Ultrasound of intra muscular lesions

1. DD OF INTRA - MUSCULAR NON -
TRAUMATIC LESIONS BY
ULTRASOUND
ppt by
Dr. Ahmed ElShahat
FEBR - 2nd
year residency FEBIR
Based on
European society of radiology article
Intramuscular non - traumatic lesions: Ultrasonographic
evaluation
file:///C:/Users/DELL/Downloads/ECR2010_C-2341.pdf

2. DDDD
 LIPOMAS
 GANGLIA
 HEMANGIOMA
 MYXOMA
 SCHWANNOMA
 ABSCESS (Pyomiositis)
 HYDATIC DISEASE
 DESMOID FIBROMATOSIS
 METASTASIS
 SARCOMAS

3. LIPOMA:
 The most frequent soft - tissue tumor (nearly 50% of all
mesenchimal tumors).
 Benign lesion of fat mature tissue.
 Intramuscular lipomas predominantly occur in adults.
 C/P … palpable mass.
 Fat in intra - muscular lipoma may infiltrate between
skeletal muscle fibers giving it a striated appearance.
 Sites: The most frequent locations;
 Lower extremity (45%),
 Trunk (17%),
 Shoulder girdle (12%) and
 Upper extremity (10%).

4. LIPOMA:
Imaging:
 US:
 Intramuscular lesion
 Of similar echogenicity to subcutaneous fat tissue or hyper -
echogenic,
 Usually well defined and sharply circumscribed.
 Long axis parallel to the muscle fibers.
 ± areas to muscle extending into the lesion (infiltrating lipomas)
 Also may contain other mesenchymal elements, especially fibrous
connective tissue, appearing as thin linear, hyperechogenic septa
(usually, better seen in CT, as linear densities and in MRI as
linear areas of decreased signal on all pulse sequences)
 Non - adipose areas representing fat necrosis, associated
calcification, fibrosis, inflammation, areas of myxoid changes or
hibernoma, are reported in up to 30% of cases and may
simulated well-differentiated liposarcoma.

5. Intramuscular lipoma of the triceps brachii muscle.
US show mass (arrows) with similar echogenicity to muscle
(M).
Conventional radiography show fat density lesion (arrows)

6. CT and MRI T1-weighted images show intramuscular, well
defined mass, with similar attenuation (*) and signal
intensity (arrows) to the subcutaneous tissue

7. Woman with painless mass over distal thigh.
Conventional radiography showing lesion with striated, low density
pattern.
US … large, hypoechoic mass within vastus medialis muscle.

8. US, CT and T1WI of the same patient showing the mass (arrows) with
characterisitic striated pattern of infiltrating lipoma, due to intermingled
muscle fibers with fat.

9. GANGLIA:
Def. - Imaging
 Common space - occupying lesions, usually derive from
degeneration of periarticular soft tissues, but also can be found far
from these structures.
 Probably, due to chronic microtrauma, mucoid degeneration or
synovial herniation.
 US
 Well - defined, anechoic structures.
 Posterior acoustic enhancement.
 Uni- or multi - lobulated,
 without Doppler signal.
 ± septa or thick walls, specially longstanding lesions.
 Intramuscular ganglia, with no relation to adjacent joint, are rare.
 Commonly localized around the knee joint, specially in the
quadriceps and gastrocnemius muscles.

10. Patient with palpable
lesion over distal thigh.
US … cystic lesion with
thin septa localized
within vastus lateralis,
corresponding to
intramuscular ganglion.

11. GANGLIA:
Imaging:
 MRI:
 Hypo - intense signal on T1WI.
 Hyper - intense signal on T2 and DP WI.
 Sometimes with septa.
 No enhancement following IV contrast administration.

12. Intramuscular ganglia.
US … cystic, homogeneous, non-vascularized lesion.
Sagital T2WI hyperintense lesion - Sagital and axial Gd- enhanced T1WIs hypointense
lesion with peripheral enhancement.

13. HEMANGIOMA:
 The term "hemangioma" include broad spectrum of lesions; from
capillary forms to vascular malformations (capillary, cavernous,
arteriovenous, venous and mixed types).
 Hemangioma is composed of vascular component and may contain
thrombus, calcification, hemosiderin, fat, smooth muscle and
fibrous tissue.
 Reactive fat is the most frequent non vascular element associated
with this tumor.

14. HEMANGIOMA:
Imaging:
 US:
 Heterogeneous appearance.
 Complex, intramuscular, ill defined tumor.
 Hypoechoic and anechoic areas corresponding to vascular channels that
may showing Doppler signal.
 Hyperechoic areas … due to fat component.
 Phleboliths … seen in 50% of cases as hyperechogenic foci with acoustic
shadowing, normally within the hypoechogenic intralesional component.
 Occassionally, hemangiomas evaluation can be difficult,
specially if they have large size, involve more than single
muscle or their limits are not well defined … In these cases
and when surgery is required, too, MRI studies are needed.

