Age / Sex : 53 / F

Chief complaint: left proximal forearm pain

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:  한종규(Jong Kyu Han), 순천향의대천안병원(Soonchunhyang University Cheonan Hospital)

Bicipitoradial bursitis ( with infection )

Discussion

Findings: Comma
shaped nodule is seen between biceps tendon and radial tuberosity. The lesion
show low SI on T1WI, homogeneous high SI on T2WI and peripheral enhancing and
central low SI on Gd-T1WI with surrounding soft tissue edema.

Differential Diagnosis:  Interosseous
bursitis

Diagnosis:
Bicipitoradial bursitis ( with infection )

Discussion: The
role of the bicipitoradial bursa is to reduce friction between the biceps
tendon and the tuberosity of the radius. In this fashion, the bicipitoradial
bursa may allow free movement of the biceps tendon over a limited range of
pronation and supination of the forearm. Sometimes the bicipitoradial bursa
ensheaths the distal insertion of the biceps tendon for a short distance.
Histologically, the bicipitoradial bursa contains a synovial lining, and its
apposed walls are separated by a thin film of fluid. At histologic examination,
the posterior wall of the bicipitoradial bursa is easily visualized close to
the cortex of the radius, but the anterior wall is hard to distinguish from the
paratenon of the biceps tendon.

The distal portion of the biceps tendon is formed by
the union of two muscle bellies, the long and short heads of the biceps
brachii; individual components of the biceps brachii can be readily separated
until a level approximately 7 cm above the elbow joint, where they join and
terminate in a flattened tendon that is attached to the rough posterior portion
of the radial tuberosity. The distal tendon of the biceps brachii has no tendon
sheath.

Bursitis leading to enlargement of the bicipitoradial
bursa can result from a number of causes, but most frequently it results from
repetitive mechanical trauma; other causes include infection, inflammatory
arthropathy, chemical synovitis, bone proliferation, and synovial
chondromatosis.

When the bicipitoradial bursa is enlarged, it often
is palpable and can impair normal flexion and extension of the elbow. With pronation,
the tuberosity of the radius rotates posteriorly, causing compression of the
bursa between the biceps tendon and the radial tuberosity, consequently
increasing the tension within the bursa. With the accumulation of fluid in the
bicipitoradial bursa, a mass effect in the cubital fossa may lead to
compression of the adjacent nerves. Resultant symptoms depend on which nerve is
compressed. When the superficial branch of the radial nerve is affected, the
symptoms are sensory related; when the deep branch of the radial nerve
(posterior interosseous nerve) is affected, the symptoms are motor related
(weakness of the extensor muscles).

MR imaging allows assessment of the relationship between the bicipitoradial
bursa and the adjacent structures and, owing to the signal intensity
characteristics of the bursal fluid, is helpful in defining cystic masses in
this area, such as ganglion cysts. However, with MR imaging, it may be
difficult to distinguish bicipitoradial bursitis from interosseous bursitis,
especially in patients with a very enlarged bicipitoradial bursa.

Conservative treatment of bicipitoradial bursitis consists of aspiration of
the bursa and injection of corticosteroid medications. Surgical resection may
be required if failure of conservative treatment occurs, with recurrence of
pain after aspiration, neurologic impairment, or mechanical limitation to
flexion and extension of the elbow.

References: Bicipitoradial
bursitis: MR imaging findings in eight patients and anatomic data from contrast material opacification of bursae followed by routine radiography and MR imaging in cadavers. Skaf AY, Boutin RD, Dantas RW, et
al. Radiology 1999;212(1):111-6