Hematoma/Seroma

KEY FACTS

Imaging

• Hematoma: Acute

Quite well-defined heterogeneous mass ± echogenic pseudosolid appearance

Multilaminated whorled appearance

Anechoic cystic areas

Echogenic foci due to gas locules

Surrounding soft tissue edema

Mild surrounding hyperemia

No internal hyperemia

Underlying cause of hematoma, such as muscle tear or vascular malformation, may be apparent
• Hematoma: Subacute and chronic

More well-defined margin ± distinct capsule

Reduces in size on serial examination

Hypoechoic fluid areas due to separation of serum from cellular elements in process of liquefaction

Mild marginal hyperemia on color Doppler imaging

± more central hyperemia if of long duration
• Organizing hematoma

Encapsulated, increasing size due to recurrent bleeding, intrinsic hyperemia

May simulate soft tissue tumor

May need biopsy to distinguish
• Seroma

Often close to site of surgery (chest wall, abdomen, groin)

Echo-poor or anechoic with strong posterior acoustic enhancement

Usually no wall or barely discernible wall
• Lymphocele

Close to site of vascular surgery

Very similar US appearances to seroma
• Serial follow-up helpful to confirm hematoma and to check for underlying cause
• Relate to clinical setting

TERMINOLOGY

Definitions

• Hematoma: Localized collection of blood outside of blood vessel
• Seroma: Serous fluid collection within soft tissues
• Lymphocele: Collection of lymphatic fluid due to leakage from lymphatics

IMAGING

General Features

• Best diagnostic clue

Hematoma: Largely solid-looking echogenic mass with small cystic areas and no intrinsic hyperemia

– Often history of trauma

Seroma: Anechoic fluid collection ± internal debris; minimal or no wall hyperemia

– Nearby surgery

Lymphocele: Anechoic fluid collection, no internal debris, no wall hyperemia

– Nearby vascular surgery

– Difficult to distinguish seroma from lymphocele
• Location

Usually at site of trauma or surgery
• Size

Variable but usually large in buttock or thigh

Radiographic Findings

• Radiography

Mildly hyperdense soft tissue opacity and swelling

– ± calcification in old hematoma

MR Findings

• T1WI and T2WI

Hematoma

– Acute: Isointense on T1WI; variable hyper- to hypointense on T2WI

– Subacute/chronic: Hyperintense on T1WI and T2WI

– T2* GRE: Hemosiderin deposition with susceptibility blooming artifact

Seroma/lymphocele

– Fluid-like collection near site of surgery

Ultrasonographic Findings

• Internal echogenicity depends on degree of blood coagulation, liquefaction, and organization
• Hematoma

Appearances depend on chronicity

Acute: Fairly well-defined heterogeneous mass in subcutaneous or muscle layer

– Echogenic pseudosolid appearance

– Multilaminated whorled appearance

– Anechoic cystic components

– Echogenic foci due to gas locules

– Surrounding soft tissue edema

– Usually no surrounding hyperemia in hyperacute stage; develops over a few days; no intrinsic hyperemia

– Mild acoustic enhancement

– Underlying cause of hematoma, such as muscle tear or vascular malformation, may be apparent

Subacute and chronic: Well-defined, variable echogenicity depending on liquefaction and degree of reparative organization

– More well-defined margin ± distinct capsule

– Reduces in size on serial examination

– Hypoechoic fluid areas due to separation of serum from cellular elements during liquefaction process

– Mild marginal hyperemia; ± more central hyperemia if hematoma is of long duration; may remain avascular

– ± marginal calcification

– Acoustic enhancement if liquefaction; acoustic shadowing if calcification or fibrosis

– Underlying cause may become more apparent

Organizing hematoma

– May simulate soft tissue mass; may require biopsy for confirmation

– Encapsulated, increasing in size due to recurrent internal bleeding, internal hyperemia

– Neovascularization, although present, may not show on color Doppler imaging due to small size of neovascular vessels

Hemophiliac pseudotumor

– Organizing hematoma of hemophilia; affecting 1-2% of all hemophiliacs

– Thick-walled hematoma with internal vascularity

– Can grow due to repeated bleeding

– Mass effect with bone scalloping

– Usually in soft tissues but can be subperiosteal or intraosseous

Rectus sheath hematoma

– Above arcuate line

Ovoid in shape with long axis superoinferior

Localized to one rectus muscle, does not cross midline

Expansile in appearance, mimicking soft tissue tumor

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Tags: Diagnostic Ultrasound Musculoskeletal

Apr 9, 2020 | Posted by admin in MUSCULOSKELETAL IMAGING | Comments Off

KEY FACTS

Imaging

TERMINOLOGY

Definitions

IMAGING

General Features

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Hematoma/Seroma

Hematoma/Seroma

Radiographic Findings

MR Findings

Ultrasonographic Findings

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Hematoma/Seroma

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