Sarcopedia

Benign acral fibromyxoid tumour with predilection for subungal and periungual regions Complete excision prevents recurrence

Diagnosis of exclusion - rule out MPNST, synovial sarcoma, leiomyosarcoma, DFSP Herringbone pattern characteristic Grade determines prognosis and treatment

PAX-FOXO1 positive alveolar RMS is high-risk Older age of presentation than embryonal More aggressive and higher metastatic potential

Deceptively Slow-growing despite High-grade histology and metastatic propensity TFE3 rearrangement is diagnostic PAS-positive crystals pathognomonic but not always seen Long-term surveillance required - late metastasis well recognised

Peak incidence in older adults

No summary available yet.

Pain is a cardinal feature - often out of proportion to size Female predominance and Lower extremity location are characteristic Must be distinguished from leiomyosarcoma (which is rare in subcutaneous tissue) Simple excision is curative

Can mimic haematoma or cyst clinically and radiologically EWSR1 rearrangement is diagnostically useful Paraneoplastic symptoms resolve after excision Despite intermediate classification, behaves nearly Benign

Rare aggressive Vascular malignancy Early metastatic spread typical Poor prognosis despite treatment Paclitaxel shows benefit in angiosarcoma

MDM2 amplification is the key diagnostic marker Extremity ALT has no metastatic potential (but can recur locally) Retroperitoneal location has significantly worse prognosis Terminology: ALT in extremity, WD liposarcoma in retroperitoneum

Represents a spectrum between Benign neurofibroma and MPNST CDKN2A loss and H3K27me3 loss are molecular markers of progression FDG-PET useful to identify lesions at Highest risk of Malignant transformation in NF1 Diagnosis requires careful pathological assessment

Benign nerve sheath tumour variant

No summary available yet.

Distinct entity from cutaneous melanoma despite similar IHC profile EWSR1 rearrangement essential for diagnosis - melanoma lacks this Lymph node involvement more common than most STS - sentinel node biopsy should be considered Foot/ankle location in young adults is characteristic

MDM2 FISH is diagnostic - essential for all lipomatous tumours in retroperitoneum Retroperitoneal location prevents adequate margins - leading cause of death from local recurrence CDK4/6 inhibitors (palbociclib) showing activity in clinical trials De novo DDLPS (no WDLPS component seen) still harbours MDM2 amplification

COL1A1-PDGFB fusion is diagnostic and also a therapeutic target (imatinib) CD34 is Highly characteristic on IHC but lost in FS-DFSP Mohs surgery achieves best local control for facial lesions Imatinib is Highly effective for PDGFB-rearranged tumours

Watch-and-wait is now first-line management for most asymptomatic lesions CTNNB1 mutation type predicts recurrence risk Screen for FAP when intra-abdominal/mesenteric desmoid is diagnosed Sorafenib is currently the most active systemic treatment based on RCT data

Virtually always in subscapular region - unique anatomical predilection Imaging characteristics alone are diagnostic in appropriate clinical setting - biopsy rarely needed Bilateral in majority - always examine opposite side Elderly women with repetitive shoulder activity (scrubbing, climbing) classically affected

Cytokeratin positivity is a diagnostic pitfall - may be confused with carcinoma or mesothelioma CD31 and ERG are the most sensitive Vascular markers MYC amplification confirms radiation-association Management as per conventional angiosarcoma

Loss of INI1 (SMARCB1) on IHC is diagnostically key Tazemetostat (EZH2 inhibitor) is the first targeted therapy approved for this disease Proximal type is more aggressive and carries worse prognosis than distal/classic type Lymph node dissection or sentinel node biopsy should be considered

Bone formation in soft tissue is key diagnostic feature Younger adults than typical soft tissue sarcomas Aggressive with metastatic potential

Benign hamartoma of infants Axilla is classic location Often no treatment needed

Benign fibromatosis variant Associated with familial adenomatous polyposis

KIT mutations define GIST Risk stratification guides treatment Tyrosine kinase inhibitors transforming prognosis

Rare Malignant variant of hemangiopericytoma High-grade malignancy with aggressive course

