Age / Sex : 67 / F

Chief complaint : palpable mass in the right anterior thigh

What is your impression?

Two weeks later, you can see the final diagonosis with a brief discussion of this case (Please submit only one answer).

Courtesy : Seon-Jeong Kim, Myongji Hospital

Discussion

Answer:  

Unilateral hypertrophy of tensor fascia lata

Findings:

Fusiform enlargement of the right tensor fascia lata muscle

Differential Diagnosis:

Pseudohypertrophy, tumors (intramuscular hemangioma, lipoma)

Discussion:

• Uncommon clinical entity that may simulate a soft tissue tumor.


• Usually older female patients


• Enlargement of muscles may take two forms:

-True hypertrophy : result of an increase in size of muscle fibers

-Pseudohypertrophy

-- Secondary to accumulation of excess fat and connective tissue within the muscle

-- Well-recognized phenomenon in patients with Duchenne and other muscular dystrophies

-On imaging studies, it is helpful to assess the amount of fatty tissue to distinguish

pseudohypertrophy from true hypertrophy.

• Muscle hypertrophy presenting as a soft tissue mass has been reported with various muscle groups

-Iliopsoas (M/C), semimembranosus, gastrocnemius, soleus and abductor hallucis

muscles in the lower Extremities

• Exercise, denervation, radiation and myopathies are frequently implicated in muscle hypertrophy


• Familiarity with this entity and the characteristic imaging features of TFL hypertrophy will aid in making an accurate diagnosis and avoiding unnecessary biopsy or surgical intervention.

References:

Ilaslan H, Wenger DE, Shives TC, Unni KK. Unilateral hypertrophy of tensor fascia lata: a soft tissue tumor simulator.Skeletal Radiol. 2003 ;32(11):628-32.