Residual Byproducts of Peroxide Crosslinked Vitamin E-Blended Ultrahigh Molecular Weight Polyethylene.

BACKGROUND: Wear resistance of ultrahigh molecular weight polyethylene (UHMWPE) is improved via ionizing radiation crosslinking and subsequent high temperature melting for improved toughness. Our group has previously reported that crosslinking can also be achieved chemically using organic peroxides. However, volatile peroxide byproducts are generated during consolidation. The purpose of this study was to quantify elution of volatile peroxide byproducts from UHMWPE before and after in vivo implantation, and to determine their effects on local tissues. METHODS: We prepared crosslinked UHMWPE samples with 5 times the nominal concentration of peroxide needed for improved wear resistance. Control samples (not crosslinked), crosslinked samples, and crosslinked high temperature melting samples were implanted subcutaneously in New Zealand white rabbits for 28 days. Fourier-transform infrared spectroscopy (FTIR) was used to quantify elution of residual peroxide byproducts, and biocompatibility was determined via histological analysis of periprosthetic tissues. RESULTS: Fourier-transform infrared spectroscopy demonstrated elution of residual peroxide byproducts in vivo. No histological differences were observed between tissues in contact with any of the 3 groups of implants; tissues were characterized by fibrosis and a synovial-like lining for all groups. CONCLUSION: UHMWPE chemically crosslinked with very high concentration of organic peroxide did not show any detrimental changes to surrounding subcutaneous tissues, further demonstrating feasibility of crosslinking UHMWPE with a peroxide, rather than irradiation, for the potential use of the material as a bearing surface for joint arthroplasty.

Giant Cell Tumor of the Uterus: A Report of 3 Cases With a Spectrum of Morphologic Features.

Giant cell tumors, a well-recognized neoplasm of bone, can rarely be found in the uterus. Such tumors are characterized by a dual population of mononuclear and osteoclast-like giant cells that lack epithelial and specific mesenchymal differentiation. In this study, the clinicopathologic features of 3 giant cell tumors of the uterus were reviewed. Immunohistochemistry for CD68, CD163, h-caldesmon, desmin, SMA, AE1/AE3, CD10, ER, PR, cyclin D1, CD1a, CD34, CD30, S100, myogenin/myoglobin, and Ki-67 was performed in all tumors, along with ultrastructural analysis in one. The patients were 47, 57, and 59 yr and the tumors measured 2.5, 7.5, and 16.0 cm. One neoplasm was confined to the endometrium, whereas the other 2 were myometrial. All 3 tumors showed a nodular growth comprised of mononuclear and osteoclast-like giant cells. The endometrial-confined tumor consisted of histologically benign mononuclear cells, whereas the others exhibited marked atypia. Mitotic activity was up to 5/10 HPF in the benign tumor and up to 22/10 HPF in the malignant. No cytologic atypia or mitoses were observed in the giant cells. CD68 and CD10 were strongly and diffusely expressed in both components of 3 and 2 neoplasms, respectively. Cyclin D1 was focal in the mononuclear cells and focal to diffuse in the giant cells. CD163 was diffuse in the mononuclear cells, but absent to focal in the giant cells. Ultrastructural analysis lacked diagnostic features of epithelial or specific mesenchymal differentiation. Both malignant tumors demonstrated an aggressive behavior. In summary, although rare, giant cell tumor of the uterus should be included in the differential diagnosis of benign or malignant tumors containing osteoclast-like giant cells.

Role of post-operative radiation boost for soft tissue sarcomas with positive margins following pre-operative radiation and surgery.

