A League of Its Own? Established and Emerging Therapies in Undifferentiated Pleomorphic Sarcoma.

OPINION STATEMENT: Over the last decade in soft tissue sarcoma (STS) research, the shifting landscape towards more precise subtype classification and the increasing study of novel therapeutic strategies has prompted a need to highlight current knowledge of effective subtype specific therapies. Undifferentiated pleomorphic sarcoma (UPS), formerly known as malignant fibrous histiocytoma (MFH), is among the most common subtypes of STS arising in the trunk or extremities of adults. Administration of systemic chemotherapy is the primary management in locally advanced and metastatic UPS. While anthracycline-based chemotherapy continues to be standard of care in this setting, outcomes in locally advanced or metastatic UPS remain poor. Recent studies highlight the unique characteristics of UPS that may contribute to its greater sensitivity to immune checkpoint inhibition (ICI) compared to other STS subtypes. With the promise of benefit from novel therapies, including ICI or ICI plus chemotherapy, for a subset of patients with UPS comes the need to identify biomarkers predictive of response to therapy. Ongoing and future clinical trials should place strong emphasis on correlative biomarker studies to learn more about the unique biology of UPS and to identify patients for whom ICI-based therapy will be effective.

Generation of human embryonic stem cell models to exploit the EWSR1-CREB fusion promiscuity as a common pathway of transformation in human tumors.

Chromosomal translocations constitute driver mutations in solid tumors and leukemias. The mechanisms of how related or even identical gene fusions drive the pathogenesis of various tumor types remain elusive. One remarkable example is the presence of EWSR1 fusions with CREB1 and ATF1, members of the CREB family of transcription factors, in a variety of sarcomas, carcinomas and mesotheliomas. To address this, we have developed in vitro models of oncogenic fusions, in particular, EWSR1-CREB1 and EWSR1-ATF1, in human embryonic stem (hES) cells, which are capable of multipotent differentiation, using CRISPR-Cas9 technology and HDR together with conditional fusion gene expression that allows investigation into the early steps of cellular transformation. We show that expression of EWSR1-CREB1/ATF1 fusion in hES cells recapitulates the core gene signatures, respectively, of angiomatoid fibrous histiocytoma (AFH) and gastrointestinal clear cell sarcoma (GI-CCS), although both fusions lead to cell lethality. Conversely, expression of the fusions in hES cells differentiated to mesenchymal progenitors is compatible with prolonged viability while maintaining the core gene signatures. Moreover, in the context of a mesenchymal lineage, the proliferation of cells expressing the EWSR1-CREB1 fusion is further extended by deletion of the tumor suppressor TP53. We expect the generation of isogenic lines carrying oncogenic fusions in various cell lineages to expand our general understanding of how those single genetic events drive tumorigenesis while providing valuable resources for drug discovery.

Conception and Management of a Poorly Understood Spectrum of Dermatologic Neoplasms: Atypical Fibroxanthoma, Pleomorphic Dermal Sarcoma, and Undifferentiated Pleomorphic Sarcoma.

OPINION STATEMENT: Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) tumors share many clinical, etiologic, and histologic features and likely represent components of a tumor spectrum. In dermatologic oncology, differentiating between AFX and PDS is pivotal as tumors with histological features consistent with PDS are more likely to behave in a clinically aggressive manner. Importantly, the term "pleomorphic dermal sarcoma" (PDS) is a more appropriate designation than "undifferentiated pleomorphic sarcoma" (UPS) for describing deeper, more aggressive, histologically high-grade cutaneous tumors that otherwise resemble AFX. Surgery remains the gold standard for treatment. In the setting of AFX, excision with the Mohs micrographic technique appears to offer superior tumor control rates while maintaining greater tissue preservation over wide local excision and should be considered first line. In the setting of PDS, optimal management is less clear given the paucity of available data. However, due to its greater propensity to recur and metastasize, extirpation with complete tumor margin control appears paramount. The roles of imaging and SLNB in management and clinical outcomes of AFX and PDS are unclear given the lack of available data. In reality, these tools are unlikely to be helpful in most cases of AFX. However, in the setting of PDS, emerging literature indicates that these tumors are inherently higher risk, and thus, imaging and SLNB may be helpful in select cases. Additionally, radiation therapy may be of adjuvant benefit for these tumors when clear surgical margins cannot be obtained. While traditional chemotherapy has been largely ineffectual, the recent discovery of key oncogenetic mutations has allowed for the identification of several potential molecular drug targets that may have a therapeutic role with future study. In the unfortunate setting of metastatic disease, a multidisciplinary approach is optimal. Further studies are needed to establish definitive conclusions regarding risk stratification and best management practices.

