Research Article

Time and Accuracy to Establish the Diagnosis of Soft Tissue Tumors: A Comparative Analysis from the Swiss Sarcoma Network

Table 3

Minor/major discrepancies.

Minor discrepancies
Benign
Institution AInstitution B

L107Fibroblastic/myofibroblastic proliferates in predominantly tight connective tissue with partly regressive changes.Collagen-rich myofibroblastic proliferation
L108Chondrogenic neoplasm, highly differentiatedEnchondroma
L198Fibrin and blood, intercalated with some lamellar bone tissue and connective tissueIntraosseous ganglion
Intermediate
Institution AInstitution B
L31Spindle-cell, partly multinucleated giant-cell tumor with osteoid formationAneurysmal bone cyst
L34Giant cell tumor of the soft tissuePlexiform fibrohistiocytic tumour
L112Chondroid neoplasia with cancellous boneEpiphyseal atypic chondrogenic tumor
Malignant
Institution AInstitution B
L4Spindle-cell high-grade sarcomaSpindle and pleomorphic high-grade malignant unclassified sarcoma G3
L11Spindle-cell pleomorphic sarcoma, high grade, with evidence of myogenic differentiationLeiomyosarcoma
L19Epithelioid sarcoma (proximal type)Epithelioid angiosarcoma
L29Lymph node metastasis of a solid tumor (differential diagnosis: clear cell sarcoma or malignant melanoma)Lymph node metastasis of malignant melanoma
L35Pleomorphic undifferentiated sarcoma with necrosis zonesPleomorphic liposarcoma (G3)
L60Spindle-cell pleomorphic neoplasia with striated musclesSclerosing epithelioid fibrosarcoma
L63Sarcoma, spinel and partly pleomorphic cellsSpindle and pleomorphic cell soft tissue sarcoma at least G2 with FNCLCC score of 4
L64Highly differentiated liposarcomaDedifferentiated liposarcoma with low-grade dedifferentiated portion, malignancy grade at least G2
L84MyxofibrosarcomaUndifferentiated spindle cell sarcoma
L110Myxofibrosarcoma (high grade)High-grade, unclassifiable spindle cell sarcoma (G2)
L140Undifferenciated pleomorphic sarcomaHigh-grade, unclassifiable spindle cell sarcoma (G2)
L157Myxofibrosarcoma, high gradeHigh-grade, unclassifiable spindle cell sarcoma (G2)
L188Pleomorphic highly proliferative tumorGiant cell-rich leiomyosarcoma at least G2
L201Myxofibrosarcoma (high grade)Spindle cell sarcoma at least G2

Major discrepancies
Benign
Institution AInstitution B

L2Fat necrosisPHAT (pleomorphic hyalinizing angiectatic tumor of soft parts)
L37Fibrin-rich connective tissue with low chronic inflammation and regressive changesNodular fasciitis
L52Mature teratoma/dermoidSpinal dermoid cyst
L57Spindle-cell mesenchymal myofibroblastic proliferation with low MIB-1 proliferation rate along with skeletal musclesIntramuscular myxoma
L66Parts of a spindle-cell myxoid-chondroid impinging neoplasiaBenign portion of a peripheral nerve sheath tumor
L109Slightly atypical spindle cell tumor with myxoid background and increased proliferation (Ki67) of approx. 30%.Myofibroblastic proliferation of the nodular fasciitis type
L113Low-grade fibromyxoid sarcomaIntramuscular myxoma
L145Smooth-muscular proliferation with scaly calcifications as well as circumscribed ossification without necrosis or evidence of mitosesLeiomyoma of the deep somatic soft tissues
L195Intramuscular lipomaIntramuscular haemangioma
Intermediate
Institution AInstitution B
L100Spindle cell mast cell-rich proliferation with low proliferation rate and immunohistochemically S-100 positive with negativity for SOX-10Solitary fibrous tumor (SFT)
L101Plump spindle-cell tumour with multiple multinucleated giant cellsPeriosteal aneurysmal bone cyst (ABC)
L117Cell-rich neoplasia of oval, plump spindle mononuclear cells intermixed with giant cells and haemorrhage residues in connective tissue.Tenosynovial giant cell tumor of the diffuse type
Malignant
Institution AInstitution B
L1Epithelioid sarcomaAngiosarcoma
L6OsteosarcomaChondrosarcoma
L7Highly differentiated/dedifferentiated or a myxoid liposarcomaDedifferentiated liposarcoma (low grade)
L51Myxoid chondrosarcomaMyxoid liposarcoma (G1)
L70Chondroid and focal spindle cell neoplasiaMesenchymal chondrosarcoma
L76Slightly hypercellular chondrogenic tissue, connective tissue and skeletal muscleConventional chondrosarcoma
L94Pleomorphic liposarcomaRound cell liposarcoma G3
L150Small blue round cell tumor with low proliferation (Ki67) of approx. 10-15%.Granulosa cell tumor
L164Atypical lipomatous tumor/well-differentiated liposarcomaDedifferentiated liposarcoma, at least G2
L171Neoplasia, predominantly spindle cell in cancellous bone with focal evidence of irregular osteoid.Osteosarcoma, high grade
L191Infiltrates of small, round and blue cell neoplasiaPoorly differentiated neuroendocrine carcinoma (Merkel cell carcinoma)
L204Spindle and pleomorphic cell neoplasm with myxoid background of partial expression of MDM2High-grade myxofibrosarcoma (G2-3)