Bone metastases with "false negative" findings on 18F-FDG PET/CT in patients with angiosarcoma: A case series with literature review.

RATIONALE: Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) is considered a reliable and indispensable imaging method when evaluating distant metastases and clinical staging of angiosarcomas. Here, we report 2 cases of angiosarcoma with bone metastases with "false negative" findings on 18F-FDG PET/CT. PATIENT CONCERNS: Case 1, a 39-year-old woman, who had undergone mastectomy for primary angiosarcoma 2 years prior, presented with a 5-month history of right coxalgia. Case 2 was a 37-year-old woman, who had undergone mastectomy for primary angiosarcoma 4 months prior. During postoperative follow-up, multiple bone lesions were detected on magnetic resonance imaging (MRI). DIAGNOSES: Based on the histopathological findings, both cases were diagnosed with bone metastases of angiosarcoma. Although MRI showed multiple bone metastatic lesions, 18F-FDG PET/CT showed no uptake or osteolytic destruction in both cases. INTERVENTIONS: Weekly paclitaxel was initiated as a salvage chemotherapy in both cases. OUTCOMES: No uptake or osteolytic lesions were observed on 18F-FDG PET/CT, despite multiple bone metastases detected on MRI. LESSONS: False-negative findings on 18F-FDG PET/CT should be considered when evaluating bone metastases of angiosarcoma. Even with negative findings on 18F-FDG PET/CT, open biopsy should be performed if MRI indicates bone metastases.

HEY1-NCOA2 expression modulates chondrogenic differentiation and induces mesenchymal chondrosarcoma in mice.

Mesenchymal chondrosarcoma affects adolescents and young adults, and most cases usually have the HEY1::NCOA2 fusion gene. However, the functional role of HEY1-NCOA2 in the development and progression of mesenchymal chondrosarcoma remains largely unknown. This study aimed to clarify the functional role of HEY1-NCOA2 in transformation of the cell of origin and induction of typical biphasic morphology of mesenchymal chondrosarcoma. We generated a mouse model for mesenchymal chondrosarcoma by introducing HEY1-NCOA2 into mouse embryonic superficial zone (eSZ) followed by subcutaneous transplantation into nude mice. HEY1-NCOA2 expression in eSZ cells successfully induced subcutaneous tumors in 68.9% of recipients, showing biphasic morphologies and expression of Sox9, a master regulator of chondrogenic differentiation. ChIP sequencing analyses indicated frequent interaction between HEY1-NCOA2 binding peaks and active enhancers. Runx2, which is important for differentiation and proliferation of the chondrocytic lineage, is invariably expressed in mouse mesenchymal chondrosarcoma, and interaction between HEY1-NCOA2 and Runx2 is observed using NCOA2 C-terminal domains. Although Runx2 knockout resulted in significant delay in tumor onset, it also induced aggressive growth of immature small round cells. Runx3, which is also expressed in mesenchymal chondrosarcoma and interacts with HEY1-NCOA2, replaced the DNA-binding property of Runx2 only in part. Treatment with the HDAC inhibitor panobinostat suppressed tumor growth both in vitro and in vivo, abrogating expression of genes downstream of HEY1-NCOA2 and Runx2. In conclusion, HEY1::NCOA2 expression modulates the transcriptional program in chondrogenic differentiation, affecting cartilage-specific transcription factor functions.

ASPSCR1::TFE3 orchestrates the angiogenic program of alveolar soft part sarcoma.

