Myositis Ossificans of the Breast Mimicking Breast Cancer: A Case Report.

Myositis ossificans (MO) is an uncommon tumor characterized by a rapidly growing mass following a history of local trauma. Few cases of MO affecting the breast have been reported, and some were misdiagnosed as primary osteosarcoma of the breast or metaplastic breast carcinoma. The following case report presents a patient with a growing breast lump whose core biopsy result was suspicious for breast cancer. MO was diagnosed after analysis of the mastectomy specimen. This case highlights the importance of MO as a differential diagnosis of a growing soft-tissue mass after trauma to avoid unnecessary overtreatment. Keywords: Myositis Ossificans, Osteosarcoma, Breast Cancer, Mastectomy, Heterotopic Ossification © RSNA, 2023.

Epithelioid Rhabdomyosarcoma: Report of a Cutaneous Case and Literature Review of a Recently Described Variant of Rhabdomyosarcoma.

Rhabdomyosarcoma affects mainly pediatric patients and is currently classified into 4 categories: embryonal, alveolar, pleomorphic, and spindle cell/sclerosing. Epithelioid rhabdomyosarcoma is a recently described variant of rhabdomyosarcoma in which primary cutaneous presentation is infrequent. In this brief report, we describe a rare case of epithelioid rhabdomyosarcoma in an 81-year-old man, presenting as a skin lesion in the neck, which increased in size in 1 month. After imaging evaluation, a solid cervical mass was discovered. A biopsy was performed, and the diagnosis of epithelioid rhabdomyosarcoma was rendered. The patient died due to rapid progression of the tumor. To make an accurate diagnosis and ensure appropriate patient management, it is necessary to be aware of this variant and use proper immunohistochemical stains when facing an epithelioid malignancy, expanding the differential diagnosis of epithelioid neoplasms.

The impact of rapid on-site evaluation on thyroid fine-needle aspiration biopsy: A 2-year cancer center institutional experience.

BACKGROUND: The impact of rapid on-site evaluation (ROSE) on thyroid aspirates has been a matter of extensive debate. In the current study, the authors reviewed all thyroid fine-needle aspiration biopsies (FNABs) performed in their service in recent years to evaluate the impact of ROSE on final adequacy and diagnostic rates. METHODS: All ultrasound-guided FNABs of the thyroid performed between July 2015 and July 2017 were included retrospectively. ROSE was performed by experienced cytopathologists, with production of Romanowsky-stained slides for immediate evaluation. When ROSE was not performed, a total of 3 needle passes were performed as the default. Final specimen adequacy and the risk of malignancy (ROM) of each The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) category were calculated in the 2 groups (ROSE and non-ROSE) and compared using the chi-square test. RESULTS: An initial search obtained 4649 cytology specimens, 3469 of which (74.6%) underwent ROSE and 1180 of which (25.4%) did not. Patients were predominantly female (85.4%), with a mean age of 53 years. Specimen adequacy was found to be significantly higher in the ROSE group (93.4% vs 69.4%; P<.0001), with a mean number of needle passes necessary for an adequate diagnosis of 1.48 ± 0.71 (median, 1.0 needle passes; range, 1-5 needle passes). No statistical difference was observed with regard to the ROM for each TBSRTC category when the 2 groups (ROSE and non-ROSE) were compared. CONCLUSIONS: The current study data support ROSE as a valuable technique in thyroid FNAB. It was proven to significantly improve specimen adequacy with a decreased mean number of needle passes necessary to achieve an adequate cytological diagnosis and no impact on the ROM for any TBSRTC category.

Global Health Perspective in Sarcomas and Other Rare Cancers.

Sarcomas, rare and heterogenous malignancies that comprise less than 1% of all cancers, have poor outcomes in the metastatic and refractory setting. Their management requires a multidisciplinary approach that consists of medical and surgical oncologists, radiation oncologists, and pathologists as well as ancillary support. In addition to systemic treatments, most patients will require surgical resection and radiation therapy, which mandates the use of the latest technologies and specialized expertise. Management guidelines have been developed in high-income countries, but their applicability in low-income countries, where resources may be limited, remains a challenge. In this article, we propose the best possible evidence-based practices specifically for income-constrained settings to overcome this challenge. In addition, we review the different methods that can be used in low-income countries to access new and expensive treatments, which often times carry prohibitive costs for these areas.