BACKGROUND AND OBJECTIVES: The role of a radiation therapy (RT) boost for positive margins following pre-operative RT and surgery in extremity soft tissue sarcomas (STS) is unclear. We assessed the contribution of a boost to local control (LC), disease-free survival (DFS), and overall survival (OS). METHODS: We identified 67 patients treated from 1987 to 2011 with pre-operative RT and surgery with positive margin(s). Select patients received a boost delivered as peri-operative Iridium-192 brachytherapy (BRT), intra-operative electrons (IORT), or post-operative external beam RT (EBRT). RESULTS: Ten patients received no RT boost, 10 received a BRT or IORT boost, and 47 received an EBRT boost. Five-year LC rates for no boost, BRT/IORT boost, and EBRT boost were 100%, 78%, and 71% (P = 0.5). On multivariate analysis, there were no significant predictors for LC. Variables associated with improved DFS rates were single positive margin (P = 0.007) and low tumor grade (P = 0.03). Tumor size <5 cm (P = 0.003), low grade (P = 0.001), and boost (P = 0.02) were associated with longer survival. CONCLUSIONS: We did not identify a LC advantage for an RT boost. Given the unidentified selection factors for delivery of boost and its potential toxicities, its role in this setting remains unproven.

Primary Clear Cell Sarcoma of Bone: Clinicopathologic Study of a Rare Presentation.

Clear cell sarcoma (CCS) is an uncommon malignant mesenchymal neoplasm of young adults with a predilection for tendons and aponeuroses of distal extremities, a distinctive nested growth pattern, melanocytic differentiation, and usually an EWSR1::ATF1 fusion. Distinction from melanoma can be challenging but is critical for clinical management. Rare cases of primary bone CCS have been reported. The purpose of this study was to evaluate the clinicopathologic features of a series of primary bone CCS. Three cases of primary bone CCS were identified out of 140 CCS diagnosed between 2010 and 2021. Two patients were female, and 1 patient was male; ages were 19, 47, and 61 years. All tumors arose in the long bones of the extremities (femur, humerus, fibula). Two tumors also involved regional lymph nodes at presentation. Two showed characteristic histologic features, in the form of nests and fascicles of uniform epithelioid to spindle cells with prominent nucleoli and pale eosinophilic to clear cytoplasm; 1 tumor showed sheet-like growth, unusual focal pleomorphism, and more notable nuclear atypia. By immunohistochemistry, S100 protein was positive in 2/3 cases, SOX10 in 3/3, HMB-45 in 2/3, MiTF in 2/2, and melan A in 1/3. All cases were confirmed to harbor EWSR1 rearrangement and EWSR1::ATF1 fusion or t(12;22). On follow-up, all 3 patients developed metastases and died of disease, 5, 18, and 21 months after diagnosis. In summary, CCS rarely presents in the skeleton. At such locations, distinction from metastatic melanoma is particularly challenging. Clinical and pathologic features are similar to conventional CCS of soft tissue. Primary bone CCS may pursue an aggressive clinical course.

Do histologic criteria predict biologic behavior of giant cell lesions?

PURPOSE: To determine whether the clinical behavior of giant cell lesions (GCLs) or their anatomic location can be differentiated by histologic criteria alone. MATERIALS AND METHODS: We performed a retrospective study of patients with GCLs treated at Massachusetts General Hospital between 1993 and 2008. Predictor variables were histologic parameters: number of giant cells (GCs) per high-power field, number of nuclei per GC, GC size, stromal cellularity, stromal type, presence of hemorrhage and reactive osteoid, and blinded pathologists' prediction of location and behavior. Outcome variables were clinical behavior (aggressive or nonaggressive) and GCL location, that is, maxillofacial (MF) or axial/appendicular (AA). Descriptive and bivariate statistics were computed with statistical significance set at P ≤ .05. RESULTS: The sample included 88 subjects: 41 MF GCLs (35 aggressive) and 47 AA GCLs (28 aggressive). Aggressive AA lesions had more GCs per high-power field, larger mean GC size, and increased stromal cellularity, and they more frequently had a mononuclear stroma when compared with aggressive MF lesions (P < .05). There were no significant histologic differences between aggressive and nonaggressive MF lesions or between nonaggressive MF and nonaggressive AA lesions. Aggressive AA lesions had more nuclei/GC than nonaggressive AA lesions (P = .03). Using histologic criteria only, blinded pathologists predicted clinical behavior in only 45% of cases (κ = 0.19, P = .09). They predicted a lesion's location in 82% of cases with fair agreement (κ = 0.44, P < .01). CONCLUSIONS: Results of this study indicate that histologic differences between aggressive and nonaggressive GCLs are insufficient for pathologists to differentiate them consistently regardless of location.

