IMMUNOHISTOCHEMISTRY, S100

The IHC – S100 test is an immunohistochemistry-based diagnostic assay used to detect S100 protein expression in tissue samples. S100 is a family of proteins commonly found in cells derived from the neural crest, including melanocytes, Schwann cells, dendritic cells, and certain cartilage and adipose tissues.

This test is widely used in pathology to identify and classify a variety of tumors, especially melanoma, nerve sheath tumors, and certain soft tissue neoplasms. S100 is considered a highly sensitive marker for melanocytic lesions and neural tissue differentiation.

Benefits of the Test

• Helps diagnose malignant melanoma
• Assists in identifying neural and nerve sheath tumors
• Supports classification of soft tissue tumors
• Improves tumor differentiation accuracy
• Helps guide oncology treatment planning

Why Doctors Recommend This Test

Doctors recommend the IHC S100 test when there is suspicion of melanoma, neural tumors, or soft tissue neoplasms. It is commonly used in:

• Diagnosis of melanoma
• Evaluation of nerve sheath tumors
• Soft tissue tumor classification
• Differentiation of neural-origin cancers
• Oncology biopsy interpretation

S100 is often used along with markers such as HMB-45, Melan-A, SOX10, and GFAP for improved diagnostic precision.

Preparation Before Test

No special preparation is required for this test. Important considerations include:

• The test is performed on a biopsy or surgical tissue sample
• No fasting or medication restrictions are needed
• Clinical findings and imaging studies may assist interpretation

Normal Reporting Time

The typical turnaround time is 3 to 5 working days, depending on laboratory workflow and tissue processing requirements.

Who Should Take This Test

• Patients with suspicious pigmented skin lesions
• Individuals with suspected melanoma
• Cases of neural or nerve sheath tumors
• Patients undergoing soft tissue tumor evaluation
• Oncology patients requiring tumor origin classification

The IHC S100 test is an important diagnostic tool in dermatopathology, neuropathology, and oncology. It helps pathologists accurately identify melanocytic and neural differentiation in tumors, supporting early diagnosis and appropriate treatment planning.