Mesenchymal Hamartoma of the Liver in an Infant With Beckwith-Wiedemann Syndrome: A Rare Condition Mimicking Hepatoblastoma.

Patients with Beckwith-Wiedemann syndrome (BWS) are known to be at an increased risk for childhood malignancies, particularly Wilms tumor and hepatoblastoma. We report a case of genetically confirmed BWS in a 5-month-old girl who presented with a 9.5-cm abdominal mass associated with elevated α-fetoprotein levels. The clinical impression was strongly suggestive of hepatoblastoma. Histologic examination of the surgically excised mass revealed mesenchymal hamartoma of the liver (MHL), a benign hepatic neoplasm.

Low-grade sinonasal sarcoma with neural and myogenic features: a clinicopathologic analysis of 28 cases.

Sarcomas of the sinonasal region are rare. We describe a distinct spindle cell sarcoma of the sinonasal region characterized by concomitant neural and myogenic differentiation. Consultation files and surgical cases from Mayo Clinic were reviewed. Twenty-eight cases were identified that met the inclusion criteria. Clinical data were collected from medical records, consultation letters, and referring pathologists. Reverse transcriptase-polymerase chain reaction for synovial sarcoma fusion transcripts was performed on 18 cases. Cytogenetic studies were performed on 2 cases. The 21 female and 7 male patients ranged in age from 24 to 85 years (mean, 52 y). All cases showed a characteristic histology, which included a cellular spindle cell neoplasm with uniform, elongate nuclei and an infiltrative growth pattern. All tumors demonstrated expression of S-100 with actin positivity in 96% of cases tested. Reverse transcriptase-polymerase chain reaction for synovial sarcoma fusion transcripts was negative in all cases tested. Cytogenetic studies conducted on 2 cases demonstrated the chromosomal translocation t(2;4). The nasal cavity (54%) and ethmoid sinus (57%) were the most commonly involved areas, singly or in combination. Follow-up information was available for 57% (16/28) of cases, with a mean of 8.3 years. Of these, 44% (7/16) experienced at least 1 recurrence. No patient has developed metastases or died of disease. We describe a unique tumor with a characteristic morphologic, immunophenotypic, and cytogenetic profile. On the basis of the locally aggressive nature of this lesion we believe it is best considered a low-grade sarcoma and suggest the term low-grade sinonasal sarcoma with neural and myogenic features.

Molecular testing for lipomatous tumors: critical analysis and test recommendations based on the analysis of 405 extremity-based tumors.

Ancillary molecular testing has been advocated for diagnostic accuracy in the differentiation of lipomas from atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDL); however, the implications and specific indications for use are not well-established in the current literature. Herein, we extend previous findings by quantitatively evaluating the impact of molecular testing of lipomatous neoplasms in our routine clinical practice, how it modifies the historical perspective of their clinical course, and the effect of distinct surgical procedures in modulating the risk of local recurrence for these tumors after molecular classification. On the basis of these analyses, we suggest a specific set of basic recommendations for complementary molecular assessment in the diagnosis of lipomatous tumors. Four hundred and five lipomatous neoplasms located in the trunk and extremities were analyzed histologically and for the presence of 12q13-15 amplification on paraffin-embedded tissues by assessing MDM2/CPM amplification. Survival analyses were calculated with Kaplan-Meier and compared with the log-rank. Multivariate analysis was evaluated by the Cox regression method. The 405 tumors were histologically classified as ordinary lipoma (n=324), intramuscular lipoma (n=29), and ALT/WDL (n=52). The level of agreement between the histologic diagnosis and the molecular diagnosis was high (96%) but pathologists showed a tendency to overestimate cytologic atypia and the diagnosis of ALT/WDL (precision, 79%; accuracy, 88%). Molecular assessment led to a major diagnostic reclassification in 18 tumors (4%). Eleven of the tumors histologically classified as ALT/WDL were reclassified as ordinary lipoma (n=5) and intramuscular lipoma (n=6); none of which recurred. Seven ordinary lipomas were reclassified as ALT/WDL, 6 of which were larger than 15 cm and deeply located; 2 recurred locally. After molecular data, the 5-year local recurrence rates for ordinary lipoma, intramuscular lipoma, and ALT/WDL were 1%, 12%, and 44%, respectively. Multivariate analyses after molecular assessment showed tumor type and type of resection to be associated with the risk of local recurrence. Complementary molecular testing refines the histologic classification of lipomatous tumors and better estimates the impact of surgical procedures on the risk of local recurrence. Pathologists tend to overestimate the degree of cytologic atypia and the indiscriminate use of molecular testing should be avoided, especially for extremity-based tumors. Molecular testing should be considered for "relapsing lipomas," tumors with questionable cytologic atypia (even if widely excised), or for large lipomatous tumors (>15 cm) without diagnostic cytologic atypia.

