Sox10 is expressed in primary melanocytic neoplasms of various histologies but not in fibrohistiocytic proliferations and histiocytoses.
BACKGROUND
Sox10 is a transcription factor associated with neural crest development. Its expression has been reported in melanocytes and peripheral nerve sheath cells and their associated tumors.


OBJECTIVE
To assess Sox10 sensitivity in benign and malignant melanocytic neoplasms of various histologic subtypes and to discern the specificity of Sox10 in distinguishing between melanocytic neoplasms and fibrohistiocytic and histiocytic mimickers.


METHODS
Sox10 expression was examined by immunohistochemistry in 145 cases of formalin-fixed paraffin-embedded tissue, including benign and malignant melanocytic lesions of various histologies and stages (n = 83), fibrohistiocytic and histiocytic lesions (n = 33), and peripheral nerve sheath tumors (n = 19), among others (n = 10).


RESULTS
Immunoreactivity with Sox10 was observed in 100% (83/83) of benign and malignant melanocytic lesions of various subtypes, as well as in 100% (19/19) of benign and malignant peripheral nerve sheath lesions. Among the fibrohistiocytic proliferations and histiocytoses examined, Sox10 was negative in all cases (0/33). Sox10 expression did not vary by histologic subtype in nevi or melanoma; however, both the percentage of tumor nuclei demonstrating Sox10 expression and the intensity of expression were inversely correlated with malignant potential (nevi, melanoma in situ, invasive and metastatic melanoma) (P < .001, P = .016, respectively). Malignant peripheral nerve sheath tumors also showed decreased mean Sox10 expression and decreased intensity of expression when compared with benign counterparts (P < .001, P = .021, respectively).


CONCLUSIONS
This is a retrospective study with 145 cases included.


CONCLUSIONS
Sox10 is a highly sensitive marker for melanocytic proliferations and may be useful diagnostically when the differential diagnosis includes fibrohistiocytic and histiocytic proliferations demonstrating S100 expression.
Department of Dermatology, Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.
Jeonghyun
J
Shin
Jeremy G
JG
Vincent
Jonathan D
JD
Cuda
Haiyang
H
Xu
Sewon
S
Kang
Jinah
J
Kim
Janis M
JM
Taube
D018070:Biological Specimen Banks; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001706:Biopsy; D002280:Basal Cell Carcinoma / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D051677:Histiocytoma, Malignant Fibrous / Q000378:metabolism / Q000473:pathology; D015614:Histiocytosis / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D017512:Lichenoid Eruptions / Q000378:metabolism / Q000473:pathology; D008544:Melanocytes / Q000378:metabolism / Q000473:pathology; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D018294:Neoplasms, Adnexal and Skin Appendage / Q000378:metabolism / Q000473:pathology; D018317:Nerve Sheath Neoplasms / Q000378:metabolism / Q000473:pathology; D009508:Nevus, Pigmented / Q000378:metabolism / Q000473:pathology; D012189:Retrospective Studies; D055757:SOXE Transcription Factors / Q000378:metabolism*; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D014820:Vitiligo / Q000378:metabolism / Q000473:pathology
D014408:Biomarkers, Tumor; C527923:SOX10 protein, human; D055757:SOXE Transcription Factors