Alveolar soft part sarcoma (ASPS) is a soft part malignancy affecting adolescents and young adults. ASPS is characterized by a highly integrated vascular network, and its high metastatic potential indicates the importance of ASPS's prominent angiogenic activity. Here, we find that the expression of ASPSCR1::TFE3, the fusion transcription factor causatively associated with ASPS, is dispensable for in vitro tumor maintenance; however, it is required for in vivo tumor development via angiogenesis. ASPSCR1::TFE3 is frequently associated with super-enhancers (SEs) upon its DNA binding, and the loss of its expression induces SE-distribution dynamic modification related to genes belonging to the angiogenesis pathway. Using epigenomic CRISPR/dCas9 screening, we identify Pdgfb, Rab27a, Sytl2, and Vwf as critical targets associated with reduced enhancer activities due to the ASPSCR1::TFE3 loss. Upregulation of Rab27a and Sytl2 promotes angiogenic factor-trafficking to facilitate ASPS vascular network construction. ASPSCR1::TFE3 thus orchestrates higher ordered angiogenesis via modulating the SE activity.

Clinicopathologic and genetic characterization of angiofibroma of soft tissue: a study of 12 cases including two cases with AHRR::NCOA3 gene fusion.

AIMS: Angiofibroma of soft tissue (AFST) is a benign tumour characterised by prominent arborizing blood vessels throughout the lesion. Approximately two-thirds of AFST cases were reported to have AHRR::NCOA2 fusion, and only two cases have been reported to have other gene fusions: GTF2I::NCOA2 or GAB1::ABL1. Although AFST is included in fibroblastic and myofibroblastic tumours in the World Health Organization's 2020 classification, histiocytic markers, especially CD163, have been reported to be positive in almost all examined cases, and it still remains the possibility of a fibrohistiocytic nature of the tumour. Therefore, we aimed to clarify the genetic and pathological spectrum of AFST and identify whether histiocytic marker-positive cells were true neoplastic cells. METHODS AND RESULTS: We evaluated 12 AFST cases, which included 10 cases with AHRR::NCOA2 and two with AHRR::NCOA3 fusions. Pathologically, nuclear palisading, which has not been reported in AFST, was detected in two cases. Furthermore, one tumour resected by additional wide resection revealed severe infiltrative growth. Immunohistochemical analysis indicated varying levels of desmin-positive cells in nine cases, whereas CD163- and CD68-positive cells were diffusely distributed in all 12 cases. We also performed double immunofluorescence staining and immunofluorescence in situ hybridisation in four resected cases with >10% desmin-positive tumour cells. The results suggested that the CD163-positive cells differed from desmin-positive cells with AHRR::NCOA2 fusion in all four cases. CONCLUSION: Our findings suggested that AHRR::NCOA3 could be the second most frequent fusion gene, and histiocytic marker-positive cells are not genuine neoplastic cells in AFST.

Imaging findings of NTRK­rearranged spindle cell neoplasms: A case series.

NTRK-rearranged spindle cell neoplasms (NTRK-RSCNs) are a new category of soft tissue tumors with NTRK gene fusions. The present study aimed to investigate the radiological features of NTRK-RSCNs and their association with histopathological findings. The present study included six patients with NTRK-RSCNs, whose fusion genes were confirmed using next-generation sequencing. All patients underwent surgery, and their diagnosis and clinical outcomes were investigated. In addition, the magnetic resonance imaging (MRI) features of all tumors and histopathological findings of the resected specimens were assessed. The present study included three women and three men, with a mean age of 22 years (range, 2-43 years). The NTRK gene fusions included four NTRK1 and two NTRK3 fusions. Three patients were preoperatively diagnosed with solitary fibrous tumors. One patient with NTRK3 fusion experienced local recurrence and distant metastases, whereas the other five patients had no local recurrence or metastasis. MRI revealed that all tumors were highly vascular with intra- and peritumoral flow voids of differing degrees. Furthermore, a partially ill-defined border, suggesting infiltration of tumors into the surrounding tissues, particularly fat tissue, was observed in five patients, which was confirmed by histopathological findings. In conclusion, NTRK-RSCNs are highly vascular tumors that can infiltrate the surrounding tissues. These findings suggested that NTRK-RSCNs should be considered in the differential diagnosis of highly vascular-rich mesenchymal tumors, including solitary fibrous tumors and alveolar soft part sarcomas. Furthermore, wide resection may be preferred to completely resect this type of tumor, considering its invasive nature.

