| Objective:Rhabdomyosarcoma (RMS) is a rare, fast-growing, highly malignant tumor derived from striated muscle or mesenchymal cell that can differentiated to striated muscle. It can occur in any part of the body, even in some parts that didn’t have striated muscle originally. RMS is more common in children, accounted for more than 50% of soft tissue sarcoma in children, meanwhile accounted for 5% of all malignancies in children. However RMS is rare in adults are rare, accounted for only a 3% of adult soft tissue sarcomas, and accounted for less than 1% of all adult malignant tumors. RMS has a higher incidence in children, and has uncharacterized imaging manifestation that is different from other soft tissue malignant tumors. So it attracts radiologist and surgeons’ attention. Integrated surgical treatment is the best way to treat RMS. Histological type of tumors is a critical factor to affect the prognosis of the patients. Early diagnosis and information of the relationship between the tumor and surrounding tissue are critical to the treatment. As a result, preoperative imaging examination in the diagnosis of RMS is more and more important. RMS that occurs to trunk (including chest, abdominal and pelvic) is account for quite certain proportion. Trunk RMS is hard to differentiate from other malignant soft tissue tumor and very easy to misdiagnosis as other malignant soft tissue tumor. Besides, image performance of each histological type of RMS has inconspicuous differences. Currently, imaging diagnosis and differential diagnosis of trunk RMS, as well as image diagnosis of histological types, are important topics for radiologists and surgeons. At present, there are less case reports of RMS and its imaging performance. Writer retrospective analysis 15 cases of trunk RMS confirmed diagnosis by pathology. By observing CT scan, enhanced of original images and the multidimensional restructuring images, we analysis the information of the lesions about the size, form, density, and the features of enhancement scan, calcification, bleeding, bone damage and transfer, etc. Summarize imaging features, aimed to analysis its imaging performance, for clinical diagnosis and the treatment provides reliable of reference.Materials and methods:Clinical and imaging data of 15 patients with trunk RMS were collected from January 2007 to December 2015 in the southern hospital and Guangzhou women and children’s medical center. We collect the clinical data, images, biopsy specimen, postoperative pathology and immunohistochemical reports. Using the original image and multidimensional images from different angles to observe focus location, size, density, enhanced CT enhanced imaging features and boundaries of focus, and adjacent bone damage, distant metastasis or not, ascites and hydrothorax. Analyze the sex ratio of trunk RMS and the relationship between lesion pathogenesis, clinical features, and histological classification, histological type and prognosis and imaging features.Results:1. Age and gender:In our 15 patients,10 male and 5 female(Aged 7 months to 49 years old). The median age is 8 years old.8 patients aged 0-17 years old, (of which,2 aged 0-1 years old,5 aged 1-6 years old 5,1 aged 6-17 years old; contain 5 males and 3 females).7 patients aged 18-50 years old, (of which,3 aged 18-50 years old,4 aged of 31-50 years old; contain 5 male and 2 females).2. Symptoms and signs:All our 15 patients have a medical history from 1 mounth to more than 13 months. The most common clinical symptoms are mass that gradually increase (9/15); the secondary clinical symptoms are paruria, constipation (4/15). Moreover, there is one patient (1/15) for precardium pain with repeatedly cough, and expectoration, and anhelation, one patient (1/15) for menopause 3 years, irregular vaginal bleeding with abdominal pain. Except 2 patients (lesions in one patient occurred to the right atrium Area, in another one occurred in bladder) are not proper for palpation, the remaining cases are easy for palpation. There were 11 cases with hard texture (11/13),2 with medium texture (2/13).There were 13 cases with poor range of motion (13/13), one with obviously tenderness (1/13),12 cases with inconspicuous tenderness (12/13).3. Prognosis:Our 15 patients with trunk RMS were call back after discharge:Only 13 patients had follow-up records. In which,9 patients had died (9/13),4 patients were still alive (4/13). They were at different stages of the treatment. And the follow-up would continue.2 patients (cases 8 and case 14) were lost (one patient’s phone number was unobtainable; another patient’s phone number was wrong). The death cases of Alveolar RMS were 7 (7/9), the death rate was 77.8%; the death cases of embryonal RMS were 1 (1/3), the death rate was 33.3%.4. Pathology:Pathological reports of alveolar rhabdomyosarcoma in 9 cases (9/15), embryonal rhabdomyosarcoma in 4 cases (4/15), botryoid rhabdomyosarcoma in 1 case (1/15), pleomorphic rhabdomyosarcoma in 1 case (1/15).5. Location:In our 15 cases with trunk RMS, Six were found at chest (6/15). Of which, one was found inside right atrial (1/15), one was found at left chest wall (1/15), one was found near to left armpit (1/15), one was found at left back chest wall (1/15), one was found near to right armpit (1/15), one was found at right back chest wall (1/15). Three were found in the abdomen (3/15). Of which, one was found at abdominal wall (1/15), one was found in the left abdomen (1/15), one was found in the lower abdomen-pelvic zone (1/15). The rest six were found in the pelvis (6/15). Of which, one was found in the rectum to the left rear clearance around 1 (1/15), one was found in bladder (1/15), one was found in the uterus (1/15), three was found in prostate (3/15).6. Size:In our 15 patients with trunk RMS, lesion that was smaller (maximum size less than 3cm) was in 2 patients (2/15), the lesion that was large (size 3cm-10cm) was in 9 patients (9/15), lesion that was great (maximum diameter greater than 10cm) was in 4 patients(4/15).7. Lesion form and the enhancement scan manifestation:In our 15 trunk RMS cases, that the lesion’s border was clear and the boundary to peripheral soft tissue was clear contained has 1 case (1/15). The boundary was not clear enough contained 14 cases (14/15). of which, that the lesion was diffuse infiltration contained 5 cases (5/15), that the lesion invaded bladder and/or seminal vesicle contained 5 cases (5/15), the lesions that invaded left psoas major muscle and left kidney contained 1 case (1/15), that the lesion invaded near vertebral tube contained 1 case (1/15), that the lesion extruded into chest and oppressed the lung tissue contained 1 case(l/15). That the lesion stressed on the heart and liver contained 1 (1/15), that the lesion was around the manubrium and the cartilago costalis contained 1 (1/15), the lesion of blood vessel growth that contained 2 (2/15). The lesion with inhomogeneous density contained 7 (7/15). The typically appearance was that the density of lesions was similar to muscle tissue or slightly lower (CT value of 38-47 HU). The lesion with inhomogeneous density contained 8 cases (8/15). The typically appearance was that the density of lesions was similar to muscle tissue or slightly lower. But the composition was inhomogeneous, the necrotic area appear low density.15 (15/15) cases contained no calcifications or adipose tissue. After enhanced:The lesions in 13 cases (13/15) cases were light-moderate inhomogeneous enhanced, especially the peripheral area. Many thick and tortuous tumor vascular was seen, the necrosis area was not enhanced. In 1 cases (1/15), the lesion was moderate inhomogeneous enhanced; the rough and twisted tumor vascular was seen. Necrosis area was not enhanced. In 1 cases (1/15), the lesion was obviously inhomogeneous enhanced; the tortuous and increased rough tumor vascular was seen. Necrosis area was not enhanced.8. Focal bone destruction and distant metastases:of the 15 patients with RMS,6 (6/15) grow close to ribs, humerus, scapula and spine bone, including 2 cases with light bone osteolytic destruction (2/15), no tumor with bone formation and periosteal reaction. In 15 patients with RMS, distant metastasis was found in 10 (10/15), and pulmonary metastases was found in 3 patients (3/15), lymph node metastases was found in 6 cases (6/15), bone metastasis was found in 2 cases (2/15), and inferior vena cava was found in 1 case(1/15).9. Comparison the difference of CT Imaging of rhabdomyosarcoma in children and aldults:the group of 15 patients with body RMS, the tumor size (maximum diameter) was 7.6 mm in adult group (7 patients) and was 8.4 mm in children group, the tumor size had no significant difference between the two groups (p>0.05).The gender Distribution (percentage of males):adult group (7 cases) was 71.4%, children’s group (8 cases) was 62.5, gender Distribution had no statistically significant difference between the two groups (p>0.05). There were 5 Distant metastasis (percentage of transfer) in adult group (71.4%), 5 in children’s group (62.5%). Lesions density situations (Percentage of uniform density) There were 4 in adult group (57.1%),4 in children’s group (50%), there was no significant difference of density between adult and child groups (p>0.05).Enhancement of lesion (percentage of moderate-obviously enhancement):there were 2 in adult group (28.6%), but none in children’s group, The dereferences of lesions enhancement between the adult and children’s groups was significant (p< 0.05).Conclusions: 1. Incidence of trunk RMS is lightly higher in men than in women, with no significantly difference in lesion location.2. Clinical symptoms of RMS are not specific. Lesion in the body surface area is much easier to discover. Patients often seek medical advice for processive increasing of the mass or symptoms of the organs invaded or transferred. RMS texture is hard, inconspicuous tenderness. The mobility is poor. The sensation of palpation is same with the most malignant tumors.3. The major pathological type in trunk is alveolar RMS, and the prognosis is poor.4. The imaging appearances of RMS are characterless. But the following Imaging appearances can be conducive to make right diagnosis:(1) soft tissue mass with relatively large size, especially originated from the muscle layers which can be larger (3cm-10cm) or even greater than 10cm. (2) Such mass are round or oval, lightly lobulated edge, invasive growth. The boundaries are not clear. Soft tissue around can be compressed and invaded. (3) The CT scans of tumors are hybrid/low density. Intratumoral calcifications and adipose tissue cannot be seen. (4) Enhancement scan performance:the lesions could be light to moderate inhomogeneous enhancement, after enhanced, the mass is inhomogeneous light-moderate enhanced, but obvious enhanced in peripheral tissue. Intratumoral blood vessels can be seen and cystic necrosis is not enhanced. (5) The tumors often invade adjacent tissues, but invasion and destruction of adjacent bone structure is rare. Bone destruction that only occurs in the case of the bone is tightly wrapped is mild, and appear as local osteolytic bone damage. (6) Distant metastasis to lymph node or lung is common. And manifestations of metastasis are similar to metastasis of other tumors.5. It didn’t have a clear difference in CT imaging features of rhabdomyosarcoma between children and aldults, but rhabdomyosarcoma in adults may have medium-obvious enhancement sign in enhanced CT. |
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