Retroperitoneal lipomatous tumors without cytologic atypia: are they lipomas? A clinicopathologic and molecular study of 19 cases.

Most well-differentiated liposarcomas can be readily distinguished from lipomas on histologic grounds alone. However, occasional retroperitoneal lipomatous tumors show no cytologic atypia. To determine whether these tumors are well-differentiated liposarcomas devoid of cytologic atypia or lipomas was the major aim of this investigation. We comprehensively and prospectively studied 19 retroperitoneal adipocytic tumors devoid of cytologic atypia at the cytogenetic and molecular genetic levels. Median patient age was 56 years (range: 36 to 78 y). Median tumor size was 21 cm (range: 8 to 46 cm) and the median weight was 1127 g (range: 173 to 2440 g). All tumors were well-circumscribed and showed no cytologic atypia. Standard cytogenetic analysis demonstrated rearrangements of 12q15 in 4 (of 7) cases. None showed ring or giant marker chromosomes. Fluorescence in situ hybridization failed to identify amplification of MDM2, carboxypeptidase M(CPM), SAS, CDK4, DDIT3, or HMGA2 in all cases. HMGA2 rearrangement was observed in 8 (of 19) cases (42%) and was more common in larger tumors (P=0.046). HMGA2-LPP fusion was seen in only 1 case. All tumors were completely excised. Follow-up information was available from 10 cases (median, 6 mo; range: 1 to 58 mo). No tumor recurred or metastasized. In contrast, a control group of 20 well-differentiated liposarcomas diagnosed during the same time period (matched per year of diagnosis) showed 4 instances of local recurrence. We conclude that this group of retroperitoneal lipomatous tumors shows clinico-pathologic and genetic features more akin to lipomas than well-differentiated liposarcomas. Owing to their apparent rarity, additional studies are necessary to more fully understand their natural biology in this anatomic location.

Sclerosing extramedullary hematopoietic tumor: emphasis on diagnosis by renal biopsy.

Sclerosing extramedullary hematopoietic tumor (SEMHT) is a rare lesion that typically arises in patients with chronic myeloproliferative disorders. Morphologically, it exhibits atypical megakaryocytes, granulocytic precursors, and erythroid precursors set in a background of dense collagen sclerosis. Sclerosing extramedullary hematopoietic tumor may be easily mistaken for other neoplasms, such as sarcoma, carcinoma, or Hodgkin lymphoma, particularly if pertinent clinical history is not provided. Misdiagnosis may occur because of the difficulty in recognizing the megakaryocytic lineage of the atypical cells and because of the paucity of other hematopoietic elements. We report a case of a 72-year-old man with proteinuria and renal insufficiency who underwent renal biopsy to determine the etiology of the proteinuria. The kidney biopsy demonstrated an unusual tumor in which the initial morphological impression that of sclerosing liposarcoma. However, upon learning of the patient's previous history of chronic idiopathic myelofibrosis and with the aid of immunohistochemistry, the correct diagnosis of sclerosing extramedullary hematopoietic tumor was made. Sclerosing extramedullary hematopoietic tumor should be considered in the differential diagnosis when percutaneous renal biopsy or other intra-abdominal biopsy reveals a sclerotic lesion with interspersed large atypical cells, especially in a patient with a history of chronic myeloproliferative disorder.

