Thirty-year overview of Japanese autopsy cases of Takayasu arteritis - Results of analysis of Japanese autopsy reports.

OBJECTIVE: The objective of the study was to analyse the trends in Takayasu arteritis (TAK) in Japan during three recent decades based on autopsy reports. METHODS: We extracted TAK cases from the Japanese Pathological Autopsy Reports published during three decades (1991-2000, 2001-10, and 2011-20) and compared the data for the number of cases, age, gender, malignant tumour complication rate, and cause of death. RESULTS: 322 TAK cases were reported during the 30 years. They represented 0.04-0.06% of the total autopsies, with little variation among the three decades. The peak age at autopsy increased: from the 60s for 1991-2010 to the 70s for 2011-20. The malignant tumour complication rate increased to 12.2%, 18.5%, and 22.7% during the three decades. However, about half of those cases had no metastases, and malignant tumours were rarely directly involved in a TAK patient's death. TAK-associated cardiovascular lesions accounted for most deaths. CONCLUSIONS: Although the age at TAK onset showed little change during the 30 years, the age at autopsy has increased, suggesting that the long-term prognosis has improved. Although the malignant tumour complication rate increased with age, the most common causes of death were cardiovascular lesions.

Expert perspectives on pathological findings in vasculitis.

Pathological findings are important in the diagnosis of vasculitis. However, due to the rarity of the disease, standard textbooks usually devote only a few pages to this topic, and this makes it difficult for clinicians not specializing in vasculitis to fully understand the pathological findings in vasculitis. To address the paucity of information, we present representative pathological findings in vasculitis classified in the 2012 Revised International Chapel Hill Consensus Conference Nomenclature of Vasculitides (CHCC2012). The CHCC2012 classifies 26 vasculitides into seven categories: (1) large-vessel vasculitis, (2) medium-vessel vasculitis, (3) small-vessel vasculitis, including antineutrophil cytoplasmic antibody-associated vasculitis and immune complex small-vessel vasculitis, (4) variable-vessel vasculitis, (5) single-organ vasculitis, (6) vasculitis associated with systemic disease, and (7) vasculitis associated with probable aetiology. Moreover, representative pathological findings of vasculitis-related diseases and non-inflammatory vasculopathy not mentioned in the CHCC2012 are also presented. This will be useful for clinicians to refer to typical pathological findings of vasculitis in daily practice.

Recognition of alpha-mannan by dectin 2 is essential for onset of Kawasaki disease-like murine vasculitis induced by Candida albicans cell-wall polysaccharide.

Objectives: Using a murine model of systemic Kawasaki disease (KD)-like vasculitis induced by Candida albicans cell-wall-derived mannan · ß-glucan · protein complexes, the objective was to elucidate the relationships of ß-glucan receptor dectin-1 (D1) and α-mannan receptor dectin-2 (D2) to the onset of that vasculitis.Methods: The incidence and histological severity of vasculitis were compared among mice lacking the genes for D1 or D2 (i.e. D1-/- and D2-/-) and wild-type (WT) mice.Results: The incidences of vasculitis in the three animal groups were 100% (18/18) in the WT group, 100% (18/18) in the D1-/- group, and 0% (0/18) in the D2-/- group. In the WT and D1-/- mice, severe inflammatory cell infiltration, consisting mainly of neutrophils and macrophages, was seen in the aortic root and the coronary arteries. On the other hand, in the D2-/- mice, not even mild vascular lesions such as endoarteritis were seen.Conclusion: Recognition of α-mannan by D2 played an important role in the onset of vasculitis in the studied murine model.

[Association between Proposed Cancer Foci from the Results of Systematic 12-Core Transrectal Needle Biopsies and Actual Cancer Foci from Radical Prostatectomy Specimens].

We investigated the diagnostic yield for systematic 12-core transrectal prostate needle biopsies. Subjects were 56 prostatic cancer patients who were diagnosed with transrectal ultrasound-guided 12 core prostate needle biopsies and who underwent open retropubic radical prostatectomy. Pathological findings were compared between needle biopsy specimens and total prostatectomy specimens in terms of the presence or absence of cancer foci. For the comparison, the prostate was divided into 5 regions : the apical, middle, basal, far lateral and transitional regions. Then, based on the pathological findings of the biopsies, the sensitivity, specificity, positive predictive value and negative predictive value were calculated for each region. As a result, the sensitivity and the specificity in the transitional region tended to be lower than in other regions, and six of ten false positive lesions were located in the transitional region on the biopsy specimens. Also, the negative predictive value tended to be lower in the apical and far lateral regions. In conclusion, thorough punctures in the apical, transitional, and far lateral regions of the prostate at the systematic transrectal biopsy were paramount important for improving the detection of cancer foci in these regions.