Pseudocarcinomatous Squamous Hyperplasia Involving Bone: A Diagnostic Pitfall Mimicking Squamous Cell Carcinoma.

BACKGROUND: Pseudocarcinomatous squamous hyperplasia (PSH) within the bone is uncommon and closely mimics well-differentiated squamous cell carcinoma (SCC). It arises from cutaneous or mucosal surfaces and grows directly into the bone. This study analyzes a large series of PSH and discusses the clinicopathologic features that facilitate its distinction from SCC. DESIGN: Cases were identified from the surgical pathology files between 1985 and 2020. RESULTS: The 31 cases included 21 males, 9 females, 1 unknown sex; who were 20 to 87 years old (average: 59 y). Sites included mandible-17, maxilla-5, toes-4, and 1 case from finger, femur, tibia, ischium, and unknown. Fourteen patients had a history of SCC, 13 treated with resection and chemoradiation and developed infected osteoradionecrosis, 4-medication-related osteonecrosis, 3-peripheral vascular disease, and diabetes mellitus, 3-trauma, 3-osteomyelitis, 3-unknown, and 1-hematologic malignancy. All cases exhibited severe osteomyelitis and nests of reactive keratinizing squamous epithelium that matured towards the bone surface, lacked significant atypia, or mitotic activity but permeated the medullary cavity. Patients with previous SCC developed PSH after 2 months to 8 years (average: 4 y). Nineteen of 30 patients had follow-up (2 to 48 mo, average: 17 mo); 6 patients experienced repeated debridements over 2 months to 1 year; no patient developed SCC. CONCLUSIONS: PSH involving bone is infrequent, complicates severe osteomyelitis, and is often therapy related. The clinical findings are usually not concerning for malignancy, however, the histologic findings are an important diagnostic pitfall because they mimic SCC.

Clinical Utility of Anchored Multiplex Solid Fusion Assay for Diagnosis of Bone and Soft Tissue Tumors.

Sarcoma diagnosis has become increasingly complex, requiring a combination of morphology, immunohistochemistry, and molecular studies to derive specific diagnoses. We evaluated the role of anchored multiplex polymerase chain reaction-based gene fusion assay in sarcoma diagnostics. Between 2015 and 2018, bone and soft tissue sarcomas with fusion assay results were compared with the histologic diagnosis. Of 143 sarcomas tested for fusions, 43 (30%) had a detectable fusion. In review, they could be classified into 2 main categories: (1) 31 tumors with concordant morphologic and fusion data; and (2) 12 tumors where the fusion panel identified an unexpected rearrangement that played a significant role in classification. The overall concordance of the fusion assay results with morphology/immunohistochemistry or alternate confirmatory molecular studies was 83%. Collectively, anchored multiplex polymerase chain reaction-based solid fusion assay represents a robust means of detecting targeted fusions with known and novel partners. The predictive value of the panel is highest in tumors that show a monomorphic cell population, round cell tumors, as well as tumors rich in inflammatory cells. However, with an increased ability to discover fusions of uncertain significance, it remains essential to emphasize that the diagnosis of bone and soft tissue neoplasms requires the integration of morphology and immunohistochemical profile with these molecular methods, for accurate diagnosis and optimal clinical management of sarcomas.

Aberrant hyperactivation of akt and Mammalian target of rapamycin complex 1 signaling in sporadic chordomas.

