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Selected Cutaneous Soft Tissue Tumors with potential diagnostic
difficulties
By Konstantinos Linos MD, FCAP, FASDP
Bone, Soft Tissue and Dermatopathology
Assistant Professor of Pathology
Dartmouth-Hitchcock Medical Center
Geisel School of Medicine at Dartmouth
Hanover, NH, USA
• Book Royalties
Financial disclosures
Angiomatoid Fibrous Histiocytoma (AFH)
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DESMIN EMA
CD68
t(2;22)(q33;q12) EWSR1/CREB1t(12;22)(q13;q12)=EWSR1/ATF1
t(12;16)(q13;p11)= FUS/ATF1
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Differential Diagnosis
Metastasis involving a lymph node
Undifferentiated pleomorphic sarcoma
Vascular tumor
Benign fibrous histiocytoma with prominent intratumoral hemorrhage
Dermatofibrosarcoma Protuberans (DFSP)
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CD34
t(17;22)(q22;q13)=COL1A1-PDGFB
Am J Surg Pathol. 1999 Aug;23(8):910-7
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Superficial Angiomyxoma
Myxoid DFSP
Epithelioid Sarcoma
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DDX-Benign Fibrous Histiocytoma
-Interstitial Granuloma Annulare
-Fibroma of tendon sheath
-Reactive fibroblastic proliferations
-Fibroblastic Connective Tissue Nevus
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Myoepithelial Neoplasms
Cutaneous myoepithelialtumors
• Chondroid syringoma (mixed tumor)• Tubuloductal differentiation
• Rearrangement of the PLAG1 gene (8q12)
• Cutaneous myoepithelioma• Pure myoepithelial cell population
• Myoepithelial carcinoma
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AE1/AE3
EMA
S100
INI1
Absence of INI1 in myoepithelial carcinomas
10% (adults)40% (children)
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EMA S100
AE1/AE3 GFAP
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EWSR1-POU5F1EWSR1-ZNF444EWSR1-PBX1EWSR1-ATF1
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Differential Diagnosis
• Epithelioid fibrous histiocytoma
• Early stage juvenile xanthogranuloma
• Spitz nevus
• Epithelioid sarcoma
Prognosis and treatment
• Cutaneous myoepithelioma has a benign clinical course • Local recurrence in 20% of cases
• Syncytial subtype very low local recurrence rate
• Myoepithelia carcinomas (also contain EWSR1 rearrangements) pursue a more aggressive clinical course
Ossifying FibromyxoidTumor (OFMT)
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• Uncertain differentiation
• Intermediate (rarely metastasizing) biologic potential
• Can occur at any site, most frequently extremitites and trunk• Most frequently middle-aged adults
• Typically slowly enlarging subcutaneous mass
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Typical/Atypical:~20% recurrence<5% metastasis
Malignant:High risk, should be regarded as sarcomas
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S100 Desmin
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INI1 MUC4
Neurofilament CD56
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Genetics
• PHF1 rearrangements with various partners
• Most common EP400, MEAF6, JAZF1, EPC1
• ZC3H7B-BCOR, CREBBP-BCORL1
• KDM2A-WWTR1
Low Grade Fibromyxoid Sarcoma (LGFMS)
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MUC4
t(7;16)(q33;p11)= FUS-CREB3L2t(11;16)(p11;p11)=FUS-CREB3L1
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MUC4
Claudin-1 EMA
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Superficial CD34-positive Fibroblastic Tumor
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Ki-67
CD 34 AE1/AE3
INI1 p53
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FISH for MGEA5 and TGFBR3 negative
Differential Diagnosis
Undifferentiated pleomorphic sarcoma
Myxofibrosarcoma
Atypical fibroxanthoma
Pleomorphic hyalinizing angiectatic tumor (PHAT)
Myxoinflammatory fibroblastic sarcoma
Epithelioid sarcoma
• Email: [email protected]
• @ @ KonstantinosLin