Update on etio and immunopathogenesis of Kawasaki disease.

PURPOSE OF REVIEW: This review first discusses the pathogenesis of Kawasaki disease based on the results of recently performed studies aimed at identifying Kawasaki disease-susceptibility genes and the results of analyses of the immune system. Following that, we discuss the findings generated using a murine Kawasaki disease arteritis model and speculate regarding the mechanism of Kawasaki disease onset based on immune function aberrations seen in that model. RECENT FINDINGS: Recent advances in gene analysis studies of Kawasaki disease are contributing not only to prediction of disease susceptibility but also to improving our understanding of the pathogenesis of Kawasaki disease and development of new improved therapies. In addition, Th17/Treg imbalance is observed in patients with acute-phase Kawasaki disease. Th17/Treg imbalance may be an important factor causing disturbed immunological function. IL-17 induced by Th17 cells have proinflammatory properties and act on inflammatory cells, thereby inducing expression of cytokines and chemokines and resulting in tissue inflammation. SUMMARY: Kawasaki disease vasculitis may be triggered by aberrant activation of inflammatory cytokines mediated by IL-17 that is produced by Th17 cells that have been activated by some infectious agent(s).

The role of TNF-α in a murine model of Kawasaki disease arteritis induced with a Candida albicans cell wall polysaccharide.

OBJECTIVES: Various inflammatory cytokines, including tumor necrosis factor-α (TNF-α), have been reported to play roles in Kawasaki disease (KD). Recently, anti-TNF-α therapy was reported to show efficacy in patients who do not respond to high-dose intravenous immunoglobulin therapy. However, there are many gaps in our understanding of the role that TNF-α plays in the development of KD arteritis as well as whether anti-TNF-α therapy causes any histological changes in the arteritis. Accordingly, the present histopathological study was carried out to elucidate the inhibitory effect of anti-TNF-α therapy on vasculitis as well as the role of TNF-α in the development of vasculitis in a murine model of KD vasculitis. METHODS: We used two anti-TNF-α drugs (etanercept and infliximab) to treat a Candida albicans-induced murine model of KD vasculitis. We investigated the histopathological changes in terms of the incidence of vasculitis, the scope of lesions and the degree of inflammation. RESULTS: Administration of etanercept to the mice reduced not only the incidence of vasculitis but also the scope of lesions and the degree of inflammation. CONCLUSION: Based on the histological findings, TNF-α is deeply involved in the development of vasculitis.

A pathological study on the efficacy of Syk inhibitors in a Candida albicans-induced aortic root vasculitis murine model.

BACKGROUND: The activation of innate immunity may be involved in the development of Candida albicans-induced murine vasculitis, which resembles Kawasaki disease (KD) vasculitis. This study aimed to histologically clarify the time course of the development of vasculitis in this model in detail and to estimate the potential role of spleen tyrosine kinase (Syk) inhibitors in KD vasculitis. METHODS AND RESULTS: DBA/2 male mice were intraperitoneally injected with a vasculitis-inducing substance and treated with a Syk inhibitor (R788 or GS-9973). Systemic vasculitis, especially in the aortic annulus area, was histologically evaluated. Regarding lesions in the aortic annulus area, some mice in the untreated control group already showed initiation of vasculitis 1 day after the final injection of a vasculitis-inducing substance. The vasculitis expanded over time. Inflammation occurred more frequently at the aortic root than at the coronary artery. The distribution of inflammatory cells was limited to the intima, intima plus adventitia, or all layers. In the Syk inhibitor-treated groups, only one mouse had vasculitis at all observation periods. The severity and area of the vasculitis were reduced by both Syk inhibitors. CONCLUSION: Candida albicans-induced murine vasculitis may occur within 1 day after the injection of a vasculitis-inducing substance. Additionally, Syk inhibitors suppress murine vasculitis.

Histopathological study of lymph node lesions in the acute phase of Kawasaki disease.

