Courtesy: James Wittig
Orthopaedic Oncologist

Benign Soft Tissue Tumors: Structured Clinical Summary

Overview

Benign soft tissue tumors arise from soft tissues such as skin, subcutaneous tissue, muscle, and connective tissue surrounding bone.
They do not originate from bone and do not metastasize.
Common entities include lipoma, hemangioma, fibromatosis, myxoma, schwannoma, neurofibroma, giant cell tumor of tendon sheath, and pigmented villonodular synovitis.

Benign tumor composed of mature adipocytes with uniform nuclei and large cytoplasmic lipid vacuoles.
Most common benign soft tissue tumor; commonly affects adults.
Common sites include trunk, shoulder, neck, abdomen, and proximal extremities.
Usually presents as a painless, slowly enlarging mass.
MRI shows signal characteristics identical to subcutaneous fat on all sequences.
Treatment is observation for asymptomatic lesions or marginal excision for symptomatic lesions.
Recurrence is rare but higher in intramuscular lesions.

Benign proliferation of mature vascular channels, often congenital malformations rather than true neoplasms.
May occur in skin, subcutaneous tissue, muscle, synovium, or bone.
Intramuscular lesions often present with pain and enlargement after activity.
Radiographs may show phleboliths; MRI shows heterogeneous lesion with serpiginous vascular channels and fat components.
Treatment depends on symptoms and may include observation or surgical excision.

Benign but locally aggressive fibroproliferative tumor with infiltrative growth pattern.
Common in patients aged 15 to 40 and slightly more common in females.
Common sites include shoulder girdle, upper arm, buttock, trunk, and head and neck.
MRI shows infiltrative margins with variable signal depending on collagen content.
Treatment is wide excision; recurrence rates are high.
Radiotherapy and systemic therapy may be considered in selected cases.

Rare benign hypocellular tumor composed of bland spindle and stellate fibroblasts in abundant myxoid stroma.
Typically affects adults aged 40 to 60 years and commonly arises in thigh or upper arm.
MRI shows homogeneous low signal on T1 and high signal on T2 due to mucin content.
Treatment is marginal excision with low recurrence rate.

Benign nerve sheath tumor arising from Schwann cells.
Usually affects adults aged 20 to 50 and commonly involves major peripheral nerves.
Presents with pain and positive Tinel sign in many patients.
MRI shows well circumscribed mass with split fat sign and target sign.
Treatment is surgical excision with preservation of the nerve.

Benign tumor of peripheral nerves, often solitary but associated with neurofibromatosis in some cases.
Usually painless and located in superficial nerves.
Unlike schwannoma, it infiltrates nerve fascicles and cannot be separated from the nerve.
Surgical excision is rarely performed unless malignancy is suspected.

Localized nodular tenosynovitis composed of synovial like cells, giant cells, inflammatory cells, and hemosiderin.
Most common benign soft tissue tumor of the hand.
MRI shows lesion with low signal areas due to hemosiderin deposition.
Treatment is surgical excision; recurrence can occur.

Diffuse or localized synovial proliferative disorder most commonly affecting the knee.
Presents with joint swelling, pain, and recurrent effusion.
MRI shows synovial mass with low signal from hemosiderin and blooming on gradient sequences.
Treatment is synovectomy; recurrence rates are high in diffuse disease.