Fibro-Osseous Pseudotumor of the Digits

Background

Fibro-Osseous Pseudotumor of the Digits is an uncommon and benign soft tissue tumor. As the name suggests, it presents as a rapidly growing mass on the hands and feet ranging in size from 1-3 cm. The overlying skin may show reddening and there may be pain. If it occurs on the hands, the volar or sides of the fingers are most common, usually at the metacarpals and phalanges.

SYNONYMS Florid reactive periostitis
Parosteal fasciitis

INCIDENCE Rare

AGE RANGE-MEDIAN 5-70 years
Mean 34 years

PATHOGENESIS CHARACTERIZATION

Probably a reactive lesion-often a history of trauma Shares many overlapping traits with myositis ossificans, another reactive condition of soft tissue

LABORATORY/RADIOLOGIC/OTHER TESTS CHARACTERIZATION

Radiographs
Soft tissue swelling or density with irregular calcifications

May have periosteal reactions such as lamellatins or Codman's triangle

Occasionally cortical erosion and bony destruction

GROSS APPEARANCE/CLINICAL VARIANTS CHARACTERIZATION

General White-gray firm mass associated with calcifications but no hemorrhage or necrosis

HISTOLOGICAL TYPES CHARACTERIZATION

General
Osteoid and bone usually prominent and distributed haphazardly but occasionally in a zonation pattern like myositis ossificans

Poor correlation between histologic changes and age of the lesion

Scant inflammation

Minimal cartilage

DIFFERENTIAL DIAGNOSIS KEY DIFFERENTIATING FEATURES

Paraosteal, periosteal, high grade surface and extraskeletal osteosarcoma High grade cytologic appearance of the cells

Nora's lesion (Bizzare paraosteal osteochondromatous proliferation) Prominent cartilaginous component
Ossification irregular

Myositis ossificans
Zonal pattern of peripheral mature bone with central cellular areas

Present in skeletal muscle

Inflammation and hemorrhage

Ostechondroma Cartilaginous cap surfacing organized bony trabeculae

Calcifying aponeurotic fibroma Highly collagenized fibroblastic proliferation with bands of calcification arising from hyalinzed fibrous tissue

PROGNOSIS AND TREATMENT CHARACTERIZATION

Prognostic Factors May have local recurrence

Metastasis None reported

Treatment Local excision

Cancer 1986;58:2103-2109.
Am J Surg Pathol 1981;5:423-433.

Commonly Used Terms

Soft tissue tumors

Last Updated 4/1/2001

SYNONYMS	Florid reactive periostitis Parosteal fasciitis
INCIDENCE	Rare
AGE RANGE-MEDIAN	5-70 years Mean 34 years

PATHOGENESIS	CHARACTERIZATION
Probably a reactive lesion-often a history of trauma	Shares many overlapping traits with myositis ossificans, another reactive condition of soft tissue

GROSS APPEARANCE/CLINICAL VARIANTS	CHARACTERIZATION
General	White-gray firm mass associated with calcifications but no hemorrhage or necrosis

DIFFERENTIAL DIAGNOSIS	KEY DIFFERENTIATING FEATURES
Paraosteal, periosteal, high grade surface and extraskeletal osteosarcoma	High grade cytologic appearance of the cells
Nora's lesion (Bizzare paraosteal osteochondromatous proliferation)	Prominent cartilaginous component Ossification irregular
Myositis ossificans	Zonal pattern of peripheral mature bone with central cellular areas Present in skeletal muscle Inflammation and hemorrhage
Ostechondroma	Cartilaginous cap surfacing organized bony trabeculae
Calcifying aponeurotic fibroma	Highly collagenized fibroblastic proliferation with bands of calcification arising from hyalinzed fibrous tissue

PROGNOSIS AND TREATMENT	CHARACTERIZATION
Prognostic Factors	May have local recurrence
Metastasis	None reported
Treatment	Local excision