AIMS: To review the histopathological features of cervical LNs, and to clarify the changes in extracervical LNs, in acute Kawasaki disease (KD). METHODS AND RESULTS: The samples were obtained from 33 patients with acute-phase KD. We divided the LNs into those in the neck (n = 23) and those located elsewhere (n = 26), and investigated them histologically. Changes occur not only in the cervical region, but also in LNs throughout the body. Most lymphadenopathy is non-specific, caused by sinus expansion and paracortical zone enlargement, but there are also necrotic lesions of various sizes that can be surmised to result from ischaemic changes in some LNs. Necrotic foci start to develop immediately below the capsule, and are accompanied by fibrin thrombi in the small vessels and perivascular nuclear debris. Especially in the case of cervical LNs with necrosis, a high degree of non-purulent inflammation develops in the LN capsule and surrounding connective tissue. CONCLUSIONS: In addition to lymphadenopathy with necrosis, KD should be suspected if there is non-purulent inflammation of the LN capsule and/or surrounding connective tissue featuring mainly monocytes/macrophages.

Disruption of vascular homeostasis in patients with Kawasaki disease: involvement of vascular endothelial growth factor and angiopoietins.

OBJECTIVE: In Kawasaki disease (KD), a pediatric vasculitis of medium-sized arteries, the coronary arteries are most commonly affected. Angiopoietins and vascular endothelial growth factor (VEGF) play an important role in maintaining vascular homeostasis. Recently, we identified ANGPT1 and VEGFA as susceptibility loci for KD. This study was undertaken to fine-map these associations and to gain further insight into their role in this vasculitis of unknown etiology to further the search for improved diagnostic and therapeutic options. METHODS: A total of 292 single-nucleotide polymorphisms (SNPs) located in VEGF and ANGPT and their receptors were genotyped in 574 families, including 462 trios. For replication, 123 cases and 171 controls were genotyped. RESULTS: A significant association with KD susceptibility was observed with 5 SNPs in the ANGPT1 gene (most significantly associated SNP +265037 C>T; Pcombined=2.3×10(-7) ) and 2 SNPs in VEGFA (most significantly associated SNP rs3025039; Pcombined=2.5×10(-4) ). Both ANGPT1 +265037 C>T and VEGFA rs3025039 are located in 3' regulatory regions at putative transcription factor binding sites. We observed significantly down-regulated transcript levels of angiopoietin 1 (Ang-1) in patients with acute KD compared to patients with convalescent KD. In patients with acute KD, high serum protein levels of VEGF and Ang-2 were observed compared to patients with convalescent KD and to both controls with and controls without fever. Immunohistochemistry demonstrated VEGF and angiopoietin expression in the coronary artery wall in autopsy tissue. CONCLUSION: Our data support the hypothesis that dysregulation of VEGF and angiopoietins contributes to the disruption of vascular homeostasis in KD.

Kawasaki disease: basic and pathological findings.

Kawasaki disease (KD) is considered to be a kind of systemic vasculitis syndrome. It most frequently affects infants and young children and primarily invades medium-sized muscular arteries, including the coronary arteries. The etiology of KD is unknown, but epidemiological data suggest involvement of infectious agents, such as bacteria and viruses, in the onset of KD. In addition, host genetics underlie the disease's pathogenesis. Histologically, coronary arteritis begins 6-8 days after KD onset, and inflammation of all layers of the artery rapidly ensues. The inflammation spreads completely around the artery, resulting in severe damage to structural components. Then, the artery begins to dilate. KD arteritis is characterized by inflammation consisting of marked accumulation of monocytes/macrophages. Aberrant activation of monocytes/macrophages is thought to be involved in the formation of vascular lesions. Inflammatory-cell infiltration persists until about the 25th day of the disease, after which the inflammatory cells gradually decrease in number. Lesions in all arteries are relatively synchronous, as they evolve from acute to chronic injury. If a giant aneurysm remains or vessel recanalization occurs after thrombotic occlusion of an aneurysm, remodeling of the vascular structure, sometimes including even reocclusion, continues even in the remote stage.

[A case of mixed epithelial and stromal tumor (MEST) of the kidney monitored as angiomyolipoma (AML) : a case report].

A 32-year-old woman presented with left abdominal pain. Intratumoral hemorrhage within a renal angiomyolipoma (AML) was suspected and embolization was performed. However, the patient declined surgery and was thus kept under observation. During the next 5 years, the tumor increased in size, and upper left abdominal pain appeared. Therefore, left radical nephrectomy was performed. The histopathological diagnosis was mixed epithelial and stromal tumor (MEST) of the kidney. A retrospective examination of imaging findings indicated that the fat which had been regarded as evidence of AML was actually either perinephric fat displaced by either the tumor or the renal sinus. In fact, the tumor consisted mainly of a cystic component containing a solid component. The possibility of MEST must be kept in mind when distinguishing renal tumors consisting mainly of cystic components in young to middle-aged women.

