lumps – bumps pathology
lipoma
lipomas are the most common soft tissue tumour.
- they are a benign fatty tumour which usually arise in the subcutaneous tissues.
- lipomas are generally mildly echogenic or isoechoic with the subcutaneous fat.
- they can be lobulated and are contained in a fibrous capsule.
- they are slow growing.
- it is important to describe their position such as subcutaneous or intramuscular.
- they must be differentiated from other malignant tumours such as liposarcomas.
atypical lipomatous tumors are considered to be well-differentiated liposarcomas. they have a predilection for local recurrence but do not generally metastasize. this diagnosis should be suspected when a fatty tumor is encountered in an intramuscular or retroperitoneal location.generally a ct or mri scan will be done to rule out the latter.
in the subcutaneous location, the primary differential diagnosis is a sebaceous cyst and not commonly an abscess. sebaceous cysts are also rounded and subcutaneous. sebaceous cysts can be differentiated from lipomas by their overlying induration and erythema if infected.
the ultrasound appearance is isoechoic with the surrounding fat.
ultrasound image- an intramuscular thigh lipoma.
the diagnosis was confirmed via a needle biopsy (image 2).
the echogenic diagonal line is the biopsy needle.
vastus lateralis intramuscular lipoma
no enhancing nodular components are detected.
within the central muscle belly of the vastus lateralis muscle in the mid thigh , there is a well-defined ovoid shape hyperdense lesion of fat attenuation with interspersed muscle fibres coursing through the lesion.
supraclavicular lipoma. it is important to include other anatomical markers to assist in describing its description compared to landmarks.
granuloma
this is a chronic inflammatory response. they may be caused from infection or foreign bodies.
they may be hypo or hyper-echoic depending on the age of the lesion. if the lump has been there for a few years then calcification may also have formed.
ultrasound image- this patient has a history of trauma from a kick during a soccer match last season. there is a hard palpable lump corresponding with granulomatous formation.
foreign body
several soft-tissue foreign bodies, such as wood and plastic, are not radiopaque and may remain undetected on radiography; however, all foreign bodies are hyperechoic on sonography.
a non experienced operator may miss a foreign body. the sonographer must “heel and toe” the probe to ensure that they are looking at 90 degrees to the foreign body to ensure the shadowing artifact can be seen behind the foreign body along with the echogenic appearance of the object.
sonographic artifacts deep in relation to soft-tissue foreign bodies are related to the surface attributes rather than the composition of the foreign body and aid in their identification.
material such as wood or plastic tends to produce shadowing. metal objects tend to produce reverberation or comet tail artifact.
a high frequency linear transducer (7.5 to 18 mhz) is placed on the structure of interest with or without the use of a standoff pad. this allows better sound transmission and an improved view of the underlying soft tissues without the “big bang” effect.
the area is scanned throughout its entirety in search for a hyperechoic object in both the sagittal and transverse planes.
ultrasound image- palm frond in a finger.
foreign bodies will usually appear hyperechoic to the surrounding soft tissue. this palm frond does not have any shadowing. this is a longitudinal plane. once found, the depth down from the skin can be measured as well as the size of the object. survey the area surrounding the object for vessels. it is helpful for the treating physician to draw the position of the foreign body on the surface of the skin.
neuroma
there are 3 types of benign peripheral nerve tumours
- solitary neurofibroma
- schwannoma
- neurofibromas associated with neurofibromatosis (von reclinghausen’s disease)
neurofibromas are more common in the nerves of the extremities.
ultrasound appearance:
- they are non encapsulated.
- they cause a fusiform dilatation of the nerve.
- if they are less than 2cm they have a homogeneous, hypoechoic appearance.
- if they are greater than 2cm they may show a “target” appearance with a central, hyperechoic fibrous component
- in 5-10% of cases they undergo malignant transformation.
schwannomas
- they are a benign tumour of the nerve sheath.
- they grow slowly and push nerve fibres aside.
