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Age / Sex : 62 / M
Chief complaint: pain and swelling of plantar area of right foot (D: 1 month)
1) What is your impression?
Two weeks later, you can see the final diagnosis with a brief discussion of this case.
(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)
Courtesy: 박진균(Jin Gyoon Park), 전남대병원(Chonnam National University Hospital)
Diagnosis: Adventitious bursitis
Discussion
Findings: On MR
images of right forefoot, there is a poorly defined lesion in plantar fat pad
beneath 3rd MTP joint. The lesion shows intermediate signal
intensity on T1WI and inhomogeneous high signal intensity on T2WI. T1-weighted
contrast material–enhanced fat-suppressed images display fluid filled cavity
and inhomogeneous enhancement .
Diagnosis: Adventitious
bursitis
Discussion:
There are 2 different types of bursae that have been described;
these are synovial bursa and adventitious bursa. Synovial bursae are called
such as they are synovial-lined structures that function to decrease friction
and shear between 2 moving structures. These bursae develop during weeks 20 to
40 of development over areas where some degree of motion is required between
skin, tendon, and bony structures. Adventitious bursae develop postpartum at sites where subcutaneous tissue is exposed
to high friction and pressure. Adventitious
bursae arise following a sequence of connective tissue degeneration and always
lack an epithelial lining.
Forefoot pain involving
the metatarsal region, also called metatarsalgia, is a common clinical problem.
Magnetic resonance (MR) imaging has the potential to enable a specific diagnosis
in these patients. This is particularly true for disorders such as Morton
neuroma, intermetatarsal bursitis, stress fractures, tenosynovitis, and plantar
plate failure of the metatarsophalangeal (MTP) joints. In the absence of such
specific diagnoses, the radiologist may be faced with plantar fat pad signal
intensity alterations at the level of the MTP joints.
Iso- to hypointense
plantar fat pad signal intensity alterations at the level of the MTP joints on
both T1WI and T2WI images in asymptomatic patients represent reactive fibrous
tissue induced by mechanical stress. Prevalence of reactive fibrosis in
asymptomatic patients is high (84%) at MR examination.
Adventitious bursitis of
plantar fat fad of forefoot shows indistinct margin of intermediate signal
intensity beneath metatarsal head on T1WI, high signal intensity on T2WI, and
peripheral enhancement on contrast enhanced image.
References:
1. Studler U, Mengiardi B, Bode B, Schottle PB,
Phirrmann CWA, Hodler J, Janetti M. Fibrosis
and adventitious bursae in plantar fat pad of forefoot: MR imaging findings in asymptomatic
volunteers and MR imaging–histologic comparison. Radiology 2008;246:863-870
2.
Foisneau-Lottin
A, Martinet N, Henrot P, Paysant J, Blum A, Andre JM. Bursitis, adventitious
bursa, localized soft-tissue inflammation, and bone marrow edema in tibial
stumps: the contribution of magnetic resonance imaging to the diagnosis and
management of mechanical stress complications. Arch Phys Med Rehabil. 2003;84:770–777.
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