Merkel Cell Carcinoma Exhibiting Cytoplasmic OCT4 Staining: A Potential New Diagnostic Immunohistochemical Marker?

Immunohistochemical expression of PAX5 and TdT by Merkel cell carcinoma and pulmonary small cell carcinoma: a potential diagnostic pitfall but useful discriminatory marker.

BACKGROUND Merkel cell carcinoma is a high-grade neuroendocrine carcinoma of skin that is characterized by immature cells which, because of its striking morphologic similarity, may be confused with other small round blue cell tumors such as pulmonary small cell carcinoma or lymphoblastic leukemia/lymphoma. Immunohistochemistry is therefore paramount to ensuring accurate diagnostic distinction b...

Cytoplasmic staining of OCT4 is a highly sensitive marker of adrenal medullary-derived tissue.

OCT4 immunostaining has become an essential resource in diagnosing germ cell neoplasia. OCT4 is a transcription factor with a characteristic nuclear staining pattern specific to germ cell neoplasms. Our institution has observed that paraganglionic tissue consistently displayed intense cytoplasmic staining by utilizing monoclonal OCT4 antibody, and we intended to determine whether OCT4 could pro...

Cytoplasmic Her2/neu immunohistochemical staining in breast cancer; From a molecular point of view

Merkel cell carcinoma with an unusual immunohistochemical profile

The clinical and morphological picture of Merkel cell carcinoma (MCC) may be rather challenging; therefore, the immunohistochemical profile plays a relevant role in confirming the microscopic diagnosis. A panel of antibodies including cytokeratins 20, 7 and epithelial membrane antigen, and neuron-specific enolase is used in confirming the morphological diagnosis of MCC. The majority of MCCs exp...

Comparison of CD23 staining patterns in Merkel cell carcinoma and non-cutaneous small cell carcinoma.

BACKGROUND During our daily practice, we observed that cluster designation 23 (CD23) (clone BU38) labels Merkel cells in normal skin. In this study, we examined the expression of CD23 in Merkel cell carcinoma (MCC) and assessed its usefulness in distinguishing MCC from non-cutaneous small cell carcinoma (SMCC). METHODS Immunohistochemical staining of CD23 was performed on a total of 33 MCCs, ...