High prevalence of TERT aberrations in myxoid liposarcoma: TERT reactivation may play a crucial role in tumorigenesis.

Myxoid liposarcoma (MLPS) is genetically characterized by FUS-DDIT3 or EWSR1-DDIT3 gene fusion and the high frequency of hotspot mutations (C228T or C250T) in the promoter region of telomerase reverse transcriptase (TERT) that encodes the TERT protein. The latter leads to telomerase reactivation, a mechanism of telomere maintenance. Although the TERT promoter hotspot mutation is a poor prognostic factor in various tumors, its effect on MLPS has not been reported in detail. In the present study, we examined the clinicopathological characteristics, prognosis, and telomere maintenance mechanisms in 83 primary tumor samples of MLPS, which were resected surgically at the Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan, from 2008 to 2020. TERT promoter hotspot mutations were observed in 77% (63/82) cases, and alternative lengthening of telomeres (ALT) was absent in all cases. Among the cases without TERT promoter hotspot mutations, TERT rearrangements, and minor point mutations in the TERT promoter region were found in 3 and 2 cases, respectively. TERT mRNA expression was observed consistently even in patients for whom no genomic TERT aberrations were detected, and the presence of TERT promoter hotspot mutation did not correlate significantly with either overall and metastasis-free survival (P = .56, P = .83, respectively) or clinicopathological features. Therefore, patients with MLPS characteristically shows TERT expression and a high prevalence of TERT aberrations. Our findings suggest that TERT aberration is not prognostic factor, but might occur at an early stage and play a key role in tumorigenesis.

S100-negative epithelioid malignant peripheral nerve sheath tumor with possible perineurial differentiation.

Epithelioid malignant peripheral nerve sheath tumor (MPNST) is a rare subtype of MPNST composed of epithelioid cells with abundant cytoplasm. Currently, strong and diffuse immunostaining for S100 protein and SOX10 is generally regarded as a characteristic feature of epithelioid MPNST. However, malignant tumors with epithelioid morphology that arise from a peripheral nerve or a pre-existing benign nerve sheath tumor should be regarded as epithelioid MPNSTs when they do not show characteristic features that definitively lead to other specific diagnoses. Here, we describe 3 cases of epithelioid MPNST in the peripheral nerve or schwannoma that was negative for S100 protein and SOX10 expression. Instead, these tumors were positive for EMA, GLUT1, claudin 1, and cytokeratin to varying degrees, while all of them retained SMARCB1 and H3K27me3 by immunohistochemistry. EMA, GLUT1, and claudin 1 are known markers of perineurial cell differentiation; thus, they could possibly represent epithelioid MPNST with perineurial cell differentiation.

Integrated diagnosis based on transcriptome analysis in suspected pediatric sarcomas.

Pediatric solid tumors are a heterogeneous group of neoplasms with over 100 subtypes. Clinical and histopathological diagnosis remains challenging due to the overlapping morphological and immunohistochemical findings and the presence of atypical cases. To evaluate the potential utility of including RNA-sequencing (RNA-seq) in the diagnostic process, we performed RNA-seq in 47 patients with suspected pediatric sarcomas. Histopathologists specialized in pediatric cancer re-evaluated pathological specimens to reach a consensus diagnosis; 42 patients were diagnosed with known subtypes of solid tumors whereas 5 patients were diagnosed with undifferentiated sarcoma. RNA-seq analysis confirmed and refined consensus diagnoses and further identified diagnostic genetic variants in four of the five patients with undifferentiated sarcoma. Genetic lesions were detected in 23 patients, including the novel SMARCA4-THOP1 fusion gene and 22 conventional or recently reported genetic events. Unsupervised clustering analysis of the RNA-seq data identified a distinct cluster defined by the overexpression of rhabdomyosarcoma-associated genes including MYOG and CHRNG. These findings suggest that RNA-seq-based genetic analysis may aid in the diagnosis of suspected pediatric sarcomas, which would be useful for the development of stratified treatment strategies.