- they are well encapsulated which displace the nerve fibres eccentrically.
ultrasound differentiation between a neurofibroma and schwannoma
it may not be possible to differentiate a neurofibroma from a schwannoma , although an eccentric location favours a schwannoma.
ultrasound image- schwannoma of the ulnar nerve. the position of the vessels are also positioned in the image to assist the clinician in understanding their proximity to the lesion to manage safe surgical intervention.
neurofibromatosis
- a group of medical conditions causing multiple nerve tumour formations.
- an autosomal dominant condition involving the mutation of a cell division gene ( = 50% likelihood of a parent passing it onto a child).
- the most likely manifestation encountered with ultrasound involves multiple cutaneous benign lesions.
ultrasound image- a single cutaneous neurofibromatosis nodule.
ultrasound image- generally, neurofibromatosis nodules will be numerous.
sebaceous cyst
- it is a swollen hair follicle which contains keratin.
- they are slow growing.
- they may or may not be painful depending if it is infected or not.
- it may be red and hot or just a palpable lump just under the skin.
ultrasound image- there is a neck to the skin surface seen using a stand off pad.
ultrasound image- sebaceous cysts may form an abscess if left untreated by antibiotics.
ultrasound image- sebaceous cysts are rounded and subcutaneous. sebaceous cysts can be differentiated from lipomas by their overlying induration and erythema if infected.
haematoma
the ultrasound appearance of haematomas change depending on how recent they are. initially they are anechoic however very quickly the fibrin and erythrocyte deposits cause the ultrasound appearance to have highly reflective echoes within the mass. following this after a few days the clot undergoes liquefaction and decreases in reflectivity. the haematoma will then increase in size. over the course of weeks to months the haematoma will appear cystic with internal strands.
fibrous scarring may remain for a long time.
ultrasound image- resolving haematoma
this is 2 months old.
ultrasound of contused subcutaneous fat secondary to an injection.
the microtrauma visible following a subcutaneous injection such as insulin.
ultrasound of superficial hematomas secondary to multiple injections.
the red arrow shows the approach from the skin.
these can be numerous and diffuse, particularly in patients on anti-coagulant therapy.
lymph nodes
ultrasound image- palpable lump in the groin. this is an enlarged lymph node. it has lost its fatty hilum. it is hyperaemic. it should be treated as suspicious.
branchial cleft cyst
most branchial cleft cysts arise posterior to the submandibular gland and superficial to the carotid and jugular vein. the second and most common branchial cleft cyst is medial to the sternocleidomastoid muscle.
when ultrasounding these lumps the ultrasound practitioner should measure the lump in 3 planes and assess the wall thickness. branchial cleft cysts should have well defined margins. they may contain septations .
usually they will appear anechoic of have very low amplitude echoes within the cyst from floating debris. do not have the tgc turned down too low. by placing a colour box over the lesion will help accentuate the internal mobile debris rarely will they appear solid.
a fistula or sinus should be looked for when scanning.
ultrasound image- the cyst does not appear to connect to any structure. it has posterior acoustic enhancement with low level echoes.
ultrasound image- this was a palpable lump on the right side of the neck. it was progressively getting larger. it is medial to the sternocleidomastoid muscle and anterior to the carotid and jugular vessels.
pre-auricular sinuses
- they are inherited .
- in the following case, the patient’s father, brother and grandfather all had bilateral preauricular sinuses.
- they are usually narrow and short.
- they may extend into the parotid gland.
- patients may have recurrent infections which may cause absecess formation, ulceration or cellulitis.
ultrasound image – pre auricular sinus with inflammation. the hole joins with a sinus that is inflamed . the patient had a red cyst that was visible and palpable adjacent to the sinus.
ultrasound image-the patient had an infection of the canal which had manifested into a cyst. there was no connection to the parotid gland or abscess.
mandibular abscess
this may present as a swelling of the patients cheek. when questioning the patient and asking about their recent dental history it gave the clue to the possibility of an abscess forming on the gum. if it is severe and/or chronic , it may involve the bone.
ultrasound image- mandibular abscess
periapical swelling
this patient presented with an unexplained swelling over the mandible.