Primary retroperitoneal lipoma: a soft tissue pathology heresy?: report of a case with classic histologic, cytogenetics, and molecular genetic features.

Adipose tissue tumors of the retroperitoneum showing no identifiable cytologic atypia are usually classified as lipomalike well-differentiated liposarcoma. Whether a subset of these tumors represents true examples of retroperitoneal lipoma remains a controversial subject, because the diagnostic liposarcoma cells may be of difficult identification, even after extensive sampling. Herein, we describe a large retroperitoneal lipoma with classic histopathologic, cytogenetic, molecular cytogenetic, and molecular genetic features. Extensive morphologic inspection showed no evidence of cytologic atypia. Cytogenetic analysis performed on fresh tissue material revealed the classic lipoma chromosome t(3;12)(q27;q14-15). Fluorescence in situ hybridization on multiple sections excluded the presence of MDM2 and CDK4 amplification, but showed HMGA2 balanced rearrangement in most cells. Reverse-transcriptase polymerase chain reaction followed by sequencing analysis confirmed the presence of the HMGA2-LPP fusion gene, a characteristic and the most common fusion product found in lipoma. The patient has been followed for 2.5 years without evidence of recurrence or metastasis. These results indicate that retroperitoneal lipomata do exist, but their diagnosis must rely on stringent histologic, cytogenetic, and molecular genetic analysis.

Genomic gains of COL1A1-PDFGB occur in the histologic evolution of giant cell fibroblastoma into dermatofibrosarcoma protuberans.

Giant cell fibroblastoma (GCF) is a subcutaneous mesenchymal neoplasm characterized by the chromosomal t(17;22), which results in the formation of the fusion gene COL1A1-PDGFB. This same fusion gene is also seen in the supernumerary ring chromosome of dermatofibrosarcoma protuberans (DFSP). Several studies have addressed the molecular genetics of DFSP but molecular cytogenetic characterization of individual areas and cell components in pure GCF and GCF/DFSP hybrids have not been performed. Herein, we studied the frequency and genomic copy number of COL1A1-PDGFB in pure GCF and GCF/DFSP hybrids, and identified the molecular cytogenetic signatures in individual cells in each component. Four pure GCF and nine GCF/DFSP hybrids were studied. All tumors exhibited classical histological features and CD34 expression. COL1A1 and PDGFB rearrangements were evaluated by fluorescence in situ hybridization (FISH) using probes for COL1A1 and PDGFB on paraffin-embedded thin tissue sections. All GCF and GCF/DFSP hybrids showed unbalanced rearrangements of COL1A1-PDGFB at the molecular cytogenetic level. Genomic gains of COL1A1-PDGFB were found predominantly in the DFSP component of GCF/DFSP hybrids but in none of the pure GCF, suggesting that these gains are associated with the histologic evolution of GCF into DFSP. The molecular cytogenetic abnormalities were found not only in the spindle/stellated cells but also in individual nuclei of the multinucleated giant cells, suggesting that these cells may result from the fusion of individual neoplastic cells.

Myxoinflammatory fibroblastic sarcoma showing t(2;6)(q31;p21.3) as a sole cytogenetic abnormality.

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, low-grade sarcoma characterized by distinctive, large, and bizarre Reed--Sternberg--like cells associated with an intense inflammatory infiltrate. The biology of MIFS is still poorly understood, and only two previous cases had been studied cytogenetically. In the present case, analysis of MIFS in the foot of a 53-year-old man revealed the chromosome translocation t(2;6)(q31;p21.3) as the only cytogenetic abnormality. This finding is distinct from the two cases previously reported. Additional studies are needed to verify whether any of these chromosome rearrangements are involved recurrently in MIFS.

Frequency and characterization of HMGA2 and HMGA1 rearrangements in mesenchymal tumors of the lower genital tract.

