Diagnosing intramuscular myxoma by fine-needle aspiration: a multidisciplinary approach

Myxoid neoplasms of bone and soft tissue: a pattern-based approach

INTRODUCTION

The accurate diagnosis of musculoskeletal neoplasms is difficult but a pattern-based approach combined with ancillary testing has been shown to improve diagnostic accuracy. The pattern-based approach is particularly appropriate for myxoid lesions.

MATERIALS AND METHODS

The authors reviewed their personal experience of over 3 decades of diagnosing myxoid neoplasms of musculoskeletal lesions.

RESULTS

The authors found that myxoid lesions can be accurately classified based on cell type, nuclear atypia, presence of blood vessel fragments, as well as the results of immunohistochemical and molecular testing.

CONCLUSIONS

Musculoskeletal lesions with a prominence of myxoid or chondroid material in the background can be accurately diagnosed using pattern analysis and ancillary testing.

Radiomic features from MRI distinguish myxomas from myxofibrosarcomas

BACKGROUND

Myxoid tumors pose diagnostic challenges for radiologists and pathologists. All myxoid tumors can be differentiated from each other using fluorescent in-situ hybridization (FISH) or immunohistochemical markers, except for myxomas and myxofibrosarcomas. Myxomas and myxofibrosarcomas are rare tumors. Myxomas are benign and histologically bland, whereas myxofibrosarcomas are malignant and histologically heterogenous. Because of the histological heterogeneity, low grade myxofibrosarcomas may be mistaken for myxomas on core needle biopsies. We evaluated the performance of T1-weighted signal intensity (T1SI), tumor volume, and radiomic features extracted from magnetic resonance imaging (MRI) to differentiate myxomas from myxofibrosarcomas.

METHODS

The MRIs of 56 patients (29 with myxomas, 27 with myxofibrosarcomas) were analyzed. We extracted 89 radiomic features. Random forests based classifiers using the T1SI, volume features, and radiomic features were used to differentiate myxomas from myxofibrosarcomas. The classifiers were validated using a leave-one-out cross-validation. The performances of the classifiers were then compared.

RESULTS

Myxomas had lower normalized T1SI than myxofibrosaromas (p = 0.006) and the AUC using the T1SI was 0.713. However, the classification model using radiomic features had an AUC of 0.885 (accuracy = 0.839, sensitivity = 0.852, specificity = 0.828), and outperformed the classification models using T1SI (AUC = 0.713) and tumor volume (AUC = 0.838). The classification model using radiomic features was significantly better than the classifier using T1SI values (p = 0.039).

CONCLUSIONS

Myxofibrosarcomas are on average higher in T1-weighted signal intensity than myxomas. Myxofibrosarcomas are larger and have shape differences compared to myxomas. Radiomic features performed best for differentiating myxomas from myxofibrosarcomas compared to T1-weighted signal intensity and tumor volume features.

A case of intramuscular myxoma presenting as a swollen shoulder: a case report

INTRODUCTION

Intramuscular myxoma is a rare benign mesenchymal tumor. Myxomas most commonly occur in the heart. They may occur less frequently in aponeurotic tissues, bone, genitourinary tract, subcutaneous tissue and skin.

CASE PRESENTATION

The case described here is a 44-year-old Turkish woman who presented with the complaint of a swelling in her right shoulder. A preoperative magnetic resonance imaging revealed a lobular contoured mass lesion in her deltoid muscle. The mass was marginally excised and pathology revealed intramuscular myxoma.

CONCLUSION

Intramuscular myxoma of the deltoid muscle is a very rare benign tumor. In the differential diagnosis, reactive lesions, myxoid nodular fasciitis and low -grade myxoid sarcomas should be kept in mind, upon which the treatment should be planned.