Tumor Induction in Mice After Localized Single- or Fractionated-Dose Irradiation: Differences in Tumor Histotype and Genetic Susceptibility Based on Dose Scheduling.

PURPOSE: To investigate differences in tumor histotype, incidence, latency, and strain susceptibility in mice exposed to single-dose or clinically relevant, fractioned-dose γ-ray radiation. METHODS AND MATERIALS: C3Hf/Kam and C57BL/6J mice were locally irradiated to the right hindlimb with either single large doses between 10 and 70 Gy or fractionated doses totaling 40 to 80 Gy delivered at 2-Gy/d fractions, 5 d/wk, for 4 to 8 weeks. The mice were closely evaluated for tumor development in the irradiated field for 800 days after irradiation, and all tumors were characterized histologically. RESULTS: A total of 210 tumors were induced within the radiation field in 788 mice. An overall decrease in tumor incidence was observed after fractionated irradiation (16.4%) in comparison with single-dose irradiation (36.1%). Sarcomas were the predominant postirradiation tumor observed (n=201), with carcinomas occurring less frequently (n=9). The proportion of mice developing tumors increased significantly with total dose for both single-dose and fractionated schedules, and latencies were significantly decreased in mice exposed to larger total doses. C3Hf/Kam mice were more susceptible to tumor induction than C57BL/6J mice after single-dose irradiation; however, significant differences in tumor susceptibilities after fractionated radiation were not observed. For both strains of mice, osteosarcomas and hemangiosarcomas were significantly more common after fractionated irradiation, whereas fibrosarcomas and malignant fibrous histiocytomas were significantly more common after single-dose irradiation. CONCLUSIONS: This study investigated the tumorigenic effect of acute large doses in comparison with fractionated radiation in which both the dose and delivery schedule were similar to those used in clinical radiation therapy. Differences in tumor histotype after single-dose or fractionated radiation exposures provide novel in vivo evidence for differences in tumor susceptibility among stromal cell populations.

Radiation-induced undifferentiated high-grade pleomorphic sarcoma (malignant fibrous histiocytoma) of the mandible: report of a case arising in the background of long-standing osteomyelitis with a review of the literature.

We report a rare case of radiation-induced undifferentiated high-grade pleomorphic sarcoma (UPS) (malignant fibrous histiocytoma, MFH) in the right mandible of a 44-year-old woman. The patient had suffered from osteomyelitis of the same region of the mandible for several years, which was considered to be due to radiotherapy for a malignant lymphoma in her right neck 19 years before. The tumor appeared as an exophytic and invasive growth in the molar region of the mandible. Histopathologically, the tumor consisted of an interlacing proliferation of vimentin-immunopositive spindle-shaped fibroblastic cells with bizarre nuclei with high Ki-67 labeling scores, and tumor cells showed storiform patterns mixed with pleomorphic cells. Taking the history of radiation into consideration, we diagnosed the lesion as radiation-induced MFH/UPS. Including the present case, there have been only 14 documented cases of radiation-induced UPS in the jawbone, and this is the first UPS case arising in the follow-up period of long-standing osteomyelitis.

Radiation-induced malignant fibrous histiocytoma of the occipital: a case report.

