superficial structures pathology

superficial epidermal cyst/epidermal inclusion cyst/epidermoid cyst

• most likely found in the scalp, face, neck, trunk, or back

• can be congenital or the result of trauma

• potentially results from an obstructed hair follicle

sebaceous cyst

a type of superficial epidermal cyst that is sebaceous in origin

clinical findings of a superficial epidermal cyst:

• visible, palpable mass just under the skin

• pain and redness in the area

sonographic findings of a superficial epidermal cyst:

• anechoic, hypoechoic, complex, or hyperechoic cyst or mass

• pseudotestis appearance

ganglion cyst

a common mass found along the dorsal aspect of the hand and wrist, although they can arise from any joint and are thus discovered in the knee, foot, and ankle as well

dorsal ganglion cysts

• ganglion cysts within the wrist

• most common

volar ganglion cysts

ganglion cysts located near the radial artery

how are ganglion cysts treated?

• corticosteroid injections

• surgery

clinical findings of a ganglion cyst:

• palpable mass most often located along the dorsal aspect of the hand or wrist

• can be painful

sonographic findings of a ganglion cyst:

• noncompressible, anechoic mass with acoustic enhancement

• may contain debris or septations

lipoma

benign, fatty tumor

clinical findings of a superficial lipoma:

• asymptomatic

• obvious mass under the skin

• compressible

sonographic findings of a superficial lipoma:

• most likely an hypoechoic or isoechoic mass as compared to the surrounding tissues

• typically have an oval shape

superficial hemangioma

a benign mass that is composed of vascular channels

clinical findings of a superficial hemangioma:

• asymptomatic

• red or reddish purple, raised mass on the skin

sonographic findings of a superficial hemangioma:

• hypoechoic

• blood flow may be detectable with color Doppler

meniscus

a thin, fibrocartilaginous tissue between the surfaces of some joints, like the knee

meniscal cysts

most often thought to occur because of a fluid collection following a meniscal tear in the knee

meniscal tear

typically results from trauma or degenerative changes within the knee

clinical findings of a meniscal cyst:

• previous trauma

• focal knee pain

• knee swelling

• palpable mass within the knee joint

• popping, stiffness, or locking knee joint

sonographic findings of a meniscal cyst:

anechoic or hypoechoic mass with posterior enhancement

Baker cyst/popliteal cyst/synovial cyst

• located in the popliteal fossa, behind the knee

• common and a result from the accumulation of synovial fluid from a weakening in the joint capsule of the knee, as seen in conditions such as rheumatoid arthritis or osteoarthritis

clinical findings of a Baker cyst:

• asymptomatic

• focal tenderness in the popliteal fossa

• may mimic clinical findings of a deep venous thrombosis

sonographic findings of a Baker cyst:

• anechoic mass with posterior enhancement

• complicated Baker cysts may contain echogenic fluid, debris, pannus, or septations

• a channel or tract may be seen connecting the cyst to the joint space

pilonidal cyst/pilonidal sinus

• most often found within the natal cleft/intergluteal cleft/gluteal cleft, and is located between the buttocks

• may also be seen within the fingers or toes

• composed of loose hairs and skin debris

clinical findings of a pilonidal cyst:

• edema, warmth, and pain in the area of the cyst

• bloody drainage from the cyst may be present

sonographic findings of a pilonidal cyst:

• complex, subcutaneous mass

• hyperemia around the mass

• hypoechoic tract may be seen extending from the cyst to the skin surface

cellulitis

infection and subsequent inflammation of the skin and subcutaneous tissue

cellulitis is most often caused by:

Staphylococcus aureus and Streptococcus pyogenes

clinical findings of cellulitis:

• red, tender, warm area of the skin

• possible elevated white blood cell count (especially with abscess development)

sonographic findings of cellulitis:

hypoechoic, edematous strands within the soft tissue → cobblestone appearance

sonographic findings of a superficial abscess:

• hypoechoic, edematous strands within the soft tissue → cobblestone appearance

• focal fluid collection that is often complex, denoting the abscess

• a peripheral rim of hyperemia may be detectable with color Doppler

malignant melanoma

• accounts for up to 11% of skin cancers

• the most likely primary tumor to metastasize to the subcutaneous fat

sonographic findings of metastatic melanoma

solid, vascular hypoechoic mass

what type of transducer is used to image foreign bodies?

a high-frequency linear array transducer

sonographic appearance of foreign bodies:

• most appear as hyperechoic structures with some degree of posterior shadowing

• bullets, shrapnel, and other metallic objects may cause ring-down or comet-tail artifact as well

• inflammation around a foreign body will appear as a hypoechoic area adjacent to the structure

• air at the site of a foreign body may produce bright echoes and, therefore, cause some ambiguity about the correct orientation of the object