CASE 143

By: Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: 70-year-old female with sensation of clicking in the shoulder and scapular region.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

A poorly defined soft tissue mass with signal attenuation similar to the adjacent skeletal muscle is noted in the left retroscapular/infra scapular region deep to serratus anterior and latissimus dorsi with alternating fibrous and fatty components. The fibrous component is isointense to the muscle on gradient and T1-weighted images, where as the fatty component is high in signal on these sequences.

DIFFERENTIAL DIAGNOSIS:

Not much in the differential diagnosis as this is considered an aunt Minnie. However, be aware of sarcomas and metastasis which can occur in this location but have different signal characteristics.

DIAGNOSIS:

Elastofibroma dorsi.

PEARLS AND DISCUSSION:

Elastofibroma dorsi is a benign soft tissue tumor. It is more frequently in women. The estimated age is in the sixth to the seventh decade of life.

At a microscopic level, it is composed of fibrous and fatty tissues which account for the imaging characteristics.

Clinically it may be painless however, some patients report some clicking or pain in the region. A mass can be palpated. Rarely it can be bilateral. Elastofibroma dorsi can be found in other locations including adjacent to the ischial tuberosity, deep to the olecranon, or within the thoracic wall.

Treatment is by simple excision.

In conclusion, elastofibroma dorsi may be seen in up to 2% of the population, particularly in older women. These indistinct soft-tissue masses have a classic infrascapular location, signal attenuation like that of the adjacent skeletal muscle, and (often) scattered or striated internal fatty attenuation at CT/MR. Therefore, radiologists should be comfortable diagnosing this benign and often asymptomatic condition and incidentally found soft-tissue tumor at CT/MR. Further imaging studies or tissue sampling is not required for diagnosis when the classic CT/MR findings of elastofibroma dorsi are present.

FURTHER READING:

1.      JarviO, Saxen AE. Elastofibroma dorsi. Acta Pathol Microbiol Scand1961; 51(suppl 144): 83–84.

2.      BrandserEA, Goree JC, El-Khoury GY. Elastofibroma dorsi: prevalence in an elderly population as revealed by CT. AJR Am J Roentgenol1998; 171: 977–9

3.      NaylorMF, Nascimento AG, Sherrick AD, McLeod RA. Elastofibroma dorsi: radiologic findings in 12 patients. AJR Am J Roentgenol1996; 167: 683–68