Adult genitourinary sarcoma: The era of optional chemotherapeutic agents for soft tissue sarcoma.

OBJECTIVE: To report our institutional experience with treatment of primary genitourinary soft tissue sarcoma. METHODS: We retrospectively reviewed the medical records of adult soft tissue sarcoma patients treated between March 2005 and May 2019. The primary tumor sites included the prostate, kidney, urinary bladder and the paratesticular structures. RESULTS: A total of 19 patients - 16 men (84%) and three women (16%) - were enrolled in the study. The median age was 41 years (range 20-79 years). The most common primary site was the prostate (in eight patients; 42%), and prostatic sarcoma patients were younger than patients with sarcomas of other origins. The most common histological subtype was leiomyosarcoma (in five patients; 26%). The overall survival rates after 1, 3 and 5 years were 61.5%, 34.4% and 25.8%, respectively. The median survival time was 20.7 months (95% confidence interval 5.9-35.5 months). Univariate analysis showed that an absence of metastasis at diagnosis and complete surgical resection were predictive of favorable survival. In the chemotherapy group, the objective response rate was 20.5%. Pazopanib was administered to nine patients in the late-line setting, and the objective response rate was 11.1%; six grade ≥3 adverse events were observed in three patients. CONCLUSIONS: Inoperable metastatic genitourinary soft tissue sarcoma remains difficult to treat, as previously reported. Further investigation on this malignancy, including optimization of currently available antitumor drugs and the development of novel therapeutic agents, is required.

Prognostic significance of the MDM2/HMGA2 ratio and histological tumor grade in dedifferentiated liposarcoma.

Dedifferentiated liposarcoma (DDLPS) is a relatively common soft tissue sarcoma that results from the progression of well-differentiated liposarcoma (WDLPS). This study aimed to investigate the progression process and to clarify the pathological and genetic factors related to poor prognosis in DDLPS. In 32 DDLPS cases and five WDLPS cases, genetic factors were analyzed by custom comparative genomic hybridization (CGH) array, which was designed to densely cover gene regions known to be frequently amplified in WD/DDLPS. The analyses comparing primary and metastatic lesions and those comparing histologically different areas in the same tumor revealed intra-tumoral genetic heterogeneity and progression. According to a prognostic analysis comparing the good-prognosis and the poor-prognosis groups, we selected MDM2 and HMGA2 as candidate genes associated with poor and good prognosis, respectively. The ratios of the amplification or gain levels of MDM2 and HMGA2 expressed in log ratios (log[MDM2/HMGA2] = log[MDM2]-log[HMGA2]) were significantly associated with prognosis. An amplification or gain level of MDM2 that was more than twice that of HMGA2 (MDM2/HMGA2 > 2, log[MDM2/HMGA2] > 1) was strongly related to poor OS (P < .001) and poor distant metastasis-free survival (DMFS) (P < .001). In the pathological analysis of 44 cases of DDLPS, histological tumor grade, cellular atypia, and MDM2 immunoreactivity were related to overall survival (OS), while HMGA2 immunoreactivity tended to be associated with OS. Cellular atypia was also associated with DMFS. In conclusion, histological grade and MDM2 expression were determined to be prognostically important, and the MDM2/HMGA2 amplification or gain ratio was found to have significant prognostic value by the custom CGH array analysis.

Primary intramucosal synovial sarcoma of the sigmoid colon in a patient with a germline mutation in the MSH2 gene: A case report.