Mesenchymal tumors of the lower genital tract predominantly occur in women of reproductive age and are mainly represented by aggressive angiomyxoma (AAM) and angiomyofibroblastoma (AMF). Whether these tumors are different phenotypic expressions of the same biological entity is still debatable. Genetic rearrangements of HMGA2 have been reported in a few cases of AAM but its frequency and clinicobiological implications have not been studied systematically. We evaluated 90 cases of mesenchymal tumors of the lower genital tract that comprised 42 AAMs, 18 AMFs, 6 cellular angiofibromas, 5 fibroepithelial stromal polyps, 15 genital leiomyomas, 3 superficial angiomyxomas, and 1 spindle cell lipoma. Fluorescence in situ hybridization was used to identify rearrangements of HMGA2 and its homologue HMGA1. HMGA2 rearrangements were identified in 14 AAMs (33%) and in 1 vaginal leiomyoma. All other tumors were negative for HMGA2 rearrangements. HMGA1 rearrangement was not found in any of the cases. RT-PCR confirmed transcriptional upregulation of HMGA2 only in tumors with HMGA2 rearrangements. Standard cytogenetic analyses were performed in two AAMs and one AMF. One AAM had a t(1;12)(p32;q15); the other tumors had normal karyotypes. Mapping and sequence analysis of the breakpoint showed fusion to the 3' untranslated region of HMGA2 to genomic sequences derived from the contig NT 032977.8 on chromosome 1p32. Our findings support the hypothesis that AAM and AMF are distinct biological entities. The diagnostic usefulness of HMGA2 rearrangements to differentiate between AAM and other tumors of the lower genital tract may be limited due to the their low frequency.

Cytogenetic and molecular cytogenetic findings in dedifferentiated liposarcoma with neural-like whorling pattern and metaplastic bone formation.

Dedifferentiated liposarcoma is a subtype of liposarcoma characterized by juxtaposition of well-differentiated liposarcoma with a nonadipocytic sarcoma. A peculiar form of dedifferentiated liposarcoma has been described, characterized by a nonlipogenic component with a neural-like whorling pattern of growth and metaplastic bone formation. We report the cytogenetic and molecular genetic findings of this peculiar form of dedifferentiation in a retroperitoneal tumor found in a 58-year-old female. The neoplasm had typical histologic findings and a complex karyotype characterized by several numeric and structural chromosomal abnormalities, including the presence of ring and giant rod chromosomes. Molecular cytogenetic studies found high levels of amplification of the MDM2 oncogene, consistent with the amplification of the 12q14 chromosome band, a cytogenetic abnormality commonly found in these tumors. These findings indicate that, despite its unique and peculiar morphologic features, this unusual type of dedifferentiated liposarcoma shares many of the cytogenetic features and molecular genetic abnormalities found in other forms of dedifferentiation. The specific cytogenetics and molecular determinants of these peculiar morphologic findings, however, remain unknown.

Cytogenetic and molecular genetic findings in dedifferentiated liposarcoma with neural-like whorling pattern and metaplastic bone formation.

Dedifferentiated liposarcoma, a subtype of liposarcoma, is characterized by juxtaposition of well-differentiated liposarcoma with a nonadipocytic sarcoma. A peculiar form of dedifferentiated liposarcoma has been described, characterized by a nonlipogenic component with a neural-like whorling pattern of growth and metaplastic bone formation. We report the cytogenetic and molecular genetic findings of this peculiar form of dedifferentiation in a retroperitoneal tumor found in a 58-year-old woman. The neoplasm had the typical histologic findings and a complex karyotype characterized by several numeric and structural chromosome abnormalities, including the presence of ring and giant rod chromosomes. Molecular genetic studies found high levels of amplification of the MDM2 oncogene, consistent with the amplification of the 12q14 chromosome band, a cytogenetic abnormality commonly found in these tumors. These findings indicate that, despite its unique and peculiar morphologic features, this unusual type of dedifferentiated liposarcoma shares many of the cytogenetic and molecular genetic abnormalities found in other forms of dedifferentiation. However, the specific cytogenetic and molecular determinants of these peculiar morphologic findings remain unknown.

