2026 年 13 巻 p. 493-498
Intratumoral hemorrhage caused by metastatic brain tumors originating from intimal sarcoma is extremely rare. We report a diagnostically challenging case of cerebral metastasis from a left atrial intimal sarcoma that initially presented as subcortical hemorrhage in a young adult. A 24-year-old woman presented with right homonymous hemianopia and was diagnosed with a subcortical hemorrhage in the left parietal lobe. No obvious source of bleeding was identified, and the patient was managed conservatively and discharged. One month later, fever, dyspnea, and palpitations developed in the patient. Echocardiography revealed a large mass in the left atrium. Brain imaging indicated a mass-like lesion within the prior hematoma cavity, suggesting that the hemorrhage might have been secondary to an underlying neoplasm. After surgical removal of the cardiac tumor, the patient experienced recurrent bleeding in the left parietal lobe and underwent emergency craniotomy for hematoma evacuation. Histopathological analysis of the resected lesion confirmed metastasis involvement from a primary left atrial intimal sarcoma. Although the patient underwent radiotherapy for the left parietal and cardiac lesions followed by systemic chemotherapy, she died 8 months after the initial diagnosis. This case highlights the importance of considering intratumoral bleeding in cases of spontaneous intracerebral hemorrhage without an identifiable cause. Comprehensive follow-up using multiple imaging and systemic evaluations is essential for early detection and accurate diagnosis.
Intimal sarcomas are rare malignant mesenchymal tumors that originate from the intimal layer of large blood vessels in both the systemic and pulmonary circulation, and within the heart.1) At the time of diagnosis, metastases are present in approximately 75% of patients, most commonly involving the bone, lung, liver, spleen, kidney, and skin.2,3) Treatment typically involves aggressive surgical resection followed by adjuvant chemotherapy and radiotherapy; however, the prognosis remains poor.2)
Brain metastasis from intimal sarcoma is extremely rare, with only a few cases reported in the literature.2) Moreover, among the reported cases, only 1 has been described as presenting with intracerebral hemorrhage (ICH).4)
Here, we describe a diagnostically challenging case of cerebral metastasis from a left atrial intimal sarcoma that initially manifested as an ICH.
A previously healthy 24-year-old woman presented with a chief report of right homonymous hemianopia. The patient was diagnosed with a subcortical hemorrhage in the left parietal lobe and was admitted for management (Figure 1A and B). Magnetic resonance imaging (MRI) and angiography revealed no clear vascular or structural source of bleeding (Figure 1C-E). Chest radiography showed no apparent abnormalities (Figure 1F). The patient received conservative treatment and was discharged with a modified Rankin Scale (mRS) score of 2.
Imaging at the onset of intracerebral hemorrhage (A-F). Computed tomography (CT) showing a subcortical hemorrhage in the left parietal lobe (A, B). Fluid-attenuated inversion recovery showing an acute hematoma in the left parietal lobe (C). Right common carotid angiography showing no obvious source of intracerebral hemorrhage (D, E). Supine chest radiography showing no apparent abnormalities (F).
One month after symptom onset, the patient presented with fever, dyspnea, and palpitations. Although chest radiography performed at that time remained unremarkable, transthoracic echocardiography revealed a large mass in the left atrium (Figure 2A and B). Owing to concerns about sudden cardiac death or embolic complications, the patient was admitted for surgical excision of the left atrial tumor. Head computed tomography (CT) performed on admission showed resolution of the prior hematoma. However, a slightly hyperdense mass-like lesion with contrast enhancement was observed within the previous hematoma cavity (Figure 2C and D). The lesion showed isointensity on fluid-attenuated inversion recovery MRI (Figure 2E). Collectively, these imaging findings suggested an underlying neoplastic lesion with intratumoral hemorrhage.
Imaging 1 month after intracerebral hemorrhage, at the time of presentation with fever, dyspnea, and palpitations (A-G). Sitting chest radiography showing no apparent abnormalities (A). Transthoracic echocardiography showing a large mass in the left atrium (B: arrowhead). Computed tomography (CT) showing a slightly hyperdense mass-like lesion in the resolved hematoma cavity (C: arrowhead). Contrast-enhanced CT showing an enhanced mass-like lesion (D: arrowhead). Fluid-attenuated inversion recovery showing an isointense lesion within the chronic hematoma cavity (E: arrowhead). CT on the day after cardiac tumor surgery showing a subcortical rebleeding in the left parietal lobe (F). Postoperative CT showing mostly removed hematoma (G).
