From the archives of the AFIP: imaging of musculoskeletal liposarcoma with radiologic-pathologic correlation

Myxoid liposarcoma involving the liver, subcutaneous tissue, and epidural space in a polycystic disease patient

We present a case of a myxoid liposarcoma involving the liver, subcutaneous tissue, and epidural space in a polycystic disease patient with minimally increased F-18 FDG activity and review the image findings of myxoid liposarcoma.

Retroperitoneal well-differentiated inflammatory liposarcoma: a diagnostic dilemma

We present a case of retroperitoneal well-differentiated inflammatory liposarcoma that was extremely difficult to diagnose preoperatively. Computed tomography and magnetic resonance images showed a 5-cm homogeneous soft-tissue mass with a decreased apparent diffusion coefficient and without fat component in the retroperitoneum. Minimal fat stranding was detected around the mass. The preoperative working diagnosis was malignant lymphoma or inflammatory pseudotumor, whereas the final diagnosis after surgery was well-differentiated inflammatory liposarcoma. As a result, only a large component of lymphoid infiltration was recognized as a tumor preoperatively, and minimal fat stranding represented a component of lipoma-like liposarcoma. In this entity, a lipomatous component could easily be missed on radiologic imaging because of the conspicuity of lymphoid infiltration. We should consider the possibility of this variant when we evaluate a retroperitoneal tumor.

MR imaging evaluation of disorders of the chest wall

Chest wall lesions constitute a diverse group of thoracic diseases, including those of soft tissue and osseous origin. MR imaging, with its superior tissue-resolving capability and multiplanar image acquisition, is an important tool for assessing chest wall lesions. In this article, the authors review common and uncommon diseases of the chest wall, with an emphasis on the MR imaging characteristics of these diseases. Among the diseases they discuss are diseases of the soft tissue including lipoma, hibernoma, liposarcoma, hemangioma, and lymphoma. They also examine diseases of the osseous thorax, including benign osseous tumors, fibrous dysplasia, and aneurysmal bone cyst. In addition, they discuss such malignant osseous tumors as osteosarcoma and Ewing's sarcoma.

Fluorine-18-deoxyglucose-positron emission tomography imaging with magnetic resonance and computed tomographic correlation in the evaluation of bone and soft-tissue sarcomas: a pictorial essay

Positron emission tomography (PET) imaging has a growing role as an imaging modality to be used in conjunction with magnetic resonance and computed tomographic imaging in the detection, staging, and management of many sarcomas and carcinomas. Since PET is a relatively new modality and the incidence of sarcomas is low, it has not yet been approved for use in all bone and soft-tissue sarcomas. The purpose of this article is to pictorially evaluate soft-tissue and bone sarcomas, including malignant peripheral nerve sheath tumor, synovial sarcoma, osteosarcoma, liposarcoma, rhabdomyosarcoma, malignant fibrous histiocytoma, fibrosarcoma, and myxofibrosarcoma. This pictorial essay illustrates and describes these tumors in various stages of disease progression vis-à-vis fluorine-18-deoxyglucose-PET imaging with computed tomographic and magnetic resonance correlation. Various stages of disease progression will be discussed including initial diagnosis, treatment response, and metastatic involvement.

Giant hemorrhagic myelolipoma in a patient with sickle cell disease

Adrenal myelolipoma is a rare, benign tumor consisting of adipose tissue and hematopoetic elements. It is generally diagnosed as an incidental finding due to its nonfunctioning, asymptomatic nature (Meaglia and Schmidt J Urol 147:1089, 1992). With increasing size, however, as seen in this case, myelolipomas can cause flank pain and abdominal distention. This lesion was diagnosed in a young male with sickle cell disease during a vaso-occlusive crisis.

Diagnostic efficacy of bone scintigraphy, magnetic resonance imaging, and positron emission tomography in bone metastases of myxoid liposarcoma

Myxoid liposarcomas (MLS) have a tendency to metastasize to unusual sites. We report an unusual case of bone metastases not detected by bone scan and neither by fluorodeoxyglucose positron emission tomography (PET-FDG) and successfully identified with magnetic resonance imaging (MRI) in a patient with metachronic MLS. Histopathological examination of the primary tumor evidenced a tumor with unfavorable prognostic markers, and the biopsy of an iliac bone lesion confirmed the diagnosis of metastatic disease. On histological grounds, the tumor showed features of a more differentiated neoplasm without foci of round cells or necrosis in the latter. MRI allowed the identification of disseminated disease compared to computed tomography (CT) and PET scans. Thus, because of the heterogeneous histological features of MLS and the biological behavior of the disease, a combined approach of FDGPET-CT and MRI, may allow a more accurate staging of soft tissue sarcomas.

