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Bone and Soft-Tissue Disorders

= benign disease with somewhat aggressive biologic behavior between that of fibrous proliferation and fibrosarcoma arising from fascia or aponeurosis

Histo: spindle-shaped myofibroplastic cells in dense deposits of intercellular collagen fibers with variable amounts of extracellular myxoid matrix + compressed elongated vessels

Infantile Digital Fibromatosis!!navigator!!

= INCLUSION BODY FIBROMATOSIS = REYE TUMOR = INFANTILE DIGITAL FIBROMA / MYOFIBROMATOSIS / MYOFIBROBLASTOMA / FIBROMATOSIS = INFANTILE DERMAL FIBROMATOSIS /FIBROMA = DIGITAL FIBROUS TUMOR OF INFANCY AND CHILDHOOD

= single / multiple nodular dermal protrusion of fibrous tissue on extensor surface of digits

Age: 1st year of life (80%); 33% congenital; M <F

Histo: intracytoplasmic perinuclear inclusion bodies

Location: fingers (60%), toes (40%)

Site: lateral aspect of distal / middle phalanx

  • nonspecific soft-tissue mass involving a digit
  • infrequently bone involvement

Prognosis: spontaneous regression (in 8%); 60% recurrence rate after excision

Juvenile Aponeurotic Fibroma!!navigator!!

= CALCIFYING APONEUROTIC FIBROMA

= rare locally aggressive benign fibrous tumor in childhood

Prevalence: 0.4% of all benign soft-tissue tumors

Histo: cellular dense fibrous tissue with focal often calcified chondral elements infiltrating adjacent structures (= cartilaginous tumor)

Peak age: 8–14 years; M÷F = 2÷1

  • slow-growing asymptomatic soft-tissue mass

Location: palm of hand (67–75%); sole of foot; neck, thigh, forearm, popliteal fossa, lumbosacral region

Site: deep volar (palmar) fascia + tendon + aponeurosis

  • nonspecific soft-tissue mass overlying inflamed bursa (often mistaken for calcified bursitis)
  • stippled calcifications (frequent)
  • interosseous soft-tissue mass of forearm + wrist
  • erosion / scalloping of bone may occur

Prognosis: recurrence rate of >50% after resection

Dx: biopsy (to differentiate from synovial sarcoma)

DDx: synovial sarcoma (commonly calcifies, bone erosion), chondroma, fibrosarcoma, osteosarcoma, myositis ossificans

Palmar Fibromatosis!!navigator!!

= DUPUYTREN DISEASE / CONTRACTURE

◊Most common type of superficial fibromatosis

Prevalence: 1–2%

Ethnicity: Caucasians esp. of Northern European ancestry; northern Scotland, Iceland, Norway, Australia

Age:>65 years(in 20%); M÷F = 4÷1

Path:<1 cm small often coalescent nodules attached to palmar aponeurosis and adherent to overlying skin; 2–10 mm in diameter, 10–55 mm in length; terminate in branching configuration at level of distal metacarpals

Histo: uniform fibromyoblastic proliferation of spindle-shaped cells with variably prominent vascularity

Associated with: plantar fibromatosis (5–20%), Peyronie disease, knuckle pads; diabetes (20%), epilepsy, alcoholism, keloids

  • painless subcutaneous nodules on palmar surface of distal crease of hand progressing to cords and bands causing skin puckering / dimpling
  • flexion contractures of digits ← fibrous attachment to flexor tendons

Location: 4th + 5th (most commonly) >2nd + 3rd digit; bilateral in 40–60%

Site: volar aponeurosis = flexor tendons

  • hypervascular hypoechoic nodules
  • nodular thickening iso- to hyperattenuating to muscle
  1. early stage hypercellular mitotically active lesion → higher rate of recurrence after local excision
    • high to intermediate signal intensity on T2WI
  2. mature lesion with high collagen content
    • low signal intensity on T2WI

Rx: surgical excision (of mature lesion)

Prognosis: 70% recurrence rate for early stage disease

Plantar Fibromatosis!!navigator!!

= PLANTAR FASCIITIS = LEDDERHOSE DISEASE

Prevalence: 0.23%

Cause: trauma; likely multifactorial

Age: 30–50 years; <30 years (44%); M÷F = 2÷1

Path: abnormal fibrous tissue replacing the plantar aponeurosis and infiltrating subcutaneous tissue + skin

Histo: nonencapsulated proliferation of fibroblasts separated by variable amounts of collagen

At risk: runners, obese patients

Associated with: Dupuytren contracture (10–65%), knuckle pads (42%), Peyronie disease; diabetes, epilepsy, keloids, alcoholism

  • heel pain (one of the most common causes)
  • one / multiple firm fixed subcutaneous nodules

Location: proximal / central portion of plantar aponeurosis; bilateral in 20–50%, typically metachronous with a 2–7-year interval

Site: middle to medial aspect of plantar arch; may involve skin + deep structures of the foot

  • hypervascular (92%) hypoechoic / mixed echogenic nodules in subcutaneous tissues superficial to often thickened plantar aponeurosis, medially (60%) / centrally (40%)
  • calcaneal spur

MR:

  • single or multiple nodules / poorly defined infiltrative heterogeneous (92%) mass iso- / hypointense compared to plantar muscles on T1WI + T2WI
  • marked contrast enhancement in 64%
  • ± subcutaneous edema

Rx: local excision with wide margins (for painful or disabling lesion); intralesional steroid injection; postoperative radiation therapy

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