Helena Willén

Clinicopathologic Re-Evaluation of 100 Malignant Fibrous Histiocytomas: Prognostic Relevance of Subclassification

PURPOSE Malignant fibrous histiocytoma (MFH) has been regarded as the most common soft tissue sarcoma (STS) in adults. Yet its true nature and the validity of this diagnostic concept have increasingly been questioned. Available data suggest that most patients with MFH can be subclassified into specific STS types, but the clinical relevance of such categorization has been argued. In a retrospective study, we reclassified 100 tumors of the extremity and trunk wall primarily diagnosed as MFH and analyzed the outcome. PATIENTS AND METHODS Patients were adults (median age, 70 years; range, 32 to 94 years). The median tumor size was 8 cm (range, 1 to 30 cm), and the thigh was the most common tumor location (n = 31). Median follow-up was 8 years (range, 3 to 16 years). The overall 5-year metastasis-free survival rate was 0.64. The tumors were reanalyzed histologically, immunohistochemically, and, where available, ultrastructurally, and were classified according to strict diagnostic criteria. Patients were staged according to the American Joint Committee on Cancer system, and prognoses were compared among different groups of the reclassified diagnoses, paying special attention to myogenic tumors. RESULTS In 84 of 100 tumors, a specific line of differentiation was either proved or strongly suggested. The most common diagnoses were myxofibrosarcoma (n = 22) and leiomyosarcoma (n = 20). Overall, 30 tumors could be grouped as some form of myogenic sarcoma. These tumors had a worse prognosis, even within the same American Joint Committee on Cancer stage, and a shorter time to metastasis than nonmyogenic tumors. CONCLUSION This retrospective study confirms that most so-called MFH can be subclassified by defined criteria; it provides evidence that such classification is clinically important. Specifically, pleomorphic STS showing myogenic differentiation are significantly more aggressive, a finding that allows planning future therapeutic trials.

Three major cytogenetic subgroups can be identified among chromosomally abnormal solitary lipomas.

SummaryWe have investigated cytogenetically a total of 35 solitary lipomas, 10 of which have been reported previously. Of the 25 tumours presented herein for the first time, clonal chromosome aberrations were detected in 17. The remaining eight had normal karyotypes, although two of them had nonclonal aberrations in about one quarter of the cells. Based on the cytogenetic findings in all 35 lipomas, four major subgroups can be distinguished. These are characterized by: (I) hyperdiploid karyotypes including one or more supernumerary ring chromosomes (5 cases); (II) diploid karyotypes with mostly balanced rearrangements involving 12q13-14 (13 cases), including the rearrangement t(3;12) (q27-28;q13-14) in 4 cases; (III) hypodiploid or diploid karyotypes with other aberrations than ring chromosomes or rearrangements of 12q13-14 (8 cases); and (IV) normal karyotypes (9 cases).

Combined morphologic and karyotypic study of 59 atypical lipomatous tumors : Evaluation of their relationship and differential diagnosis with other adipose tissue tumors (a report of the CHAMP study group)

Fifty-nine cases of atypical lipomatous tumors (ALT) of soft tissue (atypical lipomas, well-differentiated liposarcomas) were studied morphologically and cytogenetically as part of an international collaborative study. Forty-nine cases were deeply seated (including retroperitoneum), and 10 were superficial. Clonal chromosomal abnormalities were found in 55 cases (93%). Supernumerary ring or giant marker chromosomes (RGCs), the sole consistent alteration, were found in 37 ALTs (63%). They were more common in tumors that were large (p < 0.001), deeply seated (p < 0.005), that contained lipoblasts (p < 0.05), and that had marked cytologic atypia (p < 0.05). In a relatively short follow-up period (average, 3 years), only three of 59 cases recurred, one resulting in the patients death. All three cases had RGCs. Also, five of the six cases that underwent dedifferentiation had RGCs, indicating that RGCs are associated not only with low-grade malignant behavior (in the form of local recurrence) but also with the potential for tumor progression. When the karyotypic profile of ALT was compared with that of 233 other types of adipose tissue tumors similarly analyzed by the authors, a statistically highly significant correlation (p < 0.0001) was found between ALT and RGCs. These results support the existence of ALT as a distinct tumor subtype that is different from ordinary lipoma and from spindle or pleomorphic lipoma, albeit histogenetically closely related to them. It also supports the proposed pathogenetic link between ALT and dedifferentiated liposarcoma. The association between chromosomal and morphologic findings indicates the potential role of karyotypic analysis in the differential diagnosis of ALT with ordinary lipoma, spindle or pleomorphic lipoma, hibernoma, and myxoid liposarcoma.

Limb-sparing surgery without radiotherapy based on anatomic location of soft tissue sarcoma.