PURPOSE: Chordomas are rare, malignant bone neoplasms in which the pathogenic mechanisms remain unknown. Interestingly, tuberous sclerosis complex (TSC) is the only syndrome in which the incidence of chordomas has been described. We previously reported the pathogenic role of the TSC genes in TSC-associated chordomas. In this study, we investigated whether aberrant TSC/mammalian target of rapamycin complex 1 (mTORC1) signaling pathway is associated with sporadic chordomas. EXPERIMENTAL DESIGN: We assessed the status of mTORC1 signaling in primary tumors/cell lines of sacral chordomas and further examined upstream of mTORC1 signaling, including the PTEN (phosphatase and tensin homologue deleted on chromosome ten) tumor suppressor. We also tested the efficacy of the mTOR inhibitor rapamycin on signaling and growth of chordoma cell lines. RESULTS: Sporadic sacral chordoma tumors and cell lines examined commonly displayed hyperactivated Akt and mTORC1 signaling. Strikingly, expression of PTEN, a negative regulator of mTORC1 signaling, was not detected or significantly reduced in chordoma-derived cell lines and primary tumors. Furthermore, rapamycin inhibited mTORC1 activation and suppressed proliferation of chordoma-derived cell line. CONCLUSIONS: Our results suggest that loss of PTEN as well as other genetic alterations that result in constitutive activation of Akt/mTORC1 signaling may contribute to the development of sporadic chordomas. More importantly, a combination of Akt and mTORC1 inhibition may provide clinical benefits to chordoma patients.

Ultrastructural Characterization of Mammary Analogue Secretory Carcinoma of the Salivary Glands: A Distinct Entity from Acinic Cell Carcinoma?

Mammary analogue secretory carcinoma (MASC) of the salivary glands is a recently described neoplasm of the salivary glands with a characteristic morphology complemented by a specific cytogenetic translocation and gene rearrangements. Although immunophenotypic and cytogenetic differences allow for a more reliable distinction, ultrastructural features can also provide important information about the relationship between MASC, classic acinic cell carcinoma (AciCC), and AciCC intercalated duct cell-predominant variant. Following approval from the hospital's institutional review board, 7 cases of MASC, 8 cases of classic AciCC, and 4 cases of AciCC intercalated duct cell-predominant variant were retrieved from the pathology files of Massachusetts General Hospital from 2012 to 2015. Electron microscopy was performed using formalin-fixed, paraffin-embedded tissue. Ultrastructural features of all 19 neoplasms of the salivary glands were recorded. The predominant cell-types observed in MASC are those with intercalated/striated duct cell differentiation. These features include prominent invaginations of the cell surface studded with microvilli, and some intra- and intercellular lumina also with a microvillous surface. Classic AciCC dominant cell-type recapitulates acinar cell differentiation. These cells contain large intracytoplasmic zymogen-like granules. AciCC intercalated duct cell-predominant variant showed both cell populations in various proportions with the intercalated/striated duct cell type usually being the dominant one. MASC presents with distinctive ultrastructural features that allows its proper differentiation from classic AciCC. However, significant ultrastructural features overlaps between both AciCC intercalated duct cells-predominant and classic AciCC and MASC. These findings indicate a very close proximity between these tumors.

Base of skull chordomas in children and adolescents: a clinicopathologic study of 73 cases.

Chordomas in children and adolescents comprise <5% of all chordomas and most frequently develop in the skull base. These tumors are believed to behave more aggressively than chordomas in adults and may have unusual morphology. This study examines a large series of pediatric skull base chordomas treated with a standardized protocol to characterize the behavior and morphology of these tumors. There were 31 males and 42 females ranging from 1 to 18 (mean 9.7) years. Forty-two cases (58%) were conventional chordomas, some of which had unusual histopathologic features. Chondroid chordomas comprised 23% of cases. Fourteen tumors (19%) were highly cellular and had a solid growth pattern with no myxoid matrix or lobular architecture. Eight of these had cytologic features of conventional chordoma cells including physaliferous cells (cellular chordoma). The remaining cellular tumors were composed of poorly differentiated epithelioid cells set in a fibrous stroma and lacked physaliferous cells (poorly differentiated chordoma). All variants studied by immunohistochemistry showed positive staining for cytokeratin, epithelial membrane antigen, S100 protein, and vimentin. Mitoses and necrosis were seen in all variants. Follow-up data were available for all patients and ranged from 1 to 21 (mean 7.25) years. The survival rate was 81%. All but 1 patient with poorly differentiated chordoma died of disease. Overall, base of skull chordomas in children and adolescents treated with proton beam radiation have better survival than chordomas in adults. However, poorly differentiated chordomas are highly aggressive tumors.