Synovial sarcoma is a high-grade soft tissue sarcoma that occurs primarily in the deep soft tissue of extremities, and primary colorectal synovial sarcoma is extremely rare. In this report, we present a synovial sarcoma mostly located within the mucosa of the sigmoid colon. The patient was a man in his forties with a germline deletion in the MSH2 gene. He had experienced undifferentiated pleomorphic sarcoma of the left forearm 7 years before and adenocarcinoma of the transverse colon 6 years before, both of which were successfully treated and exhibited no recurrence to date. A surveillance colonoscopy for Lynch syndrome revealed the tumor which had a submucosal tumor-like appearance with central erosion and endoscopic resection was performed. Histologically, it was composed of monotonous proliferation of spindle cells arranged in cellular fascicles; these findings were compatible with monophasic fibrous synovial sarcoma. In the tumor cells, the presence of the SS18-SSX1 fusion gene was confirmed. Protein expression of mismatch repair genes was intact in the tumor cells, indicating the association between microsatellite instability and synovial sarcoma was weak. The present case highlights a rare primary site of synovial sarcoma in a patient with Lynch syndrome.

Identification of Novel Fusion Genes in Bone and Soft Tissue Sarcoma and Their Implication in the Generation of a Mouse Model.

Fusion genes induced by chromosomal aberrations are common mutations causally associated with bone and soft tissue sarcomas (BSTS). These fusions are usually disease type-specific, and identification of the fusion genes greatly helps in making precise diagnoses and determining therapeutic directions. However, there are limitations in detecting unknown fusion genes or rare fusion variants when using standard fusion gene detection techniques, such as reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence in situ hybridization (FISH). In the present study, we have identified 19 novel fusion genes using target RNA sequencing (RNA-seq) in 55 cases of round or spindle cell sarcomas in which no fusion genes were detected by RT-PCR. Subsequent analysis using Sanger sequencing confirmed that seven out of 19 novel fusion genes would produce functional fusion proteins. Seven fusion genes detected in this study affect signal transduction and are ideal targets of small molecule inhibitors. YWHAE-NTRK3 expression in mouse embryonic mesenchymal cells (eMCs) induced spindle cell sarcoma, and the tumor was sensitive to the TRK inhibitor LOXO-101 both in vitro and in vivo. The combination of target RNA-seq and generation of an ex vivo mouse model expressing novel fusions provides important information both for sarcoma biology and the appropriate diagnosis of BSTS.

Simultaneous bifocal and asymptomatic intramuscular nodular fasciitis of the thigh: A case report.

Nodular fasciitis (NF) is a rapid-growth benign that is misdiagnosed as sarcoma and leads to overtreatment. The spontaneous regression of NF is a possible phenomenon. "Wait and see" ideal is one of the treatment strategies of NF.

Connective tissue growth factor produced by cancer­associated fibroblasts correlates with poor prognosis in epithelioid malignant pleural mesothelioma.

Malignant mesothelioma is an aggressive neoplasm for which effective treatments are lacking. We often encounter mesothelioma cases with a profound desmoplastic reaction, suggesting the involvement of cancer­associated fibroblasts (CAFs) in mesothelioma progression. While the roles of CAFs have been extensively studied in other tumors and have led to the view that the cancer stroma contains heterogeneous populations of CAFs, their roles in mesothelioma remain unknown. We previously showed that connective tissue growth factor (CTGF), a secreted protein, is produced by both mesothelioma cells and fibroblasts and promotes the invasion of mesothelioma cells in vitro. In this study, we examined the clinical relevance of CAFs in mesothelioma. Using surgical specimens of epithelioid malignant pleural mesothelioma, we evaluated the clinicopathological significance of the expression of α­smooth muscle actin (αSMA), the most widely used marker of CAFs, the expression of CTGF, and the extent of fibrosis by immunohistochemistry and Elastica­Masson staining. We also analyzed the expression of mesenchymal stromal cell­ and fibroblast­expressing Linx paralogue (Meflin; ISLR), a recently reported CAF marker that labels cancer­restraining CAFs and differ from αSMA­positive CAFs, by in situ hybridization. The extent of fibrosis and CTGF expression in mesothelioma cells did not correlate with patient prognosis. However, the expression of αSMA and CTGF, but not Meflin, in CAFs correlated with poor prognosis. The data suggest that CTGF+ CAFs are involved in mesothelioma progression and represent a potential molecular target for mesothelioma therapy.