ct confirming the diagnosis of a suspected periapical swelling. it is important to see if the cause is a lateral periodontal abscess.
ultrasound image- there is subcutaneous swelling when compared to the other side. the tissue has increased in echogenicity and also increased colour (mouse over) over the region of interest.
muscle herniation through a fascial defect
a patient may present with a palpable lump that is most or only noticable following exercise.if the patient dorsiflexes and extends it can accentuate the hernia and the fascial defect. the patient generally knows what the movements are that create pain or a lump so ask them to mimic the actions that may recreate this situation.
ultrasound image- herniating muscle through the fascia (arrows).
ultrasound image- longitudinal view showing the defect.
abdominal wall fibromatosis
also known as extraabdominal desmoids are rare soft tissue tumours arising from the connective tissue. lesions along the fascia appear as nodular lesions .they are subcutaneous.
the echogenicity , margins and vascularity can vary in appearance with these tumours. they are generally hypoechoic with a heterogeneous appearance.
the diagnosis is found with a confirmed biopsy result. there may be infiltration into the surrounding structures.
abdominal wall fibromatosis was confirmed with a biopsy.
this patient presented with a non specific lump that was starting to become painful. the referrer was surprised to find out that it was not a lipoma.
groin fibromatosis ultrasound image.
ultrasound image – transverse.
subcutaneous abdominal wall fibromatosis.
patient presented with a firm tender immobile paraumbilical lump. no wound, erythema, or history of trauma/injections etc.
images courtesy of callum linehan
b-mode and colour doppler image – longitudinal. an irregular hypoechoic and vascular lesion with surrounding oedema and shadowing. the underlying deep fascia is intact. biopsy concluded fibromatosis and surrounding inflammatory changes.
images courtesy of callum linehan
incisional hernia
are caused from incisions during abdominal surgery of the abdominal wall . an area of weakness develops in which a hernia may develop.
careful scanning of the scar site and its surrounds and deeper tissue is necessary. the scar may be shorter than the peritoneal incision.
there is usually some distortion of the tissue and irregular shadowing making it difficult to assess for true defects.
a panoramic view gives the surgeon a better idea of the relationship of the hernia to other structures as seen here . the hernia is superior to the umbilicus. a measurement from the umbilicus is also helpful.
measurements should be done in longitudinal and transverse of the defect. it should be noted if the hernia is reducible and if it contains any bowel.
chest wall bony swelling on a 2 year old
the mother noticed asymmetry of the child’s chest wall. it was a firm lump over the rib.
ultrasound confirmed there was asymmetric prominence of a left costosternal cartilage. the cartilage appears otherwise normal with no abnormal solid or cystic mass.
sternoclavicular joint inflamation
inflammation can be caused by osteoarthritis,rheumatoid arthritis, infection, anterior subluxation, seronegative spondyloarthropathies, sternocostoclavicular hyperostosis, condensing osteitis and friedrich’s disease.
ultrasound image- b mode.
ultrasound image- colour.
for a great website on sternoclavicular disease.
melanoma
b-mode and power doppler image – cutaneous melanoma presenting as a lobulated hypoechoic and vascular dermal lesion.
b-mode and power doppler image – an example of a small cutaneous melanoma. note the feeding vessel.
b-mode and colour doppler image – subcutaneous melanoma presenting as an irregular, hypoechoic and vascular lesion with surrounding oedema.
b-mode and colour doppler image – metastatic melanoma of a lymph node. the melanoma completely distorts the normal architecture and vasculature.
ultrasound image – invasive subcutaneous melanoma. an ill-defined lobulated hypoechoic lesion disrupting the deep fascia.
colour doppler image – note the increased vascularity.
ultrasound image – metastatic melanoma deposit presenting as an ovoid hypoechoic nodule within a lymph node.
colour doppler image – no definable vascularity. this does not exclude a neoplastic process and given the clinical context of a history of melanoma, it is highly suspicious requiring biopsy.
ultrasound image – metastatic melanoma within a lymph node demonstrating enlargement, necrosis and surrounding oedema.
colour doppler image – only peripheral vascularity is detected.