Soft tissue sarcoma in children

Liposarcomas in young patients: a study of 82 cases occurring in patients younger than 22 years of age

Liposarcomas typically occur in middle aged to older adults. Altogether, approximately 50 bona fide liposarcomas have been reported in children and adolescents, most of which have represented myxoid liposarcomas, with a good prognosis. We undertook a retrospective study of 82 liposarcomas occurring in patients below 22 years of age. Clinicopathologic and follow-up information was obtained. Fluorescence in situ hybridization for FUS, EWSR1, CHOP (DDIT3), and MDM2 was performed in 30 cases. The tumors occurred in 28 males and 54 females (5 to 22 y of age) and involved many locations. Fifty-six cases were typical myxoid liposarcomas, including 2 with round cell areas. The tumors were grade 1 (56 cases) and grade 3 (2 cases). Thirty-seven of 38 patients with follow-up are alive without disease and 1 is alive with disease (median 59 mo follow-up duration, range: 8 to 108 mo). Six cases showed myxoid liposarcoma with spindled growth ("spindle cell myxoid liposarcoma"); these arose in 5 females and 1 male (median age 14 y) and involved the thigh in 40% of cases. All were grade 1. Follow-up (4 of 6 patients) showed local recurrences in 2 cases and metastases in 1 case. Twelve tumors consisted of conventional myxoid liposarcoma and pleomorphic liposarcoma ("pleomorphic myxoid liposarcoma"); these arose in 4 males and 8 females (10 to 22 y of age) and often involved the mediastinum. Tumor grades were 2 (4 cases) and 3 (8 cases). Follow-up (10 patients) showed 7 dead of disease, 1 alive with disease, and 2 disease free. Four atypical lipomatous tumors were seen including 2 with low-grade dedifferentiation. Two local recurrences were seen; all patients are disease free. Two conventional pleomorphic liposarcomas were seen; 1 patient with follow-up is disease free. FUS-CHOP and EWSR1-CHOP rearrangements were identified by fluorescence in situ hybridization in 15/23 and 2/23 conventional myxoid liposarcomas, respectively, and in no other tumors. Amplification for MDM2 was absent in all cases. We conclude that conventional myxoid liposarcoma is by far the most common subtype of liposarcoma in young patients, with an excellent prognosis. Two apparently novel subtypes of liposarcoma, termed pleomorphic myxoid liposarcoma and spindle cell myxoid liposarcoma comprise considerable percentages of liposarcomas in this age group and should be distinguished from conventional myxoid liposarcoma and conventional pleomorphic liposarcoma. Pleomorphic myxoid liposarcoma and spindle cell myxoid liposarcoma most likely represent high-grade and low-grade variants of myxoid liposarcoma, respectively. Additional study of such cases will be necessary for definitive classification.

Undifferentiated sarcomas of children: pathology and clinical behavior--an Intergroup Rhabdomyosarcoma study

Undifferentiated soft tissue sarcoma (UND-STS) is the most poorly defined tumor eligible for intergroup Rhabdomyosarcoma Studies (IRS). Recent IRS UND-STS experience was reviewed to assess the histologic characteristics and clinical behavior of undifferentiated sarcomas. Of the 1,527 patients entered on IRS-III and IRS pilot-IV, 96 had tumors classified by the IRS Pathology Committee as UND-STS. Of these, 52 had adequate histologic material for this study. After application of immunohistochemistry, 18 tumors were reclassified, mostly as embryonal rhabdomyosarcomas (RMS), primitive neuroectodermal tumors, and intraabdominal desmoplastic small found cell tumors. The remaining 34 UND-STS had a diffuse hypercellular histologic pattern made up of sheets of medium-sized cells. The tumor cells had a minimal to moderate amount of cytoplasm and a variable nuclear morphology, predominately vesicular with finely granular chromatin. Except for reactivity with antibodies against vimentin, most tumors had a negative immunohistochemical profile. The 5 year Kaplan-Meier survival estimate for patients with non-metastatic disease was 72%, a significant improvement when contrasted with patients diagnosed to have UND-STS in IRS-I and IRS-II.

Congenital fibrosarcoma

Congenital fibrosarcoma is a rare fibrous tissue malignancy occurring most commonly in the extremities (71%), but presenting in axial locations as well (29%). Two of our five patients had lower extremity tumors and three had axial lesions located in the thoracolumbar region and anterior neck. Amputation was considered necessary to treat the extremity tumors. Two of the patients with axial lesions had incomplete resection, which raised the question of adjunctive therapy and prompted this review. Forty-seven additional cases of fibrosarcoma, present at birth or diagnosed within the first 3 months of life, were adequately described and documented in the literature giving a total of 52 cases. There was no sex predominance (male 26, female 20, unknown 6). Thirty-seven (71%) of the patients had extremity lesions. The local recurrence rate for extremity tumors was 32% with metastatic and mortality rates of 8% and 5%, respectively. Axial tumors (15 cases, 29%) had a local recurrence rate of 33%, which is similar to that for extremity lesions, but the metatstatic and mortality rates were 26% each indicating a more aggressive behavior for axial lesions. The overall mortality rate of 11.5% and metastatic rate of 13.5% for congenital fibrosarcoma, are not dissimilar to the figures quoted for older children. This pattern of tumor behavior, therefore, does not seem to warrant a different attitude because of the "congenital" occurrence of the tumor. Surgery must be considered the mainstay of therapy for fibrosarcoma, but there is a need for adjunctive therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibrosarcoma in infants and children: a review of 110 cases

This retrospective study summarizes the clinicopathologic findings in 110 children with fibrosarcoma. Seventy cases were selected from previous reports and 40 were from our files. The histologic criteria used for diagnosis are the same as those used for adults. Sixty-eight patients were in the first quinquennium of life, 13 in the second, and 29 in the third. Eleven patients died of their tumor, three in the first quinquennium and eight in ght third. Our findings indicate that children who are less than 5 years old have a 7.3% chance of developing metastatic spread even though the local recurrence rate is 43%. Children who are 10 years old or older had a metastatic rate of 50% at 5-year follow-up, a figure closely approximating that for adults. We believe that infants and children less than 5 years old may be treated initially by local excision of the lesion, without sacrificing significant function of the part. Recurrent tumor does not seem to predispose to metastatic disease.