Malignant fibrous histiocytoma (MFH) is a rare neoplasm exhibiting a propensity for aggressive clinical behavior. Effective treatment modality is surgical resection with wide margins, but its rate of recurrence and metastasis is still high. Early detection and complete excision of the tumor is necessary. A MFH of the occipital developed in a 51-year-old woman eight years after surgery and radiation for medulloblastoma of the cerebellar vermis. The secondary neoplasm arose at the site of tumor resection within the irradiated field, and was resected. The development of sarcomas is a recognized complication of radiation therapy. The final diagnosis after the operation was MFH. Radiation-induced sarcoma (RIS) is well known, but radiation-induced MFH is relatively rare in the head and neck region, especially in the occipital. The imaging findings are not diagnosis specific, but strict follow-up within the radiation field by computerized tomography (CT) and magnetic resonance imaging (MRI) and appreciation of the expected latency period may help in providing the diagnosis of RIS.

Case report of sarcoma of the sella caused by postoperative radiotherapy for a prolactin-producing pituitary adenoma.

We report a case of sarcomatous transformation of a prolactin (PRL)-producing pituitary adenoma in a 27-year-old man. He originally presented with bitemporal visual disturbance, headache, and hyperprolactinemia 8 years earlier. Tumor shrinkage was confirmed by magnetic resonance imaging (MRI) during treatment with dopamine-receptor agonist. However, 3 years later transsphenoidal surgery had to be performed because of tumor re-growth. Histopathological examination revealed a PRL-producing adenoma with fibrotic changes. One year later, he presented with right-sided visual disturbance, and tumor re-growth was confirmed using MRI. He underwent transcranial surgery, followed by radiation therapy (50 Gy in 25 fractions). The histological and immunostaining features were similar in both specimens obtained from the two operations. Four years later, he presented with left-sided visual disturbance, and tumor re-growth was confirmed using MRI. The mass lesion dramatically increased in size within 2 months, and partial removal of the tumor by craniotomy was performed. The specimen was histologically diagnosed as malignant fibrous histiocytoma (MFH). Regardless of aggressive chemotherapy, his clinical symptoms and imaging findings worsened rapidly. He died 7 months after the diagnosis of MFH. Because patients with pituitary tumor undergoing radiotherapy face the possibility of developing such neoplasm, long-term follow-up is required.

Low-grade myxofibrosarcoma following a metal implantation in femur: a case report.

Myxofibrosarcoma is a myxoid variant of malignant fibrous histiocytoma that most commonly involves the extremities of elderly people. However, a primary myxofibrosarcoma with bone invasion in young adults is extremely rare. Herein, we report the case of a 31-year-old male with a gradually enlarging left thigh mass, who had a history of left femur fracture and received an open reduction and internal fixation with titanium alloy plates and screws 33 months previously. Imaging investigations revealed an irregularly shaped soft tissue mass around the left femur shaft and a partial bone defect in the middle one-third of the left femur. Pathological examination of the resected specimen showed a multi-nodular appearance, abundant myxoid matrix and elongated curvilinear capillaries. Immunohistochemical studies revealed that the tumor cells was positive for VIM and MDM2, and was negative for CK, MSA, SMA, DES, S-100 and CD34. Labeling index of Ki-67 was 25%. Based on the morphological finding and immunostaining, it was diagnosed as a low-grade myxofibrosarcoma. The clinical and imaging examinations did not reveal the evidence of a primary cancer elsewhere, and the patient had no personal or family history of malignancy. To our knowledge, this is the first case of a primary myxofibrosarcoma developed following a fracture and metal implantation in young adults. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1745984882113605.

A rare type of secondary cancer in a child with acute lymphoblastic leukemia: malignant fibrous histiocytoma.

