Laboratory & Pathology: IHC Staining

Immunostains are ordered on cytology and surgical specimens to determine the origin of malignant cells. When there is no history of a primary several different stains are sometimes necessary to reach an answer. The algorithm below is a very basic interpretation of understanding immunocyto/histo chemistry. It includes some of the most common stains ordered and the origin that they stain positive or negative for. If this is helpful please let me know and I will find more literature on the interpretation of ICC/IHC.

Figure 35.22 Algorithmic approach to carcinoma of unknown primary. CK, cytokeratin; ER, estrogen receptor; LCA, leukocyte common antigen; PDSCC, poorly differentiated squamous cells carcinoma; PLAP, placenta-like alkaline phosphatase; TTF, thyroid transcription factor.

Comprehensive Cytopathology 3rd Edition edited by Marluce Bibbo and David C. Wilbur.