A 57-year-old female presented with a two-week history of pain and swelling in her left arm, dyspnoea and general malaise.
A 57-year-old woman presented to our emergency department with a two-week history of pain and swelling in her left upper limb, shortness of breath and general malaise. On clinical examination, mild, diffuse swelling of the entire left upper limb was identified. A provisional diagnosis of a deep venous thrombosis (DVT) was made, and a Doppler ultrasound was arranged. The ultrasound showed no evidence of a DVT. However, there were innumerable small hypoechoic nodules present within all of the muscles of the left upper limb (Fig. 1a and 1b). The largest of these was 1.7 cm in diameter; however the majority of the lesions were less than a centimetre in size. Examination of the right upper limb, which was asymptomatic, showed a similar appearance, although the intramuscular lesions were confined to the upper arm on that side (Fig. 1c). No colour flow was identified within any of the nodules on Doppler interrogation (Fig. 1d).
Percutaneous ultrasound guided biopsy of the larger of the left upper limb lesions was performed, and histology revealed metastatic epithelioid haemangioendothelioma. A staging CT of the thorax, abdomen and pelvis was subsequently carried out. This showed two hepatic lesions which demonstrated a 'halo' appearance of central low density with a surrounding ring of enhancement (Fig. 2a and 2b). In addition, there were bilateral pleural effusions, multiple tiny pulmonary nodules, bone metastases and splenic metastases (Fig. 2b, 2c and 2d). The patient was referred to the oncology service for palliative management.
Skeletal muscle is an unusual site for metastases and these are only rarely detected clinically. Occasionally, as in the case described here, patients with an unknown primary malignancy present with a mass due to one or more muscle metastases. The most common primary neoplasm to metastasize to muscle is lung carcinoma [1]. The lower extremities are the most common site for metastases to muscle but they are not imaged routinely in the staging of malignant disease, nor are the upper limbs. FDG-PET is a very sensitive technique for detection of soft-tissue metastases, and generally uses a wider field of view than staging CT; therefore it is likely that with the more widespread use of FDG-PET imaging, metastases to skeletal muscle will be detected with greater frequency.
Epithelioid haemangioendothelioma (EHE) is a rare well-differentiated endothelial tumour of vascular origin. Weiss and Enzinger first described the tumour in 1982 [2]. It can arise in any organ but is most commonly found in the liver, where it is often multifocal involving both lobes [3]. It is of low- to intermediate-grade malignancy. The lungs are the most common extrahepatic site for metastases [2]. There is a female preponderance and it is most prevalent during the third and fourth decades of life. Its aetiology is unknown and clinical findings tend to be non-specific; many patients are asymptomatic at the time of diagnosis [3]. CT of liver lesions in EHE typically shows hypoattenuating lesions that may become confluent, often in a subcapsular distribution. A halo pattern of enhancement is typically seen in larger lesions (as present in this case) [2]. MRI (not done in our case) offers the best tissue contrast for diagnosis of EHE, revealing hypointense lesions relative to normal liver parenchyma on T1-weighted images. The classic finding is again a peripheral halo or target enhancement pattern after administration of a gadolinium-based contrast agent [4]. Focal hepatic capsular retraction is also a feature of EHE, and is caused by lesion-related fibrosis.
Pathologic demonstration of epithelioid cells arranged in solid nests with anastamosing vascular channels and immunostaining for endothelial markers factor VIII-related antigen, CD31 and CD34 are required for diagnosis [5].
When disease is confined to the liver, transplantation results in a 5-year survival of 83% [3].
Although the liver lesions in this case demonstrated the typical halo pattern of enhancement encountered in patients with primary hepatic EHE, as this neoplasm has been reported to develop de novo in many locations such as the lungs, brain, skeleton, spleen, and soft tissues and its histological features are independent of the primary site, it is not possible to determine the organ of origin in this case. The fact that only two small lesions were present in the liver in our patient raises the possibility that these represented metastases from an extrahepatic primary.
Intramuscular metastases from epithelioid haemangioendothelioma.
