Types of Soft Tissue Tumors – WHO Classification - Health

Types of Soft Tissue Tumors/Soft tissue sarcomas are cancerous (malignant) tumors that originate in the soft tissues of your body. This illustration shows a soft tissue sarcoma of the thigh muscle just above the knee. Soft tissue sarcoma is a rare type of cancer that begins in the tissues that connect, support, and surround other body structures

WHO classification of Soft Tissue Tumors

The World Health Organization (WHO) classification of soft tissue tumors is the most widely used pathologic classification system for such disorders. The current revision, part of the 5^th edition of the WHO series, was published in 2020 and is reflected in the article below ¹.

Classification

Adipocytic tumors

lipoma
lipomatosis
lipomatosis of nerve
lipoblastoma and lipoblastomatosis
angiolipoma
myolipoma of soft tissue
chondroid lipoma
spindle cell/pleomorphic lipoma
hibernoma
atypical spindle cell/pleomorphic lipomatous tumor
atypical lipomatous tumor/well-differentiated liposarcoma
dedifferentiated liposarcoma
myxoid liposarcoma
pleomorphic liposarcoma
myxoid pleomorphic liposarcoma

Fibroblastic/myofibroblastic tumors

nodular fasciitis
proliferative fasciitis and proliferative myositis
myositis ossificans and fibro-osseous pseudotumor of digits
ischemic fasciitis
elastofibroma
fibrous hamartoma of infancy
fibromatosis colli
juvenile hyaline fibromatosis
inclusion body fibromatosis
fibroma of the tendon sheath
desmoplastic fibroblastoma
myofibroblastoma
calcifying aponeurotic fibroma
EWSR-SMAD3-positive fibroblastic tumor (emerging)
angiomyofibroblastoma
cellular angiofibroma
angiofibroma of soft tissue
acral fibromyxoma
nuchal-type fibroma
Gardner fibroma
calcifying fibrous tumor
palmar/plantar fibromatosis
desmoid-type fibromatosis
lipofibromatosis
giant cell fibroblastoma
dermatofibrosarcoma protuberans
solitary fibrous tumor
inflammatory myofibroblastic tumor
low-grade myofibroblastic sarcoma
superficial CD34-positive fibroblastic tumor
my inflammatory fibroblastic sarcoma
infantile fibrosarcoma
adult fibrosarcoma
myxofibrosarcoma
low-grade fibromyxoid sarcoma
sclerosing epithelioid fibrosarcoma

So-called fibrohistiocytic tumors

tenosynovial giant cell tumor
deep benign fibrous histiocytoma
plexiform fibrohistiocytic tumor
giant cell tumor of soft tissue

Vascular tumors

hemangiomas
- synovial hemangioma
- intramuscular hemangioma
- arteriovenous malformation/hemangioma
- venous hemangioma
anastomosing hemangioma
epithelioid hemangioma
lymphangioma and lymphangiomatosis
tufted angioma and Kaposiform hemangioendothelioma
retiform hemangioendothelioma
papillary intralymphatic angioendothelioma
composite hemangioendothelioma
Kaposi sarcoma
pseudomyogenic hemangioendothelioma
epithelioid hemangioendothelioma
angiosarcoma

Pericytic (perivascular) tumors

glomus tumors
myopericytoma, including myofibroma
angioleiomyoma

Smooth muscle tumors

leiomyoma of deep soft tissue
EBV-associated smooth muscle tumor
inflammatory leiomyosarcoma
leiomyosarcoma

Skeletal-muscle tumors

rhabdomyoma
embryonal rhabdomyosarcoma
alveolar rhabdomyosarcoma
pleomorphic rhabdomyosarcoma
spindle cell/sclerosing rhabdomyosarcoma
ectomesenchymoma

Gastrointestinal stromal tumors

gastrointestinal stromal tumors

Chondro-osseous tumors

soft-tissue chondroma
extraskeletal osteosarcoma

Peripheral nerve sheath tumors

schwannoma (including variants)
neurofibroma (including variants)
perineurioma
granular cell tumor
dermal nerve sheath myxoma
solitary circumscribed neuroma
ectopic meningioma and meningothelial hamartoma
benign triton tumor/neuromuscular choristoma
hybrid nerve sheath tumors
malignant peripheral nerve sheath tumor
malignant melanotic nerve sheath tumor

Tumors of uncertain differentiation

intramuscular myxoma
juxta-articular myxoma
deep (“aggressive”) angiomyxoma
atypical fibroxanthoma
angiomatoid fibrous histiocytoma
ossifying fibromyxoid tumor
myoepithelioma/myoepithelial carcinoma/mixed tumor
pleomorphic hyalinizing angiectatic tumor of soft parts
haemosiderotic fibrolipomatous tumor
phosphaturic mesenchymal tumor
NTRK-rearranged soft tissue neoplasms
synovial sarcoma
epithelioid sarcoma
alveolar soft part sarcoma
clear cell sarcoma of soft tissue
extraskeletal myxoid chondrosarcoma
desmoplastic small round cell tumor
extrarenal rhabdoid tumor
PEComa
intimal sarcoma
undifferentiated sarcoma

Changes from the prior version

New entities and variants

Newly introduced entities include the following

adipocytic tumors
- atypical spindle cell/pleomorphic lipomatous tumor
- myxoid pleomorphic liposarcoma
fibroblastic and myofibroblastic tumors
- angiofibroma of soft tissue
- superficial CD34-positive fibroblastic tumor
- EWSR-SMAD3-positive fibroblastic tumor
vascular tumors
- epithelioid hemangioendothelioma features two newly recognized subtypes
- anastomosing hemangioma
- tufted angioma and Kaposiform hemangioendothelioma are classified together
pericytic (perivascular) tumors
- myopericytoma, including myofibroma – new subtype: cellular myofibroma/myopericytoma
smooth muscle tumors
- EBV-associated smooth muscle tumor
- inflammatory leiomyosarcoma
skeletal muscle tumors
- spindle cell/sclerosing rhabdomyosarcoma – three subtypes
tumors of uncertain differentiation
- NTRK-rearranged soft tissue neoplasms

Other changes

melanotic schwannoma – now renamed to malignant melanotic nerve sheath tumor
dedifferentiated liposarcoma – the adverse prognostic impact of myogenic and rhabdomyoblastic differentiation as well of a high grade on the FNCLCC (French Federation of Cancer Centers Sarcoma Group) grading system
solitary fibrous tumor – extrapleural’ has been removed

References

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