Gains of COL1A1-PDGFB genomic copies occur in fibrosarcomatous transformation of dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans is a superficial low-grade sarcoma that rarely evolves into a high-grade fibrosarcoma. Dermatofibrosarcoma protuberans is genetically characterized by the unbalanced chromosomal t(17;22)(q21;q13), usually in the form of a supernumerary ring chromosome. The product of this chromosomal translocation is the chimeric gene COL1A1-PDGFB (collagen type I alpha I-platelet-derived growth factor beta), which is amplified at low levels in the ring chromosome. The aims of this study were to evaluate (1) whether genomic gains of this fusion gene occur during the clonal evolution of dermatofibrosarcoma protuberans into fibrosarcomatous dermatofibrosarcoma protuberans and (2) whether there is a difference between the number of genomic copies of COL1A1-PDGFB between classic dermatofibrosarcoma protuberans and dermatofibrosarcoma protuberans areas associated with fibrosarcomatous dermatofibrosarcoma protuberans. Eleven cases of fibrosarcomatous dermatofibrosarcoma protuberans with both dermatofibrosarcoma protuberans and fibrosarcomatous areas and 10 cases of classic dermatofibrosarcoma protuberans were studied. Genomic copies of COL1A1-PDGFB were evaluated by fluorescence in situ hybridization using a custom designed probe for the PDGFB locus on 4 mum thick paraffin-embedded tissue sections. Genomic gains of the COL1A1-PDGFB gene were observed in six (of 10) fibrosarcomatous dermatofibrosarcoma protuberans in the fibrosarcomatous areas when compared to the dermatofibrosarcoma protuberans areas of the same tumor (2-7 gene copies (median PDGFB copy gain, 2.8) versus 1-3 gene copies (median PDGFB copy gain, 1.7), respectively, P=0.004). Four fibrosarcomatous dermatofibrosarcoma protuberans did not show genomic gains of COL1A1-PDGFB fusion gene between the two areas. Essentially no difference in the copy number of COL1A1-PDGFB fusion gene was observed between dermatofibrosarcoma protuberans areas of classic dermatofibrosarcoma protuberans and dermatofibrosarcoma protuberans areas of fibrosarcomatous dermatofibrosarcoma protuberans (median PDGFB copy gain of 1.8 versus 1.7, respectively, P=0.36). Genomic gains of COL1A1-PDGFB fusion gene is possibly an oncogenic mechanism that is identified in the clonal evolution of a subset of dermatofibrosarcoma protuberans that evolves into fibrosarcomatous dermatofibrosarcoma protuberans. Since this finding was not observed in all cases of fibrosarcomatous dermatofibrosarcoma protuberans, other oncogenic mechanisms may be operating in this form of tumor progression. Copy number of COL1A1-PDGFB fusion gene in the classic dermatofibrosarcoma protuberans areas does not seem to be a major predisposing mechanism for fibrosarcomatous transformation.

Multifocal penile epithelioid hemangioendothelioma masquerading as superficial penile vein thrombosis.

A 42-year-old man presented with a progressively painful mass of the penile shaft that clinically resembled superficial penile vein thrombosis. The patient's symptoms were refractory to conservative therapy, and surgical excision revealed multifocal penile epithelioid hemangioendothelioma. He had no evidence of metastatic disease and was well 1 year after excision. Vascular neoplasms should be included in the differential diagnosis of painful penile masses and penile thrombophlebitis. To our knowledge, this is only the second reported case of multifocal penile epithelioid hemangioendothelioma.

The prognostic significance of fibrosarcomatous transformation in dermatofibrosarcoma protuberans.