Secondary cancers which are related with treatment of childhood acute lymphoblastic leukemia (ALL) is a significant problem with longer term. For development of secondary cancer after treatment, the latency period varies between 5 and 10 years. In this case, a 13 year-old-boy diagnosed as high-risk ALL was treated with chemotherapy and prophylactic cranial radiotherapy at a dose of 1800 cGy. Six years after the end of treatment he developed a 5 × 5 × 4 cm mass at the right temporal region of the cranium. The mass was excised totally with clear surgical margin. Pathology of mass has been diagnosed as malignant fibrous histiocytoma (MFH), recently referred to as an undifferentiated pleomorphic sarcoma (UPS). After treatment of childhood ALL, reported cases of secondary MFH is extremely rare in the literature. Herein we present a case of MFH/UPS that developed as a secondary cancer 6 years after the end of ALL treatment.

Two-stage, combined, three-level en bloc spondylectomy for a recurrent post-radiation sarcoma of the lumbar spine.

En bloc or extralesional resection means resection of the tumor in one piece together with a layer of healthy tissue: the margin is either marginal or wide. The prerequisite for an en bloc or extralesional spondylectomy is a tumor involvement of no more than one side of the posterior structures, so that a corridor can be created through which the spinal cord is released. This article presents a two-stage, combined anterior and posterolateral, three-level en bloc spondylectomy, and local flap wound coverage for a patient with a recurrent post-radiation sarcoma of the lumbar spine and infected wound after intralesional treatment. The patient had radiation therapy for an L4 Hodgkin's lymphoma 5 years before the development of the post-radiation sarcoma. Two-stage, three-level en bloc spondylectomy was done through a combined anterior and posterolateral approach. The resection margins were microscopically negative. Dural tear occurred intraoperatively because of tightly adherent dense scar tissue. Two years after spondylectomy, there was no evidence of tumor or infection recurrence; however, the patient died from her lymphoma. In surgically difficult spinal resections, we recommend the two-stage, combined anterior and posterolateral approach for en bloc spondylectomy. The staged procedure may provide for reduced perioperative complications and mortality, and meticulous dissection in the irradiated area, especially if infected. The combined approach provides for easier and safer dissection of the tumor and the spine from the anterior elements under direct visual control, and wide tumor resection.

Atypical fibroxanthoma developing on a pacemaker pocket mimicking a pyogenic granuloma.

Malignant tumors at the site of implantation of a pacemaker generator, although rare, have been reported in the literature. We present a case of an 89-year-old man with atypical fibroxanthoma in a pacemaker pocket. The device had been implanted for more than 4 years. An exophytic tumor had developed in this place and was clinically interpreted as a pyogenic granuloma. An excisional biopsy revealed the nature of the tumor. To our knowledge, the association of atypical fibroxanthoma arising from a pacemaker pocket has not been previously reported. A review of the literature has revealed four malignant soft tissue tumors previously reported at the pacemaker site. Routine examination in all patients with implanted pacemaker generators should be practiced at follow-up visits. This would allow an early diagnosis of a malignant associated neoplasm. Pathologists should become familiar with this type of devices and their potential neoplastic complications.

Uncommon cutaneous neoplasms of the head and neck.

This article concentrates on the less-common cutaneous malignancies such as merkel cell, atypical fibroxanthoma, malignant fibrous histiocytoma, dermatofibrosarcoma protuberans, microcystic adnexal carcinoma, and sebaceous carcinoma. The clinical and histopathologic descriptions of each, most current and emerging etiologies, diagnosis, staging, treatment, and prognosis are discussed.

A new complication of retained surgical gauze: development of malignant fibrous histiocytoma--report of a case with a literature review.

BACKGROUND: Primary visceral malignant fibrous histiocytoma (MFH) is a rare disease, and few cases have been reported in the English literature. However, retained foreign bodies in the abdomen after surgical procedures are important causes of intra-abdominal infections. For legal and ethical reasons, there are few publications in the literature. In this article, we describe for the first time a case of malign abdominal fibrous histiocytoma associated with a surgical sponge forgotten in the abdominal cavity a long time ago. CASE PRESENTATION: A 64-year-old male presented to our surgical department with cachexia, abdominal pain, distention and pyrexia of unknown origin. He had a medical history of abdominal surgery for peptic ulcer perforation 32 years ago. Clinical examination revealed fever with a distended and painful abdominal wall. Radiological imaging of the abdomen showed multiple heterogeneous masses in one large cystic cavityalmost completely filling the abdomen. The patient underwent a laparotomy, and interestingly, opening the cyst revealed retained surgical gauze (RSG). The origin of the tumor was the visceral peritoneum, and it was excised totally. CONCLUSIONS: Primary intra-abdominal MFH can present as a complication of long-lasting RSG. Therefore, clinicians must remember this while establishing the differential diagnosis for patients with a history of previous abdominal surgery and presenting with symptoms associated with both the tumor and systemic inflammatory response.