Comparative pathology of nerve sheath tumors in mouse models and humans.

Despite the progress made in our understanding of the biology of neurofibromatosis (NF), the long-term clinical outcome for affected patients has not changed significantly in the past decades, and both NF1 and NF2 are still associated with a significant morbidity and a decreased life span. A number of NF1 and NF2 murine models have been generated to aid in the study of NF tumor biology and in the development of targeted therapies for NF patients. A single, universal pathological classification of the lesions generated in these murine models is essential for the validation of the models, for their analysis and comparison with other models, and for their future effective use in preclinical treatment trials. For the formulation of a pathological classification of these lesions, the WHO classification of human tumors was used as a reference. However, it was not adopted for the classification of the GEM lesions because of some important differences between the human and murine lesions. A novel classification scheme for peripheral nerve sheath tumors in murine models was therefore devised.

Primary Pseudomyogenic Hemangioendothelioma of Bone.

Pseudomyogenic hemangioendothelioma (PMH) is a well-recognized neoplasm that usually arises in the soft tissue; concurrent bone involvement occurs in 24% of cases. PMH of bone without soft tissue involvement is rare. We describe the clinicopathologic findings of 10 such cases, the largest series reported to date. The study included 9 male and 1 female patient; their ages ranged from 12 to 74 years (mean 36.7 y). All patients had multiple tumors with a distinct regional distribution: 45% restricted to the lower extremity; 25% to the spine and pelvis; and 15% to the upper extremity. On imaging studies the tumors were well circumscribed and lytic. The neoplasms were composed of spindled cells arranged in intersecting fascicles with scattered epithelioid cells; epithelioid cells predominated in 3 cases. The neoplastic cells contained abundant densely eosinophilic cytoplasm and vesicular nuclei. There was limited cytologic atypia and necrosis, few mitoses (0 to 2/10 high-power fields), and inconspicuous stroma. Unique findings included abundant intratumoral reactive woven bone and hemorrhage with numerous osteoclast-like giant cells. Immunohistochemically, most tumors were positive for keratin, ERG, and CD31; CD34 was negative. The balanced t(7:19)(q22;13) translocation was documented in 3 cases. Follow-up is limited, but no patient developed documented visceral dissemination, and all have stable or progressive osseous disease. PMH exclusively involving bone is rare. It is multicentric, often involves the lower extremity, and has unusual morphology. The differential diagnosis includes epithelioid vascular neoplasms, giant cell tumor, bone forming neoplasms, and metastatic carcinoma. Because of its rarity, unusual presentation, and morphology, accurate diagnosis can be challenging.

High-resolution array CGH and gene expression profiling of alveolar soft part sarcoma.

PURPOSE: Alveolar soft part sarcoma (ASPS) is a soft tissue sarcoma with poor prognosis, and little molecular evidence exists for its origin, initiation, and progression. The aim of this study was to elucidate candidate molecular pathways involved in tumor pathogenesis. EXPERIMENTAL DESIGN: We employed high-throughput array comparative genomic hybridization (aCGH) and cDNA-Mediated Annealing, Selection, Ligation, and Extension Assay to profile the genomic and expression signatures of primary and metastatic ASPS from 17 tumors derived from 11 patients. We used an integrative bioinformatics approach to elucidate the molecular pathways associated with ASPS progression. FISH was performed to validate the presence of the t(X;17)(p11.2;q25) ASPL-TFE3 fusion and, hence, confirm the aCGH observations. RESULTS: FISH analysis identified the ASPL-TFE3 fusion in all cases. aCGH revealed a higher number of numerical aberrations in metastatic tumors relative to primaries, but failed to identify consistent alterations in either group. Gene expression analysis highlighted 1,063 genes that were differentially expressed between the two groups. Gene set enrichment analysis identified 16 enriched gene sets (P < 0.1) associated with differentially expressed genes. Notable among these were several stem cell gene expression signatures and pathways related to differentiation. In particular, the paired box transcription factor PAX6 was upregulated in the primary tumors, along with several genes whose mouse orthologs have previously been implicated in Pax6 DNA binding during neural stem cell differentiation. CONCLUSION: In addition to suggesting a tentative neural line of differentiation for ASPS, these results implicate transcriptional deregulation from fusion genes in the pathogenesis of ASPS.

