Mediastinal malignant carcinoid with Cushing's syndrome: immunohistochemical and ultrastructural study.
A case of thymic atypical carcinoid with Cushing's syndrome and unfavorable clinical course is reported. Immunohistochemical analysis reveals distinct staining of tumor cells for ACTH, neuron-specific enolase, chromogranins (CG) and S-100 protein and with PHE-5 monoclonal antibody. At an ultrastructural level, the cells are undifferentiated with only a few neurosecretory granules. In the present case, immunohistochemical stainings for CG and with PHE-5 antibody seem reliable diagnostic tools, easily demonstrating the neuroendocrine nature of the neoplasm. NSE immunoreactivity can be an additional criterion. S-100-positive cells, which are present throughout the tumor, recall 'sustentacular cells', described in other neuroendocrine tumors.
Barbareschi
M
M
Department of Morbid Anatomy and Histopathology, State University of Milan, School of Medicine, Italy.
Mariscotti
C
C
Frigo
B
B
Guercilena
S
S
Ambrosi
B
B
Bonato
M
M
Mosca
L
L
Baroni
M
M
D000324:Adrenocorticotropic Hormone / Q000032:analysis; D000328:Adult; D000911:Antibodies, Monoclonal; D002276:Carcinoid Tumor / Q000032:analysis / Q000150:complications / Q000648:ultrastructure*; D002467:Cell Nucleus / Q000648:ultrastructure; D002864:Chromogranins / Q000032:analysis; D003480:Cushing Syndrome / Q000209:etiology*; D003593:Cytoplasm / Q000648:ultrastructure; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008479:Mediastinal Neoplasms / Q000032:analysis / Q000150:complications / Q000648:ultrastructure*; D009474:Neurons / Q000201:enzymology; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D009418:S100 Proteins / Q000032:analysis
D000911:Antibodies, Monoclonal; D002864:Chromogranins; D009418:S100 Proteins; D000324:Adrenocorticotropic Hormone; D010751:Phosphopyruvate Hydratase