What does HMB-45 positive mean?
HMB-45 is a monoclonal antibody that reacts against an antigen present in melanocytic tumors such as melanomas, and stands for Human Melanoma Black. It is used in anatomic pathology as a marker for such tumors.
What does HMB-45 stain?
HMB-45 is a widely used immunohistochemical stain for detection of primary as well as metastatic melanoma (1). Presumably, this method uses monoclonal antibodies to a glycoprotein that is present in premelanosomes (11).
What is HMB-45 negative?
Desmoplastic malignant melanoma (DMM) and spindle cell malignant melanoma (SCMM) form a continuum without a discrete separation. One feature characteristic of DMM is a negative reaction for HMB45, a marker for premelanosomes. Fifty-six cases of SCMM were stained with HMB45.
What does Melan A positive mean?
The presence of Melan-A positive dermal cells in excisions for melanoma in situ represents a frequent conundrum for pathologists. These cells may represent superficially invasive melanoma, benign, incidental, dermal nevi or non-specific staining of dermal melanophages.
What is mart1 stain?
Melanoma antigen recognized by T cells or Melan-A (MART-1), is a protein with unknown function that is associated with endoplasmic reticulum and melanosomes. Melan A is a sensitive and specific marker for the diagnosis of melanoma.
How common is Spitz nevus?
Spitz nevi are not very common. Some estimates suggest they affect around 7 out of every 100,000 people. About 70 percent of people who are diagnosed with a Spitz nevus are 20 years old or younger. These lesions can develop in older adults, too.
What is Melan a melanoma?
What is Melan A staining?
Melan-A, also known as MART-1, is an additional melanocytic marker and has proved to be useful in identifying metastatic tumors of melanocytic origin. The usefulness of this marker to discriminate pigmented actinic keratosis from early melanoma in situ, however, has not yet been a subject of investigation.
What is S100 Immunostain?
S-100 expression is seen in cartilaginous tumors, myoepithelial tumors, Schwann cells and neural tumors, Langerhans cell proliferations, benign and malignant melanocytes, clear cell sarcoma, and some carcinomas (particularly of the breast). S-100 staining occurs both in the nucleus and cytoplasm.
Which malignant melanoma subtype is S100 positive only?
S100 negative melanomas are rare. S100P is positive in all subtypes of melanoma, including desmoplastic melanoma, for the diagnosis of which it remains an important reagent. Along with Sox10 and nerve growth factor receptor (NGFR), it is the most sensitive marker to visualize invasive melanoma (Fig.