The patient underwent surgical resection of the left atrial tumor, which was performed by a cardiovascular surgeon. On the day after surgery, a disturbance of consciousness with a Glasgow Coma Scale score of 12 (E3V3M6) developed in the patient, accompanied by right hemiparesis and Gerstmann syndrome. Head CT revealed recurrent bleeding in the left parietal subcortical region (Figure 2F). Emergency craniotomy was subsequently performed for hematoma evacuation. Intraoperatively, a firm, elastic lesion was observed within the hematoma cavity and was completely resected. Postoperative CT confirmed near-complete removal of the hematoma (Figure 2G).
Histopathological examination revealed a densely packed proliferation of spindle-shaped cells displaying marked nuclear atypia and frequent mitotic figures on hematoxylin–eosin staining of the left parietal lesion (Figure 3A and B). Immunohistochemical analysis indicated diffuse positivity for vimentin, whereas desmin, smooth muscle actin, cytokeratin, S-100, and CD34 test results were negative. These histological and immunohistochemical features were essentially identical to those of the cardiac tumors (Figure 3C). In addition, both the cardiac tumor and the left parietal lesion exhibited positive immunoreactivity for mouse double-minute 2 (Figure 3D), confirming the diagnosis of brain metastasis from a left atrial intimal sarcoma with ICH.
Histopathological findings showing a highly dense proliferation of spindle-shaped cells, with marked nuclear atypia in individual cells and mitotic activity on hematoxylin-eosin staining of the left parietal lesion (A: ×50, B: ×400). The cardiac tumor shows similar histological features on hematoxylin and eosin staining (C: ×200). The left parietal lesion showing positive staining for mouse double-minute 2 (D: ×400).
Postoperatively, the patient showed an improvement in consciousness and hemiparesis. Contrast-enhanced MRI of the brain revealed no evidence of residual tumor, and systemic evaluation revealed no metastases in other organs. The patient was discharged with an mRS score of 2 and a Karnofsky Performance Status score of 70. The patient was then transferred to another hospital for adjuvant chemotherapy and radiotherapy. At that hospital, the left parietal lesion was treated with stereotactic radiotherapy at 42 Gy in 10 fractions, and the primary left atrial tumor received radiotherapy at 50 Gy in 25 fractions. Although adjuvant gemcitabine–docetaxel combination chemotherapy was subsequently initiated, pazopanib was introduced because of progression of the metastatic lesions. At 6 months after surgery, contrast-enhanced MRI revealed no definite residual tumor or recurrence. However, metastatic lesions later developed in the spine, jejunum, and ovaries, and the patient died 8 months after diagnosis.
Intimal sarcoma is a rare, malignant mesenchymal tumor that arises from the endothelial lining of large vessels, such as the pulmonary artery, aorta, and heart.1) It carries an extremely poor prognosis, with a reported median survival ranging from 3 to 12 months in primary cardiac cases.5) Clinical manifestations are often nonspecific, and patients typically present with symptoms of heart failure due to impaired intracardiac flow or with embolic events resulting from tumor fragmentation.6) At the time of diagnosis, metastases are present in approximately 75% of cases, most frequently affecting the bone, lungs, spleen, kidneys, and skin.2,3) Brain metastases are exceedingly rare. According to our literature review, only 10 cases of brain metastases from intimal sarcoma have been reported to date, and among them, only 1 case—other than ours—was initially detected because of a hemorrhagic presentation (Table 1).2,4,7-13)
Summary of 10 Reported Cases of Brain Metastasis from Intimal Sarcoma
| No. | Author, (year), reference | Age (years)/sex | Lesions | Hemorrhage | Primary site | Metastatic sites outside the CNS | Timing of brain metastasis (m) | Immunostaining for MDM2 | Treatment for brain metastasis | Overall survival (m) |
|---|---|---|---|---|---|---|---|---|---|---|
| CNS: central nervous system; F: female; M: male; MDM2: Mouse double minute protein 2; NA: not available; Rt.: right; Lt.: left Overall survival was calculated from the onset of brain metastasis of an intimal sarcoma. |
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| 1 | Araki et al. (1997) (7) | 67/M | NA | NA | Pulmonary artery | Lung, pancreas, adrenal gland | NA | NA | No treatment | NA |
| 2 | Penel et al. (2003) (8) | 53/F | NA | NA | Pulmonary artery | Bones | 6 | NA | NA | 2 |
| 3 | Scharl et al. (2014) (9) | 60/F | Rt. hemisphere, cerebellum | - | Aorta | Scapula | Simultaneous | - | Biopsy, radiation | 2 |
| 4 | Mecklai et al. (2014) (10) | 56/F | Lt. frontal | - | Aorta | - | Simultaneous | NA | Surgical resection | NA |
| 5 | Tanaka et al. (2014) (11) | 61/M | NA | NA | Pulmonary artery | Lung | 84 | NA | Surgical resection | NA |
| 6 | Saith et al. (2015) (4) | 43/M | Rt. thalamus, rt. cerebellum | + | Lt. atrium | Lung, liver | Simultaneous | + | Surgical resection | 5 |