Malignant fibrous histiocytoma at the site of an alumina-on-alumina-bearing total hip arthroplasty mimicking infected trochanteric bursitis.

Although the incidence of malignant tumors in patients undergoing total hip arthroplasties (THAs) is known to be lower than the general population, there exist several reports on the development of malignant tumors at the site of THAs. We report another case of malignant fibrous histiocytoma at the site of a THA, which was developed in an older patient who presented a cystic mass around the total hip prosthesis using a ceramic-on-ceramic bearing system, even without evidence of osteolysis or loosening of implants. This is the second case associated with an aluminum oxide prosthesis in English literature.

Clinical spectrum of atypical fibroxanthoma and undifferentiated pleomorphic sarcoma in solid organ transplant recipients: a collective experience.

BACKGROUND: Atypical fibroxanthoma (AFX) and undifferentiated pleomorphic sarcoma (UPS) are uncommon, spindle cell cutaneous malignancies. Solid organ transplant recipients (SOTRs) are immunosuppressed and therefore have a higher incidence of cutaneous malignancies. OBJECTIVE: We describe the clinical spectrum of AFX and a more-aggressive, deeper variant, UPS, in SOTRs. MATERIALS AND METHODS: A retrospective chart review of AFX and UPS in SOTRs was implemented. Cases from Vanderbilt University, Emory University, Mayo Clinic-Jacksonville, and University of Rochester were included. A literature search included previously published cases. RESULTS: The average age of SOTRs at time of tumor presentation was younger than typically seen in immunocompetent patients for AFX. Rates of local recurrences and metastases were higher in the SOTRs than is noted in the immunocompetent literature. Rates of recurrence were higher in those treated with excision than in those treated with Mohs micrographic surgery (MMS). CONCLUSION: AFX and UPS may have a greater risk for recurrence, metastases, and mortality in SOTRs, in whom early treatment with MMS may demonstrate certain advantages in terms of minimizing risk of recurrence and metastasis. UPS and recurrent tumors should be staged appropriately and may respond to adjuvant radiation therapy and reduction of immunosuppression. Immunohistochemical evaluation is recommended to exclude other spindle cell tumors.

Malignant fibrous histiocytoma is a rare Lynch syndrome-associated tumor in two German families.

Lynch syndrome is characterized by germline mutations of the DNA mismatch repair genes MLH1 and MSH2. The tumor spectrum includes early onset colorectal, urogenital and other cancers. Soft tissue sarcomas have been anecdotally reported in patients with Lynch syndrome, but coincidental manifestation could not be excluded. In this report, we screened a cohort of Lynch syndrome families for tumors outside the established tumor spectrum. We identified two patients with Lynch syndrome and a malignant fibrous histiocytoma (MFH). In both families a causative MSH2 germline mutation (MSH2 c.2038C ≥ T or MSH2 c.942 ± 3A ≥ T) could be detected. Archival tumor material from both resected MFH was analyzed for microsatellite instability expression of MLH1 and MSH2. A mutator phenotype was detected in both MFH with loss of MSH2 protein expression. Subsequently, the causative MSH2 germline mutation was confirmed in both patients. Of note, both tumors were diagnosed at a local advanced stage but could be curatively resected 21 and 11 year ago, respectively. Both patients are alive without local or distant recurrence. In conclusion, our data further support that patients with Lynch syndrome are at increased risk for rare tumors such as MFH. However, the prognosis compared to sporadic MFH seems to be favorable.