Pathology and grading of soft tissue sarcomas

MFH revisited: outcome after surgical treatment of undifferentiated pleomorphic or not otherwise specified (NOS) sarcomas of the extremities -- an analysis of 140 patients

BACKGROUND

Undifferentiated pleomorphic sarcoma/NOS (not otherwise specified; former pleomorphic and storiform MFH) of the extremities is a common malignant soft tissue tumor in adults. The objective of this study is to determine prognostic factors for the outcome after surgical treatment with respect to the recent developments in classification.

METHODS

From 1996 to 2004, 140 undifferentiated pleomorphic sarcomas/NOS were identified out of 1,200 soft tissue sarcomas of the extremities that were treated at our institution and recorded in a prospective database. Overall survival (OS) and isolated local recurrence (ILR) were determined by Kaplan-Meier analysis. All tumors were retrospectively analyzed regarding prognostic factors of the disease, including patient's background (primary or recurrent), histological grade (G2/G3), adjuvant chemotherapy and radiotherapy, size (T1-2) and depth of the tumor, and surgical margins (R0, R1, R2).

RESULTS

In 123 patients, a wide resection was performed (limb-sparing surgery). In nine patients, an amputation was necessary. The overall 5-year survival rate was 72% (median follow up: 52 months). There was a significant difference between the group presenting with primary tumors (5-year survival: 84%, p < 0.05) and recurrent tumors (5-year survival: 62%, p < 0.05). Isolated local recurrence occurred in 36 patients.

CONCLUSIONS

In terms of OS and ILR, primary or recurrence, negative surgical margins, size and grading had a highly significant influence, whereas the site of surgery and adjuvant chemotherapy, adjuvant radiation and tumor depth did not. Prognosis for patients with undifferentiated pleomorphic sarcoma of the extremities depends predominantly on adequate wide resection of the primary tumor.

Low-grade fibromyxoid sarcoma and hyalinizing spindle cell tumor with giant rosettes: a clinicopathologic study of 73 cases supporting their identity and assessing the impact of high-grade areas

Low-grade fibromyxoid sarcoma (LGFMS) is a rare sarcoma characterized by bland histologic features and a paradoxically aggressive clinical course. The hyalinizing spindle cell tumor with giant rosettes (HSCT) is a closely related tumor characterized by the presence of giant collagen rosettes. Only a single example of a metastasizing HSCT has been reported. A small subset of both LGFMS and HSCT display areas of increased cellularity and atypia which qualify as intermediate- to high-grade sarcoma; the significance of these features has not been definitively assessed. We present the clinicopathologic features of 77 cases of LGFMS and HSCT to determine the degree of overlap of these two lesions, their biologic behavior, and the significance of the occasional presence of intermediate- to high-grade sarcoma within both. The patients (33 female, 40 male) ranged from 3 to 78 years of age (median, 34 yrs). Fourteen cases occurred in patients less than 18 years of age. The tumors measured from 1 to 23 cm (median, 4.5 cm) and occurred predominantly in the trunk and lower extremities in both the deep (66 cases) and superficial (7 cases) soft tissues. In 15 cases, the tumor was present > 1 year before diagnosis. All tumors showed predominantly the typical hypocellularity and bland cytologic features of typical LGFMS; however, areas of hypercellularity and nuclear enlargement and hyperchromatism were identified in 12 of 73 (16%) and 7 of 73 (10%), respectively. Necrosis and mitotic activity >5/50 high-powered fields (HPF) were present in 6 of 73 (8%) and 5 of 73 (7%), respectively. Epithelioid areas were present in 33 of 73 (45%) and rosettes in 22 of 73 (30%). Follow up (54 cases; range, 2-192 mos; median, 24 mos; mean, 38 mos) showed 5 recurrences, 3 metastases, and 1 death. The diagnosis of LGFMS or HSCT was made prospectively in 51 patients; none had metastatic disease. Two of the metastatic tumors were LGFMS and one was a HSCT. LGFMS may occur more often in the pediatric population and show a much wider histologic spectrum than previously thought. A significant number of LGFMS possess inconspicuous collagen rosettes characteristic of HSCT, indicating that these two tumors are ends of a common spectrum rather than distinct entities. HSCT, like LGFMS, are low-grade sarcomas with metastatic potential. The presence of focal areas of intermediate- to high-grade sarcoma does not portend a worse outcome in the short term. The better prognosis reflected in this study compared with previous ones might reflect the fact that all were initially diagnosed as sarcomas and treated with aggressive surgery. The fact that the only three patients to develop metastatic disease were patients whose LGFMS or HSCT was identified retrospectively supports this concept.

Molecular and immunohistochemical p53 status in liposarcoma and malignant fibrous histiocytoma: identification of seven new mutations for soft tissue sarcomas

BACKGROUND

p53 mutations are the most frequently observed tumor-related genetic changes. Mutational analysis concerns mostly carcinomas and is not comprehensive for soft tissue sarcomas. Among soft tissue sarcomas, malignant fibrous histiocytoma (MFH) and liposarcoma represent the most frequent tumor types. Most of the few identified mutations for soft tissue sarcomas are localized in the core domain of p53. A correlation between p53 positive immunoreactivity, missense mutations, and a poor prognosis is generally assumed. However, the character of p53 mutations and their functional importance for the clinical process is still unknown.

METHODS

Sixty-two soft tissue sarcoma samples were investigated for the presence of p53 mutations and for p53 immunoreactivity. Exons 4-9 of the p53 gene were amplified from genomic DNA with the polymerase chain reaction. A prescreen for mutations was performed by nonradioactive single strand conformation polymorphism analysis; striking cases were sequenced directly. For an evaluation of the immunohistochemical status, five p53 antibodies were used.

RESULTS

In 10 tumor samples 7 new p53 mutations and one polymorphism were identified. Mutations were detected for five liposarcomas (four patients) and four MFHs (three patients). Of the seven mutations, three were missense point mutations, three were deletions, and one was a complex conversion. All mutations but one were localized in the core domain of p53. Of 62 tumor samples, 56% (14 of 32 liposarcomas and 21 of 30 MFHs) were positive for p53 immunostaining.

CONCLUSIONS

The mutations identified in the core domain affect codons that are structurally or functionally involved in DNA binding. A relation between p53 positive immunoreactivity and a poor prognosis, but not with an exclusively high tumor grade, is evident. p53 mutations in soft tissue sarcomas have a similar spectrum to those in carcinomas.