Typical and atypical pulmonary carcinoid tumor overdiagnosed as small-cell carcinoma on biopsy specimens: a major pitfall in the management of lung cancer patients.
Seven patients with typical or atypical pulmonary carcinoid tumors overdiagnosed as small-cell carcinoma on bronchoscopic biopsies are described. Bronchial biopsies from 9 consecutive small-cell lung carcinoma patients were used as control group for histologic and immunohistochemical studies (cytokeratins, chromogranin A, synaptophysin, Ki-67 [MIB-1], and TTF-1). The carcinoid tumors presented as either central or peripheral lesions composed of tumor cells with granular, sometimes coarse chromatin pattern, high levels of chromogranin A/synaptophysin immunoreactivity, and low (<20%) Ki-67 (MIB-1) labeling index. The tumor stroma contained thin-walled blood vessels. Small-cell carcinomas always showed central tumor location, finely dispersed nuclear chromatin, lower levels of chromogranin A/synaptophysin, and high (>50%) Ki-67 (MIB-1) labeling index. The stroma contained thick-walled blood vessels with glomeruloid configuration. Judging from this study, overdiagnosis of carcinoid tumor as small-cell carcinoma in small crushed bronchial biopsies remains a significant potential problem in a worldwide sample of hospital settings. Careful evaluation of hematoxylin and eosin sections remains the most important tool for the differential diagnosis, with evaluation of tumor cell proliferation by Ki-67 (MIB-1) labeling index emerging from our review as the most useful ancillary technique for the distinction.
Pelosi
Giuseppe
G
Division of Pathology and Laboratory Medicine, European Institute of Oncology, University of Milan School of Medicine, Milan, Italy. giuseppe.pelosi@ieo.it
Rodriguez
Jaime
J
Viale
Giuseppe
G
Rosai
Juan
J
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis; D002276:Carcinoid Tumor / Q000378:metabolism / Q000473:pathology*; D018288:Carcinoma, Small Cell / Q000378:metabolism / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008175:Lung Neoplasms / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen