Cytologic, clinicopathologic, and molecular features of papillary thyroid carcinoma with prominent hobnail features: 10 case reports and systematic literature review.
The hobnail variant of papillary thyroid carcinoma (PTC) is a rare, aggressive variant in which > 30% of the tumor cells have hobnail features. The clinical behavior and pathologic characteristics of these tumors are still unclear due to the rarity of the entity. The present study aimed to investigate cytologic, clinical, pathological, and molecular features of the hobnail variant from our data and from the literature. We retrospectively retrieved 10 cases of hobnail variant from 2,904 consecutive PTC patients. Cytologic and histopathologic slides from those 10 patients were reviewed. We performed molecular analysis for BRAF, ALK, and TERT promoter mutations on paraffin blocks from surgical specimens, and further analyzed the clinicopathologic characteristics of all case reports published in the literature until now. Cytologically, all tumors were characterized by single cells with eccentric nuclei and tapering cytoplasm (comet-like cells), and syncytial or micropapillary clusters with apically placed nuclei resulting in a hobnail appearance in both conventional smears and liquid-based cytology. The BRAF V600E mutation was found in 8 cases (80%) whereas no cases had ALK fusion or TERT promoter mutations. In the literature review of 55 patients including our cases, most patients presented with advanced stage cancer, and disease-specific survival rates were 83%, 71%, and 54% at 5, 10, and 20 years after the initial surgery, respectively. Characteristic cytologic features can allow a preoperative diagnosis of the hobnail variant of PTC based on cytology specimens. Further studies should be performed to identify the molecular genetics of the variant.
Department of Hospital Pathology, College of Medicine, The Catholic University of Korea Seoul, Korea.
Young Sub
YS
Lee
Department of Biomedicine & Health Science, Graduate School, The Catholic University of Korea Seoul, Korea.
Yourha
Y
Kim
Department of Biomedicine & Health Science, Graduate School, The Catholic University of Korea Seoul, Korea.
Sora
S
Jeon
Department of Surgery, College of Medicine, The Catholic University of Korea Seoul, Korea.
Ja Seong
JS
Bae
Department of Radiology, College of Medicine, The Catholic University of Korea Seoul, Korea.
So Lyung
SL
Jung
Department of Hospital Pathology, College of Medicine, The Catholic University of Korea Seoul, Korea.
Chan Kwon
CK
Jung
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000077548:Anaplastic Lymphoma Kinase; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D001706:Biopsy; D002277:Carcinoma / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D002291:Carcinoma, Papillary; D004252:DNA Mutational Analysis; D018572:Disease-Free Survival; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009367:Neoplasm Staging; D010641:Phenotype; D011401:Promoter Regions, Genetic; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D012189:Retrospective Studies; D016019:Survival Analysis; D019098:Telomerase / Q000235:genetics; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000737:chemistry / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
D014408:Biomarkers, Tumor; C000626173:ALK protein, human; D000077548:Anaplastic Lymphoma Kinase; D020794:Receptor Protein-Tyrosine Kinases; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; C509186:TERT protein, human; D019098:Telomerase
ALK; BRAF; TERT; Thyroid cancer; fine needle aspiration; hobnail variant