Review Question - QID 215420

This patient's clinical picture is concerning for possible soft tissue sarcoma and the next best step would be a biopsy of the lesion.

Hematomas within soft tissues can result from multiple etiologies to include trauma, vascular, infection, and malignant processes. In the setting of an atypical expanding mass in soft tissues with unclear etiology, it is important to rule out soft tissue sarcoma and infection. The best method of differentiation is biopsy with tissue sent for culture, as well as, pathologic evaluation. Once a more definitive diagnosis has been made, treatment should be tailored appropriately.

Charnock presented a case report of a 68-year-old male who developed a lump on his thigh after trauma to the area. He underwent ultrasonographic evaluation and diagnosed with a hematoma. Eight months later the mass continued to increase in size and became painful to which he was ultimately diagnosed with a myxofibrosarcoma. The author concludes that ultrasounds demonstrating hematomas require careful consideration of other diagnoses including soft tissue sarcomas and recommend repeat ultrasound greater than 6 weeks apart.

Jahed et al. published a case series of three patients who had chronic expanding hematomas. Their series demonstrates the difficulties with differentiation of chronic hematomas on imaging due to the heterogeneous appearance from evolving breakdown of blood products. Each of the patients had concerning imaging studies suggestive of a possible soft tissue sarcoma. They all underwent resection with final diagnoses of chronic expanding hematomas.

Figures A and B are AP and lateral imaging of a right humerus with a large soft tissue shadow but no osseous abnormalities or evidence of soft tissue calcifications. Figure C is a T1-weighted axial MRI of the arm with a mass that enhances slightly brighter than the adjacent muscle. Figures D and E are T2-weighted MRI axial and coronal cuts that demonstrate a large mass with a fluid component and a heterogeneous enhancing solid region medially.

Incorrect Answers:
Answers 1 and 4: This patient's clinical picture is inconsistent with a hematoma with waxing-waning swelling and imaging demonstrating both fluid and solid components to the mass.
Answer 2: Prior to definitive treatment of a possible soft tissue sarcoma, it is important to have a tissue diagnosis that would require biopsy.
Answer 3: An intramuscular abscess may be possible, although it would be expected to present with significant pain and discomfort. An abscess of this size would likely require drainage.