The inguinal canal: anatomy and imaging features of common and uncommon masses

A variety of benign and malignant masses can be found in the inguinal canal (IC). Benign causes of masses in the IC include spermatic cord lipoma, hematoma, abscess, neurofibroma, varicocele, desmoid tumor, air, bowel contrast material, hydrocele, and prostheses. Primary neoplasms of the IC include liposarcoma, Burkitt lymphoma, testicular carcinoma, and sarcoma. Metastases to the IC can occur from alveolar rhabdomyosarcoma, monophasic sarcoma, prostate cancer, Wilms tumor, carcinoid tumor, melanoma, or pancreatic cancer. In patients with a known malignancy and peritoneal carcinomatosis, the diagnosis of metastases can be suggested when a mass is detected in the IC. When peritoneal disease is not evident, a mass in the IC is indicative of stage IV disease and may significantly alter clinical and surgical treatment of the patient. A combination of the clinical history, symptoms, laboratory values, and radiologic features aids the radiologist in accurately diagnosing mass lesions of the IC. Supplemental material available at radiographics.rsnajnls.org/cgi/content/full/28/3/819/DC1.

Primary hepatic sarcomas: CT findings

Primary hepatic sarcomas are rare tumors that are difficult to diagnose clinically. Different primary hepatic sarcomas may have different clinical, morphologic, and radiological features. In this pictorial review, we summarized computed tomography (CT) findings of some relatively common types of hepatic sarcomas, including angiosarcoma, epithelioid hemangioendothelioma (EHE), liposarcoma, undifferentiated embryonal sarcoma (UES), leiomyosarcoma, malignant fibrous histiocytoma (MFH), and carcinosarcoma (including cystadenocarcinosarcoma). To our knowledge, hepatic cystadenocarcinosarcoma has not been described in the English literature. The CT findings in our case are similar to that of cystadenocarcinoma, a huge, multilocular cystic mass with a large mural nodule and solid portion. The advent of CT has allowed earlier detection of primary hepatic sarcomas as well as more accurate diagnosis and characterization. In addition, we briefly discuss the MRI findings and diagnostic value of primary hepatic sarcomas.

Ultrasound and MRI findings in appendicular and truncal fat necrosis

OBJECTIVE

The objective was to evaluate ultrasound and MRI in clinical appendicular and truncal fat necrosis.

MATERIALS AND METHODS

Thirty-three patients (14 men, 19 women, median age 55, range 29-95) were retrospectively evaluated. Histologically, three groups were seen: Group 1 (n = 18) consisted of patients with subcutaneous masses with septal and extrinsic oedema; in Group 2 (n = 11) necrosis occurred within lipomatous tumours and little oedema; and in Group 3 (n = 4) there were large complex masses consistent with Morel-Lavallée lesions. Two experienced radiologists reviewed MR (n = 30) and ultrasound (n = 32) images with consensus agreement. MRI was performed on a 1.5T system with T1-weighted, T2-weighted fat-suppressed and T1-weighted fat-suppressed post-intravenous gadolinium sequences obtained in two orthogonal planes. Ultrasound (linear 5- to 13.5-MHz probe) was performed in the longitudinal and short axis. Anatomical position, size, shape (oval, linear, ill-defined), internal architecture (lobules, septi or stranding), intrinsic signal characteristics, presence of surrounding pseudocapsule, extrinsic linear stranding and vascularity (gadolinium enhancement or power Doppler) were recorded.

RESULTS

Anatomical locations were buttock/thigh (n = 17), leg (n = 6), upper limb (n = 5) and thoracic/abdominal wall (n = 5) with the majority of lesions (30 out of 33) oval/linear in shape. On ultrasound and MRI most lesions showed internal fat lobules, intervening septi and a surrounding pseudocapsule.

