Prevalence, extension and characteristics of fluid-fluid levels in bone and soft tissue tumors

Abstract

The purpose of this study was to determine the prevalence, extension and signal characteristics of fluid-fluid levels in a large series of 700 bone and 700 soft tissue tumors. Out of a multi-institutional database, MRI of 700 consecutive patients with a bone tumor and MRI of 700 consecutive patients with a soft tissue neoplasm were retrospectively reviewed for the presence of fluid-fluid levels. Extension (single, multiple and proportion of the lesion occupied by fluid-fluid levels) and signal characteristics on magnetic resonance imaging of fluid-fluid levels were determined. In all patients, pathologic correlation was available. Of 700 patients with a bone tumor, 19 (10 male and 9 female; mean age, 29 years) presented with a fluid-fluid level (prevalence 2.7%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included aneurysmal bone cyst (ten cases), fibrous dysplasia (two cases), osteoblastoma (one case), simple bone cyst (one case), telangiectatic osteosarcoma (one case), "brown tumor" (one case), chondroblastoma (one case) and giant cell tumor (two cases). Of 700 patients with a soft tissue tumor, 20 (9 males and 11 females; mean age, 34 years) presented with a fluid-fluid level (prevalence 2.9%). Multiple fluid-fluid levels occupying at least one half of the total volume of the lesion were found in the majority of patients. Diagnoses included cavernous hemangioma (12 cases), synovial sarcoma (3 cases), angiosarcoma (1 case), aneurysmal bone cyst of soft tissue (1 case), myxofibrosarcoma (1 case) and high-grade sarcoma "not otherwise specified" (2 cases). In our series, the largest reported in the literature to the best of our knowledge, the presence of fluid-fluid levels is a rare finding with a prevalence of 2.7 and 2.9% in bone and soft tissue tumors, respectively. Fluid-fluid levels remain a non-specific finding and can occur in a wide range of bone and soft tissue tumors, both benign and malignant. Therefore, they cannot be considered diagnostic of any particular type of tumor, and the diagnosis should be made on the basis of other radiological and clinical findings.

Fluid-fluid level on magnetic resonance images may predict the occurrence of pituitary adenomas in cystic sellar-suprasellar masses

“…Fluid-fluid levels have been observed in various benign or malignant tumors, such as bone and soft tissue tumors, schwannomas, and sarcomas (4,5). Nevertheless, few articles have reported fluid-fluid levels in sellar pathologic masses, and the value of fluid-fluid levels in the differential diagnosis of sellar lesions is rarely reported.…”

CT and MRI of Pediatric Skull Lesions with Fluid-Fluid Levels

“…There is no dedicated study on the most common etiology of osseous lesions with FFLs in pediatric patients, to our knowledge. In addition, large studies that may have included some pediatric patients had not published their detailed results based on age groups, [5][6][7] and the current literature is mainly limited to published case reports. [9][10][11][12][13][14] There are only 2 case reports describing the presence of fluid-fluid level in LCH.…”

“…However, 2 large studies primarily in adult patients have demonstrated that ABCs are the most common etiology of osseous lesions with FFLs throughout the body. 5,6 Despite these data, the presence of FFLs remains a nonspecific finding and can be seen in a wide range of benign and malignant bone lesions, including fibrous dysplasia, telangiectatic osteosarcoma, osteoblastoma, simple bone cyst, lymphatic malformations, Ewing sarcoma, brown tumor, giant cell tumor, and chondroblastoma. [5][6][7][8][9] In this study, head CT and MR imaging of pediatric patients having skull lesions with FFLs were retrospectively reviewed with the aim of characterizing these lesions.…”

Fluid-Fluid Level Formation: A Rare Finding of Extracranial Head and Neck Schwannomas

“…Neoplastic fluid-fluid levels are observed in 2.7% of bone tumors and in 2.9% of soft tissue tumors. 5 However, fluid-fluid levels have been reported in various tumors, regardless of benignity or malignancy. 6 In soft tissue tumors, fluid-fluid levels have been reported in schwannomas, cavernous hemangiomas, and sarcomas (eg, in synovial sarcoma and angiosarcoma, and in malignant fibrous histiocytosis).…”

“…6 In soft tissue tumors, fluid-fluid levels have been reported in schwannomas, cavernous hemangiomas, and sarcomas (eg, in synovial sarcoma and angiosarcoma, and in malignant fibrous histiocytosis). 5,6 On the basis of viscosity and protein content measurements after hemorrhage or necrosis, fluid-fluid levels are caused by the separation of unclotted blood as opposed to serous (interstitial) fluid.…”