Genotyping cancer-associated genes in chordoma identifies mutations in oncogenes and areas of chromosomal loss involving CDKN2A, PTEN, and SMARCB1.

The molecular mechanisms underlying chordoma pathogenesis are unknown. We therefore sought to identify novel mutations to better understand chordoma biology and to potentially identify therapeutic targets. Given the relatively high costs of whole genome sequencing, we performed a focused genetic analysis using matrix-assisted laser desorption/ionization-time of flight mass spectrometer (Sequenom iPLEX genotyping). We tested 865 hotspot mutations in 111 oncogenes and selected tumor suppressor genes (OncoMap v. 3.0) of 45 human chordoma tumor samples. Of the analyzed samples, seven were identified with at least one mutation. Six of these were from fresh frozen samples, and one was from a paraffin embedded sample. These observations were validated using an independent platform using homogeneous mass extend MALDI-TOF (Sequenom hME Genotyping). These genetic alterations include: ALK (A877S), CTNNB1 (T41A), NRAS (Q61R), PIK3CA (E545K), PTEN (R130), CDKN2A (R58*), and SMARCB1 (R40*). This study reports on the largest comprehensive mutational analysis of chordomas performed to date. To focus on mutations that have the greatest chance of clinical relevance, we tested only oncogenes and tumor suppressor genes that have been previously implicated in the tumorigenesis of more common malignancies. We identified rare genetic changes that may have functional significance to the underlying biology and potential therapeutics for chordomas. Mutations in CDKN2A and PTEN occurred in areas of chromosomal copy loss. When this data is paired with the studies showing 18 of 21 chordoma samples displaying copy loss at the locus for CDKN2A, 17 of 21 chordoma samples displaying copy loss at PTEN, and 3 of 4 chordoma samples displaying deletion at the SMARCB1 locus, we can infer that a loss of heterozygosity at these three loci may play a significant role in chordoma pathogenesis.

Eosinophilic angiocentric fibrosis is a form of IgG4-related systemic disease.

BACKGROUND: Eosinophilic angiocentric fibrosis (EAF) is an uncommon tumefactive lesion of the orbit and upper respiratory tract of unknown etiology. The condition is characterized histologically by concentric layers of fibrosis around small-caliber arteries and a mixed inflammatory infiltrate dominated by eosinophils. After the serendipitous observation of an elevated serum concentration of IgG4 in 1 patient with EAF, we investigated the hypothesis that EAF is an IgG4-related systemic disease. METHODS: We retrospectively identified 5 EAF cases from our files. Demographic, clinical, and serological data were reviewed, and the histologic features and tissue IgG4 staining patterns were examined on biopsies from each case. RESULTS: Patients (2 male, 3 female) ranged in age from 31 to 82 years (mean, 56 y). The extent of disease varied from isolated involvement of the nasal cavity or the lacrimal gland to multicentric disease affecting the sinuses, nasal tract, and lower respiratory tract. The duration of symptoms ranged from 6 months to >20 years. The demographic features of the patients and disease extent were consistent with previously published reports of EAF, except for involvement of the lower respiratory tract in 1 case. Four of the 5 cases showed concentric perivascular fibrosis surrounding small-caliber vascular channels, embedded in an inflammatory infiltrate composed of lymphocytes, plasma cells, and eosinophils. One lacrimal gland biopsy showed a periductal inflammatory infiltrate, and 2 cases showed a storiform pattern of fibrosis. The index case had a serum IgG4 concentration of 1490 mg/dL (normal, 8 to 140 mg/dL). IgG4-positive plasma cells were identified in biopsies from 4 of the 5 cases. The numbers of IgG4-positive plasma cells ranged from 43 to 118 per high-power field, and the IgG4:IgG ratios ranged from 0.68 to 0.97. Neither IgG4-bearing nor IgG-bearing plasma cells were identified in 1 patient, whose longstanding disease was characterized principally by concentric perivascular fibrosis. CONCLUSION: Our data suggest that EAF is part of the spectrum of IgG4-related systemic disease.

