SNUC Basaloid SCC NPC Salivary duct ca. Met (breast, ductal ca)

Warty dyskeratoma Hereditary benign intraepithelial dyskeratosis Darier disease Hereditary mucoepithelial dysplasia Pachyonychia congenital

Allergic fungal sinusitis Langerhan’s cell histiocytosis Angiolymphoid hyperplasia with eosinophilia Kimura’s disease Hodgkin’s lymphoma Peripheral T cell lymphoma (also shows fat invasion – panniculitis pattern) TUGSE Pyostomatitis Vegetans (microabcesses in epithelium)

Histo Ddx Flashcards by Khanh Trinh

Acanthosis and balloon cells in upper layer of epithelium

Hairy leukoplakia
Morsicatio
Leukoedema
Linea alba
Betel chewer’s mucosa
Uremic stomatitis
White sponge nevus

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Acantholytic lesions:

Pemphigus
Hailey-‐Hailey (chronic benign familial pemphigus – rare in mouth)
Herpes
Grover’s (transient acantholytic dermatosis – exclusively suprabasal split)
Darier’s
Warty dyskeratoma
Varicella-‐zoster
Squamous cell carcinoma
Pyostomatitis vegetans (has eos)

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Amorphous material in connective tissue

Amyloidosis (amyloid)
Systemic sclerosis (collagen)
Plasminogen deficiency (fibrin)
Lipid proteinosis (basement membrane origin)

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Clear cell neoplasms of the jaws

Clear cell odontogenic ca.
Ameloblastoma (if there’s peripheral palisading)
Mucoep, central (if there’s mucin in a mucicarmine stain)
CEOT, clear cell variant (if there’s amyloid)
Met (like Renal, breast, or clear cell melanoma)
Melanoma (HMB-‐45 +)

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Clear cell salivary gland tumors:

Hyalinizing clear cell ca. (dense hyalinized stroma)
Myoepithelioma (extremely rare, benign features)
Myoepithelial ca. (no ductal elements)
Acinic cell ca. (typical areas are normally present)
Clear cell adenoca.
Epithelial-‐myoepithelial carcinoma (biphasic)
Muco ep. (epidermoid cells present, typical areas normally present)
Oncocytoma (usually has typical oncocytic cells)
Sebaceous adenoma (clear cells have foamy cytoplasm)
Sebaceous adenoca (clear cells have foamy cytoplasm)
Metastatic renal cell carcinoma (very vascular, CD10+)

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Comedonecrosis:

SNUC
Basaloid SCC
NPC
Salivary duct ca.
Met (breast, ductal ca)

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Cystic lesions of the salivary glands:

Acinic cell
BLEL/Sjögren’s
Polycystic disease of the parotid/ HIV-‐related parotid cysts
Papillary Cystadenoma/cystadenocarcinoma
Warthin’s
Salivary duct cyst
Sclerosing polycystic adenosis
Muco Ep
Lymphoepithelial cyst/ Branchial cleft cyst
Sebaceous lymphadenoma
Dermoid/epidermoid cyst

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Dyskeratotic cells:

Warty dyskeratoma
Hereditary benign intraepithelial dyskeratosis
Darier disease
Hereditary mucoepithelial dysplasia
Pachyonychia congenital

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Eosinophils

Allergic fungal sinusitis
Langerhan’s cell histiocytosis
Angiolymphoid hyperplasia with eosinophilia
Kimura’s disease
Hodgkin’s lymphoma
Peripheral T cell lymphoma (also shows fat invasion – panniculitis pattern)
TUGSE
Pyostomatitis Vegetans (microabcesses in epithelium)

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Fibrous tumors of the jaws:

Odontogenic fibroma (w/o odontogenic epithelium, not the WHO type)
Desmoplastic fibroma
Fibromyxoma
Hyperplastic dental follicle (if related to a tooth)

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Giant cell lesions of the oral cavity and jaws:

Sarcoid
Crohn’s disease
Fungal infection
Bacterial infection (TB/ leprosy)
CGCG/ PGCG
Brown tumor (hyperparathyroidism or renal osteodystrophy)
Cherubism
ABC
Central odontogenic fibroma
Osteosarcoma
Foreign body reaction
Juvenile xanthogranuloma
Herpes

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Granular cell lesions:

Granular cell tumor
Congenital epulis
Granular cell odontogenic tumor
Granular cell ameloblastoma

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Granulomatous inflammation:
Caseating/ necrotizing-‐

Tuberculosis
Cat scratch
Syphilis
Foreign body
Blastomycosis
Wegener’s

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Granulomatous inflammation:
Non-‐necrotizing-‐

Fungal (histoplasmosis, paracoccidioides, coccidioides imitans-‐San Joaquin Valley Fever)
Leprosy
Crohn’s
Sarcoid
Wegener’s
Orofacial granulomatosis
Foreign body

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Intraepithelial Abscess:

Pyostomatitis vegetans (eos)
Inverted papilloma
Blastomycosis
Psoriasis/ BMG/ EM (also, the lesions of Reiter’s)
Papillary SCC/ VC
Candidiasis
Schneiderian oncocytic pap.

