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S-100

Monday 22 January 2018

PO

See also : S100s

Positive staining in normal cells

- neural crest derived tissue: Schwann cells, melanocytes, glial cells
- skin apocrine glands and eccrine glands
- adipocytes , chondrocytes , dendritic cells , Langerhans cells , macrophages , myoepithelial cells
- some breast epithelial cells

Expression in tumoral cells

- adenoid cystic carcinoma
- chondroid tumors
-  chordoma
- clear cell sarcoma
- dendritic cell tumors
- glial tumors
- granular cell tumor (Arch Pathol Lab Med 2004;128:771)
- Langerhans cell tumors
- adipocytic tumors / lipogenic tumors
- malignant peripheral nerve sheath tumor MPNST (50%)
- melanoma (95%, including desmoplastic and spindle cell tumors); S100- melanomas often had prior S100+ metastases, often are ocular (Hum Pathol 2005;36:1016)
- myoepithelial tumors
- neural tumors
- paragangliomas : sustentacular cells
- perivascular epithelioid cell tumors ( angiomyolipoma, clear cell "sugar" tumor , lymphangioleiomyomatosis , PEComas )
- sex cord stromal tumors

Also :
- histiocytes in mycobacterial spindle cell pseudotumor in lymph nodes
- histiocytes in Rosai-Dorfman disease

Diagnostic use

- Common marker of neural tissue / lesions and melanoma
- S100 differentiate plexiform schwannoma (S100+, Am J Surg Pathol 2005;29:1042) from MPNST (weak / negative / patchy)
- Melan-A and MART1 appear to be superior to S100 for evaluating sentinel lymph nodes for melanoma (Am J Surg Pathol 2001;25:1039)

Negative labelling in tumors

- fibroblasts , fibroblastic reticulum cells , perineural cells
- atypical fibroxanthoma (AFX)
- cardiac sarcomas
- myofibroblastoma
- solitary fibrous tumor (SFT)
- xanthoma