Fibrous MSK tumors in different location

Fibrous MSK tumors in different location: Pictorial essay with MRI and
histopathology correlation.
Abstract number : EE35
Category: Educational review
Authors:
Dr. Ashutosh Prakash
Dr. Mathew George
Diagnostic Radiology
Tan Tock Seng Hospital
11 Jalan Tan Tock Seng
Singapore 308433
E-mail of corresponding author : [email protected]
Introduction:
Fibrous musculoskeletal are common tumors with varied anatomic locations. We present the MRI
findings of fibrous musculoskeletal tumors in the soft tissues. Subcutaneous, intramuscular, intermuscular,
and intra-articular fibrous tumors with MRI appearance and histopathology diagnosis are shown.
WHO classification of soft tissue tumors:
•Adipocytic tumours
•Fibroblastic / Myofibroblastic tumours
•So-called fibrohistiocytic tumours
•Smooth muscle tumours
•Pericytic (prevascular) tumours
•Skeletal muscle tumours
•Vascular tumours
•Chondro-osseous tumours
•Tumours of uncertain diffrenentiation
FIBROBLASTIC / MYOFIBROBLASTIC SOFT TISSUE TUMOURS
BENIGN
INTERMEDIATE (locally aggressive)
Nodular fasciitis
Proliferative fasciitis
Proliferative myositis
Myositis ossificans
Fibro-osseous pseudotumour of digits
Ischaemic fasciitis
Elastofibroma
Fibrous hamartoma of infancy
Myofibroma / Myofibromatosis
Fibromatosis colli
Juvenile hyaline fibromatosis
Inclusion body fibromatosis
Fibroma of tendon sheath
Desmoplastic fibroblastoma
Mammary-type myofibroblastoma
Calcifying aponeurotic fibroma
Angiomyofibroblastoma
Cellular angiofibroma
Nuchal-type fibroma
Gardner fibroma
Calcifying fibrous tumour
Giant cell angiofibroma
Superficial fibromatoses (palmar / plantar)
Desmoid-type fibromatoses 8821/1
Lipofibromatosis
INTERMEDIATE (rarely metastasizing)
Solitary fibrous tumour and haemangiopericytoma
(incl. lipomatous haemangiopericytoma)
Inflammatory myofibroblastic tumour
Low grade myofibroblastic sarcoma
Myxoinflammatory
Fibroblastic sarcoma
Infantile fibrosarcoma
MALIGNANT
Adult fibrosarcoma
Myxofibrosarcoma
Low grade fibromyxoid sarcoma
Hyalinizing spindle cell tumour
Sclerosing epithelioid fibrosarcoma
SO-CALLED FIBROHISTIOCYTIC SOFT TISSUE TUMOURS
BENIGN
Giant cell tumour of tendon sheath
Diffuse-type giant cell tumour
Deep benign fibrous histiocytoma
INTERMEDIATE (rarely metastasizing)
Plexiform fibrohistiocytic tumour
Giant cell tumour of soft tissues
MALIGNANT
Pleomorphic ‘MFH’ / Undifferentiated Pleomorphic sarcoma
Giant cell ‘MFH’ / Undifferentiated pleomorphic sarcoma with giant cells
Inflammatory ‘MFH’ / Undifferentiated pleomorphic sarcoma with prominent inflammation
Following slides show the MRI features of histopathologically proven
“fibroblastic / myofibroblastic and so-called fibrohistocytic tumours” that we
encountered. The microscopic findings and final histopathological
diagnosis are described.
MRI of left thigh: Subcutaneous lesion
TIW
T2W FS
GRE
T1 FS with contras
of left thigh shows a subcutaneous mass; it appears slightly hyperintense on T1, heterogeneously hyperintense on T2, no
ming on GRE and shows diffuse intense contrast enhancement.
ROSCOPIC DESCRIPTION
ion shows skin and subcutaneous adipose tissue. There is a well-circumscribed and encapsulated tumor within the
utaneous tissue, composed of bland spindle cells arranged around a rich vascular network. The larger blood vessels show
vascular hyalinization. There is myxoid change in the less cellular areas. Entrapped adipocytes are present. Tumor necrosis
t identified. Mitotic activity is less than 1 per 10 hpf.
GNOSIS: Benign mesenchymal lesion, compatible with solitary fibrous tumor
MRI of left foot: subcutaneous lesion
T1W
T2W FS
GRE
T1W FS with contrast
MRI of left foot shows subcutaneous T1W, T2W and GRE hypointense mass in the sole. Mild contrast enhancement is seen, few
vessels are seen in proximity.
