Soft tissue tumors Flashcards
Internal features that are consistent with a simple lipoma
Thin, wispy septations
Internal features that are not consistent with a simple lipoma
Thick, irregular septations
Septal or nodular enhancement
Bright on fluid-sensitive sequences
Appearance of fat and fluid on PD weighted imaging
Bright
Another name for a well-differentiated liposarcoma
Atypical lipomatous tumor (ALT)
Well-differentiated liposarcomas can be locally aggressive but…
…rarely metastasize
What specific tumors are characterized by the term “high-grade liposarcoma”?
De-differentiated liposarcoma
Pleomorphic liposarcoma
(cannot be distinguished on imaging)
Appearance of necrosis on contrast-enhanced imaging
Non-enhancing
Typical MRI features of high-grade liposarcoma
Heterogenous enhancement (due to central necrosis) Minimal or absent fatty elements
Differential diagnosis
- mildly T2 bright mass
- heterogeneously enhancing (with central necrosis)
- minimal or absent fatty elements on T1
High grade liposarcoma
Undifferentiated pleomorphic sarcoma (UPS)
Rhabdomyosarcoma
Leiomyosarcoma
Differential diagnosis
- prominently T2 bright mass
- heterogeneously enhancing
- minimal or absent fatty elements on T1
Myoxoid liposarcoma
Myxofibrosarcoma
Synovial sarcoma
Malignant peripheral nerve sheath tumor
Characteristic imaging finding of a myxoid liposarcoma (compared to other liposarcomas)
Homogenously T2 bright
Diagnosis
- rare benign tumor of peripheral nerves
- proliferation of fibrous and fatty tissue
- infiltration of epineurium and perineurium
Fibrolipomatous hamartoma
Most common peripheral nerve affected by fibrolipomatous hamartoma
Median nerve
Pathognomonic imaging feature of a fibrolipomatous hamartoma
Cable-like appearance of the affected nerve
due to fatty proliferation between the fascicles
What congenital disease are fibrolipomatous hamartomas associated with?
Macrodystrophia lipomatosa
- localized giantism of single digits
- caused by overgrowth of fibroadipose tissue
Another name for an undifferentiated pleomorphic sarcoma
Malignant fibrous histiosarcoma
The two subtypes of superficial fibromatoses
Plantar and palmar
Palmar is more common, and occurs in older patients
Characteristic MRI appearance of superficial fibromatosis
Nodular foci of variable signal intensity within the subcutaneous tissue
(variable amounts of fibrotic and cellular material)
Another name for palmar fibromatosis
Dupuytren’s contracture
painless subcutaneous nodules that often require surgery
Another name for plantar fibromatosis
Ledderhose disease
Preferred management of plantar fibromatosis
Conservative (footwear modification, intra-lesional steroids)
Most likely diagnosis
- benign, rapidly growing mass
- usually located in a muscle belly
- T2 bright and T1 enhancing
Nodular fasciitis
some pathologists consider them to be myxoid
