Tyrosinase

Immunohistochemical expression

• benign melanocytic lesions

intradermal naevus	3/33
compound naevus	4/43
junctional naevus	3/33
blue naevus	3/33
Spitz naevus	4/43
Spindle cell naevus of Reed	4/43
dysplastic naevus	4/43

• malignant melanoma:

negative	7% (19/266)1
<10% of tumour cells	3% (8/266)1
10% to 30% of tumour cells	7% (18/266)1
>30% of tumour cells	82% (221/226)1

Desmoplastic melanomas^:

negative		9/202, 30/301, 0/23
positive	<5% of cells	5/202
	5-25% of cells	3/202
	25-50% of cells	2/202
	50-75% of cells	1/202
	>75% of cells	0/202
	any degree of positivity	11/202

non-melanocytic tumours¹:

clear cell sarcoma of tendons and aponeuroses	6/151
renal/retroperitoneal angiomyolipoma	1/121
lymphangioleiomyom(tosis)	0/61
MPNST	0/201
leiomyosarcoma	0/101
benign fibrous histiocytoma	0/201
fibrosarcoma	0/101
synovial sarcoma	0/11
angiosarcoma	0/201
poorly differentiated carcinoma	0/201
squamous cell carcinoma of head and neck	0/201
adenocarcinoma	breast, ductal 0/101 breast, lobular 0/101 lung 0/101 stomach   colon   pancreas   kidney   endometrium   ovary   ovarian & endometrial 0/201 prostate   total 0/50
adrenocortical carcinoma	0/121
diffuse large B cell lymphoma	0/201
anaplastic large cell lymphoma	0/41

Diagnostic utility

• Diagnosis of melanoma

References

¹Miettinen M et al. Microphthalmia transcription factor in the immunohistochemical diagnosis of metastatic melanoma: comparison with four other melanoma markers. Am J Surg Pathol 2001;25:205-211.

²KJ Busam et al. Analysis of microphthalmia transcription factor expression in normal tissues and tumors, and comparison of its expression with S-100 protein, gp100 and tyrosinase in desmoplastic malignant melanoma. Am J Surg Pathol 2001;25:197-204.

³Clarkson KS et al. The usefulness of tyrosinase in the immunohistochemical assessment of melanocytic lesions: a comparison of the novel T311 antibody (anti-tyrosinase) with S-100, HMB-45 and A103 (anti-melan-A). J Clin Pathol 2001;54:196-200.

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This page last revised 17.3.2001.

©SMUHT/PW Bishop