CONCLUSION

Fat necrosis can usually be identified as containing multiple fat lobules on ultrasound and MRI despite a varying degree of inflammatory change surrounding and within the mass.

Metastatic myxoid liposarcomas: imaging and histopathologic findings

OBJECTIVE

The objective was to describe the imaging and histopathologic characteristics of metastatic myxoid liposarcomas.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and complied with HIPAA guidelines. The study group comprised 12 patients with metastatic myxoid liposarcoma who underwent MRI, CT, or FDG-PET. The location and imaging characteristics of the metastatic lesions were recorded, and the histopathology of all metastatic lesions was reviewed.

RESULTS

There were 23 histologically proven metastases in 12 patients. Based on imaging criteria, there were 41 metastases. The mean time from the diagnosis of primary tumor to the first metastasis was 4.4 years. Sixty-seven percent of patients had bone and soft tissue metastases, 33% had pulmonary metastases, 33% had liver metastases, 25% had intra-abdominal, and 16% retroperitoneal metastases. CT demonstrated well-defined lobulated masses with soft tissue attenuation in all cases, without macroscopic fat component. In cases of osseous metastases, CT showed mixed lytic and sclerotic foci, with bone destruction in advanced cases. MRI demonstrated fluid-like signal intensity with mild heterogeneous enhancement in cases of soft tissue metastases. In osseous metastases, MRI showed avid heterogeneous enhancement. FDG-PET showed no significant FDG uptake for all metastases. MRI was the most useful imaging modality for osseous and soft tissue metastases.

CONCLUSION

Myxoid liposarcomas are soft tissue sarcomas, with a high prevalence of extrapulmonary metastases. The bones and soft tissues were the most common site of involvement, followed by the lungs and liver. MRI was the most sensitive modality in the detection of osseous and soft tissue metastases, and is the recommended modality for the diagnosis and follow-up of bone and soft tissue involvement.

Pitfalls in MR Image Interpretation Prompting Referrals to an Orthopedic Oncology Clinic

Patients referred to the authors' hospital for evaluation on suspicion of a bone or soft-tissue malignancy frequently present to the Orthopaedic Oncology Clinic with magnetic resonance (MR) images that show typical features of nonmalignant or nonneoplastic entities. The purpose of this article is to review the benign entities that may be mistaken by the radiologist for a malignancy and thus lead to needless referral to an orthopedic oncologist. Normal hematopoietic marrow and marrow edema due to a stress reaction may mimic a neoplasm at MR imaging, but knowledge of the typical patterns and locations of these features allows an accurate radiologic interpretation. The MR imaging appearance of osteonecrosis, Paget disease, benign bone lesions, and rheumatologic conditions may be confusing; in such circumstances, radiographic findings may help formulate a correct diagnosis. Knowledge of the common locations and appearances of bursae and ganglia is necessary so that radiologists do not misinterpret these benign entities as soft-tissue sarcomas. Soft-tissue trauma and inflammation also may mimic tumors at MR imaging, but a familiarity with the imaging patterns of nonneoplastic change in muscle allows the avoidance of misinterpretation. The clinical history, as always, is an important component of proper diagnosis. The radiologist can be especially useful to both the clinician and the patient by recognizing entities that are highly unlikely to represent malignancy and by confidently reporting those entities as benign, thereby sparing the patient an unnecessary trip to the orthopedic oncologist.

The role of MR imaging in the diagnostic characterisation of appendicular bone tumours and tumour-like conditions

MRI has an established role in the local staging of primary bone tumours. However, as the majority of tumours have non-specific appearances on MRI, the diagnosis is usually established on the basis of clinical history, plain film findings and biopsy. This article reviews the value of MRI in the further characterisation of appendicular bone tumours and tumour-like lesions, with particular reference to peri-lesional oedema, fluid-fluid levels, flow voids, fat signal, cartilage signal and dedifferentiation. These features are a useful adjunct for distinguishing between benign and malignant disease, pointing towards a more specific diagnosis, and guiding biopsy.

Soft-tissue masses in the shoulder girdle: an imaging perspective

We discuss the radiological assessment of soft-tissue masses presenting in the shoulder girdle and emphasise the relative strengths and weaknesses of the different imaging modalities available. The appearances of the common benign and malignant soft-tissue tumours are presented together with conditions that present with specific imaging features around the shoulder region.