dr prieto tumores de partes blandas
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Conferencia "Superficial Soft Tissue Tumors of the Skin" dictada por el Dr. Victor Prieto del MD Anderson Cancer Center en Lima, PeruTRANSCRIPT
Superficial Soft Tissue Tumors of the Skin
Victor G. Prieto, MD, PhD Professor of Pathology and Dermatology
Head of Dermatopathology
UT-MD Anderson Cancer Center Houston, Texas
Summary • Introduction • Selected entities (update, clinical relevance, differential diagnosis) • Main Features: – Clinical – Histological – Immunohistochemical
Introduction • Spectrum: reactive to malignant (clinical relevance) • Objection of some purists • Almost any soft tissue tumor can occur in the skin (subcutaneous o subfascial) �Skin biopsy�
Atypical Fibrohistocytic Lesions
• Classic concept: DF is a benign lesion completely different from DFSP, based on histologic and clinical features • Use of immunohistochemistry • But some times the differences are not so clear…
• Intermediate between DF y DFSP • Trunk, 0.6-2 cm, recurrence • Acanthosis and hyperpigmentation • Storiform pattern Horenstein et al. Am J Surg Pathol 2000; 24: 996-1003
Atypical Fibrohistiocytic
Lesions
• Keloidal collagen • Storiform pattern
• Keloidal collagen
• Infiltration of subcutaneous tissue
• Cellular atypia • Mitotic figures
FXIIIa CD34
Key Points • The immunophenotype of these lesions suggests a differentiation between DF and DFSP • Possibility of local recurrence • Achieve complete excision
Epithelioid Fibrous Histiocytoma
• Papule / nodule of 0.5 - 2 cm • Non pigmented or tan colored, elevated • Extremities in adults
• Dermal lesion, circumscribed • Collarette • No epidermal involvement
• Epithelioid cells, eosinophilic-clear • Regular nuclei with small nucleoli
• Focal keloidal collagen
S100 Protein
CD68
Factor XIIIa
Differential Diagnosis • Melanocytic lesions: – No pigment, no intraepidermal
component – S100 protein- (dendritic cells!) – HMB45, MART1 – HAM56, (CD68)
Key Points • Include this entity among the differential diagnosis of unusual melanocytic lesions • Immunohistochemistry in case of doubt
Superficial Acral Fibromyxoma
• Solitary mass on hands and feet • Asymptomatic
• 75-year-old white woman • Left palm lesion for 3 - 4 months • 1.7 x 1.5 cm • Asymptomatic, flesh-colored nodule
• Poorly circumscribed • Dermis • Spindle cells
• Close to epidermis • (No intraepidermal component
• Loose storiform pattern • Vascular
SMA
FXIIIa
CD34
Key Points • Adults • Same as cellular fibroma • Recurrence • DDx DFSP, DF
Epithelioid Sarcoma
• Papule / nodule of 0.5 - 2 cm • Non pigmented or tan colored, elevated • Extremities in young adults
• 25 yo man • Soccer player (goalie) • Lesion started �after� trauma to
the finger
• Ulcer • Acanthosis (~prurigo nodularis
• Central necrosis
Epithelioid cells Central necrosis
Distant metastasis (elbow)
Keratin
Differential Diagnosis • Granulomatous dermatitis: – Mucin (granuloma annulare) – Fibrin (rheumatoid nodule) – Multinucleated giant cells (necrobiosis
lipoidica) – Keratin! – Loss of INI NI1 (SWI/SNF chromatin
remodeling complex) Chr 22q11.2
Key Points • Include this entity among the differential diagnosis of unusual �granulomatous� dermatitides (young, fingers) • Immunohistochemistry in case of doubt
Plexiform Fibrohistiocytic Tumor • Uncommon neoplasm of intermediate malignancy • Dermis or subcutaneous tissue, on trunk and extremities in children and young adults Enzinger/ Zhang, Am J Surg Pathol 1988;12:818
• Infiltrative tumor, plexiform, small nodules • Short fascicules
• Infiltrative, plexiform, small nodules
Short fascicules with fusiform cells (fibroblasts y myofibroblasts) (sometimes the only component)
Macrophages and multinucleated giant cells (osteoclastic type)
Differential Diagnosis • Cellular DF / atypical fibrohistiocytic lesion • DFSP Both lack plexiform pattern or osteoclastic cells • Giant cell tumor of tendon sheath
Key Points • Children and young adults • Short fascicles of spindle cells • Macrophagic giant cells • Recurrent
Fibrous Hamartoma (of Infancy)
