Type	History	Examination	Imaging	Treatment
Abscess	Progressive, subcutaneous, erythematous swelling with possible drainage⁶	Erythematous mass	Ultrasonography showing focal collection vs. “cobblestoning” with cellulitis⁷	Incision and drainage with ultrasound guidance⁷ Consider antibiotics if recurrent or patient is immunocompromised^8–10
Epidermal inclusion cyst	Nodule under the skin¹¹	Arise in areas with hair follicles Pain and erythema if inflamed¹¹ Mobile subcutaneous masses Hallmark feature is central punctate^1,12	MRI: well-defined T2 hyperintense lesions, may depend on presence of internal debris; ruptured cysts have a more varied appearance¹²	For mildly inflamed epidermal inclusion cysts, incision and drainage with culture¹² Can consider excision if recurrent¹¹
Ganglion cyst	Arises from joint, ligament, or tendon injuries¹³	Most often on hands, wrists, feet, or ankles^13,14	Ultrasonography to distinguish between cystic and solid masses, locate adjacent blood vessels, and distinguish between other diagnoses, including a ruptured Baker cyst and deep venous thrombosis	Observation if no functional impairment¹⁵ Consider aspiration, steroid injection, or surgical excision if functional impairment or recurrent^14,15
Hemangiomas/arteriovenous malformations	Capillary hemangiomas are the most common type^12,16	Soft, compressible masses; diffuse blue or purple skin discoloration¹⁷	Radiography and ultrasonography may reveal lesions containing phleboliths and mixed echogenicity MRI can demonstrate depth of the lesion¹⁶	Conservative treatment can include observation or intravascular sclerotherapy¹⁷ Surgical referral reserved for patients with symptomatic tumors^17*
Hematoma	Rapid onset Should have an explanation (e.g., anticoagulation, trauma)	Fluctuant mass, sometimes with overlying ecchymosis¹⁸	Ultrasonography and MRI can show extent of the hematoma¹⁹	Mainly conservative treatment; evaluate if persisting or enlarging for more than one month²⁰ Consider embolization if progressively expanding²¹
Intramuscular myxoma	Rare (0.12% of soft tissue tumors) Typically occurs in large skeletal muscles Most common between 40 and 70 years of age; slightly more common in women	Palpable mass, most common on the thigh and lower limb girdle²²	MRI: T1 hypointense to muscle, high signal intensity on T2-weighted or fluid-sensitive sequences	Surgical excision in most cases²²
Lipoma	Most common between 40 and 70 years of age and in patients who are obese^16,23 Slightly more common in men²⁴ Some genetic syndromes cause multiple lipomas	Superficial mass that is freely mobile with a doughy consistency²⁴ Deep masses may involve muscle and move with muscle contraction²⁴	Radiographs may appear normal²⁴ Ultrasonography: often isoechoic to adjacent subcutaneous fat²⁴ MRI is required for any deep mass or subcutaneous lesion ≥ 5 cm²⁴ MRI demonstrates fat signal intensity ²⁴	Monitoring for asymptomatic lipomas Consider excision for symptomatic or painful masses, or for cosmetic reasons²⁴
Lymphangioma: capillary, cavernous, or cystic	Appears at birth or by 2 years of age Pain is uncommon unless infection is present Disfigurement can be significant²⁵	Seen on the neck and axilla Soft on palpation Respiratory compromise is the most serious complication²⁵	Chest radiography may be useful in identifying mediastinal extension or pleural effusions Ultrasonography: hypoechoic, multilocular cystic masses²⁵ CT: cystic lymphangioma; thicker septations are delineated	Observation only in the absence of symptoms Excision is the standard treatment Recurrence can be 27% and mortality about 2%²⁵ Intralesional sclerotherapy is first-line treatment for macrocystic lymphangiomas²⁶
Morton neuroma (peripheral nerve sheath tumor)²⁷	Sensation of a “pebble in the shoe” or burning in toes distal to the neuroma²⁷	No visual clues to neuroma Mulder click test (dorsiflexing the foot and squeezing the metatarsals produces a clicking sound)	Radiography to rule out other sources of foot pain Ultrasonography can be used to identify a neuroma and guide injection MRI: neuroma seen on T1 axial slice²⁸	Wide toe box shoes Cortisone injections Surgical excision
Mucous cyst	Finger swelling, pain, tenderness, decreased range of motion 80% occur between 50 and 70 years of age²⁹ Twice as likely in women than men²⁹ Approximate prevalence: thumb 18%, second finger 26%, third finger 38%, fourth finger 9%, fifth finger 8%²⁹	Nail changes Translucent mass adjacent to the nail bed³⁰	Dermoscopic examination has reduced need for ultrasonography and radiography ³⁰	Surgical excision yielded the highest cure rate (mean of 95%) Second-line: sclerotherapy and cryotherapy Third-line: corticosteroid injections, expression of cyst content³¹
Pilar cyst	90% occur on the scalp³² Most common after 15 years of age Slightly more common in women³²	Swelling over the scalp Area of alopecia Well-defined, oval mass Occurs in areas with dense hair follicles³²	Imaging not usually warranted Ultrasonography: internal echogenic foci with demonstrated calcification, cholesterol crystals, or both; no blood flow in the lesion³³ MRI: homogeneous, isointense signal on T1-weighted images; homogeneous, hyperintense signal on T2-weighted images³² CT: well-defined, hypodense masses with occasional calcification³⁴	If benign, treat with simple local excision If malignant, refer for wide local excision and possible Mohs surgery³²
Plantar fibroma	Mild pain that worsens after walking or standing for longer periods Bilateral in 20% to 50% of cases May have had trauma to the area or family history³⁵	Palpable nodule or focal thickening along the plantar fascia	Ultrasonography: fusiform nodules that are hypoechoic to isoechoic without intrinsic vascularity (comb sign)³⁶ MRI: well-defined mass, isointense to muscle on T1-weighted images; well-defined, broad base at the superficial fascia demonstrates a fascial tail from extension of the tumor along the fascial plane	Can locally recur³⁵ Orthotics Intralesional corticosteroid injection Consider subtotal fasciectomy with wide excision if conservative therapies are ineffective³⁶
Myositis ossificans	Common after trauma³⁷	Painful, rock-like mass Commonly affects quadriceps femoris and brachialis muscles Organized calcification within the muscle³⁸	MRI: classic hyperintense mass, calcifications may appear on T2-weighted images Radiography or CT: early detection with typical peripheral zonal ossification³⁷	Self-limiting with prolonged resolution common Consider referral for debilitating cases
Schwannoma in the foot	Swelling along the flexor surface Most common between 30 and 40 years of age Men and women affected equally³⁹ Account for 5% of benign soft tissue tumors⁴⁰ May present similarly to Morton neuroma	Clinical presentation depends on tumor size and location⁴¹ Motor or sensory disturbances along the flexor surface	Radiograph findings are often negative MRI shows lesions along a neurovascular bundle; a nerve may enter or exit a mass	Small asymptomatic tumors may be followed clinically If symptomatic, patient should be referred for biopsy with histologic examination and surgical excision⁴¹
Tenosynovial giant cell tumor	Swelling most often in hands or feet Common between 30 and 50 years of age Slightly more common in women Second finger is most often affected⁴²	Rounded or lobulated mass appears to encase the surface of a tendon	Radiography: bony erosions Ultrasonography: small tumor with blood flow that does not attach to tendon MRI: lesion has low signal compared with muscle on T1-weighted images; hemosiderin deposition on T2-weighted images⁴¹	Surgical resection Recurrence rate as high as 15%⁴⁰