Not all pain in the left iliac fossa is diverticular disease: A case study of a psoas myxoma and review

Intramuscular myxomas are rare, benign, mesenchymal tumours that may present to a wide variety of specialties. We present a case study of an intramuscular myxoma in the psoas muscle, followed by a review of the literature regarding the diagnosis and treatment of intramuscular myxomas

Soft tissue masses with “cyst-like” appearance on MR imaging: distinction of benign and malignant lesions

The purpose of this study was to assess the reliability of MR imaging features in distinguishing between benign and malignant soft tissue masses that have a "cyst-like" appearance (hypointense to muscle on T1-weighted and hyperintense on T2-weighted or fluid-sensitive MR sequences). MR imaging features of 40 patients with histologically proven soft tissue masses (27 benign and 13 malignant lesions) that were hypointense to muscle on T1-weighted and hyperintense on T2-weighted or fluid-sensitive MR sequences were analysed to see if a distinction could be made between benign and malignant lesions. There were 23 females and 17 males (mean age, 56 years; age range, 23-82 years). MR imaging features analysed for statistical significance included lesion size, lesion homogeneity, presence of lobulation, depth in relation to fascia and border definition. Clinical assessment included the age and sex of the patient and location of the lesion. Statistically significant MR imaging features favouring a diagnosis of a malignant lesion included larger average dimension of the mass (P < or = 0.004), larger greatest dimension of the mass (P < or = 0.028) and heterogeneity of the lesion on T1-weighted sequences (P = 0.017). The most statistically significant predictor of malignancy was the larger average dimension of the mass.

Magnetic resonance imaging of intramuscular myxoma with histological comparison and a review of the literature

OBJECTIVE

To evaluate the magnetic resonance (MR) features of intramuscular myxoma (IM) compared with its pathological findings.

DESIGN

Two radiologists retrospectively reviewed records and imaging studies of patients with histologically proven IM. Two radiologists also analyzed by consensus all the MR studies (pre- and post-contrast T1-weighted and T2-weighted sequences) and a pathologist reviewed the available histological material.

PATIENTS

Seventeen patients with 18 histologically proven IM were reviewed. Histological samples of 11 of these 18 tumors were available for pathological analysis.

RESULTS

There were 14 women and three men, with a mean age of 58.9 years. IM involved predominantly the thigh (n=10). MR imaging showed well-circumscribed intramuscular masses, hypointense on T1-weighted and hyperintense on T2-weighted images. Eleven masses were homogeneous and seven slightly heterogeneous due to fibrous septa. Enhanced MR imaging demonstrated three different patterns: peripheral enhancement (n=1), peripheral and patchy internal enhancement (n=7) or peripheral and linear internal enhancement (n=4). Intratumoral cysts were detected in four masses. MR imaging showed the presence of a pseudocapsule (n=12), fat around the lesion (n=16) and peritumoral edema (n=16). Histologically, all the tumors were hypocellular, hypovascular and myxoid. Peripheral areas of collagenous fibers formed a partial capsule and IM often merged into surrounding muscular fibers. More cellular tumors and those with scanty myxoid stroma tended to show a more prominent internal enhancement.

CONCLUSION

IM shows several recognizable MR features which suggest its diagnosis.

Imaging evaluation of patients with soft tissue sarcoma

Imaging provides the clinician with crucial information in the diagnosis, staging, treatment planning, treatment evaluation, and post-treatment assessment of patients with soft tissue sarcoma. MRI, including contrast-enhanced sequences, usually is preferred for evaluating the primary site in extremity sarcomas and lesions of the head and neck. CT generally is preferred for imaging of the chest, abdomen, and pelvis, either in the evaluation of the primary site in those regions or for identifying metastatic disease. The experienced radiologist often can suggest a specific diagnosis or narrow differential diagnosis from the imaging characteristics, particularly with MRI. It is imperative that imaging be performed in a manner specific for the evaluation of soft tissue masses, and before biopsy or surgery, to provide the most accurate preoperative assessment and treatment planning [56, 57].

