Myxoma

Epidemiology:

Common sites:

• deep within muscle of an extremity

Gross features:

• circumscribed
• extremely gelatinous

Histologic features:

• circumscribed
• nearly avascular
• slightly basophilic proteoglycan matrix
• very hypocellular
• scattered stellate or bipolar cells
• oval nuclei
• no pleomorphism
• at the periphery there is an increased number of spindle cells abutting on a lightly collagenized capsule
• mucinous cyst or focal eosinophilic fibrinous quality centrally
• nerve sheath myxoma:
• nerve at periphery

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

Other features:

• rarely recurs (if ever)

References:

• Sternberg 2004