15. Intramuscular hemangioma in
brachioradialis muscle.
US longitudinal plane →
heterogeneous lesion with
hyperechoic areas (*) (fat tissue),
hyperechoic foci with posterior
achoustic shadowing (phleboliths).
Cystic areas represent blood-filled
cavities, demonstrated by the
power Doppler study.

16. MYXOMA:
 Benign lesion characterized by abundant myxoid matrix and a paucity of
spindle-shaped stromal cells.
 Female predominance, between 48 and 70 years.
 No recurrence or metastasize.
 US; Typical intramuscular myxoma:
 Ovoid,
 Well – defined.
 Hypo – echogenic.
 Usually with cystic component.
 Posterior enhancement.
 MRI:
 Myxoma shows fluid - like SI
 Peri - tumoral fat ring, mainly visible on T1WI.
 Variable enhancement
 Although myxomas appear well defined, they non - capsule and infiltrate the
adjacent athrophic and edematous striated muscle. Fat tail also described.

17. 58 ys F, with shoulder pain - US → hypoechoic, intradeltoid, well defined lesion with
posterior enhancement, non vascularized (arrows) with a fat tail (*).
Axial T2WI and sagital T1WI images show a hyperintense and isointense respect to
muscle lesion, respectively. Biopsy confirmed intramuscular myxoma.

18. SCHWANNOMA
 Benign nerve tumor, derive from Schwann cells.
 Incidence lower than 5% of all soft-tissue tumors.
 Typically presents as solitary slow growing mass, usually asymptomatic.
 Normally occur in middle-aged individuals
 Generally:
 Solitary,
 Size less than 5 cm,
 Capsulated and
 Show slowly eccentrically growth along the nerve axis within the
epineurium.

19. SCHWANNOMA
Imaging:
 US:
 Well - defined, solid, hypoechogenic lesion.
 Posterior enhancement.
 Occassionally showing hyper - echogenic areas, due to collagen deposits, or
anechoic cystic areas.
 Well - vascularized, and power Doppler study demonstrates abundant
vascular signal.
 When the nerve is identified entering and exiting from lesion
extremities → accuretly diagnose nerve tumor, but not always
possible, specially when the affected nerves are small as some
muscular branches. In these cases, when intramuscular lesion is
present, schwannoma is diagnosed by finding characteristics previosly
described.
 DD: mostly myxoma, also fat tail can be present in intramuscular
schawnnomas.

20. US → reveals lesion with wide cystic area inside, thick walls and fat tail (*),
corresponding to schwanoma within the adductor longus muscle.

21. MYOSITIS
pyomyositis
 Suppurative bacterial infection of muscle.
 Site:
 Involve any muscle group in the body.
 Typically, only single muscle is affected, but in 11 - 43% of patients with pyomyositis
there is multiple sites of involvement .
 Most common site of infection → the quadriceps muscle, followed by the gluteal and
iliopsoas muscles.
 Upper extremity muscles being affected less frequently.
 Risk factors:
 Diabetic.
 Inmunocompromised
 After minor blunt trauma
 Local hematoma.
 Common organisms: staph. followed by mycobacterium tuberculosis and strep.
 C/P:
 Dull cramping pain.
 Localized muscle tenderness
 ± fever.

22. MYOSITIS – pyomyositis
Imaging - US
Initial phase
 Muscle swelling (edema)
 Diffuse hyper – echogenicity.
 Doppler hypervascularization
 Small hypo - echoic foci due
to early necrosis and
formation of small
abscesses.
Suppurative phase
 Fluid collections.
 Well - defined posterior
enhancement
 Variable echotexture.
 Debris consistent
 Local abscess formation of
thick wall and turbid content.
 Doppler color study show
peripheral hyperemia around
the abscess.

23. 60 ys old woman with fever and right thigh pain.
CT and US show swollen right vastus intermedius (arrows) and SC edema.
Muscle tissue preserves its normal appearance (L) corresponding to normal
side.

24. HYDATID DISEASE
 World wide zoonosis produced by echinococcus granulosus.
 Humans beings are accidental hosts.
 Infection by infesting ova from fomites, contaminated water or direct
contact with dogs.
 Embryos from duodenum pass through mucosa to reach liver through
portal venous system where they form hydatic cysts.
 Primary intramuscular form of hydatidosis without thoracic or
abdominal disease is rare (0.7- 3%).
 Usually associated with involvement of other solid organs.
 On clinical basis, infection mimics a soft-tissue tumor, and the
preoperative radiological diagnosis is very important to avoid biopsy.

25. HYDATID
Imaging:
 US:
 Hydatic cyst of thin or thick wall resembling pericystic structure wich consisted of
connective tissue and scattered hyaline cells.
 Internal echoes or vesicular fibrils.
 Multiple echogenic foci due to hydatic sand giving the "snow storm" sign.
 Simple cysts with no internal structure.
 CT:
• Well - defined cystic lesion with daughter cysts (multiple small rounded hypo -
densities occupying the lesion)
• May contain septa or debris
• No enhancement.
 MRI:
 Typically shows thin, low intensity rim, probably representing the pericyst.
 Chronic cases lesion is mummified → calcified lesion.
 Hydatic disease should be included in DD of any cystic soft tissue
mass found in patients from endemic areas.