Maxillary odontogenic myxoma: a diagnostic pitfall on aspiration cytology

A painless, slow-growing cheek swelling in a young male clinically considered a salivary gland mass was aspirated. Cytology smears were hypocellular. The striking feature was abundant myxoid material with a few monomorphic oval cells, interpreted as myxoid variant of pleomorphic adenoma. Subsequent CT scan was suggestive of a malignant tumor but biopsy confirmed it as myxoma. Myxoma of the jaw is a rare benign tumor that has a tendency for bone destruction, invasion into surrounding structures, and a relatively high recurrence rate. Maxillary myxoma is less frequent but behaves more aggressively than in the mandible, as it spreads through the maxillary sinus. Cytologically, it should be differentiated from other tumors showing predominant myxoid change. Awareness of potential diagnostic pitfalls and careful evaluation of clinical and radiological data is necessary to narrow the differential diagnosis.

Intramuscular myxoma causing lumbar radiculopathy. Case report and review of the literature

The authors present the rare case of a myxoma, a benign soft-tissue tumor of mesenchymal origin noted for occurring in the left atrium of the heart, which was found in the lumbar paraspinal muscles of an 80-year-old woman. This patient experienced low-back pain for over 20 years and had noted its increasing severity with the development of an L-5 radiculopathy over a 3-month period. Magnetic resonance imaging of the lumbar spine revealed a large paraspinal mass that invaded the L-5 vertebral body and the left foramen of L5-S1. A computerized tomography-guided biopsy sampling procedure was performed, and examination of the specimen revealed an intramuscular myxoma. The patient underwent resection of the tumor and nerve root decompression. The diagnosis of intramuscular myxoma was confirmed, and the patient experienced complete resolution of her presenting symptoms. This patient represents the third reported case (the first in the English-language literature) of an intramuscular (paraspinal) myxoma presenting with lumbar nerve root compression.

Myxoma is not a single entity: a review of the concept of myxoma

Myxoid lesions can be subdivided into (1) mainstream myxomas of soft tissues, (2) mainstream myxomas located outside the soft tissue, (3) inadequately substantiated myxomas, (4) myxoid soft tissue tumors or lesions not regarded as myxomas, (5) myxoid fatty conditions, (6) other soft tissue lesions and tumors that are sometimes markedly myxoid, (7) other soft tissue tumors in which myxoid foci may be seen, and (8) nonneoplastic myxoid conditions of soft tissue. More than 60 such conditions are listed and the five entities regarded as mainstream soft tissue myxomas (namely, intramuscular myxoma, juxta-articular myxoma, superficial angiomyxoma, aggressive angiomyxoma, and myxoid neurothekeoma [myxoma of nerve sheath]) are reviewed in detail. Intramuscular myxoma is exclusively intramuscular, usually affects middle-aged women, is most commonly located in the thigh, and does not recur after simple excision. Multiple intramuscular myxomas are rare and are usually associated with monostotic or polyostotic fibrous dysplasia and Albright's syndrome. Juxta-articular myxoma histologically resembles an intramuscular myxoma, but involves periarticular tendons, ligaments, joint capsules, muscles, and even the subcutis of adults. It may be associated with osteoarthritis of the adjacent joint. Some 30% recur locally. Superficial angiomyxoma also has been called cutaneous myxoma. It affects all ages, with a peak incidence in the third and fourth decades; arises in the trunk, lower limb, head, and neck regions; and usually measures less than 5 cm in diameter. Epithelial components are present in approximately 25% of tumors. Approximately one third recur locally, but there have been no metastases. Patients with multiple lesions may have the Carney complex. Aggressive angiomyxoma usually arises in the pelvic and perineal regions and affects females seven times as often as males. Tumors usually measure 10 cm or more in diameter, invade surrounding tissues, and recur in approximately 50% of cases. None have metastasized. Myxoma of nerve sheath (the myxoid variant of neurothekeoma) preferentially affects the dermis and subcutis of the cervicofacial areas and shoulders of young women. Most patients are younger than 40 years; one third of them are in the second decade of life. The majority of tumors measure between 0.5 and 1.5 cm. Only three of 102 cases compiled from the two largest published series recurred; none metastasized. The different clinicopathologic features and behavior of these five mainstream myxomas indicate that myxoma is not a single entity.