• First year of life (23% congenital) • Axilla, arm, trunk, groin, and genital area • Solitary, asymptomatic, sometimes quick growth • t(6;12;8)(q25;q24.3;q13); t(2;3)(q31;q21) • Recurrence
Triphasic pattern: • Fascicles of fibroblasts • Adipocytes • Fusiform cells (�primitive� mesenchyma)
Three components
Fusiform cells
Fascicles Mesenchyma/nerves
Differential Diagnosis
• Neurofibroma • Giant cell tumor of tendon sheath
Key Points • Triphasic pattern • Similarities with neural lesions (neurofibroma, neurofibrosarcoma, schwannoma) • Negative for S100 protein
Neurothekeomas • Harkin and Reed (1969), Gallager (1980) • Superficial tumor of purported nerve sheath origin • Head and neck, extremities • Cellular and myxoid • Myxoid variant of the cellular type
• Dermal nodule • Fascicles
Myxoid background
Small cells, myxoid stroma S100
Dermal nodule
Fascicles
Epidermis is spared
Uniform cells, fibromyxoid stroma
• Spindle, fusiform cells • Fibrous stroma
Ki67
S100 A6
Histologic Features • 25% moderate cytologic atypia (very rarely marked) • Mitotic figures 0 - > 10/mm2 • Pattern whorled or fascicular • Different amounts of myxoid background
IPOX Features • S100 in myxoid lesions (nerve sheath myxoma) • S100A6 in neurothekeoma • NKI/C3, CD10, microphthalmia transcription factor, and PGP9.5 • Focal expression of SMA and CD68
Key Points • Possibly two types (cellular/myxoid) • Myxoid variant of cellular NTK • S100 in the myxoid • S100 A6 in the cellular • Mostly non-aggresive • Careful with melanoma (S100)
Ossifying Fibromyxoid Tumor of Soft Tissue
• Very rare, circumscribed • Deep nodules, slow growth • Trunk and extremities, 1 to 14 cm
• Fibrous capsule, ring of mature bone
• Fusiform or epithelioid cells • Irregular fascicles
• Myxoid areas
OFMST: Atypical Variant
• 20% of cases show local recurrence !!!!!!!! • 10% distant metastases • Infiltrative border
• Infiltrating border, hypercellularity, high nuclear grade, more than 2 mit/50 HPF
Atypical variant
Key Points • Gross the hard areas at the periphery of the lesion • Mixture of fibrous and myxoid areas • Atypical variant
Pleomorphic Hyalinizing Angioectoid Tumor of Soft Parts • Firm, lobulated, tan, with focal hemorrhage, several cm in size • Lower extremity, middle age • Infiltrative, deep dermis and subcutaneous tissue • Local recurrence (50%)
• Loose connective stroma • Dilated vessels, hyaline ring
• Dilated vessels, fibrin
• Fusiform and epithelioid cells with pseudoinclusions • Pleomorphic cells (~ MFH) • Rare mitotic figures • Negative anti-S100
PHAT: DDx • �Ancient� schwannomas (dilated vessels with hyaline and nuclear pseudoinclusions) circumscribed, S100+ • MFH lacks hyalinized vessels, nuclear pseudoinclusions o CD34 expression. Numerous mitotic figures • Vascular tumors (hemangioma, hemangioendothelioma). CD31 and FVIIIra
S100 Protein
Key Points • Hyaline vessels • Nuclear atypia • Rare mitotic figures • Negative S100 protein
Acral Myxoinflammatory Tumor with Atypical Giant
Cells • Inflammatory myxohyaline tumor of the extremities with virocytes or Reed-Sternberg cells • Inflammatory myxoid tumor of soft parts with atypical giant cells
AMTAGC • Rare, adults and older individuals • Distal extremities (hands and feet) • Frequent local recurrence (metastasis) • 1 - 6 cm • Clinical Dx: ganglion, tenosynovitis, giant cell tumor of tendon sheath
• Multinodular, infiltrative, ~hamartoma
• Fibrous stroma, pleomorphism
Key Points
• Infiltrative • Mixed with adipose tissue • Large, �virocytes� • (Metastasis)
Soft Tissue Lesions in the Skin: Summary
• At least five �new� lesions recently described • Possibility of local recurrence (even metastasis) • In case of doubt, complete excision
Pigmented Melanotic Schwannoma
• Paraspinal
• 20-50% recurrence or metastasis
• Unclear histogenesis
C5, 36 yo man
• Infiltrating border, hypercellularity, high nuclear grade, more than 2 mit/50 HPF
• Psammoma bodies • Cytologic atypia
• S100
• MART1
• HMB45
Key Points • �Melanoma� in the wrong place • Rule out metastasis • Schwannian features (EM) • Recurrence and metastasis