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Lichenoid

Lichen planus
Lichenoid drug reaction
Amalgam reaction
Graft versus host disease
Systemic lupus erythematosum
Chronic ulcerative stomatitis
Cinnamon stomatitis

Lymph node follicular hyperplasia

Cat-‐scratch disease (shows necrosis)
Kikuchi-‐Fujimoto (has necrotic areas without neutrophils)
Toxoplasmosis (aggregates of histiocytes between follicles)
Angiolymphoid hyperplasia with eosinophilia
Kimura’s disease (peripheral eosinophilia)
Follicular lymphoma (back-‐to-‐back, lacks starry sky, same size follicles?)
Lymphoid hyperplasia
Rosai-‐Dorfmann (emperipolesis)
Castleman’s disease (onion-‐skin)

Multiple CGCG

Hyperparathyroidism
Cherubism
Ramon syndrome
Jaffe-‐Campanacci
Noonan-‐like syndrome
Renal osteodystrophy

Myxoid lesions:

Myxoma (intrabony)
Neurofibroma (cells usually seen in sheets, absence of well defined nodules)
Oral focal mucinosis (no multinodularity, absence of S100 reactivity)
Neurothekeoma (myxoid nodules of varying size/shape, separated by dense collagen septa)
Lipoma/Liposarcoma
Leiomyosarcoma
Chondrosarcoma
Rhabdomyosarcoma

Necrotic Lymph Node:

Kawasaki disease
Kikuchi-‐Fujimoto (Histiocytic Necrotizing Lymphadenitis-‐ without neutrophils)
Cat Scratch Disease (granulomatous inflammation with stellate abscess)
Rosai-‐Dorfmann

Nested Tumors:

Paraganglioma
Alveolar soft part sarcoma
Plasmacytoma
Melanoma
Sebaceous adenocarcinoma
Metastasis (renal)
Meningioma (a little similar to the chondromyxoid fibroma)
Alveolar rhabdomyosarcoma
Salivary gland tumor

Perivascular Inflammation:

Wegener’s (“leukocytoclastic vasculitis”)
Cinnamon contact stomatitis (lymphocytes and plasma cells)
Lupus
Syphilis (plasma cells)
Behçet’s (“leukocytoclastic vasculitis”)
Erythema multiforme
Scleroderma

Perivascular Tumor Sparing Pattern of Necrosis:

MPNST
Ewing’s sarcoma
PNET
Synovial sarcoma

Psammoma Bodies:

Meningioma
Psammomatoid juvenile ossifying fibroma
Nasopharyngeal papillary adenocarcinoma (low grade)
Papillary thyroid ca.
Chordoma
Pindborg tumor (CEOT)
Alveolar soft part sarcoma
Renal papillary cell ca.
Paraganglioma
Malignant mesothelioma

Psoriasiform mucositis

* Erythema migrans * Psoriasis * Cinnamon reaction * Candidiasis * Reiter’s syndrome

PEH:

* Deep fungal (Blastomycosis and paracoccidiomycosis) * Nicotine stomatitis * Inflammatory papillary hyperplasia * Pyostomatitis vegetans * GCT * Gumma * IFH (epulis fissuratum) * Necrotizing sialometaplasia * Gingival fibromatosis

Skin tumors:

* Chondroid syringoma: mixed tumor of skin * Cylindroma: aka turban tumor; looks like basal cell adenoma, jigsaw puzzle * Eccrine spiradenoma: ~ cylindroma, but lacks jigsaw puzzle. Dilated vessels on periphery of tumor islands * Hydrocystoma: cystadenoma of skin * Pilar cyst: aka trichilemmal cyst; looks like epidermoid cyst, but abrupt keratin filling lumen * Pilomatrixoma: Gorlin cyst of skin, lots of ghost cells * Syringocystadenoma papilliferum: looks like sialadenoma papilliferum of SG * Syringoma: tadpole or comma-‐shaped tubules of cells * Tricoepithelioma: ~ BCC, with horn cysts, no retraction artefact, rare connections to epidermis * Tricofolliculoma * Trichilemmoma: similar to tricoepithelioma but central cells are clear (seen in Cowden’s) * Microcystic adnexal carcinoma: horn cysts on surface, ductal elements deeper, desmoplastic * Lichen sclerosus et atrophicus

Small Blue Cell Tumors Adult

* Melanoma * Rhabdomyosarcoma * SNUC * Lymphoma * Ewing’s sarcoma * Esthesioneuroblastoma (Olfactory neuroblastoma) * PNET

Small Blue Cell Tumors Kids

Meduloblastoma Rhrabdomyosarcoma DSRCT (Desmoplastic small round cell) Osteosarcoma Wilms Neuroblastoma Ewing sarcoma Retinoblastoma

Spindle Cell Neoplasms (benign):

* Spindle cell lipoma * Leiomyoma * Hemangiopericytoma (CD34+) * Fibromatosis * Benign fibrous histiocytoma (Factor XIIIa +) * Solitary fibrous tumor (CD34+) * Neurofibroma (S100+) * Nodular fasciitis * Myofibroma (SMA+)

Spindle cell neoplasms (malignant)

* Mesenchymal chondrosarcoma * Malignant fibrous histiocytoma * Angiosarcoma * Fibrosarcoma * Spindle cell carcinoma * Malignant peripheral nerve sheath tumor (S100+) * Leiomyosarcoma (SMA+) * Rhabdomyosarcoma (myogenin +) * Melanoma (HMB45+) * Synovial sarcoma (CD99+) * Kaposi’s (HHV8+)

Staghorn Vessels:

* Solitary fibrous tumor (CD34, CD99+) * Hemagiopericytoma (CD34, CD99+) * Benign fibrous histiocytoma * Mesenchymal chondrosarc. * Vascular leiomyoma * Leiomyosarcoma * Infantile fibrosarcoma * Myofibroma (actin+) * Juv. nasoph. angiofibroma (ant. bowing of the post. wall of the max. sinus) * Angiofibroma (like in tuberous sclerosis) * Synovial sarcoma