From 1980 through 1986, 119 patients with soft tissue sarcomas of the extremities were referred to our tumor center either before surgery (n = 78) or immediately after incisional biopsy or marginal excision (n = 41). The tumors were classified according to anatomic location at admittance as subcutaneous (n = 40), intramuscular (n = 30), and extramuscular tumors (n = 49). Open biopsy was omitted in 75 of the 78 patients referred before surgery; the preoperative diagnosis was based on physical and radiographic findings and fine-needle aspiration cytology. The surgical intention for subcutaneous tumor was to obtain a wide margin, which required a cuff of fat tissue around the tumor and inclusion of the deep fascia beneath the tumor. A wide margin for an intramuscular tumor implied no open biopsy and an unbroken muscle fascia or thick muscle cuff around the tumor (primary myectomy). The 70 patients with subcutaneous and intramuscular tumors were all treated by local surgery. A wide margin was obtained in 56 patients who were not given radiotherapy. During a median follow-up of 5 years (range, 3.5 to 10 years), four of these 56 patients--47 of whom had high-grade malignant tumors--had a local recurrence. We conclude that routine combination of limb-sparing surgery with adjuvant radiotherapy is not necessary in patients with soft tissue sarcoma. Two thirds of soft tissue sarcomas of the extremities are primarily subcutaneous or intramuscular tumors, the majority of which can be treated by local surgery without local adjuvant therapy with a local recurrence rate of less than 10%, irrespective of malignancy grade.

Cytogenetic analysis of 46 pleomorphic soft tissue sarcomas and correlation with morphologic and clinical features: A report of the CHAMP study group

With the aim of identifying objective cytogenetic‐morphologic correlations, we evaluated 46 pleomorphic soft tissue sarcomas (mainly diagnosed originally as malignant fibrous histiocytomas) with clonal chromosome aberrations both cytogenetically and morphologically as part of an international collaborative study. By detailed histopathologic examination, most cases could be categorized into specific tumor types. Eight sarcomas were diagnosed as lipogenic (4 pleomorphic, 1 combined pleomorphic and myxoid/round cell, and 3 dedifferentiated liposarcomas), 19 as myogenic [11 leiomyosarcomas, 1 rhabdomyosarcoma, 4 myosarcomas not otherwise specified (NOS), and 3 probable myosarcomas NOS], 8 as myxofibrosarcomas, 1 as a malignant peripheral nerve sheath tumor, 1 as malignant mesenchymoma, 1 as extraskeletal osteosarcoma, 1 as sarcoma resembling proliferative fasciitis, and 7 as pleomorphic sarcomas NOS. In a three‐grade system, 10 tumors were grade 2 and 36 were grade 3. The majority had highly complex karyotypes. A total of 24 recurrent abnormalities (defined by their presence in at least five cases) were detected: ring chromosomes, homogeneously staining regions (hsr) and/or double minute chromosomes (dmin), and structural rearrangement of 22 different chromosome bands or regions. The frequency and distribution of the recurrent karyotypic features were uneven. Grade 3 tumors displayed, on average, more aberrations per case than did grade 2 tumors. Nine of the selected abnormalities, including hsr/dmin and rearrangements of 19p13 and 19q13, were found only among the high‐grade tumors. When the tumors were subdivided according to lineage of differentiation, the highest frequency of aberrations was seen in pleomorphic sarcomas NOS, followed by myxofibrosarcomas, myogenic sarcomas, and lipogenic sarcomas. None of the selected rearrangements was, however, specific for any of these subgroups. The sole consistent cytogenetic‐morphologic association was that all three dedifferentiated liposarcomas had multiple abnormal clones, at least one of which contained supernumerary ring chromosomes. Due mainly to karyotype complexity, it therefore seems unlikely that cytogenetic analysis can assist in the differential diagnostic subclassification of pleomorphic sarcomas, nor was there any clear‐cut indication that the karyotypic picture could be used to predict clinical outcome. Although the mean number of recurrent chromosome aberrations was almost twice as high in sarcomas that gave rise to metastases as among those that did not, no particular aberration was restricted to either of the two subgroups. Genes Chromosomes Cancer 22:16–25, 1998.

Soft tissue leiomyosarcoma. A population-based epidemiologic and prognostic study of 48 patients, including cellular DNA content

Background. Leiomyosarcoma of soft tissue is a rare tumor. There are different opinions regarding epidemiology and prognosis.