MICROSCOPIC DESCRIPTION
Sections show skin and subcutaneous tissue with a lesion displaying a multinodular to plexiform growth pattern. The lesion
involves the dermal-subcutaneous junction as well as the subcutaneous fat. The nodular areas are composed of spindle cells
arranged in short fascicles associated with a storiform appearance in some areas. In some nodules, plump to slightly oval cells
are noted in the center. There are accompanying osteoclast like giant cells. Areas of hemorrhage with hemosiderin pigments are
present. The tumor appears to infiltrate the walls of some blood vessels. No significant mitotic activity or necrosis is present.
On immunohistochemistry, the tumor shows diffuse positivity for CD 163. Factor 13a highlights the osteoclast like giant cells
and scattered stromal dendritic cells within the tumor. CD 34 also shows focal positivity in the tumor cells. The tumor cells
are negative for S-100 protein, desmin and SMA.
DIAGNOSIS: PLEXIFORM FIBROHISTIOCYTIC TUMOUR
MRI of left knee: subcutaneous lesion
T1W
T2W FS
GRE
T1W FS with contrast
MRI of left knee shows subcutaneous T1W, T2W and GRE hypointense mass in the knee. Mild contrast enhancement is seen.
MICROSCOPIC DESCRIPTION
LEFT KNEE TUMOUR, EXCISION BIOPSY:
Sections show a circumscribed, hypocellular nodule composed of bland spindle cells set within markedly collagenous stroma with
scattered blood vessels and slit-like spaces. The spindle cells do not exhibit cytologic atypia, mitotic activity or necrosis. No
stellate cells can be seen. Foci of calcification and ossification are present. Some foreign body-type multinucleated giant cells
surrounding birefringent suture material can be seen. A few mature adipocytes are also seen within the tumour. There is no
evidence of malignancy.
DIAGNOSIS: BENIGN HYPOCELLULAR SPINDLE CELL AND FIBROUS NODULE.
MRI of left leg: subcutaneous lesion
T1W
T2W FS
GRE
T1W FS with contrast
MRI of left leg shows subcutaneous T1W, T2W FS and GRE isointense nodule. Contrast enhancement is seen.
MICROSCOPIC DESCRIPTION
Sections of show a circumscribed lesion within the subcutaneous tissue. It is composed of a hypocellular proliferation of
cytologically bland spindle and stellate shaped myofibroblastic cells separated by abundant thick collagen bundles. Focally, the
stroma appears more myxoid and extravasated red blood cells are seen. There is no significant atypia, increased mitotic activity
or necrosis. The lesion abuts the skeletal muscle at the base of the specimen. The overlying epidermis is unremarkable.
DIAGNOSIS: DESMOPLASTIC FIBROBLASTOMA.
MRI of foot : Fascial lesion
T1W
T2W FS
GRE
T1W FS with contrast
MRI of left foot shows nodular thickening in the medial plantar fascia. It appears isointense on T1, hyperintense on T2, no
blooming on GRE and shows diffuse contrast enhancement.
MICROSCOPIC DESCRIPTION
The section shows fibrous connective tissue with adjacent fatty tissue, consistent with being derived from the plantar
fascia. Focally there appears to be mild increase of cellularity in the fibrous tissue, probably reactive in nature.
There is no evidence of malignancy.
DIAGNOSIS: PLANTAR FASCIA LESION / FIBROMATOSIS; NO EVIDENCE OF MALIGNANCY
MRI of right forearm: Fascial based
T1W
T2W FS
GRE
T1W with contrast
MRI shows a fascia based nodule; it is hypointense on T1w, T2w, GRE and does not show contrast enhancement.
MICROSCOPIC DESCRIPTION
The lesion shows nodular circumscribed spindle cell proliferation with features suggestive of a fibroma of tendon sheath. Nerve
bundles are seen in the outer fibroadipose tissue. No evidence of malignancy.
DIAGNOSIS: FEATURES SUGGESTIVE OF A FIBROMA OF TENDON SHEATH.
MRI of right hand: intramuscular lesion
MRI findings:
Intramuscular mass lesion in the 1st web space isointense on T1W, hypointense on
T2 W FS, hypointense on GRE and shows heterogeneous contrast enhancement.
