Liposarcoma is the second most common soft tissue sarcoma in adults with a peak incidence between the 4th and 6th decade of life and slight preponderance to the male gender. It originates from multipotential primitive mesenchymal cells, rather than mature adipose tissue.
Benign periarticular, bone and joint lipomatous lesions are rare entities that are increasingly being identified using current imaging techniques. This pictorial review illustrates the wide range of imaging presentations of these lesions at various sites and their pathognomonic features. The main lesions reviewed include intraosseous lipoma, liposclerosing myxofibrous tumour, lipoma arborescens and intra-articular lipoma.
Spindle-cell lipoma (SCL) of the oral cavity is very rare. There are only four such reported cases in the literature. A concise literature review of SCL and a case report of a SCL affecting the cheek and lip of a 23-year-old man is presented.
A 38-year-old female presented with a 10-month history of right shoulder pain with impingement symptoms. She was diagnosed on magnetic resonance (MR) imaging to have supraspinatus tendon tear and degenerative changes contributing to subacromial impingement. She also had lipoma arborescens of the subacromial-subdeltoid bursa, an uncommon condition in a particularly rare location. Lipoma arborescens is a benign intra-articular condition characterized by lipomatous proliferation of synovium with replacement of subsynovial tissue by mature adipocytes. It is typically a monoarticular process affecting the knee. Due to the presence of pathognomonic fat, diagnosis is usually straightforward with MR as the preferred imaging modality.
Dendritic fibromyxolipoma (DFML), a rare, recently described distinct benign soft tissue tumor, has many clinicopathological features reminiscent of spindle cell lipoma and solitary fibrous tumor with myxoid change. It is distinguished histologically from both entities by the presence of spindle and stellate cells with dendritic cytoplasmic prolongations, prominent myxoid stroma with abundant keloidal collagen and occasional small plexiform vascular proliferation. We describe a case of histologically confirmed DFML of the left shoulder in a 67-year-old male, in which subsequent cytogenetic analysis revealed deletion involving 13q14.3 region in all the tumor cells, typically detected in spindle cell lipoma. In the presence of many clinicopathological similarities between DFML and spindle cell lipoma including chromosomal abnormalities, we postulate that DFML is merely a rare variant of spindle cell lipoma with extensive myxoid degeneration, and may not be considered as a separate entity. The possible differential diagnosis and their distinguishing features are briefly discussed.