| 7 | Ropp et al. (2021) (12) | 58/M | Lt. temporal, rt. occipital | NA | Aorta | Adrenal gland, lymph | 1 | NA | NA | NA |
| 8 | Zdunek et al. (2022) (2) | 63/F | Lt. temporal | - | Lt. atrium | Pulmonary artery, lower limb | 24 | + | Surgical resection, radiation | 6 |
| 9 | Honda et al. (2025) (13) | 40/M | Lt. parietal, rt. temporal, rt. cerebellum | - | Subclavian artery | Pancreas, adrenal gland, upper limb, head skin | Simultaneous | - | Surgical resection, radiation | 18 |
| 10 | Present case | 24/F | Lt. parietal | + | Lt. atrium | Spine, jejunum, ovary | Simultaneous | + | Surgical resection | 8 |
In the present case, no radiological features suggesting an underlying tumor were apparent on the initial imaging, which may have contributed to the delayed diagnosis. In the only other reported hemorrhagic case, a cystic lesion detected on the initial CT raised the suspicion of a tumor; however, such findings were absent in our case. Moreover, perihematomal edema—commonly observed in intratumoral hemorrhage—was minimal and atypical. Previous studies reported that a relative perihematomal edema (relative PHE) ratio ≥0.5 strongly suggests tumor-related hemorrhage.14) In our case, the relative PHE was less than 0.5, indicating minimal edema. Furthermore, a previous study reported that metastatic brain tumors larger than 3 cm are associated with a higher risk of hemorrhage.15) In our case, the tumor-like lesion identified before cardiac surgery was smaller than 3 cm, suggesting that even small intimal sarcomas may have a high hemorrhagic potential. These findings suggest that brain metastases from intimal sarcomas presenting with ICH may show less perihematomal edema than other metastatic tumors and that even small lesions can cause hemorrhage.
Both the present case and the previously reported hemorrhagic brain metastasis originated from cardiac intimal sarcoma.4) Suematsu et al.3) also reported an aortic arch intimal sarcoma that caused subarachnoid hemorrhage through the formation of a neoplastic cerebral aneurysm by hematogenous tumor spread. Although that case was not strictly a brain metastasis, it suggests that intimal sarcoma can hematogenously involve intracranial arteries and form fragile vascular lesions. Thus, intimal sarcomas arising from the left-sided heart or the ascending aorta/aortic arch may tend toward hemorrhagic intracranial manifestations because tumor cells can directly enter the systemic circulation and increase cerebral vascular fragility. However, because of the limited number of reported cases, this hypothesis requires further validation through the accumulation of additional cases.
Our patient, aged 24 years, represents the youngest known case of brain metastasis from intimal sarcoma among the 9 previously published reports. Although the mean age of onset of intimal sarcoma is approximately 47-50 years,16-18) this case highlights that, even in young adults, metastatic intimal sarcoma should be considered in the differential diagnosis of ICH. In young patients with ICH of unknown etiology, secondary causes should be carefully considered, including arteriovenous malformations, aneurysms, moyamoya disease, cavernous malformations, drug-related hemorrhage, cerebral venous sinus thrombosis, and intratumoral hemorrhage from primary or metastatic brain tumors. Although MRI, magnetic resonance angiography, and CT angiography are useful for detecting vascular lesions, digital subtraction angiography is recommended when no definite bleeding source is identified on noninvasive imaging.19) Importantly, metastatic malignancy should remain in the differential diagnosis even without a known primary cancer; therefore, systemic examination, including whole-body CT or fluorodeoxyglucose positron emission tomography/CT, should be considered, particularly when the clinical course or imaging findings are atypical. In addition, as illustrated by the present case, an underlying tumor may be obscured by an acute hematoma in cases of intratumoral hemorrhage. Follow-up contrast-enhanced CT or MRI after hematoma resolution is therefore recommended.20) This case underscores the importance of serial multimodal imaging follow-up and comprehensive systemic examinations in patients with unexplained ICH. Such an approach may facilitate earlier detection of rare but aggressive conditions such as metastatic intimal sarcoma and guide appropriate management strategies.
ConclusionWe report a rare case of brain metastasis from a left atrial intimal sarcoma that presented as a subcortical hemorrhage in a young adult. This case underscores the importance of considering an underlying malignancy in patients with unexplained ICH. Comprehensive multimodal imaging and systemic examination are crucial for establishing an accurate and timely diagnosis.
The authors thank Editage (www.editage.jp) for English language editing.
All authors have no conflict of interest.
Ethical approval was not required for this single-case report because it involved retrospective analysis of anonymized data obtained during routine clinical practice.
Written informed consent for publication was obtained from the patient's family.
