongiosa and extends into periosteum, resulting
in osteoblastic reaction.[3] Unfortunately in some patients the disease process can further extend to the perimandibular
soft tissue with resultant abscess and fistula formation.[3]
[4] In such a scenario, there can be severe trismus resulting from the masticator space
infection.[4]
Imaging plays a very important role in the diagnosis of this condition.[3] The CT imaging features of periostitis ossificans include cortical thinning and
periosteal thickening with lamellar appearance (onion skin), commonly affecting the
ramus of mandible.[2]
[3]
[6] The laminated appearance is due to modulation of fibroblasts in the adjacent soft
tissue, which develop osteoblastic capacity and give rise to sheets of new bone in
multiple layers.[7] The differential diagnosis of this type of periostitis includes Caffey disease,
Ewing's sarcoma, osteosarcoma, fibrous dysplasia, osteoma, exostosis, and ossifying
subperiosteal hematoma.[3]
[8]
Caffey disease or infantile cortical hyperostosis is a rare self-limiting condition
of infancy that is characterized by cortical hyperostosis, particularly affecting
the mandible and facial bones.[7] This condition is bilateral and multiple bones are involved unlike Garrè's osteomyelitis.[3] Ewing's sarcoma and osteosarcoma are the two malignant conditions with similar periosteal
reaction, although they are very rare in mandible and characterized by “sun ray” appearance.[3]
[8] While the latter is characterized by Codman triangle, the former, in addition, shows
osteolytic areas and neurological symptoms like facial neuralgia and lip paresthesia.[3]
Fibrous dysplasia is typically characterized by the “ground glass appearance” and
the enlargement is seen in the bone matrix, whereas in Garré's osteomyelitis it is
seen on the outer surface of the cortex.[3] The appearance of ossifying subperiosteal hematoma or fracture with callus formation
may mimic Garré's osteomyelitis clinically. However, the former does not exhibit uniform
radiopacity and display mottled appearance or trabecular structure while the absence
of trauma history can exclude both the conditions.[3]
Once the diagnosis of Garré's osteomyelitis is made, the most commonly accepted treatment
is the administration of antibiotics and the extraction of the infected tooth.[3] However, when complicated with abscess formation as demonstrated in CECT as peripherally
enhancing fluid collection, it requires incision and drainage.[4] MRI is helpful in presuppurative stages, when muscle edema is detected as increased
signals within the muscles in the T2 and short tau inversion recovery sequences. It
is important to identify the perimandibular soft tissue infection, as otherwise conservative
therapy and removing the causative factor are usually sufficient for Garré's osteomyelitis.[1]