TI W
T2 W FS
GRE
TI W FS with contrast
MICROSCOPIC DESCRIPTION
TUMOUR FROM RIGHT HAND, EXCISION:
Sections show a relatively well circumscribed hypocellular lesion comprising
scattered bland spindled fibroblasts and stellate-shaped myofibroblasts in a
collagenous background. Several small blood vessels are seen. There is no
cytological atypia or mitoses. However, the lesion is invading into the skeletal
muscle and bone. There is no evidence of malignancy.
DIAGNOSIS: BENIGN DESMOPLASTIC FIBROBLASTOMA.
MRI of left leg: intramuscular lesion
T1W
T2W FS
GRE
TIW FS with contrast
MRI shows a heterogeneous intramuscular mass; it has hypointense and hyperintense areas on T1W, T2W FS, GRE and shows
heterogeneous contrast enhancement.
MICROSCOPIC DESCRIPTION
Sections show a moderately cellular tumor with a heterogeneous composition located within the skeletal muscle. The tumor
comprises spindle cells arranged in fascicles with a vague storiform pattern in some areas. In some areas, the tumor cells appear
epithelioid and rhabdoid. Some cells show abundant eosinophilic cytoplasm with some resemblance towards rhabdomyoblasts. A
significant population of foam cells is present. Some scattered multinucleated cells as well as bizarre cells are seen. No necrosis is
noted. Mitotic index is about 6 per 10 high power fields. Brown pigments shown to be iron special stains are present. No acid fast
bacilli or fungi are seen on special stains. On immunohistochemistry, the tumor stains for desmin and factor XIIIa. The stains for
SMA, S-100, HMB45, CD34, myo-D1 and myogenin. EBER ISH is negative.
DIAGNOSIS: SPINDLE CELL TUMOUR WITH FIBROHISTIOCYTIC PATTERN.
MRI of left thigh: intramuscular lesion
T1W
FSEIR
TIW FS with contrast
MRI shows an intramuscular mass; it is hyperintense on T1W, FSEIR and shows diffuse homogenous contrast enhancement.
MICROSCOPIC DESCRIPTION
LEFT THIGH TUMOR, WIDE EXCISION:
The tumor comprises a cellular, well-circumscribed proliferation of fibrohistiocytic cells arranged in short fascicular and
storiform patterns, containing scattered chronic inflammatory cells, foamy macrophages and Touton-type giant cells.
There is no evidence of malignancy.
DIAGNOSIS: DEEP DERMATOFIBROMA
MRI of left hip: Intramuscular lesion
T1W
T2 W
GRE
T1W FS with contrast
MRI of left hip shows T1w and T2w hyperintense lesion with the left iliopsoas muscle. It shows peripheral blooming on GRE and
peripheral irregular contrast enhancement.
MICROSCOPIC DESCRIPTION
The sections show pieces of a fibro-osseous lesion featuring proliferation of irregular and anastamosing trabeculae of woven
bone rimmed by osteoblasts intermixed with myofibroblastic spindle cell proliferation with deposition of variable collagenous
fibrous tissue. The lesion demonstrates a zonal pattern of proliferation characterised by more cellular, haemorrhagic and loose
myofibroblastic matrix centrally, while more mature fibrous tissue and organizing trabeculae of woven bone exhibiting evidence of
a lamellar pattern are present towards the periphery. There is no significant cytologic atypia or increased mitotic activity. There is
no evidence of malignancy.
DIAGNOSIS: BENIGN FIBRO-OSSEOUS LESION, SUGGESTIVE OF MYOSITIS OSSIFICANS.
MRI of left middle finger : tendon based lesion
MRI of the middle finger shows T1w, T2W and GRE hyperintense mass with contrast
enhancement abutting the flexor tendon.
T1W
T2W FS
LEFT MIDDLE FINGER LUMP, EXCISION BIOPSY:
Sections show a circumscribed tumour composed of multiple nodular collections of
mononuclear cells, foamy macrophages and osteoclast-like multinucleated giant cells. The
nuclei of the mononuclear cells and the multinucleated giant cells appear similar and are
devoid of cytologic atypia. Scattered mitotic figures can be identified. The stroma appears
sclerotic and hyalinised. Cholesterol clefts and a few foci of necrosis are seen. There is no
evidence of malignancy.
DIAGNOSIS: GIANT CELL TUMOUR OF TENDON SHEATH (NODULAR TENOSYNOVITIS).