Chromosome analysis of 96 uterine leiomyomas

From September 1989 to May 1990, we attempted cytogenetic analysis on 96 uterine leiomyomas removed from 64 women. Of the 90 tumors in which analysis was successful, 59 had a normal karyotype while 31 had clonal abnormalities. The most common aberration (13 tumors) was 7q-, mostly del(7)(q21.2q31.2); in two tumors with +12 and t(12;14) as the primary abnormalities, the 7q- was obviously a secondary change since it was found only in a subclone. A t(12;14)(q14-15;q23-24) was detected in two tumors, complex aberrations involving both 12q14-15 and 14q23-24 were also present in two, and rearrangements of 12q without concomitant 14q changes were seen in another two myomas. Rearrangements of 6p were present in five tumors, and trisomy 12 was found in two. More than one abnormality could be detected in 17 leiomyomas. Evidence of clonal evolution in the form of subclones was found in eight tumors, all of which were cellular and had histologically detectable mitotic activity. In addition to their clonal complexity, these myomas also frequently exhibited clonal telomeric associations (four tumors) and ring chromosome formation (three tumors; twice affecting chromosome 1). Monosomy 22 occurred as a secondary abnormality in three tumors; it, too, may reflect a preferred pathway in the karyotypic evolution of uterine leiomyomas.

Rings, dicentrics, and telomeric association in histiocytomas

We report clonal karyotypic abnormalities in six of 12 cytogenetically investigated malignant fibrous histiocytomas. Four of eight tumors of the pleomorphic subtype had complex clonal chromosome aberrations, including ring chromosomes, dicentric chromosomes, and/or telomeric associations. No common characteristic aberration could be distinguished. Two of four myxoid tumors had clonal changes: One had one to two ring chromosomes and an extra chromosome #2; another had a supernumerary ring chromosome as the sole abnormality.

Correlation between clinicopathological features and karyotype in 100 cartilaginous and chordoid tumours. A report from the Chromosomes and Morphology (CHAMP) Collaborative Study Group

The evaluation of chondroid lesions requires full integration of clinical, radiographic, and pathological data; tumour typing is often a challenge for the diagnostic pathologist. Although a variety of chromosomal abnormalities have been documented in chondroid lesions, the potential usefulness of cytogenetic analysis remains unclear. This study has critically reviewed and analysed 117 karyotyped samples from 100 patients with cartilaginous and chordoid tumours. Cases were selected based on successful chromosomal analysis and adequacy of clinical, radiographic, and pathological information. To ensure objective evaluation, the cytogenetic results were correlated in a double‐blind setting with consensus diagnoses independently determined on each case, after complete review of the histological, radiographic, and clinical findings. Karyotypic aberrations were identified in 41/92 cartilaginous tumours (5/11 osteochondromas, 2/3 chondromyxoid fibromas, 0/4 chondroblastomas, 11/29 chondromas, 0/3 chondroid tumours of undetermined malignant potential, 22/40 chondrosarcomas and 1/2 miscellaneous cartilaginous lesions) and 5/8 chordomas. Complex karyotypic changes were a feature of malignant tumours (chondrosarcoma and chordoma) and of chondrosarcoma among cartilaginous tumours, where they correlated with high tumour grade. Among primary well‐differentiated cartilaginous lesions of bone, the finding of an abnormal karyotype was consistently associated with a grade 1 chondrosarcoma diagnosis. Among karyotypically abnormal cartilaginous tumours, loss of distal 8q was associated with osteochondroma, +5 with synovial chondroma/chondromatosis and parosteal or soft tissue chondroma, alterations of chromosome arm 6q with chondromyxoid fibroma, +7 with bone chondrosarcoma, and 17p1 alterations with grade 3 chondrosarcoma. Alterations involving 12q13 characterized synovial chondroma/chondromatosis in the chondroma group and myxoid chondrosarcoma of bone in the chondrosarcoma group. In conclusion, cytogenetic abnormalities in chondroid lesions are common and are not randomly distributed. They are associated with malignancy/tumour grade as well as with specific diagnoses in many cases, and can therefore be of potential value for tumour typing. Copyright

Characteristic chromosome abnormalities, including rearrangements of 6p, del(7q), +12, and t(12;14), in 44 uterine leiomyomas

SummaryThe cytogenetic analysis of 224 leiomyomas from 138 patients is presented. An insufficient number of mitoses was found in 35 tumors, normal karyotypes in 145, and clonal chromosome aberrations were detected in 44. The three previously identified cytogenetic subgroups were all represented in this series: del(7) (q21.2q31.2) was found in 11, trisomy 12 in five, and t(12;14)(q14-15;q23-24) in one leiomyoma. Rearrangements of 6p, including deletions, inversions, and various translocations, were found in eight tumors, thus delineating a new cytogenetic subgroup of uterine leiomyoma. The remaining 21 karyotypically abnormal tumors had nonrecurrent changes. One leiomyoma had two cytogenetically unrelated clones characterized by del(7)(q21.2 q31.2) and +12. Karyotypic changes in two separate leiomyomas from the same uterus were identified in five patients; in three of them, different anomalies were found in the two tumors, whereas cytogenetically identical aberrations − del(7q) and dic(21;22) − were detected in two macroscopically discrete tumors. These findings suggest that whereas some multiple leiomyomas originate independently, others may be derived from the same neoplastic clone.