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Histopathology of Basal Cell Carcinoma Back to Squamous Cell
Valencia Thomas, MD Carcinomas Associate Professor Section of Dermatopathology UT Houston School of Medicine Director, Mohs and Dermasurgery Unit M.D. Anderson Cancer Center Duplicate
CSSC Head and Neck CSCC Head and Neck Tumor Diameter Depth ofor Tumor • Maximum clinical diameter based on preoperative physical exam • Tumor depth of invasion and level of invasion are important • T2: Tumors greater than 2 cm • 5-20% increase in nodal metastasis risk for each 1-mm increase in tumor thickness • 2.1-fold to 7-fold risk of nodal metastasis • 5.6-fold risk of local recurrence • DO NOT USE THE BRESLOW DEPTH
AJCC 8 AJCC • 15.9-fold risk of death 8 AJCC • T3: Tumors greater than 4 cm • 4.5-fold increase in disease-specific death
Distribute CSCC Head and Neck Determining tumor thickness • Depth of Invasion (DOI) • Millimeter depth measured from the granular layer of the adjacent normal skin to the base of the tumor • Breslow depth DOI • Measurement from the granular layer to the base of the tumor AJCC 8 AJCC Not 8 AJCC Do Breslow (AJCC7)
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Depth of Invasion (DOI) Millimeter depth measured from the granular layer of the adjacent normal skin to the base of the tumor
• Deep Invasion of greater than 6mm in depth • Invasion past subcutaneous fat to muscle, perichondrium, periosteum, etc.
AJCC 8 AJCC • 9.3-fold increased risk of nodal metastasis • 13-fold increased risk of death • Consider combining the AJCC 7 and 8 info • Begin to consider tumors high-risk at 4mm in high risk areas as an intermediate risk
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Pleomorphic BCCor
Back to Basal Cell Carcinomas
Distribute Pleomorphic BCC not Ulcerated BCCs more aggressive • Ulceration led to misidentification of nodular as infiltrative subtype in 21% of cases subsequently re- excised. * Not • BCCs keratinize (cornify) under ulcers – misread as SCC
Do *Haws A, Phung T, Tahan S – ASDP abstract poster #102 Oct 2010
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BCC can connect to follicles and sweat glands as well as epidermis •Lever placed BCC in the “Tumor of the appendages” chapter •BCC might be considered to be a poorly differentiated primitive adnexal tumor •“Differentiation TOWARD” adnexal structure does not imply “Origin from”
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Terms used: BCC resembling follicles
•Keratotic BCC (old Lever book) •BCC with follicular differentiation (Tozawa, Ackerman: Am J DP 9:474, 1987) •Infundibulocystic BCC (Walsh, Ackerman: Mod Pathol 3:599, 1990)
Duplicate Fibroepithelioma or • Pinkus 1953 • Clinically like a fibroma • Trunk – not so much sun damage • Reticulated strands connect to epidermis Is that a BCC? • Edematous stroma BCC Mimics Differentiating other tumors from basal cell carcinomas
Distribute Common Mimics BCC
• Follicular tumors • The most primitive adnexal tumor? • Sweat glands • Pluripotential basaloid cells • Other basaloid proliferations • Differentiation toward sweat ducts, follicles, sebaceous Not glands common and does not usually change prognosis Do
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Normal Skin Normal Skin
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Sebaceous differentiation in a carcinoma
Distribute BCC vs Adnexae
• Deeper levels • Cytologic atypia, mitoses, necrosis • Peripheral palisading, stromal retraction • MucinousNot stroma • Inflammatory reaction (“smart bombs”) • Hair shafts, trichohyalin • Lumina • Papillary mesenchymal bodies and follicular Dolayers
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Retraction within the stroma favors a benign follicular tumor
Basaloid Follicular Hamartoma Duplicate
Folliculocentric Basaloid Proliferation (FBP) “Funnyor looking follicles” • Nose of elderly women, closely mimics BCC • Vertically oriented, axial distribution • Folliculocentric • Ribbon-like hyaline basement membrane, normal surrounding stroma • Proliferations have pinwheel, floret-like configuration • Mitotic figures absent • ?Proliferative epiphenomenon when near a real BCC
Hitchcock, Leshin 1998 Adv Dermatol, vol 13, 1998; Arch Dermatol 126:900, 1990
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FBP pinwheel Not Do
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Syringoma vs BCC
• Clusters of small islands of basaloid cells or • Some islands may have central horn cyst, others may have comma-shaped or tadpole configuration representing duct differentiation. • Can be mistaken for morpheaform BCC • Usu well circumscribed, confined to upper dermis in contrast to BCC • Dense sclerotic stroma
Distribute Microcystic Adnexal Carcinoma Desmoplastic Trichoepithelioma vs BCC
• Irregularly-sized aggregates of cells forming ducts • Nests and cords of basaloid cells, within often cellular, • Widely-invasive but with a low metastatic potential sclerotic stroma • May closely resemble morpheaform/infiltrative BCC • Stroma predominates over epithelial component, Not contains delicate epithelial cords, does not extend into subcut fat • Keratin cysts, often calcifications Do
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Trichoepithelioma
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Keratin cysts or Nests, cords of basaloid cells
Distribute Brooke-Speigler Syndrome Not
Do Desmoplastic trichoepithelioma
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Trichoepithelioma
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Papillary mesenchymal bodies Papillary mesenchymal bodies
Distribute Follicular “tumorlets” vs BCC Trichoepithelioma vs BCC •Usually the distinction can be made but Not sometimes the answer is uncertain Do
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BCC vs trichoepithelioma FBP vs • Immunostains mostly overrated follicular • If you must stain it, best one is: bcl-2 diffuse within neoplasm BCC, more focal in trichoepithelioma • CD34 overrated – present in stroma immediately adjacent to the tumor in trichoep, present in stroma away from the tumor in BCC • CK20+ Merkel cells populate trichoep, not BCC
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Bottom line: Follicular neoplasm vs BCC Basaloidor hyperplasia • Solitary tumor on sun-damaged skin •Dermatofibromas usually best considered BCC rather •Nevus sebaceous than trichoepithelioma (Rapini, J Am Acad Dermatol Nov 2002) •Possibly represents “follicular induction” by the lesion •“trichoblastoma” term
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Ameloblastoma – mouth! Pilomatricoma
Duplicate orMucin vs Sweat (on H&E) Mucin is blue Sweat is pink
Shadow cells - pilomatricoma
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BCC Not Poroma Do
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Blue mucin
BCC Sweat ducts
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Pigmented Porocarcinoma poroma or
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Beware of apparent basal cell carcinomas Not with ductal structures Do Porocarcinoma
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Breast ca
Met breast Duplicate or
Mucinous carcinoma aka Adenocystic carcinoma
Met breast
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Mucinous Ca
Adenoid Cystic Ca cribriform pattern
Duplicate orcylindroma A thick, eosinophilic cuticle may be a clue to an adnexal tumor over a basal cell carcinoma
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Sebaceous Carcinoma • Multivesicular and vacuolated clear cytoplasm • Pagetoid intraepidermal component
Met adenocarcinoma
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Other situations resembling BCC •Inflammatory cell aggregates (may or resemble BCC or mean that BCC is near) - judgment whether to take another layer •Tangential adnexae •Tangential epidermis •Prominent blood vessels or endothelial strands Inflammatory cell aggregate
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