Management of acral myxoinflammatory fibroblastic sarcoma.

BACKGROUND: Acral myxoinflammatory fibroblastic sarcoma (AMFS) is a rare, low-grade sarcoma that commonly affects the distal extremities. From the published cases, therapy for AMFS to date has been comprised of excision or amputation, with limited use of radiotherapy (RT) or chemotherapy. In this report, the outcome of 17 patients with AMFS treated at the study institution was reported. METHODS: A retrospective review of all cases of AMFS identified in the Sarcoma Database in the Department of Radiation Oncology at the study institution was conducted. Treatment records and data from follow-up visits of patients were reviewed. RESULTS: Seventeen patients were identified. All the patients underwent surgical resection (15 excisions and 2 amputations). Positive surgical margins after excisions were noted in 5 patients and were widely positive in 1 patient. Of the 17 patients, 14 patients received some form of RT. The average total dose was 56.4 Gray (Gy). Eight patients received preoperative RT alone, 5 patients received preoperative RT and postoperative RT, and 1 patient received preoperative RT and intraoperative RT. Median follow-up was 24.5 months. One patient presented with recurrent disease and was treated with resection, and both pre- and postoperative RT. He was free of disease 23 months after his last treatment. No local recurrence was noted in the remaining patients. Of the 14 patients undergoing preoperative RT, complete pathologic necrosis or no tumor was noted in 1 of the patients. No metastatic disease was observed in any of the patients. There was no significant radiation toxicity observed in any of the patients. CONCLUSIONS: Data were consistent with local control of distal extremity sarcomas with resection and RT, suggesting that limb-sparing surgery with this treatment combination is an appropriate option in the limb-sparing control of patients with AMFS, even those with positive surgical margins.

Metastatic patterns of extremity myxoid liposarcoma and their outcome.

BACKGROUND AND OBJECTIVES: Extremity myxoid liposarcomas have a unique extrapulmonary metastatic potential. We studied the metastatic pattern of extremity liposarcomas to determine what types of posttreatment imaging may be of value in the follow-up these patients. METHODS: Twenty-two patients from a total of 128 patients with primary extremity liposarcoma were treated at a tertiary care institution for subsequent metastases from January 1981 to January 2000. Median follow-up was 45 months (range: 6-270 months). Data on these patients was prospectively collected and then retrospectively analyzed for effect of metastatic pattern and treatment on outcome. RESULTS: Of these 22 patients, extrapulmonary metastases developed in 10, combined pulmonary and extrapulmonary metastases developed in 6, and isolated pulmonary metastases developed in 6. Of the 16 patients with extrapulmonary metastases, 13 were of the myxoid subtype. Of the 49 patients with extremity myxoid liposarcomas, metastases developed in 14 (29%). The most common sites of metastases among these 14 patients include: the retroperitoneum, 10 patients (71)%; intra-abdominal extra-hepatic, 7 patients (50%); spinal/paraspinal, 6 patients (43%). Only 3 of the patients are alive and disease free and all 3 of these patients are from the subgroup of 10 patients with only extra-pulmonary metastases (2 intra-abdominal and 1 retroperitoneal). CONCLUSIONS: Extremity myxoid liposarcomas have an unusually high predilection for extra-pulmonary metastases, frequently without any pulmonary metastases. After treatment of the primary tumor, these patients should be followed with periodic chest X-ray and abdominal/pelvic computed tomography (CT) scans. Any back or neurologic complaints should prompt additional imaging of the appropriate spinal area. Consideration should be given to surgical and adjuvant treatment of metastatic disease when appropriate.