GRE
T1W with contrast
T1W with contrast
MRI of right shoulder: Intermuscular lesion
T1W
T2W
T1W FS with contrast axial
T1W FS with contrast sagittal
MRI of the right shoulder shows two intermuscular mass lesions; it appears isointense on T1W, hyperintense on T2W and
shows
intense heterogeneous contrast enhancement.
MICROSCOPIC DESCRIPTION
RIGHT SHOULDER TUMOR, INCISIONAL BIOPSY:
The tumor comprises well circumscribed and irregular lobules of mostly spindled cells with mild nuclear atypia amidst a
fibromyxoid stroma. The tumor cells also demonstrate focal epithelioid morphology and vacuolated cytoplasm especially within
myxoid areas. There is focal necrosis and apparent involvement of intertrabecular stroma in an adjacent fragment of trabecular
bone. The tumor cells are diffusely positive for calponin and focally positive for S-100, desmin and SMA. AE1/3, CAM5.2, CK14,
EMA, p63 and GFAP are negative. No foci of ductal differentiation are seen.
DIAGNOSIS:
MYXOID TUMOUR WITH CHONDROID AREAS IN KEEPING WITH A MALIGNANT OSSIFYING FIBROMYXOID TUMOR.
MRI of right knee : intra-articular lesion
PD
PD FS
MRI shows intra-articular PD hypointense nodule in the Hoffa’s fat pad.
MICROSCOPIC DESCRIPTION
RIGHT KNEE INTRA-ARTICULAR LUMP:
Sections show synovium with a lobulated, poorly circumscribed lesion consisting of solid sheets of foamy
xanthomatous cells, small round to spindled mononuclear cells and multinucleated giant cells. The cells have
bland ovoid, frequently grooved nuclei and evenly dispersed chromatin. Occasional mitotic activity is seen. There
is no necrosis. Hemosiderin deposits and scattered lymphocytes are present. The stroma is focally hyalinised.
DIAGNOSIS: NODULAR TENOSYNOVITIS (GIANT CELL TUMOUR OF TENDON SHEATH).
MRI of right knee: Intra-articular lesion
PD
PD FS
GRE
T1W FS with contrast
MRI of right knee shows PD FS and GRE hyperintense nodule showing contrast enhancement in the suprapatellar region.
MICROSCOPIC FINDINGS:
Sections show fibroadipose tissue with a circumscribed nodular moderately cellular lesion composed of bland mononuclear cells,
scattered giant cells and aggregates of foamy histiocytes. There are also chronic inflammatory cells and fibrosis. There is no
evidence of malignancy.
DIAGNOSIS: GIANT CELL TUMOUR OF TENDON SHEATH
MRI of left hip: Intra-articular lesion
T1W
T2W FS
T1W FS with contrast
MRI of left hip shows T1w isointense, T2w slightly hyperintense intra-articular nodule not showing significant contrast
enhancement.
MICROSCOPIC DESCRIPTION
Sections show cores of fibroadipose tissue in which there are portions of a lesion composed a proliferation of sheets of
mononuclear cells admixed with foam cells, few osteoclast-like multinucleated giant cells and scattered haemosiderophages.
Mononuclear cells are relatively uniform and lack significant cytologic atypia or increased mitotic activity. The lesion is focally
covered by synovial type cells and shows interspersed variably sized blood vessels and fibrous stroma. No necrosis is seen. No
epithelioid histiocyte granulomas are seen. No bone is present.
DIAGNOSIS: GIANT CELL TUMOUR OF TENDON SHEATH
CONCLUSION:
Awareness of the MRI features of this common group of fibrous soft tissue tumors is necessary for accurate
diagnosis and avoiding mistakes. Imaging features are not always diagnostic. Hypointensity on T2w images is
suggestive of high collagenous lesions and hyperintensity on T2w images is suggestive of myxoid matrix.
Differentiation between be benign and malignant fibrous tumors is not always possible. Malignant variants shows
heterogeneous signal intensity and heterogeneous contrast enhancement.
We don’t have any disclosure to make
References:
Dinauer PA, Brixey CJ, Moncur JT, Fanburg-smith JC, Murphy MD. Pathologic and MR imaging features of
Benign fibrous soft-tissue tumors in adults. Radiographics 2007;27(1):173-87.
Wignall OJ, Moskovic EC, Thyway K, Thomas JM. Solitary fibrous tumors of the soft tissue: review of the
imaging and clinical features with histopathological correlation. AJR Am J Roentgenol. 2010;195(1):W55-62.
http://www.iarc.fr/en/publications/pdfs-online/pat-gen/bb5/bb5-classifsofttissue.pdf