Dermatofibrosarcoma protuberans (DFSP) is a superficial tumor characterized by high rates of local recurrence and a small risk of metastasis. Fibrosarcomatous (FS) areas rarely arise in DFSP, and considerable controversy exists as to whether these tumors have a higher risk of metastasis than the typical DFSP. The aim of this study was to reappraise the prognostic significance of FS changes in DFSP by analyzing 41 patients from the consultation files of our institution. The study included 23 females and 18 males, with a median age of 48 years (range, 16-100 years). Eighteen lesions were located on the trunk, 16 on the extremities, and 7 on the head/neck region. All tumors were treated with local excision, and the surgical margins were considered positive for tumor in 22 of 39 cases (56%). Fibrosarcomas arose de novo in 38 cases and as a recurrence in 3 cases. All tumors involved the dermis and subcutis, and the FS component comprised 5% to 95% of the tumor area (median, 60%). Mitotic rates of the FS component (median, 20 mitoses/10 high-power fields [HPFs]; range, 5-48/10 HPFs) were considerably higher than those of the neighboring DFSP component (0-2 mitoses/10 HPFs). Immunohistochemical analyses showed that CD34 expression was stronger and more extensive in the DFSP component (97% positive; median intensity, 3+) than in the FS component (81% positive; median intensity, 2+). The MIB-1 labeling index was higher in the FS areas (median, 20%; range, 5%-45%) than in the DFSP areas (<3%). Expression of p53 was present in 92% of the FS areas and in only 3% of adjacent DFSP areas. Follow-up data revealed that 8 patients had local recurrences, 4 patients (10%) had metastases, and 2 patients died of disease. None of the variables evaluated, including margin status, FS proportion, and mitotic count, correlated with disease progression. We demonstrate that FS change in DFSP is a form of tumor progression that carries an increased risk of metastasis over classic DFSP and is associated with gains of p53 mutations and increased proliferative activity.

Intraabdominal myositis ossificans: a report of 9 new cases.

Intraabdominal myositis ossificans (IMO) is a rare benign disorder characterized by reactive bone formation in intraabdominal soft tissue that should be distinguished from a malignant condition. We retrospectively searched our patient records and report 9 new cases of IMO. The lesions occurred in 7 men and 2 women with a mean age of 50 years (range, 24--76 years), 5 of whom had previous abdominal surgery. Histologically, all the cases were similar, consisting of a reactive mesenchymal process in adipose tissue. Mitosis was observed, but with no atypical forms, and the lesions lacked malignant cytologic features. IMO is an uncommon benign lesion that develops relatively rapidly. The pathogenesis is related to intraabdominal surgical procedures, but the exact mechanism remains to be determined.

Intraabdominal desmoplastic small round cell tumors: a diagnostic and therapeutic challenge.

BACKGROUND: Intraabdominal desmoplastic small round cell tumors (IDSRCT) are uncommon but aggressive tumors that occur in young males. To the authors' knowledge, only limited data are available on the natural history and optimal treatment of this disease. METHODS: The authors reviewed 12 patients with IDSRCT who were treated at their institution between January 1991 and December 2001. RESULTS: All patients were males, with a median age of 26 years. All patients were symptomatic at the time of presentation, with a mean duration of symptoms of 2 months. Common presenting symptoms and signs were abdominal pain (67% of patients), palpable abdominal mass (58% of patients), abdominal distension (42% of patients), and hepatomegaly (33% of patients). Six patients (50%) had distant metastases at presentation. Five patients underwent biopsy only. Surgical resection was attempted in seven patients and included macroscopic total resection in three patients and debulking in four patients. All of those patients subsequently developed recurrent or progressive disease, which required a second operation in six patients. Overall, 6 patients (50%) developed symptomatic intestinal obstruction requiring surgical management, and 3 patients (25%) developed ureteral obstruction. All 12 patients received multiagent chemotherapy. Seven patients (55%) also received radiation therapy. The median survival of patients who underwent surgical resection was 34 months, whereas the median survival of patients who underwent biopsy alone was 14 months. One patient remained alive 72 months after he underwent complete resection of primary and recurrent tumors, and 1 patient remained alive with disease 32 months after he underwent complete resection of a primary tumor. CONCLUSIONS: Patients with IDSRCT presented with a short duration of nonspecific symptoms, and the disease was fatal almost uniformly, regardless of the treatment modality used. Surgical resection may prolong survival in some patients.