1. Upper Arm Ultrasound: Multiple irregularly shaped hypoechoic lesions can be seen within the muscle layer of the left arm, with relatively clear boundaries and heterogeneous internal echoes. Surrounding muscle tissue shows mild edema or disorganized structure, and local swelling is observed.
2. Liver CT: A few low-density lesions are visible in the hepatic parenchyma. After contrast enhancement, a “halo” appearance (ring enhancement in the periphery, weaker enhancement centrally) is noted, suggesting vascular involvement or subsolid characteristics.
3. Lung CT: Scattered small nodules or small patchy lesions can be seen in both lungs, some of which are adjacent to the pleura, with low density and irregular margins.
4. Sternal CT: A localized lesion is visible in the sternum, presenting as local bone destruction or sclerosis, indicating invasion of the bony structure.
Overall, the distribution of lesions is multifocal, involving bone (sternum), soft tissue (upper arm muscles), and showing lesions in the liver and lungs, consistent with possible multiple metastases or multiple primary lesions.
Considering the patient’s sex, age, the typical “halo” enhancement observed in both the liver and soft tissue lesions, and involvement of the lungs and sternum, EHE stands out as an important differential diagnosis. Additionally, metastatic lesions from common solid tumors (e.g., lung cancer, breast cancer) must be excluded.
Based on the patient’s imaging findings, clinical symptoms (upper arm swelling pain, dyspnea, fatigue), and pathological studies (where tissue biopsy with immunohistochemistry may indicate positivity for CD31, CD34, and factor VIII–related antigen), the most likely diagnosis is Epithelioid Hemangioendothelioma (EHE) involving multiple organs (liver, lungs, bone, muscle). Since EHE often arises in multiple centers and can be primary in various organs, it is challenging to determine the initial site of origin. If uncertainty remains, additional histopathological examination and immunohistochemical tests are recommended for confirmation.
1. Treatment Strategies:
· Surgery/Biopsy: For suspicious solitary or few lesions, or where a tumor focus is causing significant symptoms, surgical resection or biopsy can be considered to establish a definitive diagnosis.
· Systemic Therapy: For patients with multiple lesions or a confirmed diagnosis of EHE with a wide disease burden, systemic therapy may be the main approach, which can include chemotherapy, targeted therapy, or immunotherapy.
· Organ Transplantation: If the tumor is primarily confined to the liver and is localized, liver transplantation has shown higher long-term survival rates in the literature. However, this requires comprehensive assessment considering the patient’s overall condition, distribution of additional lesions, and metastatic status.
· Supportive Care: Includes pain management, nutritional support, alleviation of dyspnea, correction of anemia, protein supplementation, and other supportive therapies.
2. Rehabilitation and Exercise Prescription:
· Basic Principles: In the context of multiple metastatic or primary lesions, rehabilitation and exercise should prioritize safety and proceed gradually.
· FITT-VP Principles:
• Frequency: Three to four sessions of light-to-moderate intensity exercise per week are recommended.
• Intensity: Begin with low intensity (e.g., heart rate restricted to 50%–60% of the maximum) and avoid vigorous impacts or activities that could result in fractures.
• Time: Start with 15–20 minutes per session, gradually increasing to over 30 minutes as tolerated.
• Type: Low-impact aerobic exercises (e.g., slow walking on flat ground, stationary cycling) can be used. Where possible, incorporate basic resistance training (resistance bands, light dumbbells) to maintain muscle strength.
• Progression: According to tolerance and treatment response, increase exercise duration or intensity every 2–4 weeks.
• Volume & Pattern: Break exercises into shorter segments and adopt an intermittent approach to reduce fatigue and discomfort.
· Cautions: If increased bone pain, pronounced respiratory difficulties, a drop in blood counts, or adverse treatment reactions occur, suspend or adjust exercise intensity and seek medical advice promptly. Compression sleeves or bandages may help reduce swelling in affected limbs.
Disclaimer: This report is based on existing imaging and clinical information and is provided for reference only. It does not replace in-person consultation or the opinion of a qualified specialist. If symptoms change or questions arise regarding treatment, please consult a specialist promptly.
Intramuscular metastases from epithelioid haemangioendothelioma.
