In locoregional disease such as sarcoma, FQA may offer the only possibility of cure. However, in patients with axillary metastasis, FQA has no impact on survival, although local control may improve the patient's quality of life.

The classification of multifocal myxoid/round cell liposarcoma, which is defined as tumor presentation in at least two separate sites before manifestation in the lungs, as either metastasis or as a second primary tumor, has essential clinical consequences. Genetically, myxoid/round cell liposarcoma is characterized by t(12; 16)(q13;p11) or t(12;22)(q13;q12), and various exon fusion transcripts are described with varying incidences, which permits their use as markers for clonality. Moreover, in solid tumors, analysis of loss of heterozygozity is valuable for clonality analysis. Therefore, fifteen multifocal myxoid/round cell liposarcoma patients with two to five metachronous (n ‫؍‬ 12) or synchronous (n ‫؍‬ 3) localizations were investigated. Using RT-PCR, the detailed molecular characteristics of the FUS-CHOP and EWS-CHOP breakpoints were determined. Loss of heterozygozity analysis at twelve loci was then used to further analyze clonal relationships. In all patients, tumor sites showed identical FUS-CHOP fusion products. In six patients, identical rare fusion transcripts were found, supporting a clonal relationship. Nine patients had the common exon5-FUS/exon2-CHOP fusion transcript, and two of these were identified as clonally related by loss of heterozygozity analysis. In all other patients, loss of heterozygozity analysis was highly suggestive of a clonal relationship, and no evidence for interpretation of a second primary tumor was found. This study supports the metastatic nature of apparent multifocal myxoid/round cell liposarcoma. Multifocal presentation in soft tissue tumors, especially in myxoid/round cell liposarcoma (MRLS), has been a matter of debate for some time. This issue has not been fully resolved because of the limited patients for whom data are available.1-5 Multifocality in soft tissue sarcoma is defined as the presence of sarcoma on at least two separate sites before manifestation of disease in sites where sarcomas most commonly metastasize, in particular the lungs. The first reported case of multifocal sarcoma dates to 1934, when Siegmund described a patient with multiple fatty tumors, which was interpreted as "Lipoblastische Sarcomatose" or a systemic malignant disease of the soft tissue.6 Since then, the debate persists whether this entity represents separate primary tumors or an unusual pattern of metastasis.Differentiation between second primary and disseminated MRLS has major clinical consequences. A resectable second primary MRLS would indicate an optimal surgical approach combined with (neo) adjuvant radiotherapy with curative intent, whereas in metastatic disease, the choice of treatment, surgery, radiotherapy, or chemotherapy is made with a limited expectation of ultimate cure, predicting other metastases in the near future.A clonal relationship between two tumors proves their common origin in case of metastases. Conversely, the absence of a clonal relationship would suggest a second primary sarcoma. Several assays have been developed to evaluate clonal relationship between tumors....