Age / Sex : 50 / M

Chief complaint: left calf 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:  최윤선(Yun Sun Choi), 을지대을지병원(Eulji Hospital, Eulji University)

Plantaris rupture with hematoma (Tennis leg)

Discussion

Findings:

Coronal fat suppression T2-weighted FSE and axial PD-weighted MR images show a heterogeneous high signal intensity mass between the medial head of the gastrocnemius muscle and the soleus muscle at the level of upper calf. The mass shows high signal intensity, indicating hematoma on coronal T1-weighted image. There are multiple low signal intensities within the mass. The mass shows thin peripheral enhancement on the post-contrast image. Note the rupture of myotendinous junction and the path of hemorrhage corresponding to the course of the plantaris.

Differential Diagnosis:

1. Plantaris rupture with hematoma

2. Tear of medial gastrocnemius muscle or soleus muscle with hematoma

3. Hemorrhagic tumor

Diagnosis: Plantaris rupture with hematoma

Discussion:

The plantaris originates from the lateral supracondylar line of the femur, extending obliquely from lateral to medial. It is located at medial aspect to the Achilles tendon in its distal course. The plantaris tear most often occurs at the level of myotendinous junction although tendon tear also occurs at the distal portion. This lesion, together with injury of the medial head of the gastrocnemius, is known as “tennis leg”. Injuries of the plantaris are less common than those of the gastrocnemius. Plantaris muscle belly rupture or strain can be associated with ACL injury or the posterolateral corner injury of the knee. The plantaris tear occurs most commonly in young to middle-aged persons with extension of the knee and forced dorsiflexion of the ankle. MRI findings are 1) hematoma (with or without a hemosiderin ring) between the medial head of the gastrocnemius and the soleus muscle, 2) increased signal intensity in the injured plantaris muscle or myotendinous junction on T2-weighted image, 3) myotendinous rupture with proximal retraction of the plantaris muscle and distal retraction of the tendon. Edema usually exists within adjacent medial gastrocnemius and/or soleus muscle. The retracted tendon of the plantaris and associated hemorrhage may produce a condensed mass of blood and tissue with intermediate signal intensity within the hematoma. Differential diagnoses of plantaris rupture are gastrocnemius-soleus muscle partial tear, Achilles tendon partial tear, deep vein thrombosis, and posterior compartment syndrome. Although surgery is not required to repair the plantaris tendon, it may be necessary if a posterior compartment syndrome results from the swelling and hematoma associated with complete rupture of the plantaris or tear of the gastrocnemius-soleus muscle complex.

References:

1. Delgado GJ, Chung CB, Lektrakul N, Azocar P, Botte MJ, Coria D, et al.  Tennis leg: clinical US study of 141 patients and anatomic investigation of four cadavers with MR imaging and US. Radiology 2002;224(1):112-119

2. Bianchi S, Sailly M, Molini L. Isolated tear of the plantaris tendon: ultrasound and MRI appearance. Skeletal Radiol 2011;40(7):891-895

3. Stoller DW, Ferkel RD. The ankle and foot. In Stoller DW ed. Magnetic resonance imaging in orthopedics and sports medicine, 3rd ed. Philadelphia: Lippincott Williams and Wilkins, 2007:1006-1008