The patient was admitted to the hospital because of worsening of the general condition with fever, night sweats and weight loss. A CT examination of thorax and abdomen showed a mass in the right iliacus muscle with multiple enlarged right inguinal lymph nodes (LNs) followed by biopsy from the LNs.
Figure 1:
An axial CT in the portal venous phase at the pelvic level showing a heterogeneous hypodense mass measuring about 50x30 mm at the lateral part of the right iliacus muscle with irregular enhancing rim.
Figure 2:
Axial CT at the same level in bone window showing evidence of bony erosion of the lateral border of the iliac crest.
Figure 3:
Axial CT at a more caudal level showing a suspicious right inguinal lymph node of about 10 mm with central hypodensity probably due to central necrosis and a marked fat stranding in the soft tissue.
Figure 4:
Coronal CT of the abdomen showing the mass extending from the iliacus muscle into the right inguinal canal.
A. Background:
- Leiomyosarcomas are unusual soft-tissue tumours that occur in the retroperitoneum, peripheral soft tissues, gastrointestinal and genito-urinary tracts, vessels and (rarely) in bone. A small number originate in subcutaneous tissues or large vessels, such as the inferior vena cava [1].
B. Clinical presentation:
* Incidence:
-Leiomyosarcoma represents approximately 9% of all soft tissue sarcomas (including retroperitoneum) [3] and is the third most frequently documented sarcoma after malignant fibrous histiocytoma and liposarcoma.
* Age:
-It primarily affects middle-aged to older adults [1].
-Retroperitoneal leiomyosarcomas are more common in women, with peripheral soft tissue or vascular lesions predominating in men [1].
* Location:
-The most common site of origin is the retroperitoneum (20–67% of cases). Approximately 12–41% arise in the peripheral soft tissues, most commonly in the lower extremities [3, 7]. The remainder originate from the genitourinary tract, gastrointestinal tract, trunk or blood vessels.
C. Imaging findings:
-CT is the primary imaging modality for the assessment of abdominopelvic sarcomas and is used in the evaluation of metastatic disease. However, MRI allows a more confident assessment of the site of origin of a mass especially musculoskeletal lesions because of its superior soft-tissue contrast. Gadolinium is used to assess tumour margins, vascularity and vessel involvement [8].
-Masses demonstrate a central low density in keeping with haemorrhage, necrosis or cystic change [5].
-Moderate contrast enhancement is seen at the periphery of the large primary and metastatic lesions [4]. Smaller lesions may be homogeneous [6].
-Metastases from leiomyosarcoma tend to be haematogenously spread. The liver and lung are the most frequent sites (53% and 47% respectively). Soft tissue metastases (23%). Bone metastases (18%). Lymph nodes and/or the gastrointestinal tract (18%). Intraperitoneal seeding to peritoneal and mesenteric reflections occurs from gastrointestinal or mesenteric primary sites.
D. Outcome:
* Management:
-Leiomyosarcomas require detailed evaluation with imaging prior to surgery.
-The radiologist's role is pivotal in assessing the extent of disease with particular attention given to the encasement and/or displacement of adjacent vascular structures and organs.
* Prognosis:
-The prognosis for leiomyosarcoma is poor with an overall 5 year survival rate of 35%. Prognosis is worse for tumours greater than 5 cm and for those arising from the retroperitoneum [2].
E. Take Home Message:
-Leiomyosarcoma is a rare soft-tissue sarcoma with a poor prognosis.
-Retroperitoneal and peripheral soft-tissue tumours are the most common tumours.
-Large, necrotic, heterogeneous soft-tissue masses are usually seen at CT with an isointense signal to muscle on T1w images and an intermediate or high signal on T2w images.
Leiomyosarcoma of the right iliacus muscle with metastatic inguinal LN.
Based on the provided axial and coronal enhanced CT images, a relatively large soft tissue density mass is observed in the right iliacus area (within the right iliac fossa). The lesion has partially well-defined borders, and areas of decreased density can be seen locally, suggesting intratumoral necrosis or cystic degeneration.
After contrast enhancement, the rim and some solid components of the lesion show moderate enhancement.
Meanwhile, multiple enlarged lymph nodes in the right inguinal region are noted, some of which appear significantly enlarged. The enhanced appearance of these lymph nodes suggests the possibility of lymph node metastasis or active hyperplasia.
Taking into account the patient’s age, clinical symptoms (poor general condition, fever, night sweats, weight loss), and pathological findings (lymph node biopsy suggesting features of leiomyosarcoma), the most likely diagnosis is:
Leiomyosarcoma.
Further confirmation or subtyping can be achieved with MRI (to better visualize the tumor’s relationship with surrounding tissues and vessels) and additional immunohistochemical markers, aiding in subsequent treatment decisions.
During the preoperative and postoperative periods or in palliative settings, moderate and gradual exercise can help maintain muscle strength and overall fitness. Below is a general FITT-VP principle (Frequency, Intensity, Time, Type, Volume, Progression) recommendation:
If the patient has compromised bone integrity or is at risk for postoperative injury, exercises should be performed under the guidance of a professional rehabilitation therapist or clinician. Patients with cardiopulmonary insufficiency or other comorbidities should have heart rate, blood pressure, and respiration monitored during exercise, and a medical-grade exercise test or cardiopulmonary evaluation should be considered before establishing an exercise regimen.
This report is based on the current imaging and clinical information available and is provided for clinical reference only. It does not replace an in-person diagnosis or professional medical advice. Specific treatment measures and rehabilitation plans should be determined by a professional medical team after comprehensive evaluation of the patient’s condition.
Leiomyosarcoma of the right iliacus muscle with metastatic inguinal LN.
