Soft Tissue Chondroma

 Range: 0.3-6.5 cm






Microscopic




• Well circumscribed and lobulated

• Mostly composed of mature hyaline cartilage

• Variable amounts of calcification

• Ossification common

• Granulomatous inflammation in 15% of cases

• Rare tumors with extensive xanthogranulomatous inflammation

• Myxoid matrix common (myxochondroma)

• Rare tumors with extensive stromal fibrosis (fibrochondroma)

• Morphologic variant: Chondroblastoma-like chondroma


Top Differential Diagnoses




• Synovial chondromatosis

• Tophaceous pseudogout

• Tumoral calcinosis

• Extraskeletal myxoid chondrosarcoma

• Calcifying aponeurotic fibroma

• Myxochondroid metaplasia of plantar foot

• Cutaneous mixed tumor with chondroid metaplasia

• Tenosynovial giant cell tumor

image
CT Scan of Soft Tissue Chondroma
Soft tissue chondroma typically occurs in the digits of the hands and feet. It presents as a painless, well-demarcated mineralized mass, as demonstrated in this CT of a dorsal index finger lesion. Note the peripheral distribution of mineralization image.


image
Lobular Architecture of Chondroma
Soft tissue chondroma typically has a lobular architecture with islands of hyaline cartilage image separated by fibrous bands image. Matrix calcification image and ossification image are common.

image
Cytological Features of Chondroma
High-power micrograph illustrates typical cytological features of soft tissue chondroma. The chondrocytes are often arranged in clusters, situated in lacunar spaces within a pale blue hyaline matrix, and have uniform round nuclei and abundant eosinophilic cytoplasm. Rare binucleated cells can be seen image. Mitoses are rare.

image
Calcified Hyaline Cartilage
Areas of very dense calcification are common, illustrated by heavy basophilic staining image of the cartilage matrix.


TERMINOLOGY


Synonyms




• Extraskeletal chondroma

• Chondroma of soft parts

• Fibrochondroma

• Osteochondroma

• Myxochondroma

• Chondroblastoma-like chondroma


Definitions




• Benign hyaline cartilage neoplasm of soft tissue with predilection for hands and feet


ETIOLOGY/PATHOGENESIS


Neoplasm With Genetic Abnormalities




• Rearrangement of 12q13-15

• Trisomy 5

• Aberrations of chromosome 11

• HMGA2 abnormalities


CLINICAL ISSUES


Epidemiology




• Incidence
image Uncommon

– Exact incidence unknown

• Age
image Median: 4th decade
– Range: Infancy to 9th decade

• Sex
image F = M


Presentation




• Painless mass
• Most common in hands and feet (60-95%)

image Especially in fingers (40-50%)

• Rare sites
image Proximal extremities, trunk, head and neck, oral cavity, ear, upper aerodigestive tract, dura/extradural, skin, fallopian tube


Treatment




• Simple surgical excision


Prognosis




• Low recurrence rate (15-20%)
image Recurrences controlled by reexcision

• No reports of malignant degeneration


IMAGING


General Features




• Best diagnostic clue
image Small, well-demarcated lesion

image Mineralized soft tissue mass

image Acral extremity

• Location
image Hands and feet

image Often in vicinity of joint or tendon

image No intraarticular or subperiosteal localization by definition

• Morphology
image Most are calcified or ossified

image Sometimes erode and deform underlying bone


MACROSCOPIC


General Features




• Well demarcated and bosselated

• Spherical or oval

• Rubbery or hard

• Sometimes soft, friable, gelatinous, or cystic


Size




• Median: 1.6 cm
image Range: 0.3-6.5 cm


MICROSCOPIC


Histologic Features




• Well-circumscribed and lobulated subcutaneous tumor
• Mostly composed of mature hyaline cartilage

• Chondrocytes located in lacunae

image Arranged diffusely or in small clusters

image Some have enlarged nuclei and moderate pleomorphism

image Very low mitotic rate

• Variable amounts of calcification
image Granular stippled calcification that surrounds chondrocytes in lace-like pattern

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Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Soft Tissue Chondroma
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