Connective tissue growth factor-specific monoclonal antibody inhibits growth of malignant mesothelioma in an orthotopic mouse model.

Malignant mesothelioma is an aggressive neoplasm with no particularly effective treatments. We previously reported that overexpression of connective tissue growth factor (CTGF/CCN2) promotes mesothelioma growth, thus suggesting it as a novel molecular target. A human monoclonal antibody that antagonizes CTGF (FG-3019, pamrevlumab) attenuates malignant properties of different kinds of human cancers and is currently under clinical trial for the treatment of pancreatic cancer. This study reports the effects of FG-3019 on human mesothelioma in vitro and in vivo. We analyzed the effects of FG-3019 on the proliferation, apoptosis, migration/invasion, adhesion and anchorage-independent growth in three human mesothelioma cell lines, among which ACC-MESO-4 was most efficiently blocked with FG-3019 and was chosen for in vivo experiments. We also evaluated the coexistent effects of fibroblasts on mesothelioma in vitro, which are also known to produce CTGF in various pathologic situations. Coexistent fibroblasts in transwell systems remarkably promoted the proliferation and migration/invasion of mesothelioma cells. In orthotopic nude mice model, FG-3019 significantly inhibited mesothelioma growth. Histological analyses revealed that FG-3019 not only inhibited the proliferation but also induced apoptosis in both mesothelioma cells and fibroblasts. Our data suggest that FG-3019 antibody therapy could be a novel additional choice for the treatment of mesothelioma.

Osteogenic differentiation in dedifferentiated liposarcoma: a study of 36 cases in comparison to the cases without ossification.

AIMS: Ossification is found occasionally in dedifferentiated liposarcoma (DDLPS). The aims of this study were to elucidate whether the formed bone tissue is usually produced by tumour cells or by reactive non-neoplastic cells, and to reveal the clinicopathological characteristics of DDLPS with ossification. METHODS AND RESULTS: We examined 36 cases of ossified DDLPS by comparing them to 31 cases of non-ossified DDLPS. MDM2 amplification was confirmed in osteocytes and/or osteoblastic cells in all but one ossified DDLPS cases (27 of 28) using fluorescence in-situ hybridisation, although the morphological impression of ossification appeared to be mainly metaplastic (27 of 36) or high-grade osteosarcoma-like (six of 36). The bone tissue was often formed predominantly at the periphery of the DDLPS area near the well-differentiated liposarcoma component (18 of 36), and an organised structure such as bone marrow-like differentiation was not uncommon (12 of 36). According to a modified French Fédération Nationale des Centers de Lutte Contre le Cancer (FNCLCC) grading system, ossified DDLPS tended to be lower grade than non-ossified DDLPS (mean grade: 1.88 and 2.15, respectively). Ossification in DDLPS was associated significantly with shorter local recurrence-free survival by multivariate analysis (P = 0.02347), but metaplastic-appearing ossification tended to be associated with longer overall survival (P = 0.1400). CONCLUSIONS: The bone tissue formed in DDLPS was mainly neoplastic regardless of its morphology and maturity, which highlighted the osteogenic differentiation of the tumour cells. DDLPS patients with osteogenic differentiation tended to suffer from earlier local recurrences, which did not necessarily lead to poor life outcomes.

Histopathological and genetic review of phosphaturic mesenchymal tumours, mixed connective tissue variant.

