3.3 Soft Tissue Pathology Flashcards
- benign fat tumor
- most common soft tissue tumor in adults
- soft, mobile, painless, cured with excision
- histo: well encapsulated mass of mature fat cells, looks normal
lipoma
- common adipose sarcoma in adulthood, rare in children
- lipoblasts differentiate from lipoma, resemble fetal fat cells (scalloped nucleus or signet ring)
liposarcoma
MDM2 oncogene amplification, type of liposarcoma
well differentiated liposarcoma
(12;16) translocation, round cell, intermediate behavior, type of liposarcoma
myxoid (round cell) liposarcoma
aggressive and able to metastasize, type of liposarcoma
pleomorphic liposarcoma
- fibrous tumor, reactive pseduosarcoma, solitary rapidly growing mass on trunk or arm
- histo: plump random fibroblasts in background of lymphocytes and RBCs, mitoses
nodular fasciitis
-dense white lesion, can trap structures and impair function, two types (deep and superficial)
fibromatoses
-Dupuytren contracture (palmar), plantar, Peyronie (penile), due to proliferation of fibroblasts and deposition of collagen
superficial fibromatoses
- abdominal desmoid tumors, young adults
- B-catenin mutation
- associated with Gardner syndrome (FAP)
- hard to completely excise
Deep (desmoid) fibromatoses
- very rare, occurs in peritoneum, thigh, and knee
- highly aggressive
- histo: malignant spindle cells in a herringbone pattern
fibrosarcoma
- skeletal muscle tumor, commonly in head and neck
- most common soft tissue sarcoma of childhood
- histo: strap cell with eccentric nucleus and lots of pink cytoplasm w/ striations,
- stain (+) for actin, myoglobin, desmin
rhabdomyosarcoma
- most common subtype of rhabdomyosarcoma
- botryoides: develop in wall of hollow organs (nasopharynx, vagina)
embryonal
- worst prognosis subtype of rhabdomyosarcoma
- PAX3/7 fusion with FOXO1a gene, leads to dysregulation of muscle differentiation
- histo looks like lung tissue
alveolar
