A surprising green bruise on a woman’s arm during an acrobatic yoga session eventually led to the discovery of a rare soft tissue tumor, a finding documented in JAMA Dermatology.
Two years after a dislocated hand left a greenish mark on her arm, a patient in her 30s underwent imaging that revealed a small mass beneath the skin of the hand. X-ray studies and magnetic resonance imaging highlighted a lesion in the soft tissues, prompting further tissue analysis to determine its nature.
The biopsy showed a composition typical of fibrohistiocytic lipoma, a uncommon tumor characterized by a mix of fat cells, iron-containing pigment known as hemosiderin, and slender spindle-shaped cells. These spindle cells are a feature seen in a variety of skin and soft tissue tumors, including those arising from the skin, mucous membranes, bones, and surrounding soft tissues.
Experts identified the diagnosis as fibrohistiocytic lipoma, a rare growth most often reported in the foot or ankle and first described in contemporary medical literature around the turn of the century. In most cases, these tumors behave in a benign fashion and show a low likelihood of progressing to cancer, a fact supported by accumulated clinical experience and reported outcomes.
Although the precise triggers for this rare tumor remain unclear, researchers note that severe inflammation following an injury has been observed in some instances. Other scientists have proposed that damage to local blood vessels could play a role in initiating tumor formation, though this link requires more study. The current understanding emphasizes that trauma is not a guaranteed cause and does not always predict tumor development, underscoring the importance of careful diagnosis and ongoing observation when such lesions are found.