AIMS: Phosphaturic mesenchymal tumour, mixed connective tissue variant (PMT-MCT), is a tumour of uncertain differentiation, characterised by 'smudgy/grungy' calcification and vitamin D-resistant phosphaturic osteomalacia. Fibroblast growth factor (FGF)23 is recognised as a reliable marker of PMT-MCT, but quantitative evaluation has never been performed. We reviewed cases of tumour-associated osteomalacia or histologically definitive PMT-MCT without osteomalacia using histological, immunohistochemical and genetic methods and evaluated the diagnostic significance of these findings. METHODS AND RESULTS: A total of 19 tumours from 14 cases diagnosed previously as PMT-MCT were retrieved, on which immunohistochemical staining, reverse transcription-polymerase chain reaction (RT-PCR) and fluorescence in-situ hybridisation (FISH) analysis were performed. Histologically, fibrous capsule, calcification and giant cell reaction tended to be observed in soft-tissue PMT-MCT, while PMT-MCT of bone and multiple PMT-MCT showed an infiltrative growth pattern. The immunohistochemical results were as follows: the tumour cells were positive for FGF23 (nine of 12, 75%), FGFR1 (11 of 11, 100%), CD56 (12 of 14, 85.7%) and E26 oncogene homologue (ERG) (5 of 13, 38.4%). The sole malignant tumour was positive for p53. FGF23 mRNA was detected in seven of 14 formalin-fixed paraffin-embedded (FFPE) specimens and all five frozen specimens by RT-PCR. The level of FGF23 mRNA, which was determined by real-time PCR, varied among the phosphaturic cases. Two of 17 tumours were positive for FGFR1 gene rearrangement. CONCLUSIONS: It was considered that PMT-MCT is a histopathological entity with or without phosphaturia, with varying levels of FGF23 mRNA, and with or without fibronectin 1 (FN1)-FGFR1 fusion gene. The authors propose that the histology of PMT-MCT differs depending on its location, such as bone or soft tissue, which could complicate the differential diagnosis.

Phlebotomy as a preventive measure for crocidolite-induced mesothelioma in male rats.

Malignant mesothelioma (MM) is a rare but socially important neoplasm due to its association with asbestos exposure. Malignant mesothelioma is difficult to diagnose at an early stage, yet there are no particularly effective treatments available at the advanced stage, thus necessitating efficient strategies to prevent MM in individuals already exposed to asbestos. We previously showed that persistent oxidative damage caused by foreign body reaction and affinity of asbestos both to hemoglobin and histones is one of the major pathogeneses. Accordingly, as an effective strategy to prevent asbestos-induced MM, we undertook the use of an iron chelator, deferasirox, which decreased the epithelial-mesenchymal transition in a crocidolite-induced rat MM model. However, this agent may show adverse effects. Here, we studied the effects of iron removal by phlebotomy as a realistic measure on the same rat model. We injected a total of 5 mg crocidolite i.p. to F1 hybrid rats between the Fischer-344 and Brown-Norway strains at the age of 6 weeks. We repeated weekly or biweekly phlebotomy of 6-8 mL/kg/time from 10 to 60 weeks of age. The animals were observed until 120 weeks. In male rats, phlebotomy significantly decreased the weight and nuclear grade of MM, and modestly reduced the associated ascites and the fraction of more malignant sarcomatoid subtype. Weekly phlebotomy prolonged long-term survival. Our results indicate that appropriate phlebotomy may be a practical preventive measure to attenuate the initiation and promotion capacity of asbestos towards MM by reducing iron in individuals exposed to asbestos.

Leydig cell tumor of the testis, presenting with azoospermia.

Case: A case of Leydig cell tumor, associated with azoospermia, is presented. Outcome: The levels of sex hormones obviously were decreased, including luteinizing hormone (LH) and follicle-stimulating hormone (FSH), with elevated testosterone. Computed tomography revealed no adrenal gland tumor, but a significant calcification in the right scrotal content was observed. He received a right radical orchiectomy and then he was unable to ejaculate. An endocrine panel revealed significantly decreased levels of testosterone and the low LH level had remained. Hormone replacement therapy with combined LH and FSH successfully recovered and preserved spermatogenesis. Conclusions: Although the patient's sexual function deteriorated after surgery, hormone replacement therapy was successful in establishing spermatogenesis.