Myxomatous soft tissue tumors: correlation of cytopathology and histopathology

A small, uncommon group of soft tissue tumors are distinguished by their unique and consistent ability to produce an overwhelming abundance of myxoid ground substance along with the proliferating cells that constitute the tumor. Grossly, all these neoplasms have a variable gelatinous quality. Because of the voluminous stroma, most of these tumors have some findings that overlap with one another. Nonetheless, each tumor has a composite set of morphologic, immunophenotypic, ultrastructural, and genotypic features exclusive to itself. Because soft tissue masses are not a frequent site of fine-needle aspiration, the cytopathology of this set of tumors is vastly unappreciated, both in the literature and in day-to-day practice. The aim of this review is to detail the salient light microscopic findings of this group of six major myxoid soft tissue tumors, to correlate the cytopathology (particularly as obtained using the fine-needle aspiration biopsy technique) with its histopathologic counterparts, and to discuss the limitations of both cytologic and histologic methods. This cytohistopathologic correlation should assist the reader in the diagnosis of myxoid tumors of soft tissue.

Optimal radiologic imaging of soft tissue sarcomas

Radiologic evaluation of the patient with soft tissue sarcoma may include conventional radiography, scintigraphy, ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. The radiologist also plays a critical role in the evaluation of the patient with soft tissue sarcoma by guiding and performing aspiration biopsies. This review discusses the use of radiological techniques to evaluate the primary lesion and to detect recurrences. In adults, soft tissue sarcoma most commonly occurs in the extremities, and this review emphasizes the role of MR imaging in the pre- and post-treatment evaluation of extremity soft tissue sarcomas. The role of imaging studies in the evaluation of soft tissue sarcomas in the abdomen, thorax, and the head and neck region is also discussed.

Logistic regression analysis of myxoid sarcomas: a cytologic study

The objective of this study was to identify key diagnostic cytologic criteria for the most common myxoid sarcomas studied by fine-needle aspiration cytology. We reviewed 27 myxoid malignant fibrous histiocytomas, 8 chordomas, 16 chondrosarcomas, and 12 myxoid liposarcomas in which both cytologic specimens and final histopathologic diagnoses were available. All specimens were coded as to the presence or absence of the following variables: high cellularity, low cellularity, tissue fragments, epithelial fragments, pale/loose ground substance, dense ground substance, chondroid fragments, large amount of myxoid material, small amount of myxoid material, capillary vessel networks, pleomorphism, binucleate cells, multinucleate cells, physaliphorous cells, cells in lacunae, signet ring cells, lipoblasts, fibroblast-like cells, histiocyte-like cells, stellate cells, long filamentous cells, short spindle cells, osteoclastic giant cells, nuclei with pointed ends, nuclei with cigar-shaped ends, fish-hook nuclei, round/ovoid nuclei, naked nuclei, large nucleoli, small nucleoli, mitotic figures, abnormal mitotic figures, intracytoplasmic hemosiderin deposits, background cells, fat, cytoplasmic vacuoles, and pleomorphic giant cells. A logistic regression analysis was performed to identify the variables predictive of myxoid malignant fibrous histiocytoma, chordoma, myxoid chondrosarcoma, and myxoid liposarcoma. The statistical analysis selected pleomorphic giant cells and the presence of fibroblast-like cells as most predictive of malignant fibrous histiocytoma, physaliphorous cells as most closely associated with chordoma, chondroid fragments as most predictive of chondrosarcoma, and lipoblasts as most predictive of liposarcoma. While myxoid lesions have many overlapping cytologic features, key criteria including the presence of lipoblasts, physaliphorous cells, chondroid fragments, and pleomorphic giant cells are useful in subclassifying these neoplasms.