Classic clinical triad in subungual lesion is virtually diagnostic X-ray may show distal phalanx erosion - subtle but important finding MRI is investigation of choice for precise localisation pre-operatively Malignant variant characterised by large size (>2 cm), deep location, and nuclear atypia

Benign Neural tumour Rarely undergo Malignant transformation

High FDG uptake on PET-CT can be mistaken for malignancy - awareness is critical Multivacuolated granular cytoplasm of brown fat is pathognomonic Often in 'brown fat depots': interscapular, axilla, mediastinum, neck Simple excision is curative - no oncological resection needed

ETV6-NTRK3 fusion defines infantile fibrosarcoma - shared with mesoblastic nephroma NTRK inhibitors are transformative - larotrectinib has 75% response rate in TRK fusion-positive tumours Prognosis far better than adult fibrosarcoma despite aggressive histology Active surveillance/watch-and-wait being explored for very young infants

Rare genetic Fibrous disorder Autosomal recessive CMG2 mutations Multiple progressive lesions from infancy Management focuses on complications No curative treatment currently available

Benign smooth muscle tumour No Malignant transformation

Second most common STS Often presents at advanced stage Grade and depth crucial for treatment planning Regular imaging Follow-up essential

Embryonal fatty tumour of infants Benign despite somewhat immature appearance

Most common Benign soft tissue tumour No Malignant transformation

Benign proliferation of multiple lipomas No Malignant transformation

Most common STS in adults Subtype determines behaviour and prognosis Wide excision is mainstay of treatment Follow-up imaging critical for detection of recurrence

Benign lymphatic malformation Often congenital but can present later Observation reasonable if asymptomatic Excellent prognosis with appropriate management

High-grade malignancy Screen for NF1 Multimodal therapy standard NF1 association worsens prognosis

Benign developmental heterotopia Requires excision for confirmation

Tumour of periVascular epithelioid cells Fat-containing lesion in kidney characteristic TSC association in some cases

Highest-grade liposarcoma variant Aggressive behaviour - multimodal therapy required

Adult variant - generally poor prognosis Aggressive behaviour requiring multimodal therapy

Acral presentation with multifocal lesions typical Locally aggressive despite Benign appearance Wide excision essential

Benign muscle tumour No transformation to rhabdomyosarcoma

Most common soft tissue sarcoma in children PAX-FOXO1 status defines risk stratification Multimodal therapy standard

Low-grade appearance but aggressive behaviour Wide margins essential due to recurrence risk EWSR1-CREB3L1 fusion is diagnostic

Extraskeletal Ewing sarcoma is biologically identical to Bone Ewing - treated with same protocols CD99 is Highly sensitive but not specific - EWSR1 FISH required for definitive diagnosis RNA-seq increasingly replacing FISH for fusion detection Large tumour volume and metastases at presentation are adverse prognostic factors

Benign soft tissue Cartilage tumour Common in hand and foot

Intermediate-grade with Variable behaviour Risk assessment scheme guides treatment NAB2-STAT6 fusion diagnostic

Pathognomonic association with chronic lymphoedema MYC FISH useful to confirm diagnosis and distinguish from Benign Vascular proliferations Multidisciplinary management involving oncology, plastic surgery, and lymphoedema specialists essential Prevention: optimal lymphoedema management post-mastectomy

t(X;18) EWSR1-SS18 fusion diagnostic Multimodal therapy standard High-grade malignancy despite small appearance

Formerly called PVNS - now classified as diffuse TGCT per WHO 2020 Haemosiderin deposition causes characteristic Low signal on T2 MRI - 'blooming' on GRE is pathognomonic Pexidartinib is FDA-approved and can achieve durable disease control

Most common tumour of tendon sheath - palmar surface of digits is classic location Low signal on T1 and T2 MRI due to haemosiderin is characteristic Pexidartinib (CSF1R inhibitor) is FDA-approved for symptomatic unresectable TGCT Complete excision of all lobules is key to reducing recurrence

Diagnosis of exclusion - must rule out specific sarcoma subtypes Previously called Malignant Fibrous histiocytoma (MFH) Always exclude MDM2 amplification to rule out dedifferentiated liposarcoma Managed with wide excision ± radiotherapy ± chemotherapy