26. Pt. with pain and thigh soft-tissue swelling.
US and MRI → lesion with cystic areas inside and thick wall.
Lesion is localized in the medial compartment musculature
(arrows).

27. Isolated intramuscular hydatid cyst in biceps brachii muscle, showing the `Scroll
appearance` of the detached endocyst .
This appearance also suggests recent rupture of endocyst.
Hydatid cyst is an important differential diagnosis in the work-up of cystic
musculoskeletal lesions
http://www.radiologycases.com/casereports/jrcrtp.cgi?case=739#1

29. DESMOID FIBROMATOSIS
 Def.:
 Usually rapidly growing tumor.
 Of diameter more than 5 cm at presentation.
 Frequently extend along muscle.
 Lesion contains fibroblasts and variable amounts of dense collagen fibers.
 Sites; Most frequent locations are:
 Pelvis,
 Chest and mediastinum.
 Abdominal wall.

30. DESMOID FIBROMATOSIS
Imaging
 US:
 Soft tissue mass extending along fascia and muscle fibers.
 Variable echogenicity, depending on cellularity and the variable distribution of water
and collagen.
 Margins: well- or poor-defined.
 Usually can be seen a weak fibrilar echo-structure with posterior attenuation
corresponding to dense collagen.
 Doppler: variable, from hyper- to hypo-vascular lesions. Normally, lesions with more
collagen content → are hypo-vascularized.
 MRI:
 Variable signal intensity, that can be change over time, reflecting the different
amounts of their components.
 As these lesions evolve, cellularity and extracellular spaces decrease, collagen
increases and irregular morphology is present.

31. Desmoid fibromatosis in 25 ys old pt. with gluteal palpable lesion.
US → Hypoechoic lesion of the gluteus medius muscle with subcutaneous
extension and hyperechoic area inside.

32. CT study of the same patient showing gluteus medius lesion with SC involvement.
No significant enhancement seen after CECT

33. DESMOID FIBROMATOSIS
Varities
 Abdominal fibromatosis:
 A distinct entity.
 Tends to occur in:
 Women during pregnancy or within the first year after delivery
 Women using oral contraceptives (estrogen may be a growth factor for
fibroblastic tumors).
 The most frequent affected sites are rectus abdominis and
internal oblique muscles of the anterior abdominal wall.

34. 43 ys old woman with palpable
lesion in the abdominal wall.
Abdominis rectus intramuscular
(*) heterogeneous, hypoechoic
tumor with infiltrative growth
along fascial plane(arrow).
Power Doppler → hypervascular
pattern

35. MALIGNANT MASSES
METASTASIS
Metastasis
Incidence of intramuscular metastasis is low.
Usually secondary to breast, colon and lung tumors.
Diagnosis can be suspect clinically.
Sonographic findings:
 Non – specific.
 Often round or ovoid masses
 Irregular margins
 Hypoechogenic relative to muscle.
 Doppler → variable vascularization.
 Melanoma and renal carcinoma metastasis are hypervascular
Definitive diagnosis → biopsy.

36. Intramuscular metastasis of cervical carcinoma.
Solid,heterogeneous, lobulated lesion localized in the gluteus
maximus.

37. Patient with lung carcinoma, the onset of his disease was the appearance of multiple
soft-tissue masses.
US … intra-deltoid lesion and large mass in the supraspinatus muscle.
Both are hypoechoic and hypervascularized.

38. MALIGNANT MASSES
SARCOMAS
Sarcoma - Liposarcoma
The 2nd
most common type of soft - tissue sarcoma, after fibrous and
fibrohistiocytic malignancies.
About 10 - 35% of all soft-tissue sarcomas.
More in male - peak age during the 6th to 7th decades of life.
WHO categorized liposarcomas into five types; well - differentiated,
myxoid, round cell, pleomorphic and dedifferentiated.
Well- differentiated liposarcoma:
 The most common type and may locally reccur.
 US:
 Large, multi - lobulated well- circumscribed mass
 Generally similar to mature lipoma, but the presence of more complex
appearance with thick septa, nodular or globular non - lipomatous foci, different
echogenicity respect to fat and Doppler vascularization suggest liposarcoma.
 MRI and biopsy → needed.

39. MALIGNANT MASSES
METASTASIS, SARCOMAS
Sarcoma - liposarcoma
Myxoid liposarcoma
2nd
most common type of liposarcoma.
Well defined, multi - nodular mass with different amount of myxoid and
round cells components.
Areas of relatively mature adipose tissue are usually present but sparce
(< 10% of the lesion overall volume).
US:
 Complex, hypoechoic mass.
 Posterior acoustic enhancement … usually unspecific.

40. 77 ys old woman - Anterior leg mass.
US … Large mass of tibialis anterior muscle, heterogeneous and hypervascularized.
Tendon structure is preserved

41. 50 ys old woman – e previous thigh chondrosarcoma who refers a mass in the posterior thigh.
US reveals a large hyperechoic mass - CT and MRI show a mass with fat areas inside.
Biopsy reveals myxoid liposarcoma