Melan A is an antigen expressed by melanocytes.
Synonyms[]
- A103[1]
- Melan A
- Mart-1
Antibodies[]
Technical Info[]
Staining Pattern[]
- Cytoplasmic
Expression in Normal Tissues[]
- Normal Melanocytes
- Adrenal cortex
Expression in Neoplastic Entities[]
Benign[]
| Tumor name | % Positive Staining | Number of Cases |
| Adrenocortical adenoma: | 100%[2] | (15/15)[2] |
| Benign melanocytic nevus | ||
| Blue nevus | ||
Intermediate/Uncertain Malignant Potential[]
| Tumor name | % Positive Staining | Number of Cases |
| Sertoli-Leydig cell tumor of ovary[1] | ||
| PEComas (angiomyolipoma, lymphangioleiomyomatosis, etc) | 72%[3] | 13/18[3] |
| Leydig cell tumor of testis[1] | ||
Malignant[]
| Tumor name | % Positive Staining | Number of Cases | |
| Adrenocortical carcinoma | 75%[2] | 9/12[2] | |
| Melanoma | |||
| Clear Cell Sarcoma | 71%[4] | 23/32[4] | |
| Pleomorphic liposarcoma, epithelioid variant | 67%[5] | 4/6[5] | |
| Single reported case of Mart-1 expression by serous carcinoma of ovary [6] | |||
Expression in Non-Neoplastic Entities[]
Pertinent Negatives[]
This immunostain is typically NEGATIVE in the following entities:
Practical Uses / Panels[]
- Melan A is superior to S100 when evaluating sentinel lymph nodes for Melanoma since S100 stains nonmelanoma cells in the lymph node.[7]
Common Pitfalls[]
- Epithelioid pleomorphic liposarcoma may express Melan A, a finding that could potentially lead to a misdiagnosis of metastatic adrenocortical carcinoma.[5]
References[]
- ↑ 1.0 1.1 1.2 Am J Surg Pathol. 1998 Jan;22(1):57-63.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Mod Pathol 2003;16(6):591–597
- ↑ 3.0 3.1 Am J Surg Pathol. 2005 Dec;29(12):1558-75.
- ↑ 4.0 4.1 Am J Surg Pathol. 2008 Mar;32(3):452-60.
- ↑ 5.0 5.1 5.2 Ultrastructural Pathology 2002, Vol. 26, No. 5 , Pages 299-308
- ↑ Archives of Pathology & Laboratory Medicine: February 2002, Vol. 126, No. 2, pp. 170-172.
- ↑ J Surg Pathol. 2001 Aug;25(8):1039-46.