Case of uncontrolled asthma with Ceriporia lacerata-related broncholithiasis.

An 81-year-old Japanese male patient was treated for asthma. He complained of persistent cough and wheezing. Chest computed tomography scan revealed atelectasis in the right middle lobe. Fiberoptic bronchoscopy was performed. Results showed a calcified stone with filamentous fungi with septa in the right middle lobe bronchus, which was subsequently removed. Ceriporia lacerata was detected repeatedly on sputum culture. Thus, the filamentous fungi were suspected as C. lacerata. Broncholithiasis possibly caused mucous membrane damage owing to C. lacerata colonization, resulting in allergic airway inflammation. Herein, we report a rare case of C. lacerata-related broncholithiasis associated with asthma exacerbation.

Histopathological characteristics of myocarditis in acute-phase Kawasaki disease.

AIMS: To elucidate the histopathological characteristics of myocarditis in acute-phase Kawasaki disease (KD). METHODS AND RESULTS: The examined materials were from 29 autopsied KD patients who died within 40 disease days following onset. Each heart was divided into three levels: base, middle and apex. At each of these levels, the myocardium was divided further into the epicardial, middle and endocardial layers, and the time-courses of the changes in the myocarditis and the distribution of inflammation were analysed. Inflammatory cell infiltration, consisting mainly of lobulated leucocytes and large mononuclear cells, was seen in the myocardial interstitium in all cases. Inflammatory cell infiltration was already seen by disease day 6 in a patient with no coronary arteritis; it became prominent after day 10 and gradually disappeared after day 20. Myocarditis was initially distributed diffusely throughout the heart, but after day 10 it was localized in the base and epicardial layer. CONCLUSIONS: In KD, myocarditis develops even earlier than epicardial coronary arteritis; it peaks by disease day 10 and then disappears gradually after day 20. The myocarditis is distributed unevenly, ranging from the entire heart to the epicardial layer of the base of the heart.

A half-century of autopsy results--incidence of pediatric vasculitis syndromes, especially Kawasaki disease.

BACKGROUND: The objectives of this study were to clarify the details of pediatric vasculitic diseases on the basis of Japanese autopsy reports and determine whether there were cases of probable Kawasaki disease (KD) even before KD came to be widely recognized as a disease entity. METHODS AND RESULTS: Systemic vasculitis autopsy cases aged 15 years or less were selected from the total of 1,335,045 autopsy cases listed in the Annual of Pathological Autopsy Cases in Japan from 1958 through 2008. Those cases were classified into 14 disease groups and then analyzed with regard to various details. There were 380 autopsy cases of vasculitis in children (0.03% of the total autopsy cases). More than half were KD, and other diseases included unclassified vasculitis, polyarteritis nodosa, purpuric vasculitis, Takayasu arteritis, etc. The first recorded case of KD autopsy occurred in 1969. Up until 1976 there was a great difference in the number of autopsies between pediatric vasculitis and KD. However, after 1977 their numbers were in close agreement. The autopsy findings for 24 of 125 child vasculitis autopsies performed before 1976 and diagnosed as non-KD were consistent with KD. CONCLUSIONS: Although autopsies of pediatric vasculitis cases are extremely rare, the majority consists of KD. Moreover, it is likely that autopsy cases that were probably KD first appeared in the early 1960s.

[Hyaline vascula type Castleman's disease in the pelvic cavity : a case report].

A 48-year-old man was admitted to our hospital in order to treat a right lower abdominal tumor which was detected by ultrasonography in a general health check. The tumor was considered to be a pelvic sarcoma from computed tomography and magnetic resonance imaging findings, then, resection of the tumor was performed. Pathological diagnosis was a hyaline vascular type of Castleman's disease. The patient remained well without any evidence of local recurrence 12 months after surgery. The hyaline vascular type of Castleman' s disease is characterized by a solitary hypervascular tumor which is prone to adhere to neighboring great vessels. This tendency makes dissection from great vessels difficult and should be kept in mind when surgery is planned.

Mammary Paget's Disease Presenting as an Annular Plaque.

Dear Editor,Mammary Paget's disease (MPD) is an adenocarcinoma localized within the epidermis of the nipple and/or the areola of the breast, and it is as a rule associated with a carcinoma of the underlying lactiferous ducts, where it usually starts. MPD is relatively rare, observed in 0.7-4.3% of all breast cancers (1). We present a patient with MPD and atypical clinical finding as an annular plaque. A 74-year-old Japanese woman with a past medical history of hypothyroidism presented with a 6-month history of an itching plaque on the left areola. The patient had been treated with the application of topical steroids for a duration of approximately 5 months, and showed no clinical improvement. Physical examination showed a pink plaque encircling the nipple on the left areola (Figure 1, a). The right nipple and areola appeared normal (Figure 1, b). No palpable masses were detected within either breast. A 3.5 mm punch biopsy of the skin at the 6 o'clock position of the left areola was performed. Histological examination showed single and small aggregations of atypical cells with large hyperchromatic nuclei and pale-staining, ample cytoplasm throughout the epidermis. There was a lymphocytic infiltration in the dermis (Figure 1, c). Immunohistochemical studies were positive for CK7 and negative for S-100 and HMB45. With the diagnosis of MPD, the patient underwent a partial mastectomy of the left breast center area, consisting of surgical excision of the left nipple, the adjacent surrounding areolar skin, and subcutaneous tissues. Subsequently, radiation therapy for the residual breast was prepared. As has been described in detail by Kanitakis, the skin lesion develops insidiously as a scaly, fissured, or oozing erythema of the nipple and, more rarely, the areola. Advanced lesions present as a well-demarcated, round, ovoid, or polycyclic eczema-like plaque with a pink or red hue. It is occasionally slightly infiltrated and has an erosive, oozing, scaly, or crusted surface. The lesions are almost invariably unilateral, showing centrifugal spread. Retraction or ulceration of the nipple are often noted (1). The present case exhibited a very rare clinical finding of a plaque encircling the nipple, which has not been reported previously. It was initially difficult to establish the diagnosis of MPD, and biopsy was needed to obtain a definitive diagnosis. Differential diagnosis of MPD comprises eczema as atopic dermatitis or contact dermatitis, erosive adenomatosis, and malignant skin condition such as Bowen's disease, superficial basal cell carcinoma, or superficially spreading melanoma. As in the present case, individuals presenting with an annular plaque are often considered to have sebaceous hyperplasia. Sebaceous hyperplasia is a common, benign skin condition involving hypertrophy of the sebaceous glands, common in middle-aged or older adults (2). These lesions can be single or multiple and manifest as yellow, soft, small papules. These papules are occasionally seen around the nipple, forming an annular plaque. In general, sebaceous hyperplasia is described as yellow-colored papules among Caucasians. However, caution is needed, since it is characterized by skin-colored papules among some Asians.In the present case, some pigmentation (2 to 3 mm in diameter) was observed on the left nipple. Pigmented MPD have been reported, and the mechanism underlying the pigmentation is not yet fully understood, but it has been proposed that Paget cells may release melanocytic chemoattractants or basic fibroblast growth factors that stimulate the proliferation of melanocytes within the tumor nests (3). The possibility of physiological pigmentation cannot be ruled out in the present case; on the other hand, the possibility of pigmented MPD cannot be ruled out either, since no pigmentation was observed on the right nipple.

Histological studies shed new light on the initiation and characteristics of calcification of coronary artery aneurysms in Kawasaki disease.

BACKGROUND: Calcification of coronary artery aneurysms (CAAs) is common in the remote phase of Kawasaki disease (KD), but the detailed features of its development remain unclear. This study aimed to elucidate the histological characteristics of calcification in KD CAAs. MATERIALS AND METHODS: The study materials consisted of 24 coronary artery branches with aneurysms that were obtained from 14 Japanese patients who died during the period from 40 days to 3 years after the onset of KD. We first examined the CAAs for the presence of thrombi and calcification. When calcifications were observed, we determined their location and shape, and investigated the time-course of the changes based on the time-interval from KD onset until death. Then we measured the area of each calcification and examined for correlations between the calcified area, and (1) the disease duration, and (2) the aneurysm diameter. RESULTS: Calcification was observed in 14 of 24 CAAs (in 7 of 13 LCA and 7 of 11 RCA). Thrombi were also seen in 13 of 14 CAAs with calcification. Calcification showed two localizations: in the organized portion of the thrombus (seen in 12 CAAs) and deep in the thickened tunica of the intima (3 CAAs). The earliest observation of calcification was in an infant who died on the 49th disease day: it was a small, band-shaped calcified lesion in granulation tissue that had formed at the boundary between the thrombus and the blood vessel wall. As the duration of KD increased, the calcified lesion increased in size, and nodular shapes were formed. Moreover, the calcified area tended to increase as the diameter of the aneurysm increased. CONCLUSION: Histologically, CAA calcification starts early in the remote phase of KD, and it is closely related to organization of thrombi.

Myasthenia Gravis Complicated by Eosinophilic Granulomatosis with Polyangiitis: A Case Report.

A 55-year-old woman with a history of allergic sinusitis was being administered cyclosporine for ptosis and diplopia due to myasthenia gravis since age 46 years. She developed painful dysesthesia that began in her feet and later spread to her palms, leading to difficulty in walking. Eosinophils were markedly increased in the peripheral blood. Nerve conduction studies revealed mononeuritis multiplex. Nerve biopsy showed the infiltration of eosinophils in the superior neurovasculature. Based on these findings, eosinophilic granulomatous polyangiitis was diagnosed. Methylprednisolone pulse therapy was followed by oral prednisolone. Two weeks after treatment, the patient could do normal daily activities without assistance. In patients with myasthenia gravis having a history of allergic diseases, considering EGPA as a complication and monitoring prior changes in blood data are necessary for early detection before apparent tissue damage.

Beneficial effects of anti-apolipoprotein A-2 on an animal model for coronary arteritis in Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is usually treated with high-dose intravenous immunoglobulin (IVIg) as severe infectious and other diseases. Due to issues that are associated with immunoglobulin preparation, such as the risk of possible contamination by infectious agents and limited blood banking resources, recombinant immunoglobulins are required. We developed a novel recombinant antibody drug candidate, "VasSF," based on the therapeutic effects it exerted on a mouse spontaneous crescentic glomerulonephritis model (SCG/Kj). Apolipoprotein A-2 (ApoA2) has been identified as one of VasSF's target molecules. METHODS: Here, we tested the potential of anti-apolipoprotein A-2 antibodies (anti-ApoA2) as a new therapeutic drug against KD by examining its effect on a mouse model, in which KD was induced via Candida albicans water-soluble fraction (CAWS). CAWS (2 mg/mouse) was injected intraperitoneally into C57BL/6NCrSlc mice for five consecutive days. The incidence and histological severity of vasculitis in CAWS-induced coronary arteritis in mice administered anti-ApoA2 was examined. The following experimental groups were tested: solvent (only PBS (-) injection); anti-ApoA2 antibodies at dosages of 0.05 mg, 0.1 mg, and 0.5 mg/kg/day; human IgG at 0.1 mg/kg/day. RESULTS: The group treated with anti-ApoA2 0.5 mg/kg/day showed a lower incidence of panvasculitis induced by CAWS, less inflammation of the coronary arteries and aortic roots, and lower levels of serum IL-6, M-CSF, and MIP-1α and 32 cytokines/chemokines compared with those in the solvent group. CONCLUSIONS: The anti-ApoA2 treatment suppressed the development of coronary arteritis in an animal KD model and anti-ApoA2 shows potential as an effective therapeutic candidate for the treatment of KD vasculitis. The use of specific antibodies that display higher vasculitis-suppressing effects, such as anti-ApoA2, may attenuate KD as well as other infectious diseases, with less severe adverse side effects than treatment with IVIg.

Primary cardiac synovial sarcoma: a case report and literature review.

Primary cardiac synovial sarcoma is a rare disease. A 51-year-old man visited our hospital with the chief complaint of palpitations and shortness of breath while exercising. Copious bloody pericardial effusion and a multicystic intrapericardial tumor were detected. A primary cardiac malignant tumor was suspected, an open-chest tumor resection was performed with the objectives of diagnosis and treatment. Histologically, the tumor cells were uniformly spindle-shaped with an ovoid or oval nucleus, they had proliferated in fascicular fashion. In addition myxoid degeneration, a hemangiopericytomatous vascular pattern and pseudorosette formation were seen in some areas of the tumor. Based on the histopathological and immunohistochemical findings and reverse transcription polymerase chain reaction detection of SS18-SSX1 fusion transcripts, a monophasic fibrous type synovial sarcoma was diagnosed. Postoperative